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179. Ridge and Swale Live Oak Scrub, Shell Ridge Live Oak Scrub, or Running Live Oak Thicket- All these explicit titles (and some more) are used, and are appropriate, for a scrub live oak range cover type on deep sands along the coast in the general Texas Coastal Prairies and Marshes Vegetation (= Land Resource) Area. This live oak scrub is what Texans call "running live oak". It is the shrub form of what is generally regarded as southern live oak (Quercus virginiana) which spreads vegetatively by rhizomes (hence the adjective "running"). The taxonomy of running live oak has not been definitively established, and perhaps cannot be. Not only have numerous plant taxonomists arrived at varying conclusions including, as might be guessed, numerous scientific names at different taxonomic levels, but the oaks both integrade and hybridize. Running live oak has been interpreted as Quercus virginiana var. fusiformis (= Q. fusiformis), Q. virginiana var. macrophylla, Q. oleoides var. quaterna, and Q. virginina var. minima (=Q. minima). As if that is not confusing enough there are at least the following recognized hybrids: Q. minima X Q. virginiana and Q. minima X Q. stellata (post oak), and Q. virginiana X Q. stellata (Correll and Johnston, 1979, ps. 483-484).
While the running scrub live oak is the sole dominant species and the one that forms the general physigonomy of this cover type it is a species-rich thicket. The lianas of mustang grape (Vitis mustangensis), peppervine (Ampelopsis arborea, another member of Vitaceae), and Alamo vine (Ipomoea sinuata, a woody morning-glory), in that order, grow over the live oak canopy creating the appearance of a camp meeting brush arbor. The usually shaded understory is dominated by yaupon (Ilex vomitoria) and some tanglewood or panalero (Forestiera angustifolia) along with the stems of the lianas, with scattered grassland forbs like Turks cap (Malvaviscus drummondii), all entangled with cat green-briar or cat-brier (Smilax bona-nox) plus the three above dominant woody vines. At the outer edge and occasional openings in the live oak there are small trees of laurel oak (Quercus hemisphaerica), Texas persimmon (Diospyros texana), netleaf hackberry (Celtis reticulata), and Mexican buckeye (Ungnadia speciosa) plus a lower layer of tanglewood, lime prickly ash or Hercules club, and young plants of these species.
Aransas National Wildlife Refuge, Refugio County, Texas. October. No FRES Number or Kuchler Unit. Live Oak Thicket variant of SRM 719 (Mesquite-Live Oak-Seacoast Bluestem). Variant of Scrub Oak Series in Southeastern Maritime Scrub biotic community of Brown et al. (1998). Western Gulf Coastal Plains- Mid-Coast Barrier Islands and Coastal Marshes Ecoregion, 34h (Griffith et al., 2004).
The general Shell Ridge Community consist of three distinct communities distributed according to the ridges of the ridge and swale relief: 1) inner ridge, 2) middle ridge, and 3) outer ridge. The outer ridge is the swale-and-ridge gulf grassland included with the Grassland slides above and the middle ridge is a chaparral form not included in this publication. There are gradients in soil water, soil compaction, soil salinity, wind exposure, and surface insolation from the oldest (inner) ridge to youngest (outer) ridge (McAlister, 1988).
180. Detail of the exterior of the Inner Shell Ridge Running Live Oak Scrub- The dominance of mustang grape with pepper vine and Alamo vine as associates in the canopy of scrub southern live oak is obvious. The soil of this range cover type is interesting because it is "an old (about 3,000 years) well-weathered, highly compacted, oystershell base which suffers no washover except from extreme storm tides" (McAlister, 1988). Aransas National Wildlife Refuge, Refugio County, Texas. October.No FRES Number or Kuchler Unit. Live Oak Thicket variant of SRM 719 (Mesquite-Live Oak-Seacoast Bluestem). Variant of Scrub Oak Series in Southeastern Maritime Scrub biotic community of Brown et al. (1998). Western Gulf Coastal Plains- Mid-Coast Barrier Islands and Coastal Marshes Ecoregion, 34h (Griffith et al., 2004).
181. Interior of the Inner Shell Ridge Running Live Oak Scrub- This is the understory of the running live oak thicket of the two preceding slides. Trunks of live oak, Mexican buckeye, and Texas persimmon can be seen here. Netleaf hackberry is in far background. Lianas include the larger stems of mustang grape and cat green-bria as most common followed by Alamo vine and peppervine. Tanglewood is more common than yaupon in this view. This is deep inside the thicket so species like turk's cap and lime prickly ash are absent. Grass is absent from the shell ridge live oak thickets.
"The live oak thickets are incredibly dense (up to 50 sturdy stems per square foot, for acres and acres), waist-to-head-high stands of scrubby oak shoots that arise from a ramifying mass of pernicious rhizomes" (McAlister and McAlister, 1987, p. 55).
Ecological status of this vegetation is not known nor is there concensus on its position on the sere for this given range site. The range site was not described by Soil Conservation Service Soil Surveys (actually it was not recognized as a range site by the SCS). The traditional interpretation of much, probably most, of scrub vegetation in humid, subhumid, and semiarid regions has been that of a woody invasion induced by human abuse through overgrazing, underburning, cultivation, mining activity, etc. Arid regions are a clear exception as deserts are, by definition, shrublands. Exceptions under semiaridity include California and Arizona chaparral, shinnery oak, Gambel oak, and bigleaf maple seen in these Shrubland slides. The sandrough range type of the subhumid zone of central Texas was defined as postclimax oak scrub persisting on deep sand in a regional climax of tallgrass prairie and tallgrass prairie oak-hickory savanna (the Cross Timbers).
The old, weathered, saline, droughty yet deep oystershell-sandy soil of the Inner Ridge suggested to this author that some of this vegetation was likely an edaphic climax scrub. Undoubtedly there was encroachment of this cover type into the regional or climatic climax grassland, a woody invasion and typical Texas brush problem.
Undoubtedly this is the situation for most of the running live oak in the Coastal Prairies and Marshes Region. It also seemed obvious however that there had to be a "nucleus" or source of propagules for what is a very unique and diverse plant community. These scrub oak thickets are not just conglomerations of woody plant species which typically occur as scattered individuals as a savanna in a sea of grass. It is hard to imagine the lianas existing as infrequent plants in a grassland but which "thickened up" in absence of prairie fires. Throughout most of its range yaupon appears as an understory species. Turk's cap is one herbaceous species existing on the climax grassland, but it is present mostly along the outer edges of live oak thickets.
It appeared most likely that in the virgin vegetation the Inner Ridge supported running live oak thickets as edaphic climax scrub as "islands of shrubs in a sea of grass", a vegetation mosaic that included seral stages in areas recovering from local disturbance and maintained by climate, soil features, and large-scale disturbances like drought, fire, hurricanes, migratory game, etc. The Inner Ridge Live Oak Thicket is likely a postclimax range community but as the potential natural vegetation running live oak thickets would be quite restricted in scale and area. Expansion of thickets beyond the Inner Ridge would be interpreted as retrogression of range vegetation due to human abuse.
Most of this running oak thicket range type is the ultimate example of range deterioration. It is a woody disclimax which has achieved a "stranglehold" on what were once a pristine sea of grass and that now cannot now be controlled without harming other species of features of the prairie community (McAlister and McAliste, 1987, ps. 53-54). It serves as a dire warning: "Only you can prevent range abuse". Small portions that are most likely the potential natural vegetation (an edaphic climax) serve as an example of how interesting and interrelated range plant communities are.
182. One thing we can all agree on: would be one a helluva place to chase a cow. Inside the Inner Shell Ridge Running Libve Oak Scrub Type.
Aransas National Wildlife, Refugio County, Texas, October. No FRES Number or Kuchler Unit. Live Oak Thicket variant SRM 719 (Mesquite-Live Oak-Seacoast Bluestem). Variant of Scrub Oak Series in Southeastern Maritime Scrub biotic community of Brown et al. (1998). Western Gulf Coastal Plains- Mid-Coast Barrier Islands and Coastal Marshes, 34h (Griffith et al., 2004).
183. Riparian Willow Scrub Type- Along watercourses— especially mountain streams, creeks, and small rivers— from the Rocky Mountains to the Sierra Nevada-Cascade Ranges and even Pacific Slope drainages there are diverse range communities dominated by shrubs and small trees of the Salicaceae, typically willow (Salix spp.) and cottonwood or aspen (Populus spp.). Some of these riparian plant communities may be disclimaxes induced through disturbances such as overuse/overgrazing by livestock or wildlife like beaver (Castor canadensis) which concentrate along the watercourses. Other disturbances include logging and flooding (especially upstream) due to activities like road-building or hydraulic mining. Many of these salicaceous communities, however, are natural (= climax) vegetation. Willow scrub (of various forms) appears to be a riparian climax.
Strawberry River, Unita National Forest, Wasatch County, Utah. Vernal aspect, June. SRM 422 (Riparian) as a Great Basin Cover Type is general and quite variable but appears to describe the riparian willow shrubland range type. Also SRM 921 (Willow) Rangeland Cover Type of Alaska is the boreal equivalent of the riparian willow of Great Basin and western mountain streams. Grayleaf willow (Salix glauca) is one of the dominant low willows while Bebb willow (S. bebbiana) is a dominant tall willow. Both of these species occur in the Intermountain Region and along Utah streams (Welsh et al., 1993, ps. 628, 630). Willow Series in Rocky Mountain Alpine and Subalpine Swamp and Riparian Scrub biotic community or perhaps in Plains and Great Basin Riparian Scrub biotic community of Brown et al. (1998).Colorado Plateau- Semiarid Benchlands and Canyons Ecoregion, 20c (Woods et al., 2001).
184. The willows are one of those taxonomic nightmares for all but veteran taxonomists. Welsh et al. (1993) described over two dozen species of Salix found in Utah. What is more Salix species hybridize readily. Viewers can have their choices as to species. This is a willow thicket pure and simple. Strawberry River, Unita National Forest, Wasatch County, Utah. Vernal aspect, June.
All riparian sites are prone to damage by overgrazing/overbrowsing— especially by larger animals which tend to "hang in on water" —because of the availability of water and shade, fairly level terrain, congregation of fellow animals, etc. While the riparian habitat is ideal for high yields of browse and members of Salicaceae are well-adapted to it and to defoliation they can be overbrowsed (Despain, 1990, p. 82, 94, 98-101). This includes by wildlife. Despain (1990) discussed the impact of wildlife overbrowsing on willow and quaking aspen in Yellowstone National Park. Even his optimistic interpretation could not ignore the severe loss of wildlife browse in parts of Yellowstone which should be a model of pristine environments, including riparian vegetation. Overuse of riparian vegetation remains a problem in National Parks where native predators are rare or absent. McName (1997, ps. 170-171) wondered if willow and quaking aspen would rebound if the wolf was reintroduced into Yellowstone National Park. Willows have the zig-zag or sympodial growth pattern in which the upper potion fo the leader is routinely aborted (Sosebee, 1977, p. 277). Proper degree of use is very critical in shrubs like willows because they have aboveground perenniating parts. It was discussed under forest grazing that most woody plants are phanerophytes which due to location of meristems are the growth or life form most vulnerable to defoliation. For utilization evaluation in shrubs see Interagency Technical Reference (1996).
Not only can the riparian vegetation be damaged by long-term overutilization but prolonged concentration of animals can lead to physical damage to the geomorphological aspects of streams such as bank-caving. Chemical harm may occur by excessive deposites of dung and urine and high levels of coloform bacteria (ie. pollution). These combined effects can readily lead to degradation of the riparian range site, including damage to fish habitat (eg. loss of shaded banks needed for proper temperatures for eggs and fye). Under multiple-use management "writing-off" riparian ecosystems as sacrifice sites is no longer an acceptable practice. Some would argue that it was never proper management noting that turning creeks as sources of clean, fresh stock water into ditches of polluted, stagnant water is poor animal husbandry and an unacceptable practice from the standpoint of herd health.
A comparison of damage to willows (and stream bank) by animal concentration versus reduction or elimination of animal concentration with resultant willow recovery was presented below in this willow series.
Fortunately, this problem was recognized— belatedly but finally —and many conscientious stock-growers worked with conservationists like sportsmen and natural resource agencies to achieve proper animal distribution on ranges blessed with watercourses. Management of riparian range sites is extremely difficult from both the physical/biological and economic standpoints because fencing streams is usually not cost-effective. Cross-fencing pastures having streams so as to reduce concentration of livestock or duration of livestock concentration is more economically efficient but can also be expensive. Fencing may be used with specialized forms of grazing management to better manage distribution of animals and season of use. Changing season of use or changing kind or class of livestock is sometimes possible by better incorporating management of grazing units into total ranch management. Smaller ruminant species like sheep are more likely to rustle farther from water than larger ruminants like cattle. There are even breed differences within a species.
One of the most cost-effective (and romantic) ways to manage ranges containing delicate riparian sites is the time-tested use of range riders or sheep herders to herd livestock thereby achieving proper distribution of animals on range. This noble occupation traces its recorded lineage back through Abraham, Moses, David, the Good Shepherd, and Charlie Russells (and our own) Trail Boss. The most enduring of all American folk heroes is the cowboy. For the scientific approach to the art of herding livestock Moving 'Em by Smith (1998) is highly recommended.
"My heroes have always been cowboys."
—Willie Nelson
Now watch the ole range prof get in the Four Cardinal Principles of Range Management:
Proper Degree of Use
Proper Distribution of Use
Proper Season of Use
Proper Kind and Class of Range Animal.
The literature on range management on riparian ecosystems and riparian vegetation is seemingly infinite attesting to its importance. It is the one area where even the most die-hard anti-environmentalists agree on the need for inproved range management. Great strides have been made, including by the livestock industries. Continued effort in this as in all areas of management will be necessary. The following are recommended as a start in the literature of riparian range management: Myers (1989), Smith and Prichard (1992), Leonard et al. (1997), and Winward (2000). The range industry continues to carry many "success stories" on riparian range management.
185. Willow leaders- Twigs with pistillate catkins, leaves, bark, and buds of a tall Salix species. Salix species are dioecious. These are leaders of a female plant. The zig-zag pattern of twig growth in willow is obvious here. See the two aborted (dead and brown) leaders. Strawberry River, Unita National Forest, Wasatch County, Utah.
186. Shining shrub in the Shining Mountains- Shining or whiplash willow (Salix lucida subsp. caudata= S. caudata) along a mountain stream in the upper montne zone of the Southern Rocky Mountains (eastern slope of Continental Divide). As used in contemporary life zone descriptions this wetland scrub (= wet scrubland) was an example of the general montane riparian ecosystem in the montane life zone (Beidleman et al., 2000, ps. 11, 15). Dick-Peddie (1993, ps. 40, 148-151, 159) used the designation of Montane Riparian- Willow Series.These two photographs presented a textbook example of riparian range vegetation. Stream bottoms dominated by Salix species are known as willow carrs or, the much used (overused?) term, park (Beidleman et al., 2000, ps. 17). Carr was originally a Scandinavian term applied to wetland with connotations of some peat formation. Carr was later adopted in England in reference to wet habitats dominated by woody plants, especially alder (Alnus spp.) and willow or other shrubs or trees (Allaaby, 1998).
There are a "gazallion" Salix species. In areas where there are numerous of these willow species they are a "taxonomic nightmare" except for plant taxonomists who "groove out" on such details (much like anything esle such as pocket watches, stamps, steam locomotives, or hot-rod engines). For mere mortals positive identification of a Salix species can be a matter of luck (as in finding catkins for starters). Beidleman et al. (12000) listed over 20 Salix species for Rocky Mountain National Park where this willow carr was photographed as one of numerous willow habitats. Fortunately there were enough spent catkins for identification-by-elimination of S. caudata along this mountain creek. Besides, the distinctive red-colored bark on twigs is a readily available feature for who have seen it previously. Whiplash or shining willow is one of the major riparian shrubs along mid-size mountain streams. Some plants of sandbar willow (S. exigua) were also present in this riparian scrubland (and with fresh catkins), but just enough to merit mention. This was wet shrubland was clearly a consociation of S. caudata. By the way, one can usually eliminate some Salix species based on habitat. Tiny alpine willow species would not grow along montane streamsides for instance. Nor can taller-growing or tree-like willows survive in the alpine.
A wet meadow had developed on the bottomland of this creek at some distance from the willow carr which extended for several yards away from the creek bank. Above this stream bottom there was a vary narrow zone of Douglas-fir (Pseudotsuga menziesii) forest which shortly gave way to the lowest elevational levels of subalpine forest of Engelmann spruce (Picea engelmannii) and subalpine fir (Abies subalpina= A. lasiocarpa).
All of these range plant communities are critical for watershed function and conservation, including water yield for irrigation. Riparian vegetation dominated by willows such as that shown here are critical habitat for numerous animal species including fish.
In the early days of exploration of western North America the Rocky Mountain Chain was known also and, perhaps even more so, as the Shining Mountains. In the magnificant Lewis and Clark Expedition, the Corps of Discovery, Shining Mountains was a commonly used term as reflected in the book, Sacagawea Speaks: Beyond the Shining Mountains with Lewis and Clark (Hunsaker, 2001).
Rocky Mountain National Park, Larimer County, Colorado. Mid-June (late vernal aspect). No FRES or K units because 1) those units were not given for natural plant olf this small a spatial scale and 2) this could be viewed as seral not climax vegetation this second point is debatable). SRM 422 (Riparian) as a Great Basin Cover Type is general and quite variable but appears to describe the riparian willow shrubland range type. Willow Series in Rocky Mountain Alpine and Subalpine Scrub biotic community of Brown et al. (1998). Southern Rockies- Chrystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).
187. Sandy shrub on a rocky channel- Sandbar willow (Salix exigua) growing along a the rock-strewn channel of a Rocky Mountain stream along the Front Range of the Southern Rocky Mountains. Leaves and immediate pre-bloom catkins (second slide) on the same plant.
Rocky Mountain National Park, Larimer County, Colorado. Late June (early summer); pre-bloom phenological stage.
188. Willow thicket on wet subalpine mountain meadow- This savanna- or shrubland-like vegetation was composed of short-fruit or barren-ground or, sometimes-- and confusing--, grayleaf willow (Salix brachycarpa) and planeleaf or Nelson willow (S. planifolia) growing on a wet subalpine park (a mountain valley). Arguably this plant community could be viewed as a meadow in which case it should have been included under the Meadow heading of the Grasslands. It was specified in captions with slides of the strictly herbaceous form of vegetation in this valley (a Carex rostrata consociation) that the willow-dominated form of vegetation was included here to have the willow (and other wet shrublands) in one place and for consistency from standpoint of physiogonomy and growth/life forms of dominant plants.
(Viewers who desire to follow the panarama of vegetation down this drainage or watershed, the Kawuneeche Valley in Rocky Mountain National Park, can do so by exiting down and going to the table of contents from which you should turn off at the Grasslands exit and follow it to the Meadows road down which you will come to beaked sedge-dominated wet meadow.)
Viewers who stayed at this station will note the heavy degree of use of these willows by elk. Time, and response of willows to this intense defoliation, will tell if utilization was excessive (ie. overbrowsing-- if, in fact, this consumption was overbrowsing-- will eventually lead to death and inadequate regeneration of willows). These photographs were taken during the year (2002) of the most extreme drought in Colorado weather records. The drought certainly had some influence on the appearance of the willows and, in combination (perhaps synergistic) with heavy browsing, it may well have a major influence on whether or not willows survive to the next drought. At the current point in time and space readers can see a plant community with an upper storey of relatively large shrubs of willow and an herbaceous understorey of C. rostrata and some isolated individuals of Canada reedgrass or bluejoint (Calamagrostis canadensis). Isolated smaller shrubs of shrubby cinquefoil (Potentilla fruticosa= Pentaphylloides floribunda) were also present (as they were on the peaked sedge meadow). One of these plants of shrubby cinquefoil can be seen in the immediate, far left foreground of the second slide.
It should be emphasized that this is not riparian vegetation per se. This form of willow shrubland-- and that presented immediately below-- was not wetland and, as such, was distinct from willow carrs and riparian corridors presented in this section.
Kawuneeche Valley, Rocky Mountain National Park, Grand County, Colorado. June. No FRES when this is interpreted as a shrubland. No Kuchler units at this mapping scale (nor for that of montane meadows or riparian communities). No SRM cover type designation for willow except for Alaska: SRM 921 (Willow). Willow Series in Rocky Mountain Alpine and Subalpine Scrub biotic community of Brown et al. (1998). Southern Rockies- Chrystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).
189. Subalpine willow thicket- Willows, most likely barren-ground and planeleaf willows, formed a scrub patch around a localized seepage or drainage at the lower end of a small subalpine mountain meadow. This was not a wetland nor riparian vegetation, but it most certainly was a browse range on which the potential natural vegetation under existing climatic and edaphic conditions appeared to be climax shrubland, at least to this author. There was little or no understorey of vascular plants beneath the willows.
The occurrence of willow-dominated vegetation on the lower end of a meadow that had the same species distributional pattern represented in the plant community immediately above.
As in that similar-- perhaps, identical-- vegetation, browsing by elk had been heavy if not excessive. The latter could not be verified at this point. This was a good point at which to again warn readers of the danger inherent in the sin of overgrazing and overbrowsing. Wildlife are not immune nor exempt from overconsumption of feed on their ranges just because they are native species. Status as to "natural" or native or to wildlife versus domesticated or livestock (elk are either depending on the intensity with which they are managed) is meaningless whenever and wherever demands for (and consumption of) feed exceed supply (including availability) of feed. Sadly, the history of both livestock husbandry and wildlife managaement proves that people-- for many and varied reasons-- frequently prize numbers of animls more than the health and productivity of animals. And some folk value the preservation of the range, the very source of all animal existance, even less. To (and, too) many people, whether vegetarian hunting with telephoto-lensed camera or mighty, flesh-eating nimrod armed with telescoped canon, seeing or shooting an elk is a greater need than enjoying all facets of the elk's environment and knowing that the elk herd is healthy and in equilibrium with it's habitat.
Mini-editorial: If managers of Rocky Mountain National Park are not careful in their grazing management their browse range will end up like that of Yellowstone National Park. It will be woefully deteriorated to point of depletion. Then they will have to commission the National Research Council to do a "whitewash job" to cover their mismanagement. Move over Enron book-cookers.
Rocky Mountain National Park, Grand County, Colorado. June. As immediately above, no designations except SRM 921, and that out of the region, (Willow). Willow Series in Rocky Mountain Alpine and Subalpine Scrub biotic community of Brown et al. (1998). Southern Rockies- Chrystalline Subalpine Forests Ecoregion, 21b (Chapman et al., 2006).
190. Riparian Willow Scrub- This example of a willow-dominated range community grew along a section of the Donner-Blitzen River in a transition of High Lava Plains and Basin and Range provinces (generally known as the "Oregon High Desert"). Dominant species was narrowleaf or coyote willow (Salix exigua) though there were other Salix species as well that were associates. Another local associate was cluster or peafruit rose (Rosa pisocarpus). Except at edges of willow growth, there was little if any understorey the dense shrub canopy precluding development of such layer(s).
Malheur National Wildlife Refuge, Harney County, Oregon. J:une. No FRES ecosystem or Kuchler unit at the lengthy but "strip" (narrow-width) scale of this riparian vegetation. SRM 422 (Riparian) as described in previous captions. Coyote willow association of Kagan et al. (2004). Northern Basin and Range- High Desert Wetlands, 80e (Thorson et al., 2003)
191. Narrowleaf willow (Salix exigua)- Pistillate inflorescences and identifying petiole-like leaf apices of a dominant ripraian species in the Oregon or Harney High Desert. Malheur National Wildlife Refuge, Harney County, Oegon. June.
192. Wetland willows- Most willow species (Salix spp.) are intimately associated with free (surface) water. Willows are commonly found growing along streams (of sundry sizes and water temperatures), and are thought of in such context by most viewers of vegetation. Throughout much of the "Far West" (say, Rocky Mountains to Pacific Ocean) and, in particular along mountain streams, development of willow-dominated plant communities extends beyond the riparian zone into bottomlands adjacent to streams where later flow of water creates a subirrigated environment. Willow communities often expand to such degree as to ultimately occupy the entire subirrigated site (unless their expansion is checked by human management). With a large number of multiple shoots per individual shrub (genetic individual or genet) willows often form a community closed to other species except in the limited interspaces among individual willows.
Successional status of such wetland scrub vegetation continues to be discussed by scientists and laymen alike, but has not been resolved (at least not to this author's knowledge or satisfaction). Human management to willow communities varies with most ranchmen favoring some degree of control of woody species that they regard as pests (ie. brush or noxious woody plants) while sportsmen (eg. fishermen) and landowners wishing to "leave it natural" opt for willow maintenance or even increase.
This photograph illustrated the situation just descriped. Control of willows would allow development of a wet (subirrigated) meadow of sedges and grasses (with or without clumps of willows depending on degree of control). The "mixture" of willow and grass-grasslike vegetation shown here was the result of "leave it alone" or "let Nature take her course" management. This willow stand/meadow range had been grazed by beef cattle and, presumedly, by mule deer. Result was an apparent stable plant community with soil protected against erosion except immediately along stream bank (see slides below).
Situations (vegetation, human use, wildlife habitat, land stability) like the one viewed here are common in many areas throughout the West and on both public and private land.
This photograph showed physiognomy and architecture of a wetland willow scrub range, including herbaceous interspaces of sedges and mesic or hydric grasses.
Along Silvies River, Grant County, Oregon. June. No FRES or Kuchler units for willow scrub (vegetation not mapped to such small-scale units. SRM 422 (Riparian). Blue Mountains- Melange 11d (Thorson et al., 2003).
193. "Inside a willer thicket"- Interior of the willow scrub community of the preceding slide. Such range vegetation provides cover for both some species of wildlife and reclusive cows. The protection afforded by the dense willow cover is often ideal for calving, fawning, etc. It is, however, not the sort of protection necessary for calving heifers or desirable when gathering cattle. Such thickets are literally impenetrable even to skilled buckaroos but such scrub does make the case for good cow dogs. "'Sic her, Hank".
Along Silvies River, Grant County, Oregon. June. No FRES or Kuchler units for willow thickets. SRM 422 (Riparian). Blue Mountains- Melange 11d (Thorson et al., 2003).
194. Damage (disturbance) to vegetation and stream bank by animal concentration- Two views showing elimination of willows and all other plants along with soil disturbance due to congregation of cattle along a streatch of Silvies River in the Blue Mountains province of central Oregon. Mule deer also range freely across this land, but as shown below damage to vegetation and soil surface and stream bank was limited to low river banks readily accessible to cattle. Streatches of Silvies River on either side of this cattle range that had mule deer but not cattle grazing showed no such disturbance. Deer tracks were not found among cow track in the mud of the river bank.
Silvies River, Grant County, Oregon. June. SRM 422 (Riparian). Blue Mountains- Melange 11d (Thorson et al., 2003)
195. Vegetation and stream bank not damaged by cattle- This streatch of Silvies River was immediately upstream (about two cow-lengths) from that shown in the immediately preceding slide. Defoliation of herbaceous plants was obvious on the top of the river bank but not down on the steeper sides (Steepness apparently deterred cattle use of forage up to water's edge in contrast to the situation presented in the two previous slides.) Cattle grazed herbaceous plants right up to large willows and did not proceed farther up river or move into the dense willow colony.
Impact of cattle on this riparian range ecosystem would require careful analysis. Damage to river bank and potential for erosion and modification of stream channel were undisputable. Removal of vegetation and soil trampling in the area that resembled a hog wallow eliminated shading of water (compare this slide to the two immediately above). This certainly could increase water temperature in that streatch of river with potential detrimental impacts of cold-water fish like trout. Change in water temperature would also be partly a function of rate of water movement as well as initial water temperature and quantity of water exposed to radiation.
Analysis of cattle influence on this range ecosystem, including aquatic habitat as well as soil and vegetation, might (or might not) indicate that the sacrifice area seen here was of such size as to have (or not have) an overall detrimental effect. Certainly cattle impact along portions or sections of the stream looked "real bad" and degree of use of herbaceous species beyond the river seemed excessive. It is possible, however, that adequate streatches of the river were protected (even in the cow pasture due to natural barriers of vegetation and stream morphology) with net result of little or no detrimal impact on the range or aquatic environment.
This case was beyond any doubt a "black eye" for the beef cattle industry that has made remarkable progress in proper management of riparian range sites. This cattle-owner will not be receiving the National Cattlemen's Beef Association Environmental Stewardship Award any time soon! Public relations aside (though just as important), the exact or actual influence of such disturbance on the range and such range resources as the river require objective and detailed analysis.
Silvies River, Grant County, Oregon. June.
196. Recovery of vegetation- This portion of Silvies River was immediately beyond that streatch that was a "stomp lot". This section can be seen at the end of the disturbed streatch shown in the first of two slides two captions immediately above. Cow hoof-induced soil at water's edge was visible in this photograph. Yet young willow shoots had risen along the river bank and for considerable distance away from the actual riparian zone into the subirrigated bottomland.
One critical aspect of riparian grazing (proper management of riparian and adjoining range sites) is ecosystem resilience and rate of recovery. Fortunately, the "ideal" habitat of most riparian areas and sites ("ideal" for plant growth in this meaning) and potential for soil stability even in these flood plains and terraces is such that recovery from damage or disturbance (natural or human-induced) is among the fastest for any ecosystem.
This fact partially explains the many delightful "success stories" of restoration projects on riparian ranges and associated streams. Given this relatively high likelihood of success, numerous "stake-holders" like stockmen, fishermen, backpackers, agency folks,.and even Boy Scouts have "rallied to the cause" and aided restoration of riparian and related natural resources.
Recovery of willows along this stream immediately adjacent to disturbed riparian sections attested to the high potential rate of recovery and good chances for restoration of damaged riparian range. Further conservation of such natural resources depends on continued proper grazing management.
Silvies River, Grant County, Oregon. June.
197. Black willow (Salix nigra) swamp- The black willows in this stand can be interpreted as either small trees or, given the multi-stemmed growth habit, large shrubs. They are in the backwater riparian zone of the West Branch of the Trinity River in the general Cross Timbers and Prairies Region of northcentral Texas. As noted above, the successional state or seral or climax is unknown and there is neither FRES nor Kuchler designation for willow, but this could be an example of a seral stage of the sycamore-pecan-American elm type as suggested by Garrison et al. (1977, ps. 15-16 ) which puts it in climax FRES No. 17 (Elm-Ash-Cottonwood Ecosystem). Such a state would place this community as a seral stage of SAF 94 (Sycamore-Sweetgum-American elm), but SAF 95 (Black Willow) nails it perfectly at this stage. Cottonwood-Willow Series in Southeastern Swamp and Riparian Forest biotic community of Brown et al. (1998). The low-growing twigs are within easy reach of browsing white-tail deer and sign of beaver feeding on willow bark was common.
Forth Worth Nature Refuge, Tarrant County, Texas. October. No appropriate FRES, Kuchler, or SRM for this unit of vegetation. SAF 95 (Black Willow). Southeastern or Southwestern Riparian Deciduous Forest and Woodland 223.1 or 223.2, Cottonwood-Willow Series 223.14 or 223.2 of Brown et al. (1998, p. 43). Cross Timbers- Grand Prairie Ecoregion, 29d (Griffith et al., 2004).
198. Beauty in a willow swamp- At eastern margin of Cherokee Prairie of the Central Lowlands physiographic province (just west of the Ozark Plateau) a combination swamp-marsh wetland had developed. Black willow with a few scattered saplings of eastern cottonwood (Populus deltoides subsp. deltoides) dominated --both aspect and highest plant cover layer--this wetland vegetation which consisted of this tree layer as well as an herbaceous stratum comprised of rose mallow (Hibiscus lasiocarpus), broadleaf cattail (Typha latifolia), great or softstem bulrush (Scirpus validus= Schoenoplectus tabernaemontani), and a bottomland ecotype of switchgrass (Panicum virgatum). Almost all of the ground was covered with surface water even in a drier than average mid-summer (photographer got his feet wet, but the vegetation made even that slight discomfort a delight).
This range vegetation could be interpreted as either a woody or herbaceous wetland because it had dominants ranging from tree species through forbs of the mallow family (Malvaceae ) to grasslike plants. The author opted to place this delightful sample of wetland range in the willow section of this chapter given dominance of black willow along with eastern cottonwood as the largest and tallest plants commanding most of the highest layer of plant cover.
Successional status of this range vegetation was not clear: herbaceous layer was that of a climax marsh, but Society of American Foresters (Eyre, 1980, p.66) regarded the black willow type (SAF 95) as "a temporary, pioneer type of very rapid growth". Time will tell if tree species like pecan (Carya illinoensis), elm (Ulmus americana, U. rubra), and/or hackberry (Celtis occidentalis, C. laevigata) would conquer the tree zone, perhaps eventually excluding the herbaceous species along with black willow and cottonwood.
Ottawa County, Oklahoma. Late July, and peak bloom in the rose mallow. No appropriate FRES, Kuchler, or SRM for this unit of vegetation. SAF 95 (Black Willow). Southeastern or Southwestern Riparian Deciduous Forest and Woodland 223.1 or 223.2, Cottonwood-Willow Series 223.14 or 223.2 of Brown et al. (1998, p. 43). Central Irregular Plains- Cherokee Plains Ecoregion, 40d (Woods et al., 2005).
199. Summer time in a prairie swamp- Yes, a prairie (and a tallgrass prairie at that). Well, that is a regional prairie. Swamp of black willow with few saplings of eastern cottonwood and lovely understorey of rose mallow, broadleaf cattail, great or softstem bulrush, and bottomland switchgrass on Cherokee Prairie in northeastern Oklahoma. This wetland was not by a stream but rather was in a wet prairie dominated by bottomland switchgrass. Water from the surrounding prairie surfaced creating a hydric habitat for this remarkable range plant community.
Ottawa County, Oklahoma. Late July, and peak bloom in the rose mallow. No appropriate FRES, Kuchler, or SRM for this unit of vegetation. SAF 95 (Black Willow). Southeastern or Southwestern Riparian Deciduous Forest and Woodland 223.1 or 223.2, Cottonwood-Willow Series 223.14 or 223.2 of Brown et al. (1998, p. 43). Central Irregular Plains- Cherokee Plains Ecoregion, 40d (Woods et al., 2005).
200. Black willow (Salix nigra)- Whole shoot of one black willow plant growing on pond dam in Grand Prairie of northcentral Texas. Typical habit of this multi-stemed large shrub or small tree. All members of the Salicaceae (willow or poplar family) are dioecious (separate male and female plants). This plant was a male. Staminate catkins of this specific plant were presented below. Erath County, Texas. April.
201. Some shoots of black willow- Several young trees or shrubs of black willow growing in the floodplain of the Wichita River. Wichita County, Texas. October.
202. Black willow flower- Staminate catkins of the black willow growing on pond dam in Grand Prairie in northcentral Texas (same plant) that was presented above. Willow species are dioecious (having separate male and female flowers on different plants; individual plants are either male or female).
Erath County, Texas. April; peak anthesis..
The following series of slides provided more specifics of male and female catkins of black willow. These examples were produced on two shrublike trees growing side by side on a man-made wetland created by mining caliche for use on unpaved county roads. Photographs were taken in a morning under a light overcast sky so that no shadows wer cast. This set of slides also served as an example of inflorescences of the dioecious Salix species. Ladies first:
203. Female glamour- Female flowering leaders (branches) of black willow by a caliche quarry in Texas' Grand Prairie. Tarleton State University Hunewell Ranch, Erath County, Texas. Early April; full-bloom flowering stage.
204. Females in bloom- Pistillate catkins of black willow. These female flower clusters were on the leaders shown immediately above. Tarleton State University Hunewell Ranch, Erath County, Texas. Early April; full-bloom flowering stage.
Gents next:
205. Males more glamorus- Male flowering leaders (branches) of black willow by a caliche quarry in Texas' Grand Prairie. Tarleton State University Hunewell Ranch, Erath County, Texas. Early April; full-bloom flowering stage.
206. Males in bloom- Staminate catkins of black willow. Thesemale flower clusters were on the leaders shown immediately above. Tarleton State University Hunewell Ranch, Erath County, Texas. Early April; full-bloom flowering stage.
207. Long-stalked roses (of sorts) in the swamp- Rose mallow (Hibiscus lasiocarpos) blooming in the black willow swamp on Cherokee Prairie described above. This is not only one of the most brilliantly colored of all native range forbs it is also has one of the largest corollas. Add in the pronounced staminal column along the elongated style and this makes for one truly spectacular "wild flower"'. Of course, a rangeman might get his feet wet photographing it.
Halbertleaf rose mallow (Hibiscus militaris) is another rose (or, often, marsh) mallow. Both species are found on extremely moist to wet microhabitats in the central prairies and Ozark Plateau. regions. H. militaris can be viewed in Range Types of North America under the Ash-Elm-Hackberry Forests (a spring-fed example) in the chapter, Southern and Central Forests-II. Ottawa County, Oklahoma. Late July, full-bloom stage.
Directions to more willow scrub (and forests): all of the above willow scrublands plus forests of various willow and cottonwood species are in the Shrubland chapter entitled, Willow and Riparian, and the Forest chapters entitled, Central and Southern Forests and Miscellaneous Forests.
Riparian willow scrub and mesquite bosque vegetation develops and exists as adjacent zones of climax range plant communities along watercourses and their drainages in southwestern North America. Much of this range vegetation pattern occurs in regions characterized by aridity and semiaridity. Both of these vegetation zones constitute range cover types. The willow cover type was considered immediately above and continued here in conjuction with the mesquite bosque type because these two communities occur together as integral parts of a common landscape. Mesquite bosque occurs as a band or zone of potential natural vegetation between the vegetational mosaic of Chihuhuan Desert-semidesert grassland and riparian willow scrub (along with Phragamites communis grassland which was covered under the Miscellaneous Grasslands chapter).
Willow shrubland and mesquite bosque were organized and described as a subchapter because of the close spatial association and ecological interactions of these two ecosystems that were described here as range cover types.
Directional Note: In an effort to avoid confusion and frustration of readers it was again emphasized that reedbed or reedbank grassland made up of common reed (Phragmites commnis= P. australis) which grew end-to-end with willow scrub along banks of the Rio Grande was interpreted as a range cover type of grassland and as such was treated under the Grasslands biome as the Miscellaneous Grasslands chapter.
208. Route of the river- Land forms and vegetation defined by two rivers:. the Big Bend stretch of Rio Grande in the Trans-Pecos drainage of the Basin and Range province provides an environment for riverine vegetation in the midst of the Chihuhuan Desert. In the far background the Rio Grande emerges from Santa Elena Canyon. This is a chasm with sheer walls up to 1500 feet deep cut through the limestone of Sierra Ponce (the Chihuhua side in the left two-thirds of the background) and Mesa de Anguila (the Texas side in the right one-third background) by sand-laden, moving water over geologic time. Sierra Ponce- Mesa de Anguila are a mesa, "an uplifted block of Lower Cretaceous limestone", that is the remainder of a former and much higher mesa from which the softer Upper Cretaceous limestones and shales were eroded (Maxwell, 1968, ps. 87-89). Even short of its previous glory the mesa is a backdrop land form to a once-mightier river that now relies on another river, the Rio Conco, for most of its water.Even with most Rio Grande water dammed and diverted for human agricultural and municipal uses, there is adequate aquatic environment for well-defined range cover types.
Immediately along the river banks (or back a short distance where there are recently formed sand bars) there is a zone of riparian vegetation made of two end-to-end disparate plant communities or, perhaps more descriptively, stands: 1) willow and 2) reed. The woody vegetation (a willow shrubland) and the herbaceous vegetation (a grassland of common reed [Phragmites communis]) are each spatially short and narrow "strips" of distinct plant communities which obviously interact yet are physically segregated. There are of course other plant species in the willow and reed communities but the two species so dominate their respective vegetation that most other species seem of miniscule importnce, at least from standpoint of range cover types.
Adjacent to riparian vegetation on the river flood plain and covering a much broader breath of rangeland is vegetation known as bosque or bosques (mostly an Anglo-adopted Spanish word). Bosque vegetation is dominated by mesquite and other woody plants, most of which are of shrub rather than tree form and dimension.
Willows are also usually shrubs or, at most, small trees. In restricted locations along short stretches of the Rio Grande riparian vegetation consist of large cottonwood trees, often with willows as a lower woody layer, that form small gallery forests. These gallery forests were treated separately under Miscellaneous Forest Types and Southern and Central Forests (Woodlands and Forests). Gallery forests were not discernable in these landscape-scale photographs.
Technical Note: The term riparian may have somewhat different meanings or connotations as used Hydrology, Aquatic and Riparian Ecology, Range Management, or Forestry not to mention legal usages in the extremely specialized area of water law and policy. The Glossary of Hydrology (Wilson and Moore, 1998) defined riparian thusly: "Pertaining to or situated on the bank of a body of water, esp. of a watercourse such as a river; e.g. 'riparian land' situated along or abutting upon a stream bank..." (listed as synonyms were riparial and riparious). A Glossary of Terms Used in Range Management (Jacoby, 1989), an official publication of the Society for Range Management, defined riparian as: "Referring to or relating to areas adjacent to water or influencecd by free water associated with streams or rivers on geologic surfaces occupying the lowest position on a waatershed". Jacoby (1989) defined riparian zone: "The banks and adjaacent areas of water bodies, water courses, seeps and springs whose waters provide soil moisture sufficiently in excess of that otherwise available locally so as to provide a more moist habitat that that of contiguous flood plains and uplands".
Clearly, hydrophytic or streamside (= riparian) vegetation such as that dominated by willows and reeds on the edge of the Rio Grande constitutes plant communities not only different from other vegetation, but growing on a different environment from that on and of the flood plain. Alternating patches or strips of willow and reed vegetation were clearly visible in both of these photographs. Also readily discernable was the more extensive (and drier-soil) area of mesquite bosque that had developed adjacent to riparian zone vegetation.
Land in the immediate foreground was on an upland overlooking the Rio Grande and Sierra Ponce-Mesa de Anguila that provided a vista of riparian and flood plain vegetation. Vegetation on the upland foreground (vista point) was Chihuhuan Desert dominated by the climax species, creosotebush (Larrea tridentata) and tasajillo or pencil cholla (Opuntia leptocaulis). Quite a study of and contrast in range vegetation.
Big Bend National Park, Brewster County, Texas. June. No appropriate FRES, Kuchler, or SRM for units of vegetation this small and/or in southwestern North America. SAF 235 (Cottonwood-Willow). Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004).
209. River bank willows- Along this reach of the Rio Grande willows lined both river banks and formed plant communities consisting almost exclusively of vrious species of willow. Sandbar willow (Salix interior= S. exigua) was by far the most common species, but black willow (S. nigra) and yew-leaf willow (S. taxifolia) were present, even relatively abundant, locally. The conspicuous green grass in the understorey (right foreground) was naturalized common bermudagrass (Cynodon dactylodon). Common bermuda is one of the most widely distributed naturalized grass species on Earth.
Students take note of the multi-trunk form --usually the key feature distinguishing shrubs from trees-- of willows. Also take note of the readily available browse produced by willows. The escarpment of Sierra Ponce mesa in Chihuhua formed the background.
Big Bend National Park, Brewster County, Texas. June. No appropriate FRES, Kuchler, or SRM for units of vegetation this small and/or in southwestern North America. SAF 235 (Cottonwood-Willow). Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004).
210. Willows at water's edge- Stand of coyote or basket willow in the riparian zone of the Rio Grande. Willows and a few other species like naturalized common bermudagrass formed riparian plant communities lining both banks of the Rio Grande. River banks comprised primarily of flooded sand were raised at considerable heights above "normal" or regular river height by deposition during periods of high water (flooding). Willows quickly established on the sand alluvium and stabilized banks thereby minimizing soil erosion and lowered water quality.
Willow species reproduce by both asexual (= vegetative) and sexual means. Vegetative propagation consist of producing new shoots ("baby trees") from creeping rootstocks (rhizomes) of mature willows. Results of this process of producing clones or modules of existing adult trees was obvious in foreground of this photograph. "Root suckers", as these asexual secondary shoots are frequently called, also provide high-quality browse for species of range animals. Even grass-preferring grazers like cattle and elk will browse and consume copious quantities of such range feed. Range managers must carefully watch and manage this utilization of browse to prevent overbrowsing and instead insure perpetuation of willows (or cottonwoods to which the preceding applies equally). It was clear from this slide that vegetative reproduction is essential in Salix species, and that this in turn is essential to prevent accelerated soil erosion and sedimentation (deposition of eroded soil called sediment).
Lower portion of the limestone escarpment, Sierra Ponce, in Chihuhua provided the background.
Big Bend National Park, Brewster, County, Texas. June. No appropriate FRES, Kuchler, of SRM unit. SAF 235 (Cottonwood-Willow). Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004).
211. Sandbar or coyote or basket willow (Salix exigua= S. iinterior)- Sandbar willow is the major Salix species of willow communities in the riparain zone of the Rio Grande.This is also the dominant species of such riparian range vegetation. Stands of coyote willow like those shown in the two immediately preceding photographs consittute a consociation.
Basket or interior willow is most commonly a shrub not a tree. The multi-stemed habit (feature of numerous shoots or trunks) is usually the main distinguishing feature that differentiates shrubs from trees. The multi-shoot morphology of willow was quite pronounced in this single specimen. This is one plant, one genetic individual (= a genet), in which each shoot (trunk with limbs and branches) is a clone (= ramet). Sandbar willow also reproduces sexually (stay tuned).
Big Bend National Park, Brewster County, Texas.
212. Willows waving from the shore- In the riparian zone branches and leaves of sandbar or interior willow that formed narrow yet dense stands on sand banks of the Rio Grande. This is the most common and most often the dominant Salix species in this area. Twig tips, buds, leaves, and bark of willows is extremely valuable browse for many kinds of range animal from domestic and native ruminants to beaver (Castor canadensis).
Willows are of more immediate value in stabliizing the erosion-prone channels and banks of Rio Bravo. Some such erosion is natural (= geologic) erosion which of course is essential to landscape and ecosystem function. It was action of sand-laden water moving over course of river and time that carved magnificant canyons like Santa Elena through the Upper Cretaceous limestone of the Sierra Ponce-Mesa de Anguila escarpment visible in the background.
Big Bend National Park, Brewster County, Texas. June..
213. Catkin of coyote or sandbar willow, and "Its a girl"- The inflorescence type in Salicaceae, the willow or cottonwood family, is the catkin or ament defined by Smith (1977) as "an inflorescence characterized by typically unisexual, apetalous, bracteate flowers in a pendant cluster". Salix species are dioecious, but most like S. interior shown here are monoecious.
It was shown in some of the preceding photographs that most reproduction in sandbar willow is vegetative (asexual). The plant shown here, however, was apparently enjoying the renewable pleasure of sex.This catkin was female.
Big Bend National Park, Brewster County, Texas. June.
Honey mesquite (Prosopis glandulosa) forms one climax range plant community that can be recognized--and probably incontrovertably--as a range cover type. There may be more than one, but there is one kind of potential natural vegetation that even the most ardent, kill-it-any-way-you-can, hard-core, the-best-mesquite-is-a-dead-one mesquite haters (eg. this author) recognize as something besides a noxious woody invasion. That range vegetation is what Kuchler (1964, p. 27; in Garrison et al., 1977 as unit K-23 under Desert Shrub Shrubland Ecosystems) entitled and described as Mesquite Bosques. Kuchler (1964, p. 27) limited occurrence of Mesquite Bosques to southern Arizona (in the United States) and Kuchler did not include this unit in his map of potential natural vegetation in Garrison et al.(1977), but rangemen throughout the greater Southwest realize that Mesquite Bosques extends from Texas across to southern California and far down into the Mexican states (eg. Chihuhua, Sonora). One of the earliest (and still one of the best) descriptions of mesquite bosques was that in Nichol (1952, ps. 222-226).
Mesquite was recognized by Kuchler (1964) and Garrison et al. (1977) as a dominant species in other climax units of potential natural vegetation including Mesquite Savanna and Mesquite-Acacia Savanna (Kuchler, 1964, ps. and units 60 and 61), but Mesquite Bosques is a closed canopy shrubland or even low-stature woodland not savanna. Mesquite Bosques has limited herbaceous understorey in contrast to the dominant and defining herbaceous layer(s) as in savanna range cover types. This distinction corresponded roughly to that by the Society for Range Management (Shiflet, 1994) in which type-describer Bill Dahl distinguished SRM 727 (Mesquite-Buffalograss), SRM 728 (Mesquite-Granjeno-Acacia), and SRM 729 (Mesquite). Likewise the Society of American Foresters (Eyre, 1980) recognized SAF 68 (Mesquite). To some degree similarities among these units of vegetation were greater in title than in detailed description, but even in that regard there was a consistent understanding among various vegetation scientists that mesquite does develop into dense natural plant communities along stream corridors and/or adjacent habitats. "On some bottomland sites, however, honey mesquite grows to tree size and stands assume characteristics of a forest" (Eyre, 1980, p. 71).
Bosque is an interesting term. Bosque is more-or-less Spanish (it might be somewhat less so than commonly assumed as explained shortly) that was "adopted" by and has persisted in a predominately Anglo culture. In fact, bosque is one of the iconoclastic Spanish nouns (like mesa, coyote, and rodeo) that, except for slightly different pronounction, became incorporated into popular culture and that conjures up an agreed-upon image. Bosque is Spanish for "wooded thicket", but the term is very similar to (and consistent with) bosquet, the French word for "thicket" that in turn was derived from busk meaning "forest". In states like Texas where there is a rich heritage and history of French as well as Spanish occupation (ie. a legacy of La Salle as well as Columbus, Coronado, and Cortez) it is understandable that an Anglicized "bosque" would persist. An example is the Bosque River in central Texas.
As "bosque" is used today-- in both popular as well as professional-scientific usage-- the term applies to (and brings to minds of most users an image of) woody vegetation growing on flood plains or generally low-lying environments with mesic or, infrequently, hydric soils and dominated by mesquite, salt cedar (Tamarisk spp.), willow, cottonwood, seep willow or willow baccharis (Baccharis salicifolia) or, less commonly, other woody angiosperms like ash or oak. With continued ecosystem-threatening invasion of saltcedar (esp. T. chinensis= T. ramosissima), and cooperative programs attempting eradiction of this non-native species, "bosque" is often first thought of as thickets (or forests) of saltcedar or saltcedar and mesquite growing along streams including major rivers. For example, Brown et al. (1998, p. 44) listed Saltcedar Disclimax Series and Seepwillow Series under Southwestern Interior Swamp and Riparian Scrub biotic community.
Even before (and hopefully there will be an "after") saltcedar invasion there were various other species of woody plants besides mesquite (as well as herbaceous plants) in bosques. There are even other species of native woody legumes. Honey mesquite was (is), however, so dominant and provided the key physiogonomic element that the designation "mesquite bosque" was "only natural" (no pun intended).
Honey mesquite is generally regarded as a facultative phreatophyte, a plant species that can function as a "well plant" (one with some of its roots in the capillary fringe just above the water table) yet one in which this feature is not a requirement as it is in obligate phreatophytes. Woody species that have been regarded as olbigate phretophytes include saltcedar, willows, and some cottonwood species (Barbour et al. 1999, p. 553). Based on field observations, the current author felt that the preceding categorization seemed far too general. Saltcedar is commonly found growing on habitats where it could not possibly "tap" the capillary fringe or where its roots are far from subirrigated soils. Without definitive studies it seemed apparent that most plant species on Mesquite Bosques are facultative phreatophytes.
In this vein-- and in the organization of the current publication-- it was impertive to distinguish between actual or strictly riparian (= streamside or stream corridor) vegetation and vegetation on flood plains or habitats in close proxomity to water courses. The latter plant communities are not literally riparian or partially aquatic though such communities are often adjacent to (or in very close to) riparian vegetation. Both of these categories or general groups of range vegetation are on wetlands and they are, therefore, wetland range communities. The difference is roughly between more-or-less permanently saturated soil of riparain environments and the sometimes satuirated but usually mesic-more-than-hydric water condition of environments at greater distances from watercourses. This difference could be seen as that between permanently or, at least, seasonally wet or water-covered versus intermittently wet or water-covered. The concept of flood plain is central to this understanding. "Wet" (water-covered) whenever the watercourse is within its banks is riparian; "wet" (water-covered) only when the watercourse is outside its banks (ie. flooding) is flood plain. Riparian (as in riparian zone) was distinguished from flood plain by the Society for Range Management (Jacoby, 1989). This was quoted above in a Technical Note inside the first photograph caption under the Willow portion of Rio Grande Vegetation.
This somewhat arbitrary yet obvious distinction is basic to describing and providing examples of range cover types. Mesquite bosques usually or naturally (eg. without drastic disturbance such as engineering activieties on rivers) develop as a zone of vegetation adjacent to the riparian zone, this latter of which usually includes obligate phreatophytes such as numerous species of willow. Willows are a wetland scrub (= one kind of shrubland) . The willow range cover type was treated immediatlely preceding this treatment of the mesquite bosque. There are also herbaceous plant communities that are riparian vegetation and that are composed of obligate phretophytes. One of these that is climax vegetation and a rangeland cover type and that develops as a vegetation zone between streambank and mesquite bosque is the common reed (Phragmites communis) community.This is grassland, a restricted kind or form of the grassland biome. The common reed community was covered under the chapter, Miscellaneous Grasslands (grasslands biome).
The example of mesquite bosque treated here was along the Big Bend of the Rio Grande (Rio Bravo). Riparian vegetation of willow and common reed were, except where confined in canyons, bordered by flood plain vegetation, primarily by the mesquite bosque cover type. The photographs were taken either 1) inside Big Bend National Park where there was a saltcedar eradication program underway or 2) along stretches of the Rio Grande where saltcedar was absent or only a minor component of the vegetation. This was consistent with the purpose of showing natural (or naturalized) vegetation as it related to range cover types. Range improvement practices --including essential brush control-- was viewed as another topic.
Viewers should scroll back up to the first two photographs presented under Rio Grande willow scrub to see location of the mesquite bosque, especially in regards to riparian range plant communities and upland Chihuhuan Desertscrub. Now view the bosque vegetation. Use the "notch" of Santa Elena canyon in Sierra Ponce-Mesa de Anguila escarpment as your landmark. Next slides please ...
214. Mesquite bosque along Rio Bravo- The panarama of land form and vegetation were captured in these views of the broad flood plain of the Rio Grande where it emerges through Santa Elena Canyon. This river-carved "notch" has walls up to 1500 feet heigh (deep) where over geologic time moving, sand-carrying water cut thorugh the escarpment, the mesa, of Sierra Ponce (in Chihuhua and to left of the canyon)-Mesa de Anguila (in Texas and to right of canyon). As the Rio Bravo spilled out of Santa Elena Canyon it spread sand-bearing water across its flood plain leaving the alluvial sand (and other suspended particles and soil separates) to build up soil across this delta and providing water in a deset or semidesert (arid either way) for range plants.
Soil moisture conditions were (are) mesic on the delta or flood plain and not hydric as in the riparian zone. Available soil water content (chresard, the amounf of water available for plant use) is a function of both plant species as well as edaphic (of or pertaining to soil) features. The flood plain phenomenon is a function of many and varied factors, but the three-way interaction of water, soil, and plants is primal. Riparian range plant communities like willow and reed develop in the riparian zone of mostly permanently wet rooting medium (saturated soil; soil water content greater than field capacity). . Flood plain range vegetations develops on soils that are ephemerally or seasonally wet ("water-logged"), but that are below field capacity for prolonged periods of time such that plant stress due to water shortage sometimes to frequently exist. Species of plants that can but do not have to function as phretophytes (facultative phreatophytes) often thrive on such soil and water conditions. In addition sandy soils more readily absorb water (ie. have greater rates of infiltration) so that a greater quantity of overflowing river water (as well as that from precipitation) soaks into the soil for later use by plants.
A bosque is frequently the vegetational outcome of such plant environments along flood plains (and zones of soil moisture outward from the hydric riparian zone) on rivers in southwestern North America. Typically, native plant species that dominate bosques are facultative phreatophytes, honey mesquite being numero uno among these. While mesquite was the main beneficiary of such natural irrigation and fertilization other native woody legumes include screwbean or tornillo (Prosopis pubescens), retama (Parkinsonia aculeata), Texas paloverde (Cercidium texanum), blackbrush or chaparro prieto (Acacia rigidula), and huisache (A. farnesiana). All of these species are present along the Rio Grande flood plain at one location or another.
Another native shrub common on bosques (though more on the outer, hence drier, parts) is seepwillow or jara (Baccharis salicoflia). Saltcedar, a species introduced (probably by nurseymen and, ironically, by the United States Department of Agriculture) from the Old World (most likely the Mediterranean Region), locally dominates bosques. Control practices have been applied to saltcedar on parts of the Rio Grande (eg. in Big Bend National Park) and along much of the reach of the Pecos. A few plants of saltcedar were discernable by their light pink-colored flower clusters.
Herbaceous species are limited in the understorey of bossque vegetation probably as a consequence of shade from shrubs. Interesting enough many of the dominant grasses are annual cool-season Eurasian, mostly weedy, species that can get adequate light at seasons when deciduous dominant shrubs are without leaves. Examples include redor foxtail brome (Bromus rubens), Japanese brome or chess (B. japonicus), and little barley (Hordeum pusillum). Native perennial grasses include inland saltgrass (Distichlis stricta= D. spicata var spicata), tobosagrasa (Hilaria mutica), and fluffgrass (Tridens pulchellus= Erioneuron pulchellum). One of the most common introduced and now naturalized perennial grass species was bermudagrass (Cynodon dactylodon). Perennial grasses were most common along edges and on openings within the woody vegetation of the bosque. Fluffgrass was the most common of these. The most common forb was often found to be the shrublike arrowweed (Tessaria sericea); in fact, this is often regarded as a shrub.
Big Bend National Park, Brewster County, Texas. June, early estival aspect. FRES No. 30 (Desert Shrub Shrubland Ecosystem). K-23 (Mesquite Bosques). SRM 729 (Mesquite). SAF 68 (Mesquite). No appropriate unit in Brown et al. (1998) which is surprising as there should be a Mesquite Series under Southwestern Interior Swamp and Riparian Scrub the same as for Seepwillow Series. No Texas ecoregion units (Griffith et al. 2004) were small enough to describe mesquite bosques. Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004).
215. Bosque vegetation- An exterior view of a bosque along Alamito Creek just above its confluence with the Rio Grande. This was the outer (drier edge) of a mesquite bosque that had a relatively rich assembly of range plant species. Seepwillow or jara was visible as light green shrubs along the right margin of the photograph. Taller shrubs with darker green coloration included the natives honey mesquite, retama, and screwbean. and the invasive saltcedar. The most widespread herbaceous plant was common bermudagrass, but it occurred only in localized areas. Frequently bosques are primarily single-species stands of mesquite.This example was remarkable for its species diversity.
Presidio County, Texas. June, early estival aspect. FRES No. 30 (Desert Shrub Shrubland Ecosystem). K-23 (Meesquite Bosques). SRM 729 (Mesquite). SAF 68 (Mesquite). No appropriate unit in Brown et al. (1998), but it should have been given as Mesquite Series under Southwestern Interior Swamp and Riparian Scrub. No Texas ecoregions (Griffith et al., 2004) appropriate for vegetation units this small.
216. Bosque vegetation- Interior of a mesquite bosque along the Rio Bravo in an arid region. Seepwillow or jara was prominent in the foreground. Honey mesquite was the dominant species overall and it was conspicuous in the midground. Understorey plants were mostly Eurasian cool-season annual grasses including Japanese chess and little barley. There were patches of bermudagrass. The most common native grass was the annual showy or silver fingergrass (Chloris virgata). Fluffgrass was the only native perennial grass the author could find.
The relatively lush vegetation of the bosque was in stark contrast to the sparse hills of creosotebush-dominated Chihuhuan Descrub on the hills in the background.
Presidio County, Texas. June, early estival aspect.FRES No. 30 (Desert Shrub Shrubland Ecosystem). K-23 (Mesqujite Bosques). SRM 729 (Mesquite). SAF 68 (Mesquite). No appropriate biotic community in Brown et al. (1998), but should have been Mesquite Series under Southwestern Interior Swamp and Riparian Scrub. No Texas ecoregions (Griffith et al., 2004) were small enough to be descriptive. Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004).
217. Retama (Parkinsonia aculeata) on a bosque- A localized population or stand of retama had dveloped inside the larger, overall mesquite bosque. In this particular bosque along the Rio Grande retama was the associate species to the dominant honey mesquite. Understorey was composed of cool-season annual Eurasian grass species including Japanese brome, rdd or foxtail brome, and little barley.
Presidio County, Texas. June. FRES No. 30 (Desert Shrub Shrubland Ecosystem). K-23 (Mesquite Bosques). Retama variant of SRM 729 (Mesquite). SAF 68 (Mesquite). No appropriate units for biotic community in Brown et al. (1998); spatial scale too small for TExas ecoregions (Griffith et al, 2004).
218. Deep inside a bosque- Trunk of retama with dead straw of annual grasses including Japanese chess, little barley, and red brome. Multi-shoot habit designates this a woody legume as shrub, albeit a large one, and not a tree.All trunks of shrubs in this slide were retama. This was a localized stand or population of retama within the overall mesquite-dominated bosque.The gray-leafed forb was leatherweed croton (Croton pottsii) at pre-bloom stage.
Presidio County, Texas. June. FRES 30 Desert Shrub Shrubland Ecosystem). K-23 (Mesquite Bosques). Retma variant of SRM 729 (Mesquite). SAF 68 (Mesquite). No appropriate biotic community given by Brown et al. (1998), but should be Mesquite Series under Southwestern Interior Swamp and Riparian Scrub. No Texas ecoregions (Griffith et al., 2004) at this small a spatial scale.
219. Retama (Parkinsonia aculeata) characteristics- Drooping branches of retama with distinctive compound leaves and inflorescence. Retama is a woody legume with a fairly large biological (species) range extending across much of southern North America.
Maricopa County, Arizona. June.
220. Inflorescences of retama- Retama is in the legume subfamily, Caesalpinioideae. This subfamily has been treated by some authors as a separate family, Caesalpiniaceae. The flowers comprising the inflorescence in this group are not papilionaceous (having five fused petals) as in the Papilionoideae subfamily. Vines (1960, ps. 536-537) provided a good description of this species.
Maricopa County, Arizona June.
221. Sweet, thorny, and generally noxious- Leader of honey mesquie (Prosopis glandulosa= P. juliflora var glandulos) with several inflorescences. On the mesquite bosque range type honey mesquite is the natural climax dominant and the desired native range plant. On almost all other North American range types high cover and density of honey mesquite constitutes brush invasion, a major challenge to range management. Erath County, Texas. Early May.
222. Floral and foliar details of honey mesquite- Inflorescences and compound leaves of honey mesquite the dominant species of mesquite bosques. Mesquite is in the legume subfamily, Mimosoideae. Some treatments elevated this to the family level, Mimosaceae, as distinct from the Caesalpiniaceae and Papilionaceae. The latter taxon is the only one of these three subfamilies (or families) that has the papilionaceous flower consisting of five petals: two wings, two fused keels, and the banner or standard. Most authors rely on the fruit type, the legume (so-called "bean" or "pod", as the key morphological feature and which they interpret as of more taxonomic value than flower type.
Erath County, Texas. May.
223. Inflorescences of mesquite- Photographs showing details of mesquite infloresences. Good example of the flower type in the Mimosoideae subfamily of the Leguminoseae. One of the virtues (there are a few, precious damn few) of honey mesquite is value as a "bee plant". Purists insist that honey made from mesquite nectar is the sweetest of all. (There are those who swear just as strongly by white clover, alfalfa, etc.). Purists of the barbeque sect feel just as strongly in favor of mesquite wood over hickory smoke for the finest in flesh food-flavoring.
Erath County, Texas. May.
224. Further study of honey mesquite (Prosopis glandulosa= P. juliflora var glandulosa)- Leaves and on distal portion of mesquite twig or leader. Mesquite leaves are bipinately compound with up to 20 leaflets per leaf. The inflorescence (entire flower cluster) of mesquite was described thoroughly by Vines (1960, p. 515) as "yellowish-green, cylindric, axillaryy, pedunculate spikelike racemes". That description was almost as long as a mesquite legume.
Erath County, Texas. Early May.
225. Individual flowers- Close-up view of individual flowers aligned along central axes of spikelike racemes. Mesquite flowers are perfect with ten stamens and a single pistil with small stigma. These flowers were "about done for" with some stamens still alive but past their "natural prime".
Erath County, Texas. Early May.
226. Leaves and fruits of honey mesquite- Details of the compound leaf and legume fruit type in mesquite. After paying due respect to honey mesquite as a "bee plant" it should be explained that the adjective "honey" was derived from the sweet flavor of the legumes. American Indians made a bread from the meal of ground mesquite legumes and even fermented this meal into a beer (Diggs et al., 1999, p. 688). (The latter was not as effective as the whiteman's "firewater".) Sap that exudes from the fruit following injury (eg. insect damage) even has a sweet taste.
A good general reference for mesquite that is not overly technical yet science-based is that edited by Scifres et al. (1973).
Erath County, Texas. September.
227. Cattle consuming (and preparing to plant) mesquite "beans"- This photograph showed Hereford steers heartily browsing mesquite fruits. These steers had been raised on mesquite-free range and had never seen or tasted mesquite in any form until as long-yearlings they came upon this made-to-order delicacy on deteriorated black grama (Bouteloua eriopoda) range. Steers automatically began eating the fruit. Many, maybe most, of the fruits and seeds were immature so that while some seed may have been planted other seeds were removed before they could develop enough to germinate. Thee cattle were thus a form of biological brush control to some extent. These were esophageal-fistulated steers. They were used to collect forage (it fell into the canvas bag around their necks) which was then used to determine botanical and chemical composition of cattle diets on this range type (Rosiere et al., 1975; Rosiere et al, 1975).
Just about "everything ever written" about mesquite described how most mammals, including man, ate mesquite fruit (either the whole fruit or just the seeds). Some of the earliest writings about mesquite explained that when animals ate the legumes the seeds (many of them at least) passed through the gastro-intestional tract undigested and were deposited at great distances from their source plant. In this way mesquite was spread on a "wholesale" scale by the white man. Early on, cattle were implicated as being agents of mesquite propagule dispersal. This means of spread became institutionalized with cattle drives and famous cattle trails. Even before the post-Civil War cattle-trailing business, sheep and goats had been trailed across much of south and west Texas and into Mexico. Thus the time-honored story goes, was mesquite spread from its pre-Columbian restriction to bosques along watercourses and habitats where natural and Indian-set fires could not travel to its "monopoly" of the range throughout the species' biological range.
The story is true, at least in large part. It should also be remembered that much of this spread by livestock was by beasts of burden such as oxen along established trade routes (eg. El Camino Real from Santa Fe to Chihuhua City). What has never been fully explained is why the highly migratory North American buffalo (Bison bison) had not already spread mesquite in the thousands of years before the "white man's buffalo" became such an effective "mesquite seeder". Cessation of range fires enforced by legislation, "civilizing" agarian agriculture, and government propaganda facilitated spread of mesquite. Droughts (a feature of the climate for millenia) worked in concert with these and a "jillion" other factors perhps including small mammal "eradication" campaigns.
Regardless of actual details of the "man and mesquite saga", mesquite bosques served as the natural source for much of the unnatural spread of a native species that in a remarkably short time became one of the most noxious woody plants over an immense part of North American range.
New Mexico State University College Ranch, Dona Ana County, New Mexico. July.
228. Two mesquite seedlings that germinated in cattle dung- Apparently all ruminants will eat mesquite "pods" with domestic cattle appearing especially fond of them. Many rangemen have observed cattle which were so attracted to mesquite fruit that they forsook almost all other forage and browse as long as the "bean pods" were abundant. It has been long reported in the literature that consumption of mesquite fruit results in scarification and distribution of the seed in their own fertile "seedbed". This is one factor that contributes to spread of this native invader. Buffalo (Bison bison)— among other native ruminants— undoubtedly were native dispersal agents long before the "white man's buffalo" arrived on the scene. This fact continues to raise the unanswered question as to why there was not the mesquite "epidemic" on the virgin range. This is obviously a complex interaction of several factors, but presence of fire on the pre-white man range had to have been one of these (which is not to ignore overgrazing and all other anthropogenic influences including wholesale extermination of prairie dogs, a favorite hypothesis among pioneer Texas cattlemen). Kelton (1993, p. 79) reported accounts of early day farmers who told of their plows frequently hitting old burnt mesquite stumps as they broke virgin Texas sod.
229. The long of it- Long shoots in honey mesquite showing examples of long shoots in branches (upper or first slide) and in the main shoot or trunk in a mesquite sapling (lower or second slide). Long shoots are the morphological manisfestation of apical dominance. The terminal or apical bud (and it is a preformed bud in mesquite) with apical meristem (apical meristematic tissue) at terminal end or terminus of the shoot produces auxins, especially indole acetic acid, that regulate, or determines shoot growth largely via hypertrophy (increase in size) of shoot cells.
As long as the terminal bud (or, more, precisely, apical meristem) is intact apical dominance results in continued shoot elongation and suppression (more-or-less) of development and growth of lower meristems (the intercalary meristems or intercalary meristematic tissue). Apical dominance also retards--to a greater degree--development of sexual organs and, thus, sexual reproduction and, in case of angiosperms like honey mesquite, fruit and seed formation. Long shoot production with greater growth, especially elongation, of internodes is a form of vegetative or asexual reproduction (ie. growth is synonymous with reproduction or propagation of tissue of the genotype or genetic individual).
Loss or major damage to the terminal bud with its apical meristematic tissue eliminated apical dominance and often results in formation of 1) more--though shorter or smaller--long shoots, 2) short shoots which can produce fruit and seed, and/or 3) a combination of long and short shoots.
Tarleton State University Hunewell Ranch, Erath County, Texas. Mid-September.
230. The short of it- General view of a short shoot (first or upper slide) and details of a short shoot (second or lower slide) of honey mesquite. Short shoots typically lack a terminal bud (or at least lack hormonally functional apical meristematic tissue) resulted in suppressed elongation of internodes in this shoot. Short shoots frequently become sexually reproductive shoots which, in case of honey mesquite, means production of flowers followed by development and, hopefully (from a plant or genotype perspective), growth, development and maturation of fruit and seed. Seeds are the result of fertilization (double fertilization to be most specific) and genetic recombination. This "shuffling of the gene deck of cards" permits creation of new genotypes, some of which might be better adapted to a changing environment. In other words, sexual reproduction allows for the possibility of greater "fitness" or improved likelihood of the species' survival (= "survival of the fittest").
Tarleton State University Hunewell Ranch, Erath County, Texas. Mid-September.
231. The long and short of it- Two long shoots (left) and one short shoot (right) of honey mesquite. These two slightly different views of long and short shoots in honey mesquite attempted to convey to students the phenomenon of long shoot versus short shoot morphology in this major woody plant of ranges in southcentral and southwestern North America.
The combination of long (asexual) and short (often sexual) shoots in honey meaquite is just one of various easons (some perhaps still unknown to rangemen) why Prosopis glandulosa is such a survivor--be it where honey mesquite is a climax and dominant species as in mesquite bosques or, conversely, an ecological invader and one of the worst and most formitable brush species imaginable.
Tarleton State University Hunewell Ranch, Erath County, Texas. Mid-September.
New Mexico locust (Robinia neomexicana) is a woody legume (large shrub to small tree) with a discontinuous species range throughout southwestern North America from Mexico northward to Wyoming. A discontinuous or disjunct range is a biological (species) distribution in which plants or populations of a given species are separated by larger spatial areas than possible dispersal distances by propagules (dissemules) (Polunin, 1960, p.188). This papilionaceous legume is most common in mesic habitats such as stream bottoms (riparian environments), canyons, and north slopes in mountainous or hilly terrain. New Mexico locust is a member of several range plant communities along the Front Range, especially in southern extensions of the Southern Rockies. These plant communities are generally woody vegetation of either shrubland such as Gambel oak (Quercus gambelii) and Gambel oak-New Mexico locust scrub or montane forests including mixed conifer forest and ponderosa pine (Pinus ponderosa)-Gambel oak forest (Dick-Peddie, 1993, ps. 62, 66, 67, 125).
New Mexico locust also forms "its own" range vegetation as a wetland community that is more-or-less a riparian in habitat or, according to Dick-Peddie (1993, ps. 145, 153) semiriparian or facultative riparian. This specific designation was used because New Mexico locust grows in both strictly riparian habitats (ie. along stream banks) and also as scrub on mountain slopes often associated or co-dominant with Gambel oaks as a seral scrubland (Dick-Peddie, 1993, ps. 125-127, 133). Examples of both of these woody plant communities were presented in this section.
232. Wetland dominated by New Mexico locust- Riparian range vegetation consisting of multi-layers of woody and herbaceous plants along a small, slow-moving stream at foot slope of the Sangre de Cristo Range. This range plant community was dominated by New Mexico locust the crowns of which exclusively formed the canopy layer. There were several age/size classes of immature shoots of New Mexico locust which comprised the greater foliar cover of two lower woody layers. Some of these locust shoots were offshoots (= suckers, sprouts, ramets, clones, or modules arising from rhizomes). Other shoots of sizes ranging from that of seedling to sapling were probably new (sexually produced) genotypes from the bountiful crop of seeds shed by mature shoots. Based on the criterion of plant cover this plant community was interpreted as woody vegetation that could be regarded as scrubland (= scrub or shrubland) if locust was viewed as shrubs or forest (maybe woodland) if locust was considered as small trees. Crowns were usually close enough to interlock, but not in all cases as there were fairly large gaps in crown cover (thus, forest or woodland).
The author felt that shrubland was the most appropriate category for this New Mexico locust-dominated range vegetation, especially given that New Mexico locust was a component of Gambel oak-dominated scrub (the Gambe oak type; SRM rangeland cover type 413) and the Gambel oak-New Mexico locust successional series of scrubland vegetation (Dick-Peddie, 1993, p. 133).
This woody plant-dominated wetland vegetation had a low shrub layer of wax current (Ribes cereum) and western snowberry (Symphoricarpos occidentalis) as well as the intermediate woody layer made up of offshoots of New Mexico locust (secondary shoots from from rhizomes; asexual reproduction) together with chokecherry (Prunus virginiana).
Composition and structure of this very restricted wet shrubland (or forest) also included of a lower herbaceous layer comprised of Eurasian festucoid grasses led by orchardgrass (Dactylis glomerata) and followed by smooth bromegrass (Bromus inermis) with a trace of timothy (Phleum pratensis) and forbs with the native umbel, cow parsnip (Heracleum spondylium ssp. montanum) and, infrequently, the Eurasian borage, hound's tongue (Cyoglossum officinale) being most common.
The term bosque was applied to this wetland scrub to be consistent both with the similar (almost ecologically equivalent or homologous) range type of honey mesquite and retama described immediately above as well as historic designation (usage) in local idiom where (as was detailed above) bosque means "wooded thicket". In common and traditional application bosque is used in reference to woody vegetation--and even more so to vegetation made up of smaller trees and/or shrubs--growing along streams and associated wet to moist areas. Bosque has been used most commonly when designating such wetland scrub vegetation in semiarid and arid precipitation zones.
These two exterior views of New Mexico locust bosque presented the physiogonomy and structure of this scrubland. Succeeding slides showed interior views that emphasized species of lower vegetational layers.
Huerfano County, Colorado. Mid-June (late spring, vernal aspect). FRES No. 34 (Chaparral-Mountain Brush Ecosystem). . No Kuchler of SRM units for this small unit. In Brown et al. (1998, p. 44) this would be a New Mexico Locust Series within (under) the Rocky Mountain swamp and Riparian Scrub biotic community 232,5. Southern Rockies- Foothill Shrublands Ecoregion, 21d (Chapman et al., 2006).
233. Inside a New Mexico locust bosque- Interior of riparian range vegetation along a small stream at southern end of Sangre de Cristo Range of Southern Rocky Mountains dominated by New Mexico locust and with two lower woody layers and a varied herbaceous layer. Several age/size classes of locust shoots plus lot of chokecherry cover and scattered plants of wax current comprised most of the lower woody strata. The herbaceous layer, which was featured in these two slides, varied considerably among local habitats. Herbaceous species included three naturalized, cool-seasson, Eurasian grasses: orchardgrass, smooth brome, and timothy. The most abundant forb on more outer parts of the bosque was cow parsnip whereas hound's tongue, another Eurasian import, was the main forb though this latter was rather limited.
Huerfano County, Colorado. Mid-June (late spring, vernal aspect). FRES No. 34 (Chaparral-Mountain Brush Ecosystem). No Kuchler of SRM units for this small unit. In Brown et al. (1998, p. 44) this would be a New Mexico Locust Series within (under) the Rocky Mountain swamp and Riparian Scrub biotic community 232,5. Southern Rockies- Foothill Shrublands Ecoregion, 21d (Chapman et al., 2006).
234. More members of the bosque scrub- On banks and the gentle floodplain of a small stream near lower elevations of the Sangre de Cristo Range bosque vegetation had developed that was dominated by New Mexico locust and with two woody layers (much of which was different ages/sizes of locust shoots) and a tall herbaceous layer consisting mostly of natrualized, Eurasian, cool-season, perenniaol grasses. Orchardgrass was the most conspicuous of these at time of slides.
These two photographs emphasized the lower woody (shrub) layers which included shoots of New Mexico locust along with chokecherry (right foreground of first slide; center foreground of second slide) and a few plants of wax current. Chokecherry was the associate species to New Mexico locust that also dominated the two shrub layers. It could not be determined in the field what proportion of locust shoots were offshoots or clones of existing adult trees (= sprouts or suckers from rhizomes) versus new genetic individuals (saplings from seed), but there was an abundance of both. Locust seedlings attested to viability and importance of sexual reproduction, Robinia species are some of the most clonally spreading of all North American trees (although second to some of the Populus species).
Huerfano County, Colorado. Mid-June (late spring, vernal aspect). FRES No. 34 (Chaparral-Mountain Brush Ecosystem). No Kuchler of SRM units for this small unit. In Brown et al. (1998, p. 44) this would be a New Mexico Locust Series within (under) the Rocky Mountain swamp and Riparian Scrub biotic community 232,5. Southern Rockies- Foothill Shrublands Ecoregion, 21d (Chapman et al., 2006).
Mixed scrub in the Sangre de Cristo Range. Adjacent to the New Mexico locust-dominated bosque just presented and extending upslope from the small stream of (supporting) this bosque there was a seral scrub type dominated by Gambel's oak and with New Mexico locust and common, true, or alderleaf mountain mahogany (Cercocarpus montanus) as associate species. Dick Peddie (1993, ps.125-127, 133) recognized this range vegetation as the Oak-Locust Successional Series, Quercus gambelli (undulata)-Robinia neomexicana montane scrub. This scrubland range type merged into the "pure" Gambel oak type that developed on higher, drier slopes having shallower soils and which was contiguous with the pinyon pine-juniper savannah at higher elevations and position on upslopes (see three of four photographs immediately below). The Gambel's oak range type was designated by Dick-Peddie (19993, p. 133) as Oak Successional Series, Quercus gambelli (undulata) and by the Society for Range Management (Shiflet, 1994) as the Gambel Oak rangeland cover type (SRM 413).
Note on arrangement of types: the Gambel Oak range type (SRM 413) was included in the Mountain Scrub chapter under Shrublands biome of Range Types. The Gambel Oak-New Mexico Locust range type was included there also to avoid confusion even though it created redundancy. New Mexico locust bosque vegetation was included here for consistency (ie. to group together wetland shrublands). The Gambel Oak-New Mexico Locust range type was obviously an ecotone (transitional range vegetation) between the locust-dominated bosque and Gambel Oak range types so it was included in both locations.
235. A unique mixed scrub- A mixed scrubland dominated by Gambel oak and with New Mexico locust and common or alderleaf mountain mahogany as associates developed between a New Mexico locust bosque below and a"straight" Gambel oak shrubland above. This transitional (ecotonal) range plant commuinity was on soils of intermediate wetness regime (chressard) between these two other range types. Immediately above (contiguous with at higher elevations) the Gambel oak scrub was a pinyon-pine-juniper savanna. There was also a transition zone between the pinyon pine-juniper savanna and the Gambel oak scrub with scattered plants of Rocky Mountain juniper (Juniperus scopulorum) and one-seed juniper ( J. osteosprma) within otherwise homogenous stands of Gambel oak. These vegetational zonation is was visible in both of these photographs which provided "phototransects" of life zones all the way to alpine (distant background of both slides).
New Mexico locust and common, true, or curleaf mountain mahogany were in the foreground of both of these slides. The understorey of this scrub was herbaceous with naturalized smooth brome being the dominant and needle-and-thread (Stipa comata) the associate species at lower elevations with smooth brome quickly "dropping out" and being replaced by needle-and-thread as the dominant (and almost exclusive species) at slightly higher elevations.
Huerfano County, Colorado. Mid-June (late spring, vernal aspect). FRES No. 34 (Chaparral-Mountain Brush Ecosystem). K-31 (Mountain Mahogany-Oak Scrub). Variant of SRM 413 (Gambel Oak). Gambel Oak Series of Brown et al. (1998). Southern Rockies- Foothill Shrublands Ecoregion, 21d (Chapman et al., 2006).
236. They were associates and then they petered out- The Gambel oak-New Mexico locust scrubland range type in Sangre de Cristo Range with New Mexico locust and true or alderleaf mountain mahogany as associate species (first slide) and the becoming so sparse that range vegetation became more of the Gambel oak range type (second slide). The herbaceous layer was dominated by naturalized smooth bromegrass with needle-and-thread the associate herbaceous species, but at only slightly higher elevations smooth brome was no longer present at all and needle-and-thread became the herbaceous dominant.
Above the Gambel oak scrubland there was a large range community of pinyon pine-juniper savanna, but between these two range types there was a transition zone in which Rocky Mountain juniper and one-seed juniper grew within a primarily Gambel oak shrubland. There were several life zones aligned up the slopes of the Sangre de Cristo Range terminating in the alpine zone. This spatial pattern of range plant communities was presented in the second of these slides.
Huerfano County, Colorado. Mid-June (late spring, vernal aspect). FRES No. 34 (Chaparral-Mountain Brush Ecosystem). K-31 (Mountain Mahogany-Oak Scrub). Variant of SRM 413 (Gambel Oak). Gambel Oak Series of Brown et al. (1998). Southern Rockies- Foothill Shrublands Ecoregion, 21d (Chapman et al., 2006).
237. Bigger and littlier and all sexually mature- Specimens of New Mexico locust at adult, full-growth size, (local stand; first slide) and young and sub-adult size (sapling; second slide). The stand was a group of mature trees (or large shrubs) growing with Gambel oak (Quercus gambelii) in the head of a draw draining hills along the Front Range of the Rocky Mountains. The sapling was growing on the outer margin of wetland formed on floodplain of a small stream. All plants featured in these two photographs were either in bloom (eg. the sapling) or in immediate pre-bloom stage (stand of adults). The latter were several hundred feet higher in elevation and phenological development had not advanced as far as in the sapling at lower elevation. New Mexico locust reaches sexual maturity at comparatively small size and young age.
Both sexual and asexual reproduction (this latter by woody rhizomes) are responsible for maintenance and spread of this beautiful native, woody, papilionaceous legume. This combination enables New Mexico locust to spread aggressively, and under certain conditions this otherwise beautiful native can become a brush (noxious woody plant) species (Carter, 2006, ps. 158-159). New Mexico locust and black locust (R. pseudoacacia) sometimes hybridize (Carter, 2006, ps. 158-159) which would likely produce even more invasive--though native--brush.
Huerfano County, Colorado.Mid-June (late spring, veranal aspect). FRES No. 34 (Chaparral-Mountain Brush Ecosystem). K-31 (Mountain Mahogany-Oak Scrub). Variant of SRM 413 (Gambel Oak). Gambel Oak Series of Brown et al. (1998). Southern Rockies- Foothill Shrublands Ecoregion, 21d (Chapman et al., 2006).
238. Striking color and form on a foothill wetland- Leader of New Mexico locust (Robina neomexicana) at peak bloom. This example was growing on a bosque formed on the bottomland of a slow-moving, small stream. Leaves of New Mexico locust are odd-pinately compound with13-21 leaflets. The botanical description in Vines (1960, p. 567) was one of the more thorough ones.
Huerfano County, Colorado. Mid-June (late spring).
239. About as showy as a woody gets- The colorful, papilionaceous flowers of New Mexico locust are about as striking as any produced by a North American woody species. The perfect flowers are arranged in racemes (Vines, 1960, p. 567) and on wetlands (like this bosque where these were produced) such inflorescences seem to make their whole world ablaze with life.
Huerfano County, Colorado. Mid-June (late spring).
240. Now for the trunk- Two boles of New Mexico locust showing characteristic mature bark with an offshoot (young basal sprout beside, and slightly behind, right trunk) and young bark. These shoots were on the bosque presented and described above.
Huerfano County, Colorado. Mid-June (late spring).
241. Cows slipped into the locust bosque?- Big, local patch of cow parsnip (Heracleum lanatum) along the water course on which there was a bosque scrubland dominated by New Mexico locust. Cow parsnip was the major range forb in this wetland range vegetation. Cow parsnip is a member of the Umbelliferae, the carrot or parsley family that is distinguished by its umbel inflorescence.
Many members of the Umbelliferae grow into large herbaceous plants. The leaves of cow parsnip are equally impressive being of an unusually large size and unique shape. The genus name, Heracleum, was given (apparently by Pliny) in honor of the mythical hero, Hercules. A fitting name no doubt and, according to the myth, Hercules lived up to the impressiveness of this real plant.
242. Cow parsnip and its umbrellas- A single large plant of cow parsnip from the colony shown above was presented in the first photograph.The second photograph showed the shoot of the plant in the preceding photograph. In this second shot, there was an umbel in full bloom (left) and a post-bloom umbel producing immature fruit (right).
An umbel is an inflorescence, characteristically--though not always--compound, in which all branches originate on the apex of the peduncle yet spread out so as to produce a flat-topped spreading cluster of flowers resembling, as it were, the namesake umbrella.
Huerfano County, Colorado.Mid-June (late spring).
243. Umbel units and individual flowers- Units (secondary umbels) of the overall inflorescence (ie. the primary umbel) of cow parsnip were shown in the first photograph and individual flowers of two secondary umbels were detailed in the second photograph. These units and their flowers were part of the primary umbel (ie. the entire inflorescence) that was presented at the left in the immediately preceding slide. These cow parsnips were the primary range forb in the understorey of the New Mexico locust-dominated bosque scrub comunity described above.
Huerfano County, Colorado.Mid-June (late spring).
Another flood plain range cover type is the seepwillow or jara (Baccharis salcifolia)-dominated bosque. This range vegetation also develops on alluvium of deltas or other flood overflow habitats in arid and semiarid regions. Seepwillow was an associate species on mesquite bosques covered immediately above. A less common (more restricted) bosque range type is that on which seepwillow or jara is the dominant. That range cover type was treated next.
244. Seepwillow bosque- Along this gravel wash or alluvium of the Devil River seepwillow (Baccharis salcifolia) dominated a woody thicket that also consisted of (as associate species) huisache, pecan (Carya illinoinensis), and, of course, honey mesquite. Grass plants were uncommon, but species present included silver bluestem (Andropgon saccharoides= Bothriochloa saccharoides), Texas cupgrass (Eriochloa sericea), fall witchgrass (Leptoloma cognatum), red grama (Bouteloua trifida), and curly mesquite (Hilaria belangeri). Miscellaneous composites made up most of the forb group.
Devil River Ranch, Val Verde County, Texas. May. FRES No. 30 (Desert Shrub Shrubland Ecosystem). No vegetation unit in Kucler (1964; in Garrison et al., 1977) or Society for Range Management (Shiflet, 1994). Seepwillow Series under Southwestern Interior Swamp and Riparian Scrub. No Texas ecoregion (Griffith et al, 2004) unit for range cover type this small in spatial scale.
245. A widely distributed, well-adapted plant (with a lot of confusing names)- Willow baccharis (Baccharis salicina= B. salicifolia= B. neglecta= B. angustifloia) has had a lot of specific epithets (hence, confusion and argument). Plants presented in these photographs and the three that follow were of willow baccharis growing on go-back rice fields on what were once coastal marshes along the Gulf Coast. The third of this set of photographs was of a young (immature) willow baccharis produced by resprouting from a cut-off mature stump. These second-season (two growing season's worth of shoot regrowth) sprouts furnished a good example of shoot characteristics of this woody composite. These sprouts are coppice shoots (often known as stump sprouts or suckers) produced by the original shoot in response to the stimulus of defoliation when the main shoot was severed. This is an example of free growth and the coppice sprouting results in heterophyllus shoots (those that were not produced from fully preformed, over-wintering buds). Stump suckers are long shoots identified and designated by long internodes (internode elongation) and absence of a cluster of leaves at shoot apex, this latter of which is a feature of short shoots (Kramer and Kozlowski, 1979, ps. 65-71, 77).
Jefferson County, Texas. February.
246. Branch of willow baccharis- Upper portions of stump sprouts of willow baccharis that were introduced in the preceding photograph. Stump sprouting of a cut adult willow baccharis resulted in a young plant that had retained its leaves through winter. This individual of Baccharis salicina was growing along the Gulf Coast near mouth of Sabine River. It provided an example of young shoots, complete with foliage, of one of the most common and widely distributed species of woody composite.
Jefferson County, Texas. February.
247. Shoot details of Baccharis salicina- A normal or regular leader (woody shoot) of willow baccharis on an adult plant provided a good example of bark, branching pattern, and leaf features on one of the more widely distributed woody composites along the central and western Gulf Coast and also in the Trans Pecos Basin and Range Region. A short, vertical shoot (right side in first slide; the featured subject of second slide) was shown to portray characteristic leaves. This vertical shoot originated from an established internode by developing from intercalary meristem, a phenomenon much more common following damage or death of the existing shoot (especially as from defoliation).
Jefferson County, Texas. February.
248. Shrubby female in full-flower- Crown of a female willow baccharis at peak bloom. This dioecious species grows in seven of the ten vegetational (land resource) areas of Texas. This specimen, including the series of close-ups of flowers and fruit presented shortly below was growing in the West Cross Timbers.
Erath County, Texas. October; full-bloom phenological stage.
249. Flowering leaders of willis baccharis- Female inflorescences show the beauty of this shrub species (and attest to its utility for landscaping making the case for more use of native plants for this purpose).
Erath County, Texas. October; full-bloom phenological stage.
250. Beauty in density and in singularity- The extremely dense concentration of female flowers and the resultant striking characteristic of a female willow baccharis at peak bloom were evident in these photographs. This species seems to always put forth abundant flowers even under all-too-frequent drought.
Erath County, Texas. October
251. Feminine details of willow baccharis- Units of of pistillate flowers in Baccharis salicina. Baccharis species are dioecious with disk flowers fertile and ray flowers absent forming corollas that are described as filiform (Diggs, 1999, p. 322), an adjective meaning slender or filamentous (threadlike; made up of filaments or threads) (Diggs et al., 1999, p. 1437).
Erath County, Texas. October
252. Fruit of willow baccharis- Series of shots at progressively closer camera range of achenes of Baccharis salicina. Achenes, the most common fruit type of the Compositae, are single-seeded, dry, indehiscent fruits in which seed coat and pericarp (endocarp) are fused only at the funiculus, the stand uniting the ovule to its placenta (Smith, 1977, ps. 66, 296). Pappuses of long, silky bristles (Diggs et al., 1999, p. 322) are conspicuous (as evident in these photographs). Pappus refers to the cluster of plumose bristles, awns, scales, etc. at tip of achenes in Compositae and traditionally interpreted as the specialized calyx, the sepals collectively (Smith, 1977, p.303; Diggs et al., 1999, p. 1445).
Achenes are preferred concentrate feeds for birds and rodents with smaller fruit often restricted to diets of smaller animal species.
Abundant yields of these dry fruits is a major reason for the invasive nature of Baccharis species. B. salicina is a common woody weed on old fields, improperly managed tame pastures, and overgrazed ranges. This feature of populating abused, degraded sites and "go-back land" following abandoment from farming is basis for such common names as Roosevelt weed and New Deal weed indicating economic and drought conditions of the Great Depression and "Dirty Thirties" along with the crop "plow-under" policies of Franklin Roosevelt's New Deal. Incidentially, this species boast about as many common names as any range plant out there including consumption weed, seep-willow, groundsel-tree as well as willow baccharis. To add further confusion (and nomenclatural diversity), several of these common names (including FDR weed) are shared in common among several Baccharis species.
Erath County, Texas. October
253. Volcano Malpais Vegetation- Malpais (Spanish, mal pais for bad country) is southwestern idiom for badlands created by volcanic activity that formed rough country underlaid by basaltic lava that is usually dark, porous, and very abrasive (as on hooves). On the Carrizozo Plain one of the youngest malpais (lava flow) badlands in North America (only 1500-2000 years old) stretches for over 40 miles and supports a unique and diverse range plant community. The malpais constitutes another kind of barrens vegetation in that the basaltic lava-based environment and it's plant life are what Nelson (1987, p. 99) defined as "primary natural community" where "primary" referred to mostly unweathered, recent, embryonic, immature, etc. parent material such as sand, rock outcrop, talus and scree, gravel bars, igneous matter. Here Mother Nature adds a twist however. The malpais habitat is a more mesic, more favorable environment for range plants because water runs off the lava surface and soaks into cracks, fissures, sink holes, crevices, etc. where accumulated water is available for plants. Thus, malpais vegetation is more mesophytic than that of adjoining non-lava habitats (Dick-Peddie, 1993, ps. 168-169). In fact, some of the shrubs and trees of the Carrizozo malpais are riparian species. Major species seen here include sotol or desert candle (Dasylirion leiophyllum), fourwing saltbush, skunkbush sumac, soaptree yucca, beavertail cactus (Opuntia phaeacantha of one variety or hybrid among some ten subspecific taxa), longleaf joint fir, canatilla, or Mormon tea (Ephedra trifurca), sacahuiste (Nolina texana), sideoats grama, blue grama, and mesa dropseed (for starters).
Bureau of Land Management Valley of Fires Recreation Area, Lincoln County, New Mexico. June. FRES No. 33 (Southwestern Shrub Steppe Ecosystem), subunit of K-53 (Trans-Pecos Shrub Savanna) but too small to have been mapped by Kuchler (1966). No SRM for this unique range plant community. Although this range vegetation was interpreted herein as a form of scrub (= shrubland) it could be viewed as a variant of the Brown et al. (1998) unit of Mixed Grass-Scrub Series in Chihuhuan (Semidesert) Grassland biotic community.
254. Lava Flow or Volcano Malpais Vegetation- Vegetation of a kipuka which is an area of older volcano-formed land ranging in size from a few square feet to several square miles surrounded by later (more recent) lava flows resulting in an area that is more protected from fires, grazing, etc, and likely to receive more runoff water. A kipuka is an island within a larger island. The plant community in a kipuka is likely to be relict vegetation and serve as a reference area, but care must be taken in proper ecological interpretation because all malpais, and especially kipuka malpais, vegetation is probably more mesophytic than adjacent (and less protected) range plant communities.The ropy like or chocolate cake mix-looking lava is pahoehoe. Dominant species are fourwing saltbush and sotol with the same array of species as given in the preceding slide description. Note how many of these species also occurred on the gypsum dunes (eg. soaptree yucca, fourwing saltbush, skunkbush sumac) suggesting that those members of these species thriving on gypsum are gypsophilolus ecotypes of widely distributed species. Animal species (eg. reptiles like lizards) also show this ecotypic variation between the close-proximity malpais and gypsum dune ecosystems. The most ovbious variation between ecotypes of lizards living on the whitish-grey gypsum versus chocolate-brown of the malpais is in darkness of skin coloration (melanism).
Bureau of Land Management Valley of Fires Recreation Area, Lincoln County, New Mexico. June. FRES No. 33 (Southwestern Shrub Steppe Ecosystem), a subunit of K-53 (Trans-Pecos Shrub Savanna) at a mapping scale smaller than that used by Kuchler (1966). No SRM specific to this unique range vegetation. This unique vegetation seemed best interpreted as a shrubland, but given unique hydric feature and more mesic root environment it could be catalogued as a variant of the Mixed Grass-Scrub Series in the Chihuhuan (Semidesert) Grassland biotic community of Brown et al. (1998).
A similar lava flow vegetation in New Mexico is found in the Grants area. The Grants Malpais supports runt or stunted ponderosa pne regarded as a pygmy forest. Readers should see Dick-Peddie (1993, ps. 168-169, 173) for description of malpais habitat and vegetation and for further references on this primary land or volcanic materials vegetation. Similar volcanic badlands and vegetation is found in the Interior Northwest (eg. Idaho and Oregon).
255. Smooth sotol or desert candle (Dasyliron leiophyllum)- This member of the lily family is one of the most conspicuous shrubs of the Upper Sonoral Life Zone of the Chihuhuan Desert-Semidesert Grassland Region of southwest Texas and southern/southeastern New Mexico.It is a dioecious species but the separate male and female plants usually produce flower stalks each year. Indians used it as a fiber plant for ropes. Later, ranchers chopped it for emergency feed in drought, often as a poor man's silage. This specimen is growing in the malpais (lava) flow of south central New Mexico as member of a relict plant community. Bureau of Land Management Valley of Fire Recreation Area, Lincoln County, New Mexico. June.
256. Inflorescence of smooth sotol or desert candle- Bureau of Land Management Valley of Fire Reacreation Area Lincoln County, New Mexico.June.
257. Sacchuiste (Nolina texana)- Sacchuiste is a common member of range plant communities from the grasslands of the Texas Edwards Plateau across to the Semidesert Grasslands and Chihuhuan Desert Region in the Trans Pecos Basin and Range Province. In the more western (and arid) portions of this region sacchuiste is more common on north slopes or deeper soils where soil moisture is higher. This large specimen is growing in the protection of the malpais flow. Sacchuiste is sometimes toxic to sheep and, especially, goats in which it causes liver and kidney degeneration (Kingsbury, 1964, p.455-456). Lincoln County, New Mexico. June.
258. At home in the malpais- General view (first slide) and detailed view (second slide) of leaders or branches of New Mexico privet or olive (Forestiera neomexicana) growing in a local oasis, a stream of running water and a ponded overflow area, of Grants malpais in an area of semidesert grassland. This was in the Colorado Plateau physiographic province.
The pattern of secondary branches coming off of primary branches at right angles is distinctive as is the smooth, light-colored bark. The wood of New Mexico olive is very hard which is the basis of the less-common common name of "ironwood". Obviously the branches of this species are too small to be of much use for human tools.
New Mexico privet is dioecious. The plant "spotlighted" here was a most productive (and attractive) female. Spatulate leaves are another obvious and distinctive feature of this mostly water-loving shrub. Correll and Correll (1975, p. 1308) interpreted F. neomexicana as inseperable as the species level from F. pubescens there being intergradation between these two taxa as well as a taxonomic complex with these and other herbarium types.
Cibola County, New Mexico. Mid-July; ripe-fruit stage of phenology.
259. Blue fruit amidst black rock- Views of drupes and leaves of New Mexico privet or New Mexico olive in Grants malpais. Drupe is the fruit type defined as a "fleshy indehiscent fruit having its single seed enclosed in a stony endocarp" (Smith, 1977, p. 295). Drupes of F. neomexicana are quite bitter (especially when one is thirsty and has not yet quenched his thirst with spring water), but birds cherish these apparently rich--and certaily abundant, in this example--food source. Such fleshy fruit is another example of mast, "fruits and seed of shrubs, woody vines, trees, cacti, and other non-herbaceous vegetation available for animal consumption" (Bedell, 1998).
Cibola County, New Mexico. Mid-July; ripe-fruit stage of phenology.
260. High desert malpais- Lava flows in interior portions of the Pacific Northwest support malpais vegetation that is similar to that of southwestern North America, albeit usually less species-rich than that of the latter.In the High Lava Plains province just north of the Basin and Range province a weathering lava-flow Artemesia tridentata-Ribes cereum shrub community had developed. Sandberg bluegrass was the major herbaceous species and served as the community associate.
Diamond Crater, Malheur National Wildlife Refuge, Harney County, Oregon. June. No FRES, Kuchler, or SRM designations. This unique and rstricted vegetation was interpreted as climax or potential natural vegetation under existing climate and stable edaphic conditions. It is part of the greater big sagebrush regional vegetation and was viewed as a variant form therein. Northern Basin and Range- High Desert Wetlands Ecoregion, 80e (Thorson et al., 2003).
261. Squaw or wax current (Ribes cereum)- Leaves and fruit of one of the co-dominants of Oregon high desert malpais. This species lacks spines and is included in the Ribesia subgenus. Diamond Crater, Malheur National Wildlife Refuge, Harney County, Oregon.June.
A mangrove unit of potential natural vegetation was recognized by Kuchler (1964) and Kuchler (1966) as Mangrove (Avicennia-Rhizophora) 105 and 96, respectively. Mangrove was mapped at the southernmost tip of the Florida Peninsula and the Key Islands and was interpreted as part of the Broadleaf Forest category of Potential Natural Vegetation. Dominants of this unit were black mangrove (Avicennia nitida= A. germinans) and red mangrove (Rhizophora mangle). Mangrove of Kuchler (1964, 1966) was included as a component of FRES No. 16 (Oak-Gum-Cypress Forest and Woodland Ecosystem), but this was not a specific nor useful unit for description and discussion of the black mangrove range type so there was no further listing of this unit. Physiogonomy of the Kuchler (1964, 1966) mangrove unit is that of forest (even if small, often dwarfish, trees). Society of American Foresters (Eyre, 1980) did not recognize a mangrove forest cover type.
Black mangrove is a widely distributed species ranging from the West Indies through Central America and down along the coast of South America to Peru. When black mangrove communities are of shrub rather than tree size the plant community (and cover type) constitute shrubland or scrub not forest. Black mangrove communities in the Western Gulf of Mexico are generally of the architecture and physiogonomy of scrubland. This natural vegetation was described by Weakley et al. (2000) as Black Mangrove Tidal Shrubland and by Diammond, (1993) as the Black Mangrove Series. This natural vegetation was classified as Gulf Coastal Maritime Swampscrub 234.4, Mangrove Series, 234.41 by Brown et al. (1998, p. 47). Black mangrove scrub range vegetation (cover type) was interpreted and treated below as these fourth and fifth levels of Brown et al. (1998, p. 47).
262. Ring around the pond- Black mangrove stands had developed as climax (perhaps edaphic climax) range vegetation around the perimeter of naturally occurring saline ponds on tidal flats along the western Gulf of Mexico. This shoreland was in the general vicinity where the mouth of the Rio Grande emptied into the Gulf of Mexico. Soil conditions were saline to hypersaline and generally moist to wet with considerable variation. Dense shade of mangrove prevented development or persistence of an understorey immediately beneath the scrub, but the herbaceous plant community of tidal flats (mostly salt marshes or Southern Cordgrass Prairie) extended up to the outer edge of black mangrove scrub. This natural herbaceous range vegetation varied considerably at local scale ranging from grassland to a more mixed grass-forb community. Dominant species were generally grasses including in rough order of relative abundance: shoregrass (Monanthochloe littoralis), seashore dropseed (Sporobolus virginicus), Gulf cordgrass (Spartina spartinae), and marshhay cordgrass (S. patens), with patches of seashore or coastal saltgrass (Distichlis spicata). Shrub species that were locally common (and frequently co-dominant) with shoregrass and/or seashore dropseed included sea ox-eye (Borrichia frutescens), maritime saltwort or vidrillos (Batis maritima), and sea blite (Suaeda conferta). Dominant forbs were sea blite (S. linearis), Virginia glasswort or saladilla (Salicornia virginica), and cenicilla (Sesuvium portulacastrum). All these range plant species were halophytes.
This range habitat along the shore of Gulf of Mexico was a supratidal flat, that part of the shore environment that is above regular high tides such that it is flooded (= inundated) only infrequently. Submergence of this range vegetation was uncommon. Supratidal flats are low wave action environments. The soil (rooting substrate) was primarily sand (in contrast to mud flats).
Boca Chica State Park, Boca Chica subdelta (of the greater Rio Grande Delta), Cameron County, Texas. February, late hibernal or early vernal aspect. No FRES No. seemed appropriate or descriptive. K-96 by Kuchler (1966). No SRM or SAF. Gulf Coastal Maritime Swampscrub biotic community 234.4, Mangrove Series 234.41 of Brown et al. (1998, p. 47). Western Gulf Coastal Plain- Laguna Madre Barrier Islands and Coastal Marshes Ecoregion 34i (Griffith et al., 2004).
263. Mangrove pond- Black mangrove formed an exclusive stand around this natural saline pond on one of many tidal flats of the Rio Grande Delta. This pond (and several others) was surrounded by coastal Southern Cordgrass Prairie dominated by Gulf cordgrass or sacahuiste (Spartina spartae) with shoregrass and seashore dropseed as associate species. This climax grassland community extended to the outer edge of black mangrove stands (also climax range vegetation) but not as an understorey in these localized scrublands.
This coastal shore range community was on a supratidal flat meaning that it was above usual high tides such that this vegetation was partially submerged only at infrequent intervals.
Boca Chica State Park, Boca Chica subdelta (of greater Rio Grande Delta). Cameron County, Texas. February, late hibernal or vernal aspect. No FRES was specific to this shrubland; no SAF or SRM. Gulf Coastal Maritime Swampscrub biotic community 234.4, Mangrove Series 234.41 of Brown et al. (1998, p. 47). Western Gulf Coastal Plain-Laguna Madre Barrier Islands and Coastal Marshes Ecoregion 34i (Griffith et al., 2004).
264. Ecotone at a small scale- At scale of microsite or microhabitat a Southern Cordgrass Prairie community and black mangrove scrubland were engaged in a "struggle for existence" and formed a transition zone of native range vegetation. Shoregrass and, secondarily, seashore dropseed and saladilla or Varginia glasswort of the Gulf coastal tallgrass (or, physiogonomically, mixed) prairie had advanced to the perimeter of a black mangrove stand that was so dense as to exclude other vascular range plants. This range ecotone writ small was on banks of numerous small, natural, saline ponds on tidal flats of the Boca Chica subdelta of the Rio Grande Delta.
Cameron County, Texas. February, later hibernal aspect. There was not a FRES specific to black mangrove shrubland. Neither was there an SRM or SAF cover type. Shown by Brown et al. (1998, p. 47) as Gulf Coastal Maritime Swampscrub 234.4, Mangrove Series 234.41. Western Gulf Coastal Plain-Laguna Madre Barrier Islands and Coastal Marshes Ecoregion 34i (Griffith et al., 2004).
265. Black mangrove scrub- On an intratidal (or, sometimes, intertidal) mud flat black mangrove formed an extensive community that was such a "pure" consociation as to be more like a population of this species (ie. a nearly single species-stand resembling an agronomic or horticultural monoculture). Intratidal flats are coastal shore habitats that are defined as very frequently flooded or inundated (in contrast to supratidal flats that are infrequently flooded due to being above--higher in elevation--regular high tide and subtidal flats that are below low tides). Mud flats, like salt marshes, are low wave action environments, but the smaller soil separates of silt and clay rather than coarse-grained sand form the soil or rooting substrate.
General (and characteristic) physiogonomy and architecture of this range plant community was shown in these two slides. This vast stand of coastal scrub was essentially a single-species community or, perhaps more precisely, a population. There were almost no plants of other species within or beneath canopy of black mangrove. Other species of shore plants were limited to the perimeter of this extensive mangrove stand so that status or rank of plant community would probably have to include all plant species growing on the mud flats. Other such range species were shown in photographs later (below) in this series.
South Padre Island, Cameron County, Texas. February, late hibernal aspect. There were no specific FRES, SAF, or SRM designations for black mangrove. Likewise potential natural vegetation units 105 and 96 of Kuchler (1964, 1966, respectively) were shown as specific only to south Florida. The black mangrove (Avicennia nitida= A. germinas) form of Kuchler's mangrove (Avicennia-Rhizophora) in the western Gulf of Mexico was a vegetational "island" apparently of such small size or limited areal extent as to be unmappable at Kuchler scales. Gulf Coastal Maritime Swampscrub biotic community 243.4, Mangrove Series 243.41 of Brown et al. (1998, p. 47). Western Gulf Coastal Plain- Laguna Madre Barrier Islands and Coastal Marshes Ecoregion 34i (Griffith et al., 2004).
266. Advancing legions of black mangrove- Leading edge of a black mangrove shrubland on an intratidal (= intertidal) mud flat with aerial roots or pneumatophores rising conspicuously from soil in foreground. Black mangrove forms vast systems of cable roots which produce pneumatophores (Odum and McIvor in Myers and Ewel, 1990, p. 523). Pneumatophores are vertical aerial roots defined as "specialized 'breathing' roots[s] developed in some plant species that grow in waterlogged or strongly compacted soils, e.g. mangroves" (Allaby, 1998).
There were no other plant species growing in (under) or along the perimeter of this black mangrove stand. Black mangrove was regarded by Snedaker (1982) as shade tolerant and sun intolerant when immature while becoming shade intolerant at maturity. As a result of these conditions, adaptations, and probably numerous unknown factors black mangrove characteristically exists as single species-stands. Similarly, all mangrove species hav been viewed as fire-intolerant so as to be threatened by intense fires (Wade et al., 1990). Fire exclusion from mangrove stands is another likely factor responsible for lack of botanical diversity of these range plant communities or populations.
South Padre Island, Cameron County, Texas. No FRES, SRM or SAF designations. Gulf Coastal Maritime Swampscrub biotic community 243.4, Mangrove Series 243.41 of Brown et al. (1998, p. 47). Western Gulf Coastal Plain- Laguna Madre Barrier Islands and Coastal Marshes Eeoreigon 34i (Griffith et al., 2004).
267. A local "frontier" of black mangrove- A transverse view along the perimeter of a black mangrove shrubland on a intertidal (= intratidal) mud flat of the western Gulf of Mexico illustrated the single species compositional feature of this range cover type.The solitary shoot or single plant beyond the mangrove stand is an advance guard of this species as it "marches" inland on the mud flat from the existing edge of the mangrove stand. It was not determined if this was a seedling (an immature unique genetic individual) produced sexually or a far-ranging asexual module or ramet of an existing genetic individual plant. Detail of the bare soil of this very frequently flooded zone of Gulf of Mexico and dispersion of black mangrove propagules thereon was presented in the immediately succeeding slide.
South Padre Island, Cameron Texas. February, late hibernal aspect. No meaningful FRES; no SRM or SAF. Gulf Coastal Maritime Swampscrub biotic community 243.4, Mangrove Series 243.41 (Brown et al., 1998, p. 47). Western Gulf Coastal Plain- Laguna Madre Barrier Islands and Costal Marshes Ecoregion 34i (Griffith et al., 2004).
268. "Frontier" of black mangrove up close (but not dangerous)- Bare soil (at least, rooting medium) of intertidal (intratidal) mud flat with black mangrove propagules well-despersed thereon in foreground. Advancing edge of black mangrove scrub in background. Smaller shoots at leading perimeter of mangrove stand were modules, ramets, or clones of established mature plant(s) of the mangrove stand.
South paedre Island, Cameron County, Texas. February, late hibernal aspect.
269. "Seeds" of the next generation- Close-up view of black mangrove propagules on the intertidal mud flat shown in the preceding two photographs. Black mangrove reproduces both sexually and asexually. Sexual reproduction is by vivipary in which the embryo begins germination and has continuous embryonic development while fruit is still on the parent plant. Absence of an inactive stage in the embryo and general mangrove organ that forms from sexual fertilization renders the term seed inappropriate so that propagule is the more precise and preferred term (Odum and McIvor in Myers and Ewel, 1990, p. 525). The other special adapatation for sexual reproduction in mangrove species is hydrochory (means of dispersion in which water is the agent that transports the propagule). These two adaptations of sexual reproduction enable mangrove species to disperse and establish seedlings over large areas and to do so quickly.
South Padre Island, Cameron County, Texas. February.
270. "Brush skirmish" of tidal flat range vegetation- An ecotone of an herbaceous salt marsh vegetation and a black mangrove stand on an intratidal (= intertidal) mud flat in the western Gulf of Mexico. Within the same stand of black mangrove scrubland shown in prededing photographs but on slightly higher ground and with sparser cover of mangrove an herbaceous range community of shoregrass and Virginia glasswort or saladilla with lesser cover of maritime saltwort or vidrillos had developed. This transition zone was similar to that on supratidal flats of sandier substrate shown above.
South Padre Island, Cameron County, Texas. February, late hibernal or early vernal aspect. No descriptive FRES. No SRM or SAF for black mangrove. Gulf Coastal Maritime Swampscrub biotic community 243.4, Mangrove Series 243.41 of Brown et al. (1998, p. 47). West Gulf Coastal Plain- Laguna Madre Barrier Islands and Coastal Marshes Ecoregion 34i (Griffith et al., 2004).
271. Herbaceous combatants on a tidal flat- Detail of salt marsh vegetation shown in the immediately preceding photograph. Principal species were shoregrass, Virginia glasswort or saladilla, and maritime saltwort or vidrillos.
South Padre Island, Cameron County, Texas. February, late hibernal or early vernal aspect.
272. Leader of black mangrove (Avicennia germinans= A. nitida)- Main branch off black mangrove shoot showing leaf pattern.
Boca Chica State Park, Boca Chica subdelta (of greater Rio Grande Delta), Cameron County, Texas. February.
273. Shoot apices of black mangrove- Details of shoot tips, including leaves (complete with salt incrustations), of black mangrove growing around a natural saline pond on a Gulf Coast tidal flat. Shoots of shoregrass were growing with black mangrove and were clearly visible.
Boca Chica State Park, Boca Chica subdelta (of greater Rio Grande Delta) Cameron County, Texas. February.
274. Now from south Florida- Interior of a red mangrove (Rhizophora mangle) range type. No, there is not much browsable/grazable range on this land (water), but red mangrove is: 1) a source of some (perhaps precious little) feed for browsing animals, 2) a native shrub, 3) a recognized shrubland and ecosystem (Kuchler, 1963), 4) valuable as a natural watershed and provides the ultimate in shoreline protection, 5) natural vegetation that unites terrestrial and aquatic ecosystems, and 5) provides cover and other habitat features for range animals.
Red mangrove or, as it is sometimes called, American mangrove has the largest species (biological) range of any mangrove species on Earth, extending from the Americas (the Atlantic Coast and Gulf of Mexico in North America) to parts of western Africa and Oceania.
The research and general management literature of mangrove ecosystems is vast, daunting, and, as compared to equivalent book-format material with other vegetation and ecosystems, quite expensive. Literature of the red or American mangrove ranges from information regarding plant growth (Gill and Tomlinson, 1969, 1971a, 1971b, 1977), insect herbivory (Feller, 1995), forest structure (Golley et al., 1962) and production (Ross et al., 2001) to rehabilitation (Field, 1998). Much of the scientific and managerial literature on mangroves is generic and includes numerous mangrove species (eg. Lugo and Snedaker, 1974; Feller and Sitnik, undated). In this regard two of the best synoptic reviews of mangroves in south Florida were Odum et al., (1982) and Odum and McIvor (1990). The Smithsonian Marine Station at Fort Pierce described mangrove habitats such as in its Indian River Lagoon Species Inventory which is available online.
The successional status of mangrove vegetation has been discussed, and these shoreline ecosystems have generally recognized as the climax plant community for shore habitats dominated by this plant life. Lugo (1980) addressed this paramount question in light of the land-building role (a seral or successional process) of mangrove species and concluded that "mangrove ecosystems are steady-state systems in the low-energy tropical saline environment" (ie. mangrove-dominated vegetation constitute climax communities). Ball (1980) described secondary succession in a south Florida mangrove forest and cloncluded that red mangrove outcompeted other plant--including mangrove--species so that intertidal forests became monospecific stands of the shade-tolerant red mangrove. In Clementsian parlance (Clemments, 1916; Weaver and Clements, 1938) this would be a consociation of red mangrove (ie. a nearly single-species climax stand). The definitive authority of North American natural plant communities--at least for rangemen and foresters--remains Kuchler (1964, p. 105) who labeled this potential natural vegetation as: Mangrove (Avicennia-Rhizophora).
Clarification: red mangrove could be regarded as either forest or shrubland (= scrub) depending on personal interpretation. For consistency purposes with regard to black mangrove, the other major mangrove-dominated vegetation in North America, this author viewed red mangrove as shrubland rather than forest, hence its "housing" herein under Miscellaneous Shrublands.
Hillsborough County, Florida. January. No descriptive FRES. No SRM or SAF for red mangrove. Gulf Coastal Maritime Swampscrub biotic community 243.4, Mangrove Series 243.41 of Brown et al. (1998, p. 47). Southern Coastal Plain- Southwestern Florida Flatwoods Ecoregion 75b (Griffith, Omernik, Pierson, 2002).
Technical Note: The two above images of the interior of a red mangrove forest were taken with a cell telephone camera by winter vacationers and sent to the author via email. These two digital images were the first (and, so far, the only) images in Range Types of North America that were not scanned 35 mm slides.
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