Livestock distribution in extensive rangelands of North America can present management challenges to land managers. Understanding the role of topography on livestock distribution, within and across diverse rangeland ecosystems, could provide land managers valuable information for adaptive management of livestock to address both conservation and production goals from these ecosystems. Here, we examine the influence of topography on grazing distribution unevenness and intensity of use of beef cattle in seven rangeland ecosystems spanning arid, semiarid, and subtropical environments. We focused on grazing distribution during the late growing season (summer and autumn) periods when topographic variation in rangelands is more coupled to low and nonuniform availability of high-quality forage. Pasture size and water sources strongly influence grazing distribution across ecosystems. High unevenness of grazing occurred in pastures with extensive distances to water, low stock density, and more rugged topography. Conversely, more uniform grazing distribution occurred in smaller, well-watered pastures that support higher stock density (animals per unit area) and gentler terrain. Comparison of two topographic indices, topographic wetness index and topographic position class index, in terms of their ability to predict cattle grazing distribution, revealed that categorical topographic position classes were more effective. For most arid and semiarid rangelands, livestock grazing distributions showed affinities for lowlands and flat plains compared with open slopes and uplands. In contrast to drier rangelands, livestock grazing distributions exhibited preference for upland and sloped areas of subtropical pastures, as low-lying areas with water-inundation likely curtailed selection. Across these diverse rangeland ecosystems of North America, results provide benchmark information on livestock grazing distribution to formulate improvements in adaptive management and decision making and incorporate technological advancements in precision livestock management to integrate abiotic environmental information with spatial movements of livestock and temporal vegetation dynamics.

在北美广泛的牧场中分发牲畜可能给土地管理员带来管理方面的挑战。了解地形在不同牧场生态系统内部和之间的作用，可以为土地管理者提供有价值的信息，以适应性管理牲畜，从而解决这些生态系统的保护和生产目标。在这里，我们研究了地形对七个干旱，半干旱和亚热带环境的牧场生态系统中放牧分布不均和肉牛使用强度的影响。我们专注于生长后期（夏季和秋季）的放牧分布，当时牧场的地形变化与高质量草料的低利用率和不均匀利用率更加相关。牧场规模和水源强烈影响整个生态系统的放牧分布。与水距离较远，牲畜密度低且地形崎不平的牧场发生高度放牧不均。相反，在较小的，灌溉良好的牧草中分布的牧草分布更均匀，这些牧草支持较高的牲畜密度（每单位面积的动物）和较平缓的地形。比较两个地形指数，即地形湿度指数和地形位置等级指数，就其预测牛群放牧分布的能力而言，表明分类地形位置等级更为有效。对于大多数干旱和半干旱牧场，与开阔的斜坡和高地相比，牲畜的放牧分布显示出对低地和平坦平原的亲和力。与较干旱的牧场相比，牲畜放牧分布对亚热带牧场的高地和斜坡地区表现出偏爱，因为水淹的低洼地区可能会限制选择。在北美这些多样化的牧场生态系统中，研究结果提供了关于牲畜放牧分布的基准信息，以制定适应性管理和决策方面的改进，并在精确牲畜管理中纳入技术进步，以将非生物环境信息与牲畜的空间运动和时空植被动态结合起来。