Ecological dynamics

Plant tables have not been developed for this site. Until such time as they can be updated, use the plant tables in the referenced literature that correlates to this concept (refer to legacy information correlated to this site included below). With respect to the imperfect alignment of such correlations, be aware of these shortcomings in their applicability to conservation planning.
The Slopes ecological site is dominated by short grasses, but also contains a mix of shrubs, forbs, and succulents. Trees are occasionally present. As is typical of plant communities in this region, pronounced annual variations in precipitation translate to considerable short-term fluctuations in annual production within a given plant community phase.
There are numerous variables which affect the range of characteristics for this ecological site. Variables such as elevation, latitude, and orographic effects create a climatic gradient which influence the distribution of C3 and C4 plants. Soil properties such as surface texture, depth to clay layer, parent material, and accumulated salts affect species diversity and composition. Natural disturbances such as drought and wildfire affect species density and cover.
The climate gradient across the CP LRU shows a greater distribution of C3 plants such as western wheatgrass and bottlebrush squirreltail where temperatures are cooler, and moisture is more abundant. Where surface texture trends toward clay loam, western wheatgrass, galleta, and vine mesquite grass increase. In areas of sandier surface textures, sideoats grama and sand dropseed are more likely to occur.
Fire is a disturbance regime that reduces succulents and shrubs while stimulating grasses and forbs. Not all fires are equal. According to Gebow (2001), fire effects in the same location will vary, especially with fire timing, both seasonally and within the scheme of year-to-year moisture variation. Precipitation during seasons before and after fire has a major effect on recovery of plants. Fire promotes rhizomatous plant species, such as western wheatgrass, that can take advantage of below-ground rhizomes from which tillering is rapidly initiated.
Grazing pressure will tend to favor grasses such as blue grama and purple threeawn as well as shrubs such as broom snakeweed and Plains yucca.
Plant communities are quite similar on both soil components. In general, shrub cover is somewhat higher and grass cover is somewhat lower on the Mion component. Plant community phase descriptions herein apply to the entire escarpment.
Correlation to Current Ecological Sites:
The Mion components that fit the Slopes concept are currently divided among two ESDs: Shallow Savannah (R070AY019NM) and Shale Hills (R070AY009NM). While these two ESDs are very difficult to distinguish, the ecological dynamics narrative for the Shallow Savannah site (R070AY019NM) is more detailed: "The structure of the potential natural plant community is predominantly grasses with scattered overstory of one seed juniper. Grass species are dominated by warm-season mid-grasses. Woody species make up 30 percent of the vegetation. Juniper, mountain mahogany and oak are the major woody species. Forbs make up 10 percent of the vegetation."

Legacy Correlations:

From Shallow Savannah (R070AY019NM) Tables
Annual production by plant type
Plant Type-------Low(Lb/Acre)-------RV(Lb/Acre)-------High(Lb/Acre)
Grass/Grasslike-----320--------------400------------------------650
Tree---------------------150--------------200-------------------------300
Forb---------------------50-----------------70--------------------------100
Total---------------------520--------------670------------------------1050

Community 1.1 plant community composition
Common Name--------------Symbol----------Scientific Name-------Annual Production (Lb/Acre)
GRASS/GRASSLIKE
1 blue grama------------------BOGR2-----Bouteloua gracilis--------------------------50–150
2 sideoats grama--------------BOCU------Bouteloua curtipendula--------------------75–200
3 little bluestem---------------SCSCS------Schizachyrium scoparium var. scoparium--50–150
4 wolfstail----------------------LYCUR------Lycurus--------------------------------------15–50
5 western wheatgrass----------PASM-------Pascopyrum smithii------------------------25–100
7 slimspike threeawn----------ARLO16-----Aristida longespica--------------------------15–50
8 needle and thread------------HECOC8-------Hesperostipa comata ssp. comata-------25–100
11 New Mexico feathergrass----HENE5-------Hesperostipa neomexicana---------------25–100
TREE
9 oneseed juniper----------------JUMO-------Juniperus monosperma---------------------25–100
10 twoneedle pinyon--------------PIED-------Pinus edulis----------------------------------15–50
SHRUB/VINE
12 alderleaf mountain mahogany-CEMO2----Cercocarpus montanus-----------------------15–50
13 field sagewort -------------------ARCA12------Artemisia campestris----------------------15–50
14 Apache plume--------------------FAPA-------Fallugia paradoxa---------------------------15–50
15 fourwing saltbush---------------ATCAC-------Atriplex canescens var. canescens---------15–50
16 Gambel oak----------------------QUGA-------Quercus gambelii----------------------------15–50
FORB
17 buckwheat------------------------ERIOG-------Eriogonum-----------------------------------15–50

From Shale Hills (R070AY009NM) Tables
ANNUAL PRODUCTION BY PLANT TYPE
Plant Type--------Low(Lb/Acre)--------RV(Lb/Acre)--------High(Lb/Acre)
Grass/Grasslike----------360--------------------510------------------------660
Shrub/Vine---------------170--------------------240------------------------310
Forb------------------------50----------------------70-------------------------90
Total------------------------580---------------------820-----------------------1060

Community 1.1 plant community composition
Common Name-----------------Symbol-------Scientific Name----------Annual Production (Lb/Acre)
GRASS/GRASSLIKE
1 blue grama---------------------BOGR2--------Bouteloua gracilis---------------128–170
2 sideoats grama------------------BOCU--------Bouteloua curtipendula--------85–128
3 little bluestem------------------SCSC--------Schizachyrium scoparium--------85–128
4 James' galleta--------------------PLJA--------Pleuraphis jamesii----------------43–85
5 western wheatgrass------------PASM--------Pascopyrum smithii--------------43–85
6 threeawn--------------------------ARIST--------Aristida----------------------------26–43
7 needle and thread----------------HECO26-----Hesperostipa comata------------26–43
8 New Mexico feathergrass--------HENE5------Hesperostipa neomexicana-----26–43
9 Graminoid (grass or grass-like)--2GRAM------Graminoid (grass or grass-like)-26–43
FORB
10 buckwheat-------------------------ERIOG------Eriogonum----------------------------26–43
11 Forb, annual------------------------2FA---------Forb, annual------------------------26–43
12 Forb, perennial---------------------2FP--------Forb, perennial---------------------26–43
Tree
13 juniper-------------------------------JUNIP-------Juniperus---------------------------43–85
14 twoneedle pinyon------------------PIED--------Pinus edulis------------------------43–85
Shrub/Vine
15 hairy mountain mahogany---CEMOP---Cercocarpus montanus var. paucidentatus-26–43
16 prairie sagewort-------------------ARFR4------Artemisia frigida---------------------26–43
17 fourwing saltbush-----------------ATCA2------Atriplex canescens------------------26–43
18 Apache plume----------------------FAPA-------Fallugia paradoxa--------------------26–43
19 oak----------------------------------QUERC-------Quercus-------------------------------43–85
20 broom snakeweed----------------GUSA2-------Gutierrezia sarothrae--------------26–43
21 Shrub, deciduous-------------------2SD----------Shrub, deciduous------------------43–85

From the San Miguel County (NM630) soil survey :
"The potential plant community on the Mion soil is mainly sideoats grama, little bluestem, blue grama, and needleandthread. (…) As the range deteriorates, the proportion of these forage plants decreases and the proportion of ring muhly, blue grama, pricklypear, and oneseed juniper increases. Grazing management should be designed to increase the productivity and reproduction of sideoats grama, western wheatgrass, and little bluestem."
The structure of the potential natural plant community is predominantly grasses with scattered overstory of oneseed juniper. Grass species are dominated by warm season mid-grasses. Woody species make up 30 percent of the vegetation. Juniper, mountain mahogany, and oak are the major woody species. Forbs make up 10 percent of the vegetation.
Other grasses may occur in trace amounts include vine mesquite, prairie Junegrass, and big bluestem.
Other woody plants may occur in trace amounts include: winterfat, skunkbush, and Bigelow sage.
Other woody plants* may occur in trace amounts include: Asters and Indian paintbrush.
*This refers to forbs rather than woody plants.