2022-04-04_PERMIT FILE - M2022013 (37)

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of a dynamic set of plant communities that represent the complex interaction of several ecological processes. The plant composition has been determined by study of rangeland relic areas, areas protected from excessive disturbance, seasonal use pastures, short duration/time controlled grazing strategies, and historical accounts. The Salt Meadow Ecological Site is characterized by three states: Reference, Warm-Season Shortgrass, and Increased Bare Ground State. The Reference State is characterized by warm-season bunchgrass (alkali sacaton, switchgrass), cool-season midgrass (western wheatgrass), warm-season tall rhizomatous grass, and a minor component of cool-season grasslike (Nebraska sedge). The Warm-Season Shortgrass State is characterized by a warm-season short rhizomatous grass (inland saltgrass). The Increased Bare Ground State is characterized by early successional cool-season grass (foxtail barley), annual grasses, and annual forbs. The site has a high water table throughout the growing season. The availability of water has a major influence on the vegetation that will persist on this site. This region was historically occupied by large grazing animals such as bison and elk, along with pronghorn and mule deer. Grazing by these large herbivores, along with climatic fluctuations, had a major influence on the ecological dynamics of this site. Deer and pronghorn are widely distributed throughout the MLRA. Secondary influences of herbivory by species such as prairie dogs and other small rodents, insects and root feeding organisms has impacted the vegetation and continues today. Historically, it is believed, due to the migratory nature of large ungulates, herbivory consisted of very short grazing events followed by long rest/recovery periods lasting several months or longer. These migrating herds significantly impacted the ecological processes of nutrient and hydrologic cycles. Herd behavior and movements were likely affected by water and forage availability, fire, drought, and predators. Recurrent drought has historically impacted the vegetation of this region. Changes in species composition will vary depending upon the duration and severity of the drought cycle, and prior grazing management. Recent drought events have significantly increased mortality of blue grama in some locales. Tillage or any type of mechanical treatment is not recommended on this site due to the salt content of the soils and the presence of a high water table. Disturbance of any kind will cause Inland saltgrass to increase. Irrigation (pumping) or drainage will cause water table levels to drop. Persistent water table alteration or drainage causes a complete alteration and/or disruption of the hydrologic function and biotic integrity resulting in the crossing of an ecological threshold and the replacement of the natural states and plant communities applicable to the site. This site developed with occasional fire as part of the ecological processes. Historic fire frequency (pre-industrial), is estimated at 10-14 years (Guyette 2012), randomly distributed, and started by lightning at various times throughout the growing season. It is thought that early human inhabitants also were likely to start fires for various reasons (deliberate or accidental). It is believed that fires were set as a management tool for attracting herds of large migratory herbivores (Stewart, 2002). The impact of fire over the past 100 years has been relatively insignificant due to the human control of wildfires and the lack of acceptance of prescribed fire as a management tool. Today, this is an important site for livestock grazing, especially beef cattle. Today the management of livestock grazing by humans has been a major influence on the ecological dynamics of the site. This management, coupled with the effects of annual climatic variations, largely dictates the plant communities for the site. Continuous grazing without adequate recovery opportunity following each grazing occurrence will cause prairie cordgrass, switchgrass, alkali sacaton and eventually western wheatgrass to decrease in frequency and production while inland saltgrass and Baltic rush increase. In time, the plant community will become dominated by inland saltgrass and develop into a sodbound condition with alkali sacaton and western wheatgrass persisting in remnant amounts. Heavy continuous grazing will ultimately result in a plant community dominated by foxtail barley, annual invaders and increased bare ground. Excessive litter, plant mortality and decadence can result from the lack of fire and/or non-use.