Gastropod Herbivore Preference for Seedlings of Two Native and Two Exotic Grass Species
Gastropod Herbivore Preference for Seedlings of Two Native and Two Exotic Grass Species
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DOI：
10.1674/0003-0031-163.1.106
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发表时间：
2010-01-01
影响因子：
0.6
通讯作者：
Orrock, John L.
中科院分区：
文献类型：
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作者：
Motheral, Sara M.;Orrock, John L.
食草动物可以影响草原群落的组成。我们检查了引进蜗牛 Helix aspersa 对加利福尼亚草原常见四种草的幼苗食草行为。为了评估偏好，除了将活幼苗暴露于蜗牛食草性的测试之外，还使用等量的相同年龄的幼苗进行了标准化测试。 Helix aspersa 对本地雀麦表现出最大的偏好，而本地的 Nassella pulchra 和外来的 B. hordeaceus 则中等偏爱。异国燕麦是最不受欢迎的。使用标准化和活苗试验的偏好评估产生了一致的结果，表明偏好是由于幼苗质量的变化而不是田间条件下可能存在的每幼苗生物量的差异所致。 Avena fatua 在加州草原上很常见，而 B. carinatus 则相对罕见。我们的结果表明，蜗牛对 B. carinatus 的高度偏爱和对 A. fatua 的厌恶，再加上活苗完全落叶对未来生长的严重影响，可能会加强在自然群落中观察到的这些草的定植模式。
Herbivores can affect the composition of grassland communities. We examined seedling herbivory by the introduced snail, Helix aspersa, on four grass species common in California grasslands. To assess preference, standardized tests using equal amounts of seedlings Of the same age were conducted in addition to tests in which live seedlings were exposed to snail herbivory. Helix aspersa exhibited the greatest preference for native Bromus carinatus, while native Nassella pulchra and exotic B. hordeaceus were moderately preferred. Exotic Avena fatua was least preferred. Assessment Of preference using both standardized and live Seedling trials yielded consistent results, suggesting that preference is due to variation in seedling quality rather than differences in per-seedling biomass that are likely to exist under field conditions. Avena fatua is very common in California grasslands while B. carinatus is relatively rare. Our results Suggest that the high level of snail preference for B. carinatus and aversion to A. fatua, coupled with severe effects on future growth due to complete defoliation of live seedlings, may reinforce patterns of establishment of these grasses observed in natural communities.