Spatial distributions of multiple plant species affect herbivore foraging selectivity
Spatial distributions of multiple plant species affect herbivore foraging selectivity
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DOI：
10.1111/j.1600-0706.2009.17774.x
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发表时间：
2010-02
期刊：
影响因子：
3.4
通讯作者：
Ling Wang;Deli Wang;Yu-Hong Bai;Guitong Jiang;Jushan Liu;Yue Huang;Yexing Li
中科院分区：
文献类型：
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作者：
Ling Wang;Deli Wang;Yu-Hong Bai;Guitong Jiang;Jushan Liu;Yue Huang;Yexing Li
食物资源的空间分布是决定食草动物觅食的重要因素。先前的研究表明，在单物种或双物种系统中，首选物种的聚集分布增加了食草动物对其的消耗。然而，低偏好物种的分布格局对觅食的潜在影响被忽略了。在物种多样性和复杂性较高的天然草原上，偏好种的空间分布对草食动物觅食的影响可能与非偏好种的分布密切相关。我们的目的是确定在接近本地多物种觅食环境的条件下，首选植物和其他植物物种的分布对食草动物觅食的影响，并概念化食物资源空间分布与食草动物消费之间的关系。我们假设，非偏好物种的随机分布减少了偏好物种的食草动物消耗，因为不太偏好物种的分散可能会扰乱食草动物的觅食。我们以3个物种为研究对象，进行了5种聚集和随机分布模式的组合实验。羊草（Phragmites australis）和羊草（Leymus chinensis）分别是羊的高、中、低偏好种。结果表明，低偏好种的分布对偏好种的消耗有影响，而高偏好种的分布对偏好种的消耗没有影响。低偏好种呈块状分布时，绵羊对高偏好种的食用量高于随机分布。高偏好种和低偏好种聚集的距离不影响绵羊的觅食。综上所述，偏好物种的空间分布对其食用量的影响依赖于食草动物的觅食策略，当偏好物种与整个食物资源之间的空间格局一致时，绵羊会消耗更多的偏好物种，而低偏好物种在草地上的随机分散可能会减少高偏好物种的食用量，从而最大限度地减少选择性放牧。
Spatial distribution of food resources is an important factor determining herbivore foraging. Previous studies have demonstrated that clumped distribution of preferred species increases its consumption by herbivores in single- or two-species systems. However, the potential impact of distribution pattern of less preferred species on foraging was ignored. In natural grasslands with high species diversity and complexity, the spatial distribution of preferred species impacts on herbivore foraging may be strongly correlated with the distribution of less preferred species. Our aims were to determine the effect of distribution of both preferred and other plant species on herbivore foraging under conditions close to a native, multi-species foraging environment, and conceptualize the relationships between spatial distribution of food resources and herbivore consumption. We hypothesized that random distribution of non-preferred species reduces herbivore consumption of preferred species because the dispersion of less preferred species likely disturbs herbivore foraging. We conducted an experiment using three species with five combinations of clumped and random distribution patterns. Three species Lathyrus quinquenervius, Phragmites australis and Leymus chinensis, were of high, intermediate and low preferences by sheep, respectively. Results showed that distribution of low preferred species, but not that of high preferred one, affected the consumption of preferred species. Sheep obtained higher consumption of high preferred species when low preferred species followed a clumped distribution than a random distribution. Distance between aggregations of high and low preferred species did not affect sheep foraging. It was concluded that the effects of spatial distribution of preferred species on its consumption are dependent on herbivore foraging strategy, and sheep can consume more preferred species when there is a consistent spatial pattern between preferred species and the entire food resource, and that the random dispersion of low preferred species in grassland may reduce herbivore consumption of high preferred species, thus minimizing selective grazing.