Establishment of large-scale herbivore exclosures

点击翻译按钮获取中文摘要

Although we sometimes possess detailed knowledge about the causes of extinction, a dearth of information exists regarding its consequences for ecological systems. My research group and I work to understand how extinctions of large herbivores affect plant populations in African savannas. Our study sites in Laikipia, Kenya comprise an ideal system in which to study the ramifications of such extinctions. Laikipia consists of a 10,000 square km mosaic of private properties, where each property is associated with one of three scenarios reflecting the progressive, size-biased extinction typical of vertebrate communities: 1) elephant (~3000 kg) + impala (~70 kg) + dik-dik (~5 kg); 2) impala + dik-dik; or 3) dik-dik only. Worldwide, the impacts of herbivory often depend on abiotic factors, and high spatial variation in rainfall throughout East Africa obfuscates the drivers of plant population dynamics. Thus, the first step toward addressing these issues is to experimentally disentangle the relative roles of large herbivores, rainfall, and their interactions in shaping plant populations. This funding request is being submitted simultaneously with an NSERC Discovery Grant proposal. In my Discovery proposal, I seek partial support for a single set of electrified fences to simulate the aforementioned extinction scenarios stemming from land-use practices in East Africa. In this Research Tools and Instruments proposal, I seek funding for the construction of two additional sets of herbivore exclosures to be established along a natural gradient of rainfall in Laikipia. Because impacts of herbivory depend on rainfall, any conclusions about the consequences of herbivore extinction for plants would be restricted to areas receiving similar amounts of rainfall to the first set of exclosures. Thus, additional exclosures would allow us to explicitly address the role of rainfall in driving plant populations, and thus permit the generation of robust predictions under different scenarios of herbivore extinction, land use, and climate change. These exclosures will comprise the foundation upon which my research program at UBC will be built, where I anticipate training many Canadian graduate and undergraduate students throughout my professional career.