Landscape scale, heterogeneity, and the viability of Serengeti grazers
Landscape scale, heterogeneity, and the viability of Serengeti grazers
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DOI：
10.1111/j.1461-0248.2005.00727.x
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发表时间：
2005-03-01
期刊：
影响因子：
8.8
通讯作者：
Abrams, PA
中科院分区：
文献类型：
--
作者：
Fryxell, JM;Wilmshurst, JF;Abrams, PA
随着时间的推移，食物资源的大量时间变化可能会威胁到物种的持久性。另一方面，在景观尺度上的资源的空间异质性可能会允许移动的消费者，以弥补在当地规模的资源可用性的时间变化。我们评估了这一假设，使用广泛的数据集觅食，草的生长和运动汤姆森的瞪羚生活在塞伦盖蒂平原。在这里，我们表明，建模种群的汤姆森瞪羚只能坚持在塞伦盖蒂条件下，面对观察到的降雨随机性水平，通过适应性运动，以利用短暂的空间分布的食物资源。更重要的是，我们的模型表明，塞伦盖蒂的汤姆森瞪羚需要不受限制地进入相对较大的草原面积（> 1600 km（2）），以保证长期的持久性，特别是当资源丰度存在正的空间自相关时，就像塞伦盖蒂的情况一样。如果这被证明是真实的其他物种和/或其他系统，然后了解复杂的行为反应的空间和时间异质性的食物供应可能是必不可少的成功保护放牧食草动物。
Species persistence can be threatened by substantial temporal variation in food resources over time. On the other hand, spatial heterogeneity in resources at the landscape scale might allow mobile consumers to compensate for temporal variability in resource availability at the local scale. We evaluated this hypothesis, using an extensive data set on foraging, grass growth, and movement by Thomson's gazelles living on the Serengeti Plains. Here we show that modelled populations of Thomson's gazelles can only persist under Serengeti conditions in the face of observed levels of rainfall stochasticity by making adaptive movements to take advantage of ephemeral spatial distributions of food resources. More importantly, our models suggest that Thomson's gazelles in Serengeti require unrestricted access to relatively large areas of grassland (> 1600 km(2)) to guarantee long-term persistence, particularly when there is positive spatial autocorrelation in resource abundance, as is the case in Serengeti. If this proves to be true for other species and/or other systems, then understanding of complex behavioural responses to spatially and temporally heterogeneous food supplies may be essential to successful conservation of grazing herbivores.