Record number | 443091 |
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Title | Top-down and bottom-up control of large herbivore populations: a review of natural and human-induced influences |
Author(s) | Gandiwa, E. |
Source | Tropical conservation science 6 (2013)4. - ISSN 1940-0829 - p. 493 - 505. |
Department(s) |
Resource Ecology PE&RC WASS |
Publication type | Refereed Article in a scientific journal |
Publication year | 2013 |
Keyword(s) | gonarezhou national-park - community structure - african savannas - food-web - wildlife conservation - aboriginal overkill - trophic cascades - southern africa - body-size - ecosystems |
Abstract | The question whether animal populations are top-down and/or bottom-up controlled has motivated a thriving body of research over the past five decades. In this review I address two questions: 1) how do top-down and bottom-up controls influence large herbivore populations? 2) How do human activities and control systems influence the top-down and bottom-up processes that affect large herbivore population dynamics? Previous studies suggest that the relative influence of top-down vs. bottom-up control varies among ecosystems at the global level, with abrupt shifts in control possible in arid and semi-arid regions during years with large differences in rainfall. Humans as super-predators exert top-down control on large wild herbivore abundances through hunting. However, through fires and livestock grazing, humans also exert bottom-up controls on large wild herbivore abundances through altering resource availability, which influences secondary productivity. This review suggests a need for further research, especially on the human-induced top-down and bottom-up control of animal populations in different terrestrial ecosystems. |
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