Cleland Elsa E, Peters Halton A, Mooney Harold A, Field Christopher B
Department of Biological Sciences, Stanford University, Stanford, California 94305, USA.
Ecology. 2006 Mar;87(3):686-94. doi: 10.1890/05-0529.
In this study, the influence of elevated carbon dioxide (CO2) and nitrogen (N) deposition on gastropod herbivory was investigated for six annual species in a California annual grassland community. These experimentally simulated global changes increased availability of important resources for plant growth, leading to the hypothesis that species with the most positive growth and foliar nutrient responses would experience the greatest increase in herbivory. Counter to the expectations, shifts in tissue N and growth rates caused by N deposition did not predict shifts in herbivore consumption rates. N deposition increased seedling N concentrations and growth rates but did not increase herbivore consumption overall, or for any individual species. Elevated CO2 did not influence growth rates nor have a statistically significant influence on seedling N concentrations. Elevated CO2 at ambient N levels caused a decline in the number of seedlings consumed, but the interaction between CO2 and N addition differed among species. The results of this study indicate that shifting patterns of herbivory will likely influence species composition as environmental conditions change in the future; however, a simple trade-off between shifting growth rates and palatability is not evident.
在本研究中，针对加利福尼亚一年生草地群落中的六个一年生物种，研究了二氧化碳（CO₂）浓度升高和氮（N）沉降对腹足类食草动物的影响。这些实验模拟的全球变化增加了植物生长所需重要资源的可利用性，从而引出这样一个假设：生长和叶片养分反应最积极的物种，其食草率的增加幅度最大。与预期相反，氮沉降导致的组织氮含量和生长速率变化并不能预测食草动物消耗率的变化。氮沉降增加了幼苗的氮浓度和生长速率，但总体上并未增加食草动物的消耗率，对任何单个物种也是如此。二氧化碳浓度升高既不影响生长速率，对幼苗氮浓度也没有统计学上的显著影响。在环境氮水平下，二氧化碳浓度升高导致被消耗幼苗数量减少，但二氧化碳和氮添加之间的相互作用因物种而异。本研究结果表明，随着未来环境条件的变化，食草模式的转变可能会影响物种组成；然而，生长速率变化和适口性之间并没有明显的简单权衡关系。
