Mixed Prairie

The ultimate reference for mixed prairie (and shortgrass prairie) from standpoint of descriptions of range vegetation and response to disturbance is--and will likely always be--the classic Grasslands of the Great Plains by Weaver and Albertson (1956). Definitive source of knowledge regarding mixed paririe from an ecosystem perspective is that of Coupland (in Coupland, 1992, ps. 151-182).

6. Mixed prairie-mesquite savanna- Mixed prairie of blue grama, sand dropseed, sideoats grama, galleta, buffalograss, curly mesquite, and little bluestem with a relative abundance of honey mesquite such as to form a grass-shrub savannah. The species composition and physiogonomy of this range plant community was interpreted by the author as representing an example of vegetation similar to the rangeland cover type described by the Society for Range Management (Shiflet, 1994) as Mesquite-Grama (SRM 718) and as a representation of the potential natural vegetation mapped by Kuchler (1966) as a gramagrass-buffalograss-mesquite community (one of the units designated as Grassland and Forest Combinations).

The relative density and cover of honey mesquite (Prosopis glandulosa) on the virgin grasslands prior to the heavy hand of the white man as a stock-raiser, teamster, farmer, oilman, road-builder, etc. will remain "known but to God". There will always be arguments as to the extent and ecological role of this native legume on the natural grasslands, shrublands, and savannas within the biological range of mesquite. Even use of terms like grasslands and savannas reflects biases (including those based on sound, well-conducted research) because such designations of vegetation indicate assumptions about relative absence of mesquite (on grasslands), limited presence of mesquite (savanna), or presence of mesquite as a dominant or at least influencial species (on shrublands or even forests).

Accounts by such diverse frontiersmen as buffalo runners, freighters, soldiers, and pioneer cattlemen made it quite clear that the Southern Great Plains had relatively little mesquite (at least that of such size, density, and cover as to be obvious) except in isolated groves, along watercourses, on breaks sites, etc. Buffalo chips not mesquite wood was the more usual fuel source on the vast southern grasslands of the interior of semiarid North America. However as soon as farmers began to break the virgin sod-- and break plow shares and tongues on big mesquite lignotubers beneath the soil surface-- it became apparent that there had been more mesquite than was realized. Fires set by lightening and Indians had kept mesquite shoots burnt back to inconspicuous size. Perhaps browsing by such native herbivores as buffalo, elk, or even rodents and lagomorphs had been a factor that maintained mesquite and other woody range plants at lower population levels and in subordinant (vs. dominant) ecological roles. The "pet" theory among the first cattle-raisers as to the most important animals feeding on mesquite (and thereby keeping mesquite in check) was the prairie dog. Old-time cowmen made the connection in their observations between prairie dog eradication programs ("poisoning champaigns") and mesquite invasion.

That there has been a great increase in density and cover of mesquite across rangelands of southwestern North America is beyond doubt or debate, but the degree and origin or cause of this increase is widely debated, discussed, cussed, and published. Nobody half-way knowledgable of the subject can argue against some role of overgrazing, cessation of fires (both atmospheric and anthropogenic in origin), farming, oil and gas development, commercial trade (as in trail- road-building), and even some climatic changes. Perhaps the history of mesquite invasion from perspective of causes is unimportant in a practical sense except to use such knowledge to try to "stem the tide". But knowledge as to the relative "amounts" of mesquite in the various plant communities (range types) in pre-Columbian vegetation would be invaluable in establishing "base lines" or "benchmarks" from which contemporary resource managers like rangemen could measure departure from the potential natural vegetation. (It should be borne in mind, always, that the current potential natural vegetation may differ drastically from pre-white man potential natural vegetation, or for that matter, pre-red man.)

The relative emphasis on mesquite (and mesquite reduction) as a major problem (and goal) in management of brush-infested ranges (including those where mesquite is only one of many brush species) has varied over time with changes in market value of commodities and the latest academic fad and barrage of "buzz words". Emphasis and perception of the mesquite problem has swung widely from the optimistic utopia of mesquite eradication (destroy every last smidgen of it) to the equally naive-- and idiotic-- misconception that because some mesquite is valuable for deer habitat it ought to be increased on ranches that sell hunting leases. In between these mesquite-mood swings even the realistic professional goal of some degree of control of this noxious range plant has varied with changes in control costs, cattle and real estate markets, oil royalties, and rainfall.

How much mesquite should there be? The answer to that question will always vary from one pasture, one operation, one public park, etc. to the next as well as in conjuction with the factors just noted. How much mesquite was there? The answer to that question, which contemporary rangemen will never really know, also varied from one range site, one precipitation zone, one fire regimen, etc. to the next. It also depended on what point in time and the time span that the question referred to. Undoubtedly, relative abundance of mesquite varied over time scales that ranged from a few growing seasons to the end of one drought to start of the next drought to the longest period of a major climatic shift.

The relative proportion of honey mesquite on this mixed prairie was viewed by this author as being roughly the maximum amount of mesquite that could occur on climax mixed prairie (within the grassland or grass-shrub savanna based on pre-Columbian potential natural vegetation). Vegetation of the High Plains and Rolling Red Plains having mesquite populations greater than the general approximation represented by the plant community in this photograph would be in a state of retrogression according to the judgment of this author. Others might opt for substantially more mesquite and relatively less grass. They can place their photographs and state their conclusions on their web sites. This author stands by the traditional conclusion that honey mesquite is, though a native species, an ecological invader on many (in Texas, most) grasslands and savannas and that control of this noxious species is one of the major challenges to sound range management.

Honey mesquite is one of the most important range brush species in North America (the most important statewide in Texas and parts of adjoining states). Stewardship of range resources demands that mesquite be attacked with the full arsenal of current science and technology consistent with economic feasibility. And go at it "with a vegeance"!

In the context of range cover types and use of climax vegetation as a benchmark with which to measure management it will be recalled here that departure from climax is neither proper nor improper management until specific objectives-- based on ecological as well as economic principles-- are established.

Chaves County, New Mexico. June (and a dry one). FRES No.38 (Plains Grasslands Ecosystem). K-76 (Mesquite-Buffalograss; Bouteloua, Buchloe, Prosopis). SRM 718 (Mesquite-Grama). (The example of vegetation in this photograph grew west of where K-76 was mapped. It was interpreted as an "island" of the larger mapping unit, such smaller outliers of the larger mapping scale not having been delineated by Kuchler.) Mixed "Short-Grass" Series of Brown et al. (1998). Southwestern Tablelands- Conchas/Pecos Plains Ecoregion, 26n (Omernik and Griffith, 2006).

7. Mixed prairie-mesquite savanna in Texas Rolling Red Plains- This was a good example of the now nearly ubiquitous mesquite mid-grass range of the south-eastern portion of the Great Plains region. The original mixed prairie, a climax grassland type of tallgrass, mid-grass, and short grass layers, has become degraded (for whatever combination of reasons and factors) by woody plant invasions accompanied by nearly complete loss of the tallgrass element and a mid-grass layer comprised mostly of increasers and invaders. In this example sideoats grama, the climax dominant for this cover type, was reduced and largely replaced by threeawns, most notably Wright's threeawn (Aristida wrightii= A. purpurea var. wrightii). Other major mid-grasses included silver bluestem and sand dropseed. Hairy grama was locally dominant growing to dimensions and densities more typical of a mid-grass such as sideoats grama. There were distinct "patches" (microsites) of shortgrasses of buffalograss and blue grama (in that order). One such "patch" was visible in front and to left of the honey mesquite.

Rolling Red Plains of the Great Plains physiographic province.

Pitchfork Ranch, Dickens County, Texas. Estival aspect. August. FRES No. 38 (Plains Grasslands Ecosystem). K-76 (Mesquite-Buffalograss; Bouteloua, Buchloe, Prosopis). SRM 718 (mesquite-grama cover type). Mixed "Short-Grass" Series of Brown et al. (1998). Mixedland range site. Southwestern Tablelands- Flat Tablelands and Valleys Ecoregion, 26b (Griffith et al., 2004).

8. Rough land mixed prairie-redberry juniper (Juniperus pinchotii) savanna- Across many acres of mixed prairie range redberry juniper takes the place of honey mesquite as the dominant woody invader. Occurrence of redberry juniper as the dominant invader tends to be on rangeland with more prominent dendritic drainage patterns (ie. "rough land") especially near breaks sites that, being less prone to fire, serve as reserviors for seed-producing woody plants. Redberry juniper is fire-adapted being one of the rare sprouting conifers.In this example, a range infested with redberry juniper had been treated by prescription burning seven growing seasons previously. Redberry juniper had resprouted plus some of the original junipers had been "passed over" by the prescribed fire.

Herbaceous vegetation consisted of both mid-grass and shortgrass layers. The major mid-grass species was sideoats grama. In places sideoats was dominant. Other mid-grasses included silver bluestem and sand dropseed. Hairy grama was often the local dominant and it appeared to have a role more like that of a mid-grass, especially sideoats grama. Buffalograss was the major short grass species. It was associated with blue grama that grew to size more that of a short grass. Soapweed (Yucca glauca) was an associate shrub species.

Great Plains phyiographic province; Rolling Red Plains component (east of Caprock escarpment).

Pitchfork Ranch, Dickens County, Texas. Estival aspect. August. FRES No. 38 (Plains Grasslands Ecosystem). K-76 (Mesquite-Buffalograss; Bouteloua, Buchloe, Prosopis). SRM 718 (mesquite-grama) or SRM 727 (mesquite-buffalograss). SRM designation was confusing. In protected areas sideoats grama was dominant which fit descriptions of both 718 and 727. This in conjuction with local dominance of hairy grama plus prescence of blue grama in shortgrass "patches" qualified this vegetation as SRM 718 (mesquite-grama). Conversely, presence of redberry juniper as the dominant woody plant fit the variant description of SRM 727 (mesquite-buffalograss) except that buffalograss was far from dominant. The reader can reach his own conclusion. Mixed "Short-Grass" Series of Brown et al. (1998). Mixedland range site. Southewestern Tablelands- Flat Tablelands and Valleys Ecoregion, 26b (Griffith et al., 2004).

9. Advance of the enemy- Mixed prairie with onset of redberry juniper invasion. This was part of the same pasture presented in the two immediately preceding photographs except that here brush was sparse. Woody invasion was underway nonetheless. Recurrent fire-- natural or prescribed-- would prevent or reduce onset on a further brush problem.

This vegetation consisted of two herbaceous layers: 1) mid-grass dominated by Wright's threeawn with sideoats grama the associate and silver bluestem and sand dropseed locally common and 2) short grass consisting of buffalograss and blue grama.

Pitchfork Ranch, Dickens County, Texas. Estival aspect. August. FRES No.31 (Plains Grassland Ecosystem). K-76 (Mesquite-Buffalograss; Bouteloua, Buchloe, Prosopis). SRM 718 or 727 (see explanation in preceding caption). Mixed "Short-Grass" Series of Brown et al. (1998). Mixedland range site. Southwestern Tablelands- Flat Tablelands and Valleys Ecoregion, 26b (Griffith et al., 2004).

10. Sward of mixed prairie with two herbaceous layers- The distinct mid-grass and short grass strata of a mixed prairie were shown in these two slide. No, this was not spot grazing (at least not in the current growing season). The "spot" with grass of lower height was comprised of buffalograss and blue grama whereas the larger "spot" consisted of Wright's threeawn, sideoats grama, silver bluestem, and sand dropseed. Presence of smaller, "stunted"-appearing individuals of threeawn in the "low plant spots" and presence of some-- though restricted in cover and density-- buffalograss and blue grama among the cespitose mid-grasses suggested that past (previous seasons) spot grazing may have contributed to occurrence of the "patches" dominated by short grass species. Localized heavier utilization was clearly not the only factor, however, as this plant community pattern has been seen frequently on areas protected from grazing (eg. on steep slopes and larger canyon faces of breaks sites). Besides, on this site blue grama is generally interpreted as a decreaser while buffalograss is classified as an increaser. Yet these two species grew side-by-side in this vegetation. It was likely that soil differences at microsite scale were also factors in this mosaic of short grass and mid-grass.

Pitchfork Ranch, Dickens County, Texas. Estival aspect. August. FRES No. 31 (Plains Grassland Ecosystem). K-76 (Mesquite-Buffalograss; Bouteloua, Buchloe, Prosopis). SRM 718 or 727 (see explanation two captions above). Mixed "Short-Grass" Series of Brown et al. (1998). Mixedland range site. Southwestern Tablelands- Flat Tablelands and Valleys Ecoregion, 26b (Griffith et al., 2004).

11. Honey mesquite as a nurse plant- The nurse plant phenomenon has been described in the literature and is textbook knowledge (eg. Barbour et al., 1999, ps.153-156). Nurse plant relationships have been interpreted as a form of commensalism, those interactions which are positive or beneficial for one species (the "nursee") and neutral (having no meaningful impact) on the other species (the "nurser", which is mesquite in this instance). Honey mesquite functions as a nurse plant to many plant species, likely to as many or more than any other plant on the ranges of North America. This is more so in the Rio Grande Plains grass-shrub savanna than on the mixed prairie grasslands like those of the Rolling Red Plains. Even on the latter, as shown here, mesquite "plays host" to several other shrub and tree species. In this Red Plains case sugar hackberry (Celtis laevigata), lotebush, and brownspine prickleypear (Opuntia phaeacantha) have come in under the shade and moderated microenvironment afforded by honey mesquite. The most important outcome of the mesquite nurse plant drama is that mesquite-infested ranges become multi-storied, mixed-species brush thickets with noxious plant control much more complicated thereby requiring more elaborate and expensive control methods and greatly decreasing the likelihood of grassland restoration.

Taylor County, Texas. October. FRES No. 38 (Plains Grassland Ecosystem). K-76 (Mesquite-Buffalograss; Bouteloua, Buchloe, Prosopis). SRM 718 (Mesquite-Grama) in advanced retrogression.

12. Mixed species brush invasion on Rolling Red Plains mixed prairie- This is an example of the nurse plant relationship carried to it's ultimate development: mature and reproducing honey mesquite forming both canopy and part of a middle woody understorey layer with young sugar hackberry and large lotebush comprising a second brush layer and brownspine prickleypear as the latest and lowest growing shrub starting to development into a third woody plant layer. All three (or more) brush layers are more dense and taller than (and taking light and water from) what is left of the mid- and shortgrass species.

It is difficult to find "middle ground" with mesquite on grassland or savanna. Honey mesquite is a natural "monopolist". It will gain effective total control over resources required for plant growth, and bring it's co-conspiring, resource-dominating, robber baron buddies right behind it. FRES No. 38 (Plains Grassland Ecosystem). K-76 (Mesqujite-Buffalogreass, Bouteloua, Buchloe, Prosopis). SRM 718 (Mesquite-Grama) in ultimate state of ecological deterioration.

13. Mixed prairie in the Kansas Red Hills- Physiography of the northern limit of the Rolling Redlands or Rolling Red Plains and the physiogonomy of mixed prairie. Mixed prairie is the climax vegetation of this physiographic unit of the Great Plains or, according to some, the Plains Border. Presented here is the north end of a physiographic sub-province that begins in Texas and extends northward through Oklahoma following what was termed the Break of the Plains. In the Texas and Oklahoma Panhandles this break is very prominent where the western edge of the Rolling Red Plains meets the Southern High Plains. The persistent mantle of the High Plains or Llano Estacado (Staked Plains) is known as the Caprock Escarpment. Immediately east of the Staked Plains, then, is a geologic/edaphic region known, again, as the Rolling Red Plains or, still yet another synonym, Redbeds Plains. In Kansas this has traditionally been called the Red Hills. The definitive physiographic reference remains Fenneman (1931, ps. 25-30; 1938, ps. 606, 617-620).

The Redbeds Plains region had (has) some of the best developed mixed prairie vegetation. Much-- probably most-- of this general range type was either destroyed by the plow or, in Texas and southern Oklahoma, converted to a mesquite (Prosopis glandulosa) shrubland disclimax by a combination of overgrazing, underburning, oil and gas development, perhaps even by faunal changes and climatic shifts, and God alone knows what else. As if that was not enough, most of the mixed prairie that escaped the plow and the brush is in some state of vegetational retrogression (ie. range deterioration), some more so than others.

The mixed prairie vegetation shown in this and the next two slides was in the Kansas Red Hills and was in high Fair to low Good range condition class. These three photographs were followed by four photographs of mixed prairie sward in Excellent range condition class, but this latter vegetation was in the Southern High Plains province immediately north of the Red Hills.

In the present slide vegetation in the foreground is outside a pasture fence of a large ranch. This relict vegetation served as a reference which was compared to the climax or potential natural vegetation described in Soil Sruveys of adjoining counties.(A Soil Survey does not exist for the county in which this vegetation grew.) The range plant community in this "control plot" was dominated by the Four Horsemen of the Prairies tallgrass species. Big bluestem was the most common. Canada wildrye, prairie dropseed, and tall dropseed were also abundant as was sideoats grama and buffalograss to add a definite and distinctive mid-grass and shortgrass layer to the vegetation and it's physiogonomy. Leadplant was the most common legume, but the dominant forb (and locally dominant plant) was Louisiana mugwort or Louisiana sage or white sage (Artemisia ludoviciana).

Vegetation in the background of this slide was presented in the next two slides. This photograph gave a representative landscape-scale view of Red Hills mixed prairie.

Berber County, Kansas. Estival aspect, June. FRES No. 38 (Plains Grassland Ecosystem). K-62 (Bluestem-Grama Prairie). SRM 709 (Bluestem-Grama). Mixed "Short-Grass" Series of Brown et al. (1998). Predominant range site was Loamy Upland with smaller areas of Shallow Prairie. Southwestern Tablelands- Cimarron Breaks Ecoregion, 26a (Chapman et al., 2001).

14. Mixed prairie in Kansas Red Hills- Landscape view that encapsulates the "lay of the land" and the diverse grassland vegetation of mixed prairie in the rolling plains landform of the Plains Border. This land and, some to some extent, its vegetation is a transition between that of the Central Lowlands with it's tallgrass and true prairies and the Great Plains with it's mixed prairie and shortgrass plains. This ecosystem (perhaps the ecological unit of landscape is more appropriate) can be visualized as "ecotonal" between the High Plains portion of the Great Plains and the Prairie Plains of the Central Lowland physiographic provinces.

The vegetation presented here was an accurate composite of that of the Red Hills in Fair to Good ecological (range) condition class. The aspect dominant at this point in progression of the growing season was silver bluestem. It was likely that little bluestem was the overall dominant, but it was much less conspicuous than silver bluestem at phenology of full bloom and peak standing crop. (The largest-- but scattered-- grass clumps are little bluestem). Prairie dropseed was common, but the more mesic and productive species of big bluestem (dominant in protected areas), Indiangrass, and switchgrass were relatively scarce. The increaser to invader (site-dependent) tumble windmillgrass (Chloris verticillata) was locally abundant. Western wheatgrass, sand dropseed (Sporobolus cryptandrus), and tall dropseed (S. asper) were present in small amounts. Sand sagebrush (Artemisia filifolia) was the major shrub with common soapweed or yucca (Yucca glauca) present but far from common. Louisiana mugwort was locally abundant (note small, short forb in immediate lower left foreground). Buffalograss was dominant (as the sole species) across wider microsites (the tan-colored spaces on the diagonal ridge tops).

Barber County, Kansas. Estival aspect, June. FRES No. 38 (Plains Grassland Ecosytem). K-62 (Bluestem-Grama Prairie). SRM 709 (Bluestem-Grama). Mixed "Short-Grass" Series of Brown et al. (1998). Primarily Loamy Upland range site with smaller areas of Shallow Prairie range site. Southwestern Tablelands- Cimarron Breaks Ecoregion, 26a (Chapman et al., 2001).

15. Red Hills mixed prairie (bluestem-grama grassland) community- Detail view of vegetation shown in the two preceding photographs. The larger tufts were little bluestem and silver bluestem which comprised more of the interspace than any other species with sand dropseed second. Sideoats grama, hairy grama, and buffalograss were also common with buffalograss often forming exclusive colonies or stands. The prominent forb in the immediate foreground was Louisiana sage or Louisiana mugwort. Sand sagebrush was the only shrub and it was quite rare (none of it was visible from this vantage point).

Range condition class was high Fair there being almost no big bluestem (the potential dominant), Indiangrass, or switchgrass. On the other hand, invaders like red threeawn (Aristida longiseta), alien annual annual bromes (eg. Bromus japonicus), and weedy Eurasian forbs such as Kochia scoparia were absent indicating that this range was also a "fur piece" from Poor or even low Fair condition class. No accelerated soil erosion was occurring.

Barber County, Kansas. Estival aspect, June. FRES No. 38 (Plains Grassland Ecosystem). K-62 (Bluestem-Grama Prairie). SRM 709 (Bluestem-Grama). Mixed "Short-Grass" Series of Brown et al. (1998). Loamy Upland range site. Southwestern Tablelands- Cimarron Breaks Ecoregion, 26a (Chapman et al., 2001).

16. Louisiana mugwort, western mugwort, white sage, western wormwood (Artemisia ludoviciana)- This forb (primarily an herbaceous plant) is typical of the Artemisia species in being widely distributed (ie. having a large species range). This phenomenon is characterized by having several subspecies or varieties (often depending on which taxonomist's treatment is consulted). The colony of A. ludoviciana shown here was in the Rolling Red Plains of northcentral Texas in mid-spring. The official flora and manual of Texas did not follow the convention of subdividing this species because it was stated that there was little correlation between such taxa and geographic distribution of these subdivisions. Most other taxonomic workers in this geographic region disagreed.

Western mugwort is-- as obvious from this photograph-- a rhizomatous species having numerous daughter plants arising from older shoots which function as a parent plant (ie. another example of a clonal organism).

SMS Ranch, Throckmorton County, Texas. May.

17. Adult plant of western or Louisiana mugwort at post-bloom stage- An extremely hearty individual of A. ludoviciana at the early to mid-fruit ripe stage growing on a oak-hickory- tallgrass savanna in the Ozark Plateau in eastern Oklahoma. Taxonomic treatments by authors in the florae of Missouri and the Great Plains keyed this specimen to A. ludoviciana var. mexicana in contrast to A. ludoviciana var. ludoviciana of the Great Plains physiographic province that was presented immediately above. Some authors treated these subdivisions as subspecies while others interpreted them as varieties. Does any of this matter?

Stoney Point Savanna, Ottawa County, Oklahoma. September.

18a. This is a textbook example of the species composition, physiogonomy, and community structure of mixed prairie on the Southern High Plains. In this one photograph can be seen the tallgrass species of big bluestem, Indiangrass, and upland switchgrass; mid-grasses like sideoats grama and silver bluestem; and the shortgrass species of hairy grama, buffalograss, and a "smigen" of blue grama. Western wheatgrass was absent. The dominant forb was wild alfalfa (Psoralea tenuifolia).

Invaders like red threeawn, annual Bromus species, broom snakeweed, and sand sagebrush "were conspicuous by their absence".

18b. Characteristic sward of mixed prairie in the Southern High Plains- The combination of bunchgrass and bare soil with the dense turf formed by sod-forming grass is one of the most obvious physiogonomic features of this multi-storied grassland.There were the three layers formed by the tall-, mid- and shortgrass species with scattered individual plants of the leguminous forb, wild alfalfa. A shrub layer and soil surface layer (eg. of mosses, lichens, fungi) were both absent.

19. Mixed prairie used as stocker range- Steers grazing mixed prairie dominated by sand dropseed with blue grama and needle-and-thread well distributed throughout while western wheatgrass dominated small swales at local scale. Most common forb was Louisiana sagewort or Louisiana mugwort. The relatively tall, dark green stalks in left background were longstyle rush (Juncus longistylis) growing in a normally seepy depression. There were no seeps-- or much moisture anywhere-- in this spring and summer of 2002, the single driest year to-date in Colorado weather records. The remarkable ability of range plants to survive and even grow in extreme drought was illustrated by this example of plains grassland on the semiarid High Plains under devastating drought.

Lincoln County, Colorado. Estival aspect (as modified by drought), June. FRES No. 38 (Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 715 (Grama-Buffalograss, sand dropseed variant). Mixed "Short-Grass" Series of Brown et al. (1998). Southwestern Tablelands- Piedmont Plains and Tablelands Ecoregion, 26e (Chapman et al., 2006).

22. Mixed prairie in Texas Rolling Red Plains- The diverse range plant community presented here included tallgrass, mid-grass, and shortgrass species along with shrubs and a few composite forbs. Little bluestem was the dominant with sideoats grama and silver bluestem associates. Buffalograss grew in the interspaces among the cespitose tall- and midgrass species. Vine mesquite dominated the draws except in the thickets of wild plumb (Prunus sp.). There were traces of sand bluestem and sand sagebrush as postclimax components. Skunkbush sumac and soapweed (Yucca glauca) were infrequent but dominated some microsites. Sand and plains lovegrasses grew sparingly.

Gray County, Texas. Estival aspect, June. FRES No. 38 (Plains Grassland Ecosystem). K-62 (Bluestem-Gramagrass Prairie). SRM 709 (Bluestem-Grama). Mixed "Short-Grass Series" of Brown et al. (1998). Central Great Plains- Red Prairie Ecoregion, 27h (Griffith et al., 2004).

24. Rolling Red Plains rangeland as seen by the redman- Although this land is technically in the High Plains section of Great Plains physiogrphic province it is in the an example of Rolling Redlands mixed prairie range in climax condition. Little bulestem is the sole dominant while sideoats grama and silver bluestem are associates. Rich species diversity prevails however with numerous other grass speceis including hairy and blue grama, sand dropseed, buffalograss, Indiangrass, galleta, and curly mesquite present on various microsites. Wild alfalfa was also common as were several composites The only shrubs were sand sagebrush and soapweed yucca.

Wheeler County, Texas. June, early estival aspect. FRES No. 38 (Plains Grassland Ecosystem). K-62 (Bluestem-Grama Prairie). SRM 709 (Bluestem-Grama Prairie). Mixed "Short-Grass" Series of Brown et al. (1998).Central Great Plains-Red Prairie Ecoregion 27h (Griffith et al,. 2004). Central Great Plains- Red Prairie Ecoregion, 27h (Griffith et al., 2004).

25. Good range gone bad- This range vegetation was conterminous with that featured in the preceding slide. In fact part of that climax condition mixed prairie range was visible in the background of this slide. Range sites were the same. Severe disturbance(s) that could have included previous plowing, overgrazing, wrongly timed or poorly manage fires, etc. (more than likely God in His Heaven only knows what) degrated this range vegetation. This is now largely a sand sagebrush disclimax. Soapweed yucca had also increased condiderably. Perennial grasses were rare and largely replacecd by the Eurasian annual grass, Japanese chess (Bromus japonicus). Annual broomweed (Gutierrezia draculoides) was also common.

Wheeler County, Texas. June, early estival aspect. FRES No. 38 (Plains Grassland Ecosystem). K- 62 (Bluestem-Grama Prairie).SRM 709 (Bluestem-Grama). Mixed "Short-Grass" Series of Brown et al. (1998). Central Great Plains-Red Prairie Ecoregion 27h (Griffith et al., 2004). Central Great Plains- Red Prairie Ecoregion, 27h (Griffith et al., 2004).

26. Landscape-scale view of plains and mesa grassland (High Plains mixed prairie ecosystem)- This landscape-scale "shot" caught landform, physiogonomy and structure of vegetation, and typical atmospere on a "plains morning" of a semiarid Great Plains grassland. Blessings of recent rains allowed this superb example of it's range type (Excellent range condition class) to portray it's natural potential at this season. Although generally thought and spoken of as "short grass country" the climax vegetation of this range site (and general range region) is a classic mixed prairie with three pronounced herbaceous layers (short-, mid-, and tallgrass species often with forbs in each) plus a shrub layer (here represented by cholla cactus, soapweed yucca, and/or sand sagebrush on coarser textured soils).

At this early summer stage of phenological development (and delayed growing season precipitation) the tallgrass component was not conspicuous but it was well-represented by upland switchgrass. Buffalograss, the associate species, and small patches of curly mesquite comprised most of the shortgrass layer while blue gramma and galleta, the community dominants, made up most of the vegetation and the predominant mid-grass physiogonomy. (This will be more pronounced for blue grama when it soon sends up sexually reproductive shoots.) Patches of western wheatgrass along with sideoats grama and sand dropseed contribute further to the mid-grass and mixed prairie appearance. Forbs were limited, and mostly composite species at pre-bloom stages. All-in-all: pristine!

Oldham County, Texas. Early estival aspect, June. FRES No. 38 (Plains Grassland Ecosystem). K-58 (Gramagrass-Buffalograss). SRM 705 (Blue Grama-Galleta).Grama "Short-Grass" Series of Brown et al. (1998). Southwestern Tablelands- Semiarid Canadian Breaks, 26d (Griffith et al., 2004).

27. Sward of climax blue grama-galleta mixed prairie grassland- Detail photograph of the estival-aspect herbaceous vegetation of the Excellent condition mixed prairie form of plains and mesa grassland presented in the immediately preceding slide. Light grazing by cattle and delayed phenological development due to delayed rains were reflected in appearance of grass, but co-dominant galleta and blue gramma along with buffalograss as the associate species were obvious. Populations of these species were presented at community scale in the next slide.

Oldham County, Texas. Estival aspect, June. FRES No. 38 (Plains Grassland Ecosystem). K-58 (Gramagrass-Buffalograss). SRM 705 (Grama-Galleta). Grama "Short-Grass" Series of Brown et al (1998). Southwestern Tablelands- Semiarid Canadian Breaks, 26d (Griffith et al., 2004).

28. Mixed prairie plains and mesa grassland- This is a community scale scene of semiarid steppe in the southern High Plains. This is the High Plains section of the Great Plains physiographic province known also as the Llano Estacado ("Staked Plains"). Here is another view of the cattle range shown in the two immediately preceding slides. Local populations or colonies of the different plant species formed a mosaic or "patchwork" expression of vegetation. Easily discernable species were cholla, galleta (grass with light gray inflorescences in right foreground), buffalograss (the shortest grass and with spots of bare soil interspersed within), and blue gramma (the grass with the darkest green hue and comprising most of the understorey in the area beginning at right background where cholla cactus was the aspect dominant).

Oldham County, Texas. Estival aspect, June. FRES No. 38 (Plains Grassland Ecosystem). K-58 (Gramagrass-Buffalograss). SRM 705 (Grama-Galleta). Grama "Short-Grass" Series of Brown et al. (1998). Southwestern Tablelands- Semiarid Canadian Breaks, 26d (Griffith et al., 2004).

29. Mesa and plains grassland— Shortgrass plains or shortgrass form of mixed prairie depending upon interpretation and which classification of vegetation types is used. Besides blue grama and buffalograss, galleta (Hilaria jamesii) rounds out the three dominant species. Several species ofthreeawn such as Aristida purpurea and A. longiseta are present but mid-grasses like western wheatgrass, sideoats grama, and siver bluestem are absent. Cholla (Opuntia imbricata) lends a savanna-like aspect to this shortgrass country and serves as an emergency feed source in drought if spines are burned off with propane burners. Peak estival aspect, June. Quay County, New Mexico. FRES No. 38 (Plains Grasslands Ecosystem). K-58 (Gramagrass-Buffalograss). SRM 502 (Grama-Galleta). Grama "Short-Grass" Series of Brown et al. (1998). Southwestern Tablelands- Semiarid Canadian Breaks Ecoregion, 26d (Omernik and Griffith, 2006).

30. High Plains Breaks range- This was one of many varied forms of the Breaks ranges site that is widely distributed on the shortgrass and mixed prairie ranges of the High Plains (Llano Estacado). These grassland communities were entitled and described by Dick-Peddie (1993, ps. 104-106, 113-115) as Plains-Mesa Grasslands. Breaks are typically a grassland range site (again, of various forms), but some expressions of this generic range site are climax shrublands (see Breaks Scrub under Miscellaneous Shrublands). The climax grassland range breaks seen here are of mixed prairie High Plains grassland range having a shrub component consisting of skunkbush or fragrant sumac (Rhus trilobata= R. aromatica), soapweed yucca, broom snakeweed (Gutierrezia sarothrae), and fragrant mimosa (Mimosa borealis) in that order. The grassland vegetation shown here was the Galleta-Indian Ricegrass-Needlegrass Series (Hilaria jamesii-Hymenoxix oryzoides-Stipa neomexica-Mixed Forb Species) of Dick-Peddie (1993, p. 110).

Galleta and New Mexico feathergrass (=needlegrass) were the dominants; Indian ricegrass was present in small amounts as an indictor species and, perhaps, as a relict species. Other common grasses included blue, sideoats, and hairy gramas; buffalograss; silver bluestem, and threeawns (of the Aristida purpurea complex).

Major forb species growing on this specific range were featured immediately below following photographs of skunkbush sumac.

Quay County, New Mexico. June, estival aspect. FRES No. 38 (Plains Grassland Ecosystem). None of the Kuchler units comes close: this omission indicated an incomplete classification by Kuchler (1964, in Garrison et al., 1977) as documented by the more comprehensive list of climax Plains-Mesa Grassland communites provided by Dick-Peddie (1993, ps. 110-111). Likewise there was no SRM (Shiflet, 1994) rangeland cover type that accurately described this rangeland vegetation that was clearly covered by the Galleta-Indian Ricegrass-Needlegrass Series of Dick-Peddie (1993, p. 110). This could be interpretedas as one of "many variations" occurring in the SRM 716 (Grama-Feathergrass) rangeland cover type. A form or subunit of Mixed "Short-Grass" Series of Brown et al. (1998). Southwestern Tablelands- Semiarid Canadian Breaks Ecoregion, 26d (Omernik and Griffith, 2006).

.

36. Prairie bluets (Houstonia nigricans= Hedyotis nagricaus)- OK, another one the taxonomists are rilin' the herd over. Of course, this little High Plains forb is not worth much fuss, but it did add biodiversity (that catch-all virtue of the "natural crowd") on the range and the fraternity of Good Rangemen and True was proud to accept approvial where it could get it.

This range forb is in the madder family (Rubiaceae). Quay County, New Mexico. June.

40. Almost a tallgrass type on the High Plains- This little bluestem-dropseed-feathergrass mixed prairie approached the physiogonomy and had a species composition that resembled that of tallgrass prairie. This was an example of several rangeland cover types recognized by the Society for Range Manageament (Shiflet, 1994) as developing on the Canadian-Pecos Rivers drainage portion of the High Plains portion of the Southern Great Plains. Tallgrass species were represented by little bluestem an dgiant dropseed (Sporobolus giganteus) midgrasses included New Mexico feathergrass, the dominant (at least the aspect dominant), sand dropseed, and sideoats grama; while the shortgrass species of buffalograss and blue and hairy grama were common on local "spots". Relict plants of spike dropseed (Sporobolus contractus) were found on the outside of the fencerow which seemed to "clinch" this rangeland cover type.

It was possible that continued summer grazing of this specific range for a number of years had favored New Mexico fethergrass over the climax warm-season little bluestem and dropseed species. Also, abundant fall and winter moisture contributed to one of the best crops of fethergrass in recent memory such that this cool-season climax member of the community had been extremely productive. Finally, this scene in early summer was prior to the summer rainfall pattern of this climate so that there was very little current growth of the dropseeds and little bluestem.

Shrubs included soapweed yucca and broom snakeweed, but cover and densty of these species was not in excess of what would be expected on high Good range condition class which was the apparent successional status of this properly managed range. There were almost no forbs.

Quadalupe County, New Mexico. June. FRES No. 38 (Plains Grassland Ecosystem). There was no appropriately descriptive Kuchler unit. Nor did Dick-Peddie (1993, ps. 110-111) list a Plains-Mesa Grassland series that was consistent with the published SRM (Shiflet, 1994) description. This was a "tightland", New Mexico feathergrass variant of SRM 708 (Bluestem-Dropseed). Finally there was not an appropriate series offered by Brown et al. (1998). Southwestern Tablelands- Central New Mexico Plains Ecoregion, 26o (Omernik and Griffith, 2006).

41. Feathergrass-Indian ricegrass range- This Plains-Mesa Grassland had a species composition different from any series presented by Dick-Peddie (1993, ps. 104-106, 110-111), but this specific range plant community was part of the Grama-Feathergrass series.. New Mexico feathergrass was dominant and Indian ricegrass was the associate. Blue and black grama were distant "also rans". Soaptree yucca (Yucca elata) and Bigelow sagebrush (Artemisia bigelovii) were localized in microsites and present in a wide pattern of dispersion. This range vegetation whown here was commonly present on uplands at higher elevation above black grama-dominated plains both of which were in the Sacramento section of the Basin and Range physiographic province.Successional statue was not known, but range condition was probably in Good class.

Black grama-grassland range that was below the range vegetation viewed here was interpreted as being in semidesert grassland and was treated in that chapter in this publication. Higher elevation with commensurate cooler ambient temperatures and greater, more effective soil moisture allowed extension of Great Plains grassland, Dick-Peddie (1993, 104-106, 110-111) into the Basin and Range Region.

FRES No. 38 (Plains Grassland Ecosystem). Smaller unit of range vegetation as part of K-57 (Grama-Needlegrass-Wheatgrass). One of "many variations" of SRM 716 (Grama-Fethergrass). No appropriaate series in Brown et al. (1998). Technical mini-editorial: The list of series under Plains Grassland 142.1 (Brown et al., 1998, p. 40) is much too general to be of much use. In comparison Semidesert (Chihuhuan) Grassland 143.1 has 2/5ths again as many series units and the latter is far less diverse in range types, plant species, soils, topography, climate, etc. than the Plains Grassland. Southwestern Tablelands- Central New Mexico Plains Ecoregion, 26o (Omernik and Griffith, 2006).

Lincoln County, New Mexico. June.

44. Xeric expression or form of Great Plains grassland- Range vegetation that was Great Plains-mesa mixed prairie-semidesert (Chihuhuan) grassland transition, a semiarid low mountain grassland. This picturesque foothill range was in the famous Wild Rose Pass in the Arkansas Mountains at an approximate elevation of 4300 feet. This was an example of an "island" of Great Plains grassland within the Trans-Pecos Basin and Range Region resulting in characteristic and indicator species from the drier semidesert grasslands (located to the west and south) growing with the more common and abundant plains-mesa mixed prairie. This range was somewhat degraded (high seral stage community just prior to climax), but it was an approximation of the potential natural vegetation. Blue grama was the general dominant with black grama and sideoats grama associate species. Hairy grama, cane bluestem (Andropogon barbinodis= Bothriochloa barbinoidis), sand dropseed, plains bristlegrass (Setaria leucopila), buffalograss, tanglehead (Heteropogon contortus), and threeawns (Aristida purpurea complex) were also present. Dominant forb was Louisiana sagewort (Artemesia ludoviciana). Shrubs included alligator juniper (Juniperus deppeana), Havard agave (Agave havardii), pricklypear and cholla cactus (Opuntia spp.), splitleaf bricklebush (Brickellia laciniata) and whitethorn acacia (Acacia constricta).

This range type was one of "many variations" of SRM 706 (Blue Grama-Sideoats Grama) or SRM 707 (Blue Grama-Sideoats Grama-Black Grama), or perhaps more descriptively, as a transition range type between SRM 706 or SRM 707 and the mixed grass hillside semidesert grassland, the Grama-Andropogon- Trichachne community of Whitfield and Beutner, 1939, p. 35-36). The latter was covered under Semidesert Grassland. Presence of Agave and Acacia species as well as the high density and cover of cane bluestem in favorable microhabitats were indications more typical of vegetation in the Basin and Range province.

Jeff Davis County, Texas. June, early estival aspect; current growth mostly of shrubs). FRES No. 38 (Pains Grassland). No appropriate Kuchler (1964, in Garrison et al., 1977) unit or Brown et al. (1998) series. Soil Conservation Service (Soil Survey, Jeff Davis County, Texas, 1972) Igneous Hill and Mountain range site in the Mountains Grassland vegetation. Isolated unit of High Plains- Llano Estacado Ecoregion 25i within Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion 24c.

45. Interloper Great Plains-mesa grassland in Trans-Pecos Basin and Range Region- Detail of richly diverse range vegetation on Wild Rose Pass in Arkansas Mountains of the Basin and Range province. The range vegetation on this vlow mountain mixed prairie was generally a grama-bluestem transition range type: SRM 706 (Blue Grama-Sideoats Grama) or SRM 707 (Blue Grama-Sideoats Grama-Black Grama)of the Southern Great Plains with floristic and structural elements from the semidesert mixed-grass mountain grassland mixed grass of the Chihuhuan Basin and Range Region. This latter range type was treated in the chapter, Semidesert Grassland.

Plant species readily distinguished included Louisiana sagewort (= mugwort), conspicuous silver foliage in second slide, whitethorn acacia, Havard agave, and alligater juniper. Blue grama was the dominant with sideoats grama and black grama associates. Cane bluestem was scattered widely but sparse and this was taken as an indicator species of semiarid mountain grasslands to the south and west. Other Gramineae were listed in the preceding caption.

Jeff Davis County, Texas. June, early estival aspect (little current growth of warm-season grasses).FRES No. 38 (Plains Grassland Ecosystem). No appropriate units in Kuchler (1964, in Garricus, 1977) or Brown et al. (1998): both were much too general. Soil Conservation Service (Soil Survey, Jeff Davis County, Texas) Igneous Hill and Mountain range site in Mountain Grassland vegetation zone. Isolated unit of High Plains- Llano Estacado Ecoregion 25i within Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion 24c (Griffith et al. 2004).

46. Plains-mesa grassland- Bluestem-grama mixed prarie in foothills of Davis Mountains of Trans-Pecos Basin and Range. This range vegetation was photographed prior to onset of summer rains leaving the previous season's herbage as a representation of mixed praire foothill grassland. Dominant species made a a "quaratete" of both cane and silver bluestem along with sideoats and bluegrama. Black, hairy, and chino grama were also common along with buffalograss, galleta, plains and bristlegrass. The major forb was silverleaf nightshade (Solanum elaeagnifolium). Presence of sacahuiste or, sometimes, beargrass (Nolina texana), large green clumps, has traditionally been associated with overgrazing and other human-induced disturbances. Powell (2000, p. 13 described grasslands with unnaturally high cover of sacahuiste as "modified". The current author could think of more descriptive terms for the change: degraded and deteriorated are two scientific terms that are appropriate for formal usage. Sacahuiste cover on this range-- aside from an aspect dominance appearance-- was interpreted as no more than light to moderate invasion.

Physiogonomy and structure of mixed prairie plains grassland was obvious in this mixture of mid- and shortgrass species.Cane bluestem specimens approached a height arbitrarily of tallgrass stature.

Brewster County, Texas. June, early estival period but still dormant to early growth stage for most grasses. FRES No. 38 (Plains Grassland Ecosystem). K-62 (Bluestem-Grama Prairie). SRM 714 (Grama-Bluestem), but variant of bluestem species. None of the series for Plains Grassland by Brown et al. (1998) could "mow the mustard" (too few series provided for this diverse grassland biotic community). Isolated unit of High Plains- Llano Estacado Ecoregion 25i within general Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion 24c.

47. Texas sacahuiste or beargrass (Nolina texana)- This is one of the more widely distributed grass-resembling or liliaceous shrubs in the Great Plains and Trans-Pecos Basin and Range Regions. It is generlly unpalatable, but not enough. It is a poisonous range plant to sheep and goats under some conditions, namely when overstocking forces animals to eat and poison themselves or in years when flowers and fruit are in abundance. It is only flower parts and ripe fruit that cause toxicity: secondary or hepatogenic photosensitization. Hepatotoxicity is thought to be caused by accumulation of crystals from Nolina tissue in the bile duct. Cattle are not usually affected because they consume only leaves (Burrows and Tyrl, 2001, p. 16). Nolina species do provide valuable forage (browse) across some of the Western Range.

Students were referenced to the following references for discussions of sacahuiste poisoning: Kingsbury (1964, p. 56, 453-456), Sperry et al., (1964, p. 32-34), Burrows and Tyrl (2001, ps. 15-18), and Hart et al. (2003, p. 138).

Brown County, Texas. May.

49. Sand dune mixed prairie or, maybe, mixed prairie-shrub savanna- Vegetation is often deceiving. That fundamental principle was examplified by this mixed prairie on dune land. Sparcity of vegetation cover and low density of plants would suggest to the greenhorn a desert, but in reality structure and composition of this range plant community consisted of tall-, mid-, and shortgrass species producing a classic mixed prairie (in spite of sparcity of plants and plant cover). Major grass species included little bluestem, sand bluestem, sand dropseed, sand paspalum (Paspalum stramineum= setaceum var. stramineum)and perennial threeawn (Aristida purpurea complex). There were a few plants of showy fingergrass (Chloris virgata) but presence of this annual species was of little diagnostic utility. Likewise the presence of a few specimens of common sandbur (Cenchrus incertus) suggested nothing beyond the ever-present annoyance of this weed. Under virgin conditions it was likely that big sandreed (Calamovilfa gigantea) and giant dropseed (Sporobolus giganteus) were present as key indicator species. Neither of these climax species was not found at this location.

The deception (and complication) of this dune land vegetation extended to the shrubs that were present. Mixed and shortgrass prairie grasslands and sand shinnery oak (Quercus havardii) shrubland develop in a mosaic of climax vegetation throughout this region. Presence of numerous shrubs that are climax in the "shinnery sands", the sand shinnery range type (ecosystem), were also present. These shrubs-- in certain proportions-- are thus climax components of the vegetation shown in above photographs. This range plant community was actually a transition zone (= ecotone) between grassland and shrubland vegetation such that it developed into a grass-shrub savanna. These shrubs included sand shinnery oak, the scrub growth (= coppice) form of honey mesquite, and (infrequently) sand sagebrush.

An estimate of annual biomass productivity (so as NOT to be confused by accumulated plant tissue that included necromas accumulated in woody species), species diversity, and plant cover of each growing season convinced this photographer-student that this range vegetation was clearly grassland and not shrubland. This conclusion was further bolstered by the almost-always assumption that that there had been some range deterioration (= degree of departure from climax) if, by nothing else the ubiauituous increase in mesquite since arrival of whiteman. Nonetheless, it was also obvious (again, at least to the rangeman taking these photographs) that this range vegetation was a mixed prairie-shrub savanna. The shrubs are a part of this climax.

Forbs included yellow whollywhite or yellow old plainsman (shown above in this chapter) and western sensitive-briar (Schrankia occidentalis) which was introduced in the succeeding photograph.

Local topography or land form on which this range cover type developed was hummocky (circular sandy hummocks) rather than the tall dune form. The first photographs was taken from the bottom of an interdunal basin in foreground with slopes and the rim or crest (top) of the hummock in background. The second photograph was taken from the intra-dune (intra-hummock) mid-slope (foreground) across the basin (which is bottom of this inter-dunal area) to the crest (behind which is another interdunal hummock with its basin, sloping sides, and crest or rim).

Monahans Sandhills State Park, Ward County, Texas. June. FRES No. 31 Shinnery Shrubland Ecosystem & No. 38 (Plains Grassland Ecosystem) transition zone. No truly descriptive Kuchler unit. SRM 708 (Bluestem-Dropseed), and a textbook of the sparse form or expression of this rangeland cover type.There was no appropriate series under the Brown et al. (1998) Plains Grassland biotic community: inadequate Series units for this large and diverse zonal or regional community of plains grassland climax. High Plains- Shinnery Sands Ecoregion 25j (Griffith et al., 2004).

51. Great Plains-Great Basin transition mixed prairie grassland- Landscape-scale photograph of what Brown (1994, p.119) described in a photo caption as a "Plains grassland-Great Basin grassland transition", "... a mixture of both Plains species (Boutelous gracilis) and Great Basin species (Hilaria jamesii, Oryzopsis hymenoides)" and "... shrubs are mostly fourwing saltbush (Atriplex canescens)". The range vegetation shown in this slide was an example of plains and mesa grassland described by Dick-Peddie (1993, p. 119) and quoted in the last paragraph of the preceding slide caption. This climax vegetation was a consociation of New Mexico feathergrass (= New Mexico needlegrass) with blue grama, galleta, and Indian ricegrass approximately "equally divided" and functioning as associate species. Sand dropseed was present at more than "trace amounts", but it was not a major component. Greasewood (Sarcaobatus vermiculatus) and Bigelow sagebrush (Artemesia bigelovii) were the two most common shrubs with greasewood better represented. Fourwing saltbush was present (rarely) and perhaps as a relict species. None of these woody species accounted for more than trace proportions. Broom snakeweed was present but even more rare. Forbs were represented (barely) by Russian thistle and Thurber pepper-weed (Lepidium thurberi).

Relative utilization or degree of use of grass was light even under current conditions of exceptional drought. It was noted that sexual reproduction of feathergrass was remarkable for such short-moisture conditions. Winter precipitation had "saved the day" for this species.

Grand Canyon section of the Colorado Plateau physiographic province.

Coconino County, Arizona. Estival aspect during worst drought (exceptional rating) in Arizona history, June. FRES No. 38 (Plains Grassland Ecosystem). K-47 (Gramagrass-Gallata Steppe).SRM 716 (Grama-Feathergrass).

52. Vegetation of Great Plains-Great Basin transition mixed prairie- This photograph detailed at community scale the climax vegetation of the New Mexico feathergrass consociation of plains and mesa grassland, a variant of the regional gramagrass-gallata (Bouteloua-Hilaria) climax steppe. Dominance by a cespitose midgrass (a species of intermediate height between tallgrass and shortgrass) produced a physiognomy typical of mixed prairie, but absence of a tallgrass species resulted in absence of one herbaceous layer that was present in some of the other range cover types of mixed prairie.

Cover and dentisty of woody species were so limited that a shrub layer was also absent. This climax community was not a savanna-like shrub steppe, but rare presence of fourwing saltbush was of uncertain interpretation. Brown (1994, p.104) specified presence of fourwing saltbush in a similar transition grassland community located close to the one shown here, but neither Dick-Peddie (1993, p. 104-106) nor the the SRM description of this rangeland cover type, SRM 716 (Grama-Feathergrass), (Shiflet, 1994, ps. 94-95) specifically reported fourwing saltbush for this vegetation. The SRM description (Shiflet, 1994) was limited to eastern New Mexico which was essentially in the High Plains province rather than the Colorado Plateau as shown here. Likewise, none of these descriptions mentioned greasewood which was certainly the most common (least uncommon) shrub and one known to occur here.

Perhaps browsing by livestock and/or wildlife had reduced fourwing saltbush. It was conceivable also that grazing had shifted dominance from the regionally dominant blue grama to the co-dominat New Mexico feathergrass. Existing "on-the-ground" evidence argued against both of these outcomes. Species composition of vegetation in the wide right-of-way of Interstate 40 was not apparently different from that inside the range allotment except that the rarely encountered fourwing saltbush plants were larger in the right-of-way. Right-of-way vegetation had been protected from grazing and routine mowing for several decades and this could explain larger size of fourwing saltbush specimens. Otherwise the only difference between livestock presence and absence appeared to be in degree of use (and not species composition of plant community). Present (and immediately past) grazing management of the range appeared to be ideal, an example of outstanding stewardship.

Fourwing saltbush was present (far right to center midground) on New Mexico feathergrass-dominated range protected from livestock grazing and not subjected to highway mowing (shredding).

Coconino County, Arizona. Early estival aspect (conditions of exceptional drought), June. FRES No. 38 (Plains Grassland Ecosystem). K-47 (Gramagrass-Galleta Steppe). SRM 716 (Grama-Feathergrass).

53. Patch dynamics in vegetation of Great Plains-Great Basin transition mixed prairie range- These paired photographs showed details of undisturbed vegetation (first or upper slide) and disturbed vegetation (second or lower slide) of a New Mexico feathergrass-dominated (feathergrass consociation) bunchgrass steppe on the Grand Canyon section of the Colorado Plateau province. The localized "patch" in the lower photograph had Russian thistle (round-shape tumbleweed in lower left), greasewood (largest plant; center background), Bigelow sagebrush (to immediate right of greasewood), fourwing saltbush (immediately to right and also behind Bigelow sagebrush), broom snakeweed (right background), and Indian ricegrass (right-center foreground) as well as New Mexico feathergrass in contrast to the nearly single-species stand of New Mexico feathergrasss in the undistrubed patch shown in the upper photograph. This was an example of patch dynamics on a very local scale (microsite-size). Both patches were on highway right-of way not subjected to mowing.

Coconino County, Arizona. Early estival aspect (in exceptional drought), June. FRES No. 38 (Plains Grassland Ecosystem). K-47 (Gramagrass-Galleta Steppe). SRM 716 (Grama-Feathergrass).

57. Bigelow sagebrush (Artemesia bigelovii)- Both this species and big sagebrush (A. tridentata) grow in the Great Plains-Great Basin transition mixed prairie steppe on the Colorado Plateau. Bigelow sagebrush can be readily distinguished by presence of numerous stems in contrast to the usual single trunk of big sagebrush.

This specimen was growing on the climax New Mexico feathergrass-dominated range and exclosed area shown above. Coconino County, Arizona. June.

58. Galleta-blue grama plains and mesa grassland in drought- Appearance of High Plains (Llano Estacado) mixed prairie in prolonged, severe drought and under current overuse. Galleta was the obvious dominant species with blue grama, buffalograss, western wheatgrass, and sand dropseed all microsite associate species and in that relative mean (overall range community) order of abundance. This range had absolutely no mesquite, but the native plains pricklypear (Opuntia polyacantha)-- seen as small isolated patches in foreground-- had begun to appear at density and cover of an invader (greater amounts than in climax vegetation). It must be borne in mind, however, that overuse of grass had exposed pricklypear prominently. Nonetheless, there was virtually no doubt but what this range was probably being mismanaged-- to some detriment of both range and cattle. Excessive degree of use (overuse= removal by grazing animals of excessive portions of current season's leaves and stems that if conitinued will lead to overgrazing) was indeniable.

The most immediate incontrovertible evidence of current overuse was grazing of young, growing plants of broadleaf milkweed (Asclepias latifolia) by cattle. A. latifolia is one of the more toxic plants on High Plains ranges (perhaps because there are not as many poisonous plant species in this region as in some of the more botanically diverse adjoining ones like the Trans Pecos Basin and Range and Edwards Plateau). Livestock poisoning by broadleaf milkweed is enough of a problem that it was routinely covered in standard textbooks and Agricultural Experiment Station-Extension publications (eg. Sperry et al., undated). In the example shown here it was human management of range and cattle that resulted in milkweed consumption. There was no evidence of toxicity to cattle: apparently quantities eaten were below toxic levels (at time of photograph). If current overstocking does not result in overgrazing (range retrogression due to prolongued overuse) with corresponding damage to basic range resources like soil and watershed features and/or economic losses in livestock (in excess of that from emergency feeding), such periods of overuse cannot automatically be labeled as mismanagement. Cows and calves grazing this range remained in thrifty condition and as the grass species were in semi-dormancy the range was not being severely abused. The situation was that there were indications that current grazing management was allowing invasion by plains pricklypear. More frequent movement of cattle to different pastures or even culling of lower-producing cows might well be more economical in the long run.

Examples of broadleaf milkweed were presented below in this Mixed Prairie portion. The large Brangus cow beside the cholla indicated size of some of these cactus plants.

Guadalupe County, New Mexico. Early estival aspect, June. FRES No. 38 (Plains Grassland Ecosystem). K-58 (Gramagrass-Buffalograss). SRM 705 (Grama-Galleta). Grama "Short-Grass" Series of Brown et al (1998). Southwestern Tablelands- Conchas/Pecos Plains Ecoregion, 26n (Omernik and Griffith, 2006).

59. Sward of plains and mesa mixed prairie in drought and without cattle grazing- Details of galleta-blue grama-buffalograss-western wheatgrass-sand dropseed (all are visible) community shown in the preceding photograph except that grass shown in this photograph was not grazed. Vegetation seen here was immediately adjacent to but outside the fence that enclosed the currently overused range of plains and mesa mixed prairie. Difference in degree of use was obvious, but there was little difference in species composition except for absence of broadleaf milkweed and less cover of plains pricklypear. Grazing by cattle had apparently contributed to an increased number of plant species and a somewhat different plant "mixture" (ie. cattle grazing apparently increased biological diversity). Is this sort of increased biodiversity "good" or "bad"?

Western wheatgrass photographed here was in anthesis. Western wheatgrass inside the pasture shown in the preceding slide was grazed to a stubble height of less than two inches and there were no flowering shoots. In other words, even in severe, early season drought cool-season grasses were in the process of producing seed-- where they were not "grazed into the ground".

Degree of use is determined largely by the stocking rate. Proper degree of use (proper stocking rate) is the first and most important of the Four Cardinal Principles of Range Management.

Guadalupe County, New Mexico. Early estival aspect, June. FRES No. 38 (Plains Grassland Ecosystem). K-58 (Gramagrass-Buffalograss). SRM 705 (Grama-Galleta). Grama "Short-Grass" Series of Brown et al (1998). Southwestern Tablelands- Conchas/Pecos Plains Ecoregion, 26n (Omernik and Griffith, 2006).

60. Relict plains-mesa mixed prairie (shrub steppe form)- Although this semiarid grassland in the Datil section of the Colorado Plateau was enduring a severe to exceptional drought and in semi-dormancy it was the potential natural vegetation. These two photographs showed the species composition and physiogonomy of a climax mixed prairie grassland with a shrub component that appeared almost as a shrub-grassland savanna. The climax dominant shrub was fourwing saltbush. There was an occasional broom snakeweed (an all-too-common invader on adjacent range), but the vegetation here was in "mint condition". On the extremely sandy soil of this range site Indian ricegrass was the clear dominant with sand dropseed, plains lovegrass, blue grama, and sideoats grama all abundant species and growing as mixed localized "mini-communities". Sand dropseed dominated some microsites. Blue grama, the dominant species of this general regional (monoclimax or ecoregion dominant) was never a local dominant on this sandy range. Galleta was not present (or if missed, it was but a trace).

Cibola County, New Mexico. Early vernal aspect (extreme to exceptional drought), June. FRES No. 38 (Plains Grassland Ecosystem). K-47 (Gramagrass-Galleta Steppe). Variant of SRM 502 (Grama-Galleta); SRM 705 (Blue Grama-Galleta) occurs to the east of the 502 rangeland cover type but resembles it rather closely.

Dick-Peddie (1993, p. 104) described this and the mixed prairie example in the succeeding slide, Great Plains grassland-Great Basin grassland transition, as part of the plains and mesa grassland in which blue grama was a common denominator but often co-dominant with galleta on mesas in the northern half of New Mexico. He specified: "On fine-textured soils in the north and northwest, Indian ricegrass (Oryzoides hymenoides) may share dominance with blue grama, or communities can be found with New Mexico feathergrass (Stipa neomexicana) and needle-and-thread (S. comata) sharing dominance with blue grama" (Dick-Peddie, 1993, p. 119). Arizona/New Mexico Plateau- Semiarid Tablelands Ecoregion, 22j (Omernik and Griffith, 2006).

61. Shortgrass plains- This was an example of the shortgrass phase or shortgrass community form of mixed prairie. Blue grama and buffalograss were the two dominants of this climax grassland, but western wheatgrass, sideoats grama, and sand dropseed (the classic mid-grasses) were also common while silver bluestem formed distinct colonies (eg. the light tan area in left mid-ground) and individual plants of the cespitose little bluestem were also present. Dominant forb was wild alfalfa. This combination of sod-forming grasses and bunchgrasses is characteristic of mixed prairie, but the predominant sod-grasses were responsible for the shortgrass physiogonomy of this Southern High Plains grassland. The community more typical of mixed prairie (more species-rich) was featured in the foreground to show the biological diversity of plains grassland, but the less diverse blue grama-buffalograss community of the background was the more common community on this cattle range.

Commanche National Grassland, Baca County, Colorado. Estival aspect, July. FRES No. 38 (Plains Grassland Ecosystem). K- 61 (Wheatgrass-Grama-Buffalograss) in foreground; K-58 (Grama-Buffalograss) in background. SRM 715 (Grama-Buffalograss). Grama "Short-Grass" Series of Brown et al. (1998). Hardland range site. Hardland range site. High Plains- Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2005).

62. High Plains grassland- This was another example of the shortgrass physiogonomy form of mixed prairie. Blue grama, buffalograss, and galleta (in that order) were dominant species though mid-grass species were common (western wheatgrss, sideoats grama, sand dropseed, and Indian ricegrass were well-represented while prairie junegrass was present but infrequent in this sward). Common plains yucca or soapweed yucca was present as the major forb, but it was more conspicuous than it was common. Widely scattered (barely present) shrubs were cholla and four-wing saltbush.

Crowley County, Colorado. July. Estival aspect, July. FRES No. 38 (Plains Grassland Ecosystem). K- 58 (Grama-Buffalograss). SRM 715 (Grama-Buffalograss). Grama "Short-Grass" Series of Brown et al. (1998). Loamy Plains range site. Southwestern Tablelands- Piedmont Plains and Tablelands Ecoregion, 26e (Chapman et al., 2006).

63. Shortgrass plains- This landscape was included to show viewers the classic blue grama-buffalograss community interpreted by many prairiemen as a shortgrass disclimax (a grazing or zootic disturbance climax). Beginning range students are referred to Weaver and Albertson (1954, ps. 19-25). The two shortgrass species "have a monopoly" on the plant-growing resources of this ecosystem. As with the grassland communities seen in preceding slides such species as western wheatgrass, sideoats grama, and galleta were also present. Threeawns (Aristida species) were very rare while shrubs and even forbs were non-existant for all practical purposes. Textbook example of shortgrass plains grassland.

From the collection of examples presented here the most ardent plainsmen and fans of the "shortgrass country" can understand why plains-weary travelers (and som