Kenya Long-term Exclosure Experiment

Over 70% of the land area of Africa is arid or semi-arid. Rapidly growing populations and ongoing economic development are putting tremendous pressures on these lands (Bernard et al. 1989). These pressures can result in local, regional, and global problems, including soil erosion, threats to endangered species such as elephants and rhinos, and desertification, with its potential effects on global warming. In response to these serious problems, the Government of Kenya (through the National Museums and the Kenya Wildlife Service) is collaborating with the Smithsonian Institution and Princeton University to establish a research and training center for arid ecosystem studies. This center is located on Mpala ranch, a 45,000 acre property in the center of the Laikipia Plateau in Kenya. The goal of this center is to provide the information, expertise, and training that will allow Kenya (and other nations in the region) to wisely manage, develop, and conserve their arid land resources. For virtually all indigenous animal species in Kenya, there are more individuals outside protected areas than inside them, mostly on arid and semi-arid lands. The future of these populations will depend on the interaction between enlightened rangeland management and wildlife needs. There is growing evidence that many wildlife species are not incompatible with intensive livestock production, and can even be beneficial. Also, wildlife can provide much needed additional revenue in the form of tourism or game ranching. A mixed strategy of wildlife and cattle may be optimal, both for economic return and for the maintenance of biodiversity. There is considerable literature on the effects of various cattle grazing and burning strategies on range quality in Africa, and on the effects of indigenous herbivores on the vegetation of protected areas. However, almost little is known about the interactions among wildlife, domestic stock, and vegetation, and there have been no controlled experimental studies of the separate and combined effects of wild and domestic herbivores on vegetation and on each other. This information is vital if we are to make informed decisions about the future of wildlife on the vast unprotected grazing lands of Africa. We are engaged in a long-term experimental study of these interactions at the Mpala Research Centre in Laikipia, a working cattle ranch and an area rich in wildlife. For example, the Laikipia ecosystem has the second largest population of elephants in Kenya; as many as 900 elephants periodically occur on Mpala. There are also at least twenty additional species of large indigenous mammals.非洲陆地面积逾七成属于干旱或半干旱区域。快速增长的人口与持续推进的经济发展，正给这些区域带来巨大压力（Bernard等，1989）。这些压力可能引发局部、区域乃至全球性的问题，包括土壤侵蚀、对大象、犀牛等濒危物种的生存威胁，以及可能加剧全球变暖的荒漠化问题。 针对这些严峻问题，肯尼亚政府（通过国家博物馆及肯尼亚野生动物管理局）正与史密森学会、普林斯顿大学合作，建立干旱生态系统研究与培训中心。该中心坐落于肯尼亚莱基皮亚高原中部的姆帕拉牧场，这片牧场占地4.5万英亩。 该中心的目标是提供相关信息、专业技术与培训，助力肯尼亚（及该区域其他国家）科学合理地管理、开发并保护其干旱土地资源。 在肯尼亚，几乎所有本土动物物种的个体数量在保护区外均多于保护区内，且这些个体大多栖息于干旱与半干旱区域。这些种群的未来，将取决于科学合理的牧场管理与野生动物生存需求之间的协同平衡。 越来越多的研究证据表明，诸多野生动物物种与集约化畜牧生产并非互斥，甚至可能带来益处。此外，野生动物还可通过旅游业或野生动物牧场经营的形式，创造亟需的额外收入。兼顾野生动物与畜牧的混合策略，无论在经济收益还是生物多样性维护层面，都可能是最优选择。 目前已有大量文献探讨非洲地区不同畜牧放牧与焚烧策略对牧场质量的影响，以及本土草食动物对保护区植被的作用。然而，关于野生动物、家畜与植被之间的相互作用，我们却知之甚少；同时，也尚未有受控实验研究，分别或联合探究野生与家养草食动物对植被及彼此的影响。 若要针对非洲广袤无保护的牧场上的野生动物未来制定合理决策，这类信息至关重要。我们目前正于莱基皮亚的姆帕拉研究中心开展一项长期实验研究，以探究这些相互作用。该区域既是运营中的畜牧牧场，同时也是野生动物资源丰富的区域。例如，莱基皮亚生态系统拥有肯尼亚第二大象群，姆帕拉牧场定期会有多达900头大象栖息。此外，这里还至少存在20种其他大型本土哺乳动物。