Western Winter 2014 Issue 01 NATURAL RESOURCE SCIENCE AND MANAGEMENT IN THE WEST The Bird that Brought the West Together Cattle as Ecosystem Engineers The Ecology of Fear A publication of the Ruckelshaus Institute, a division of the University of Wyoming’s Haub School of Environment and Natural Resources NEW PERSPECTIVES Cattle as ecosystem New grazing management enhances rangeland biodiversity By Justin D. Derner, David J. Augustine and Emily production,1, 2, as they optimize both weight MANAGING FOR DIVERSITY J. Kachergis gain per animal and per acre. Producers have an What is vegetation heterogeneity? Livestock economic incentive to efectively use available limate, soils, topography, grazing, and can engineer rangelands to produce diferences forage and convert it to pounds of weight gain fre have shaped the composition and in vegetation structure and composition. For as the well-established market-driven system structure of vegetation on rangelands example, intensive grazing in one area may result emphasizes price per pound. However, the Cin the American West. Collectively, the many in higher amounts of bare ground, which benefts resulting “sameness” of vegetation composition possible combinations of these diferent factors species such as the mountain plover. Resting a and structure, due to the application of similar should lead to diverse plant communities and nearby area will allow the forage to grow taller, management across large land areas, has associated diverse wildlife species. Diferences providing nesting habitat for grassland species triggered the demise of many grassland birds as in vegetation structure (i.e., how tall above the such as the pintail, or in sagebrush, the sage well as reduced biodiversity. As a result, many soil surface the plants are) and composition grouse. Tis alternative approach to management of the “species of concern” on rangelands of the (kind and amounts of diferent plants) are both increases percentages of the landscape with American West live on landscapes that have important for biodiversity. short and tall vegetation structure. Possible litle variation of vegetation composition and Yet, many rangelands across the American tradeofs with livestock production merit structure. For example, the mountain plover, West have been managed through similar grazing additional investigation to provide economic adapted for breeding on bare ground, and the management practices so that extensive areas of valuations for the “costs” of providing vegetation lark bunting and western meadowlark, adapted vegetation have comparable kinds and amounts heterogeneity.3 for high cover areas, have been declining on of plant species (e.g., same grasses, forbs and Livestock can engineer diferences in semiarid rangelands. shrubs; vegetation composition). As a result, the vegetation structure and composition within Incentivizing ranchers to increase lack of many diferent plant communities can the framework of most current management diferences in vegetation composition and result in few diferences in height of vegetation practices. For example, ranchers can alter timing structure on rangelands of the American West (or vegetation structure), which are ofen needed and intensity of grazing, length of rest periods, and will require 1) understanding how livestock can by grassland birds. Tis lack of vegetation type of livestock to create diferent levels in height be used as tools to engineer rangelands for both diversity can translate to a lack of habitat of vegetation and kind and amount of plants. provision of ecosystem goods (e.g., livestock diversity and biological diversity on these lands. Ranchers can control when livestock graze certain production) and services (e.g., wildlife habitat, Rangeland plant communities ofen areas, for how long, and how much vegetation is water quality and quantity, soil health, carbon appear uniform or unvaried due to the fact that lef ungrazed (to a certain height or residue level) sequestration and storage), 2) determining ranchers have an economic incentive to graze following a grazing period. Trough management ecosystem services’ economic values, and 3) their livestock using management practices that decisions, ranchers vary the length of rest periods creating proper economic incentives that will emphasize “management to the middle” and from relatively short (weeks-months) to long (one foster vegetation&and greater biological& “avoidance of the extremes.” Tese management year or greater). Longer rest periods stockpile diversity. practices are sustainable for livestock forage resulting in greater vegetation heights. 10 10 Western Western Confluence Confluence Cattle as ecosystem engineers Western CConfluenceonfluence 11 Varying the time of grazing across years or stocking rates can shif vegetation composition. Combining diferent types of livestock, such as cow-calf pairs, yearlings, sheep, goats, or combinations of these, can strategically engineer the vegetation on rangelands due to diferent diet selections. Combining grazing with prescribed fre in the Great Plains portion of the American West modifes the amount of bare soil, forage quality and quantity, vegetation structure and, in some cases, reduces unwanted species, such as prickly pear cactus or broom snakeweed (dry areas) or smooth brome (tallgrass prairie).4, 5 Burning patches within pastures encourages livestock to graze recently burned areas where forage quality is higher. In addition, less grazing activity will occur in the non-burned parts of the pastures, which results in more vegetation structure. Tis creates a greater range of vegetation structure in pastures with patch burns, compared to those pastures managed similarly but without prescribed fre. Combining fre and grazing in the Great Plains, does not, however, consistently create vegetation heterogeneity.6 Sites where the combination works efectively are those where fre is the primary driver of livestock grazing behavior, such as the tallgrass prairie. In addition, some invasive plant species, such as Photos representing vegetation heterogeneity created by engineering rangelands using livestock through diferences in season and intensity of grazing in shortgrass steppe. Areas with high bare ground and limited plant cover were created by very heavy grazing cheatgrass in the Great Basin and in early spring (upper lef), heavy grazing in summer created areas of very short structure (lower lef), light grazing in the winter Lehmann lovegrass in the Southwest resulted in saltbush-dominated vegetation with more diverse vegetation structure (upper right), and diverse forb and grass species deserts, thrive following burns, so are enhanced with light grazing during the summer (lower right).16, 17, 18, 19, 20 inclusion of fre as a management tool without consideration of the inherent result in taller vegetation structure due of grazing, as well as dung and urine risks associated with increasing ECOSYSTEM SERVICES to an absence of grazing. However, deposition within a pasture, but vegetation heterogeneity in these AND LIVESTOCK this requires some fexibility in the with an overall objective of creating ecosystems is not recommended.7 PRODUCTION livestock enterprise to accommodate diferences among pastures and For these rangeland ecosystems of this strategy. Livestock and vegetation across years. Grazing animals for a Achieving both provision of the intermountain west and desert management require fexibility to shorter time period, in diferent times ecosystem services and maximal southwest, fre can result in 1) large- incorporate prior use paterns, and of the year and sequences across livestock production at the same scale conversions of native plant current and near-future grazing plans, years will increase diferences in time on ranches is difcult. On communities to invasive plants, and into the overall management plan. vegetation composition and structure. one hand, there is high demand to 2) altered fre regimes with fres Tis fexibility can involve using Temporary electric fencing can increase production of livestock becoming more frequent. livestock as ecosystem engineers by subdivide existing pastures to provide to feed an ever-expanding world Taller vegetation can be atained 8 puting more animals on a unit of more control of livestock grazing for population. On the other hand, by grazing an area and then not land area, but for a shorter time. Tis these shorter time periods of grazing there is growing societal desire for coming back to graze again for an will decrease the selectivity of grazing and longer periods of no grazing. rangelands to provide a suite of extended period. For example, rest 9 animals but increase the uniformity ecosystem services. Fundamental to periods greater than one year generally these challenges is the stark reality 12 Western Confluence NEW PERSPECTIVES that a developed economic market of vegetation heterogeneity. Rather, management practices and associated these commodities for the rancher, as system drives livestock production judicious approaches that take decision-making processes are driven well as for the general public, should whereas markets have yet to emerge advantage of pre-existing templates of to maximize livestock production.15 provide the foundation on which to for ecosystem services. Te benefts heterogeneity of soils or topography Tis has led to increasing the foster more engineering of rangeland of providing these services have yet to can start the process. Changes in “sameness” of vegetation composition vegetation by livestock. be