Pathways for positive cattle-wildlife interactions in semi-arid rangelands

Livestockwildlife interactions in rangelands are often viewed in terms of competition, but livestock and native ungulates can also benefit each other through longterm modifications of rangeland habitats. Here we synthesize research on rangelands in central Laikipia focusing on two types of cattlewildlife interactions that have implications for their longterm coexistence. The first interaction occurs via redistribution of soil nutrients within the ecosystem, which is a consequence of the use of bomas (temporary corrals) to manage livestock. Our studies on two different soil types show that rotational boma management creates hectarescale patches in the landscape that are enriched in soil and plant nutrients and persist for decades to centuries. In both of the predominant soil types in Laikipia, forage phosphorus content is low relative to ungulate demands during peak lactation. Nutrientrich boma sites (hereafter referred to as glades) provide a key wetseason forage resource of nutritional sufficiency for lactation. Our studies further show that a wide range of native ungulates selectively use glades relative to surrounding nutrientpoor habitats. Impala (Aepyceros melampus) in particular show intensive use of glades on sandy soils and are rare in portions of the landscape lacking glades. A second important pathway for cattlewildlife interaction occurs through the influence of native browsing ungulates on woody vegetation. Shrub and tree cover has been increasing in Laikipia over the past century, followed by increases in native browsers in recent decades on ranches where wildlife are allowed to coexist with cattle. Our exclosure experiments in central Laikipia indicate that native browsers suppress shrub encroachment on both dominant soil types. However, the strength of browser effects are three to seven times greater on sandy soils, where two browsers, dikdik and elephants, are both abundant, compared to heavy clay soils, where elephants are the only dominant browser. In the clay soils, native browsers still exert a significant influence on dynamics of the dominant tree, Acacia drepanolobium, and suppress encroachment by subdominant shrub species. Browser effects on woody vegetation likely enhance forage production for cattle and maintain open habitats favored by native grazers for predator avoidance. Taken together, our studies indicate that boma rotation and browser control of shrub encroachment are key interaction pathways that promote cattlewildlife coexistence in the Ewaso ecosystem. David J. Augustine, USDA–Agricultural Research Service, Rangeland Resources Research Unit, Fort Collins, Colorado 80526, USA. Kari E. Veblen, Department of Plant Sciences, University of California, Davis, California 95616, USA. Jacob R. Goheen, Departments of Zoology & Physiology and Botany, Laramie, Wyoming, USA 82071. Corinna Riginos, Department of Ecology, Evolution and Behavior, Princeton University, Princeton, New Jersey 08544, USA. Truman P. Young, Department of Plant Sciences, University of California, Davis, California 95616, USA. Correspondence: D. Augustine, David.Augustine@