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• R067BY024 CO: <br /> R667BY024C0--Sandy Plains Ecological Sire--Elbert County.Colorado,Eastern Part <br /> R067BY024C0— Sandy Plains Ecological Site <br /> Ecological Dynamics Description <br /> The information in this ESD,including the state-and-transition model diagram <br /> (STM),was developed using archeological and historical data.professional <br /> experience,and scientific studies.The information is representative of a dynamic <br /> set of plant communities that represent the complex interaction of several <br /> ecological processes.The plant composition has been determined by study of <br /> rangeland relic areas,areas protected from excessive disturbance, seasonal use <br /> pastures,short durationitime controlled grazing strategies,and historical <br /> accounts. <br /> The Sandy Plains ecological site is characterized by fou states:Reference, <br /> Warm-Season Shortgrass,Increased Bare Ground,and Tilled State.The <br /> Reference State rs characterized by a dominance of warm-season ta$grasses <br /> (prairie sandreed,sand bluestem,and switchgrass) Warm-season shortgress <br /> (blue grana)is the primary understory species.The Warm-Season Shortgeass <br /> State is dominated by a ware-season short bunchgrass(blue grana).The <br /> Increased Bare Ground State is characterized by early successional warm- <br /> season <br /> ar—season(Fender threeawn)and cool-season short bunchgrasses(squirrebtail) <br /> and annual grasses and(orbs,The Tilled State has been mechanically disturbed <br /> by equipment and includes either a variety of reseeded warm and cool-season <br /> grasses(Seeded Community)or early successional plants as well as annual <br /> grasses and forbs(Go-Back Community). <br /> The degree of grazing has a significant impact on the ecological dynamics of the <br /> site.This region was historically occupied by large grazing animals such as bison <br /> and elk,along with pronghorn and mule deer.Grazing by these large herbivores, <br /> along with climatic fluctuations,and seasonal weather fluctuations, had a major <br /> influence on the dynamics of the ecology of this site.Deer and pronghorn are <br /> widely distributed throughout the MLRA.Secondary influences of herbivory by <br /> species such as prairie dogs and other small rodents,insects and root feeding <br /> organisms have impacted the vegetation and continues today. <br /> Historically,it is believed,grazing patterns by herds of large ungulates was driven <br /> by water distribution,precipitation events,drought events,and fire.It is believed <br /> that grazing penods would have been shorter,toltowed by longer recovery <br /> periods.These large migrating herds impacted the ecological processes of <br /> nutrient and hydrologic cycles,by urination,trampling(incorporation of litter into <br /> the soil surface),and breaking of surface crust,to increase water infiltration. <br /> This is an important site for livestock grazing,especially beet cattle.Today the <br /> management of livestock grazing by humans has been a major influence on the <br /> ecological dynamics of the site.This management,coupled with the effects of <br /> annual climatic variations,largely dictates the plant communities for the site. <br /> Prescribed grazing that mimics the historic grazing of herds of migratory <br /> herbivores,as described earlier,has been shovm to result in desired <br /> improvements based on management goals for this ecological site <br /> vas, Natural Resources Web Soil Survey 102512017 <br /> dam Conservation Service Nasional Cooperative Soil&awry Page 1 of 2 <br /> 70 <br />