Grazing management recommendations often sacrifice the intrinsic heterogeneity of grasslands by prescribing uniform grazing distributions through smaller pastures, increased stocking densities, and reduced grazing periods. The lack of patch‐burn grazing in semi‐arid landscapes of the western Great Plains in North America requires alternative grazing management strategies to create and maintain heterogeneity of habitat structure (e.g., animal unit distribution, pasture configuration), but knowledge of their effects on grassland fauna is limited. The lesser prairie‐chicken (Tympanuchus pallidicinctus), an imperiled, grassland‐obligate, native to the southern Great Plains, is an excellent candidate for investigating effects of heterogeneity‐based grazing management strategies because it requires diverse microhabitats among life‐history stages in a semi‐arid landscape. We evaluated influences of heterogeneity‐based grazing management strategies on vegetation structure, habitat selection, and nest and adult survival of lesser prairie‐chickens in western Kansas, USA. We captured and monitored 116 female lesser prairie‐chickens marked with very high frequency (VHF) or global positioning system (GPS) transmitters and collected landscape‐scale vegetation and grazing data during 2013–2015. Vegetation structure heterogeneity increased at stocking densities ≤0.26 animal units/ha, where use by nonbreeding female lesser prairie‐chickens also increased. Probability of use for nonbreeding lesser prairie‐chickens peaked at values of cattle forage use values near 37% and steadily decreased with use ≥40%. Probability of use was positively affected by increasing pasture area. A quadratic relationship existed between growing season deferment and probability of use. We found that 70% of nests were located in grazing units in which grazing pressure was <0.8 animal unit months/ha. Daily nest survival was negatively correlated with grazing pressure. We found no relationship between adult survival and grazing management strategies. Conservation in grasslands expressing flora community composition appropriate for lesser prairie‐chickens can maintain appropriate habitat structure heterogeneity through the use of low to moderate stocking densities (<0.26 animal units/ha), greater pasture areas, and site‐appropriate deferment periods. Alternative grazing management strategies (e.g., rest‐rotation, season‐long rest) may be appropriate in grasslands requiring greater heterogeneity or during intensive drought. Grazing management favoring habitat heterogeneity instead of uniform grazing distributions will likely be more conducive for preserving lesser prairie‐chicken populations and grassland biodiversity. © 2021 The Wildlife Society.

中文翻译：

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使用放牧管理异质性鸟类的草本结构

放牧管理建议通常通过规定较小牧草的均匀放牧分布，增加放养密度和缩短放牧周期来牺牲草原的内在异质性。北美大平原西部半干旱地区缺乏斑块放牧，需要其他放牧管理策略来创造和维持生境结构的异质性（例如，动物单位分布，牧场配置），但要知道它们对栖息地的影响草原动物有限。小草原鸡（Tympanuchus pallidicinctus）是一个濒临灭绝的草原，原产于大平原南部，是研究基于异质性的放牧管理策略效果的极佳人选，因为它需要半干旱景观中生活史各阶段的不同微生境。我们评估了基于异质性放牧管理策略对美国西部堪萨斯州小草原鸡的植被结构，生境选择以及巢和成年存活的影响。我们在2013–2015年期间捕获并监测了116个标有甚高频（VHF）或全球定位系统（GPS）发射器的雌性小草原鸡，并收集了景观尺度的植被和放牧数据。放牧密度≤0.26动物单位/公顷时，植被结构异质性增加，非繁殖雌性小草原土鸡的使用也增加。非繁殖小草原土鸡的使用概率在牛饲草使用值接近37％时达到峰值，而使用率≥40％则稳定下降。牧场面积的增加对使用的可能性产生了积极的影响。生长季节延迟与使用概率之间存在二次关系。我们发现，有70％的巢位于放牧压力小于0.8动物单位月/公顷的放牧单元中。每天的巢生存与放牧压力负相关。我们发现成年人的生存与放牧管理策略之间没有关系。通过使用低至中度的放养密度（<0.26动物单位/公顷），较大的牧场面积，表达适合小草原鸡的植物群落组成的草原保护区可以维持适当的栖息地结构异质性。以及适当的站点延迟时间。在要求更大异质性的草原上或在严重干旱期间，可以采用其他放牧管理策略（例如轮作，长期休息）。有利于栖息地异质性而非统一放牧分布的放牧管理可能更有利于保护较少的草原养鸡种群和草地生物多样性。©2021野生动物协会。