CRB: Elephant Browsing and Patch Dynamics in a Colophospermum mopane African Savanna

在从亚北极针叶林到热带热带稀树草原和林地的生物1中，哺乳动物的选择性觅食可以改变植被的组成和多样性，从而改变营养循环的速度。该项目的目标是了解这一过程，因为它对健全的生态系统管理至关重要。将研究津巴布韦赞比西河地区稀树草原林地中食性哺乳动物(特别是大象)、植被和营养循环之间的相互作用。之所以选择这个系统，是因为1)它是更普遍的哺乳动物-植被-营养循环问题的经典例子，2)非洲象与其栖息地之间的相互作用本身就是国际保护的主要问题，3)津巴布韦公园和野生动物部大力支持这个项目，4)美国国际开发署(USAID)资助了这项研究的营养循环部分。具体地说，将研究非洲主要植被类型之一和关键栖息地--罗勒香草林地的觅食模式。大象的重复取食是影响莫帕内灌丛和林地斑块动态的主要自然干扰形式，因为大象重复取食一些莫帕内斑块而不是其他斑块，导致重复取食斑块的植被退化。这项提案将测试大象重新浏览莫帕内的3种替代解释：1)首选斑块附近的土壤钠富集，2)土壤营养(如氮)富集性，或3)浏览斑块接近传统的旅行路径，如水或矿物舔。

In biomes1 ranging from subarctic taiga forests to tropical savannas and woodlands, selective browsing by mammals can alter the composition and diversity of vegetation and, as a result, the rate of nutrient cycling. The objective of this project is to gain an understanding of this process, because it is of critical importance to sound ecosystem management. The interaction between browsing mammals (specially elephant), vegetation, and nutrient cycling in the savanna-woodlands of the Zambezi River Region of Zimbabwe will be studied. This system was selected because 1) it is a classic example of the more general mammal-vegetation-nutrient cycling problem, 2) the interaction between the African elephant and its habitat is, in its own right, of major concern to international conservation, 3) the Zimbabwe Department of Parks and Wildlife is strongly supporting this project, and 4) The United States Agency for International Development (USAID) has funded the nutrient cycling portion of this study. Specifically, patterns of browsing in the Colophospermum mopane woodlands, one of Africa's major vegetation types and a critical habitat will be studied. Repetitive browsing by elephant is the major form of natural disturbance influencing patch dynamics in mopane scrub and woodland, because elephant repeatedly browse some patches of mopane in preference to others with the results that the vegetation of repetitively browsed patches is degraded. This proposal will test 3 alternative explanations of the rebrowsing of mopane by elephant 1) sodium enrichment of the soil in the vicinity of preferred patches, 2) nutrient (e.g. nitrogen) enrichment of the soil, or 3) proximity of browsed patches to traditional paths of travel to focal resources such as water or mineral licks.