Departamento de Zoología, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain.
Philos Trans R Soc Lond B Biol Sci. 2012 Nov 19;367(1606):3115-24. doi: 10.1098/rstb.2011.0346.
Individual species respond to climate change by altering their abundance, distribution and phenology. Less is known, however, about how climate change affects multitrophic interactions, and its consequences for food-web dynamics. Here, we investigate the effect of future changes in rainfall patterns on detritivore-plant-herbivore interactions in a semiarid region in southern Spain by experimentally manipulating rainfall intensity and frequency during late spring-early summer. Our results show that rain intensity changes the effect of below-ground detritivores on both plant traits and above-ground herbivore abundance. Enhanced rain altered the interaction between detritivores and plants affecting flower and fruit production, and also had a direct effect on fruit and seed set. Despite this finding, there was no net effect on plant reproductive output. This finding supports the idea that plants will be less affected by climatic changes than by other trophic levels. Enhanced rain also affected the interaction between detritivores and free-living herbivores. The effect, however, was apparent only for generalist and not for specialist herbivores, demonstrating a differential response to climate change within the same trophic level. The complex responses found in this study suggest that future climate change will affect trophic levels and their interactions differentially, making extrapolation from individual species' responses and from one ecosystem to another very difficult.
各个物种通过改变其丰度、分布和物候来应对气候变化。然而，人们对于气候变化如何影响多营养级相互作用及其对食物网动态的影响知之甚少。在这里，我们通过在西班牙南部半干旱地区的春末夏初期间实验性地改变降雨强度和频率，研究了未来降雨模式变化对碎屑食者-植物-草食者相互作用的影响。我们的结果表明，降雨强度改变了地下碎屑食者对植物特征和地上草食者丰度的影响。增强的降雨改变了碎屑食者与植物之间的相互作用，影响了花和果实的产量，并且对果实和种子的形成也有直接影响。尽管有此发现，但对植物繁殖的总产出没有净影响。这一发现支持了这样一种观点，即与其他营养级相比，植物受气候变化的影响较小。增强的降雨也影响了碎屑食者和自由生活的草食者之间的相互作用。然而，这种影响仅对一般的而非专门的草食者明显，表明在同一营养级内对气候变化有不同的反应。本研究中发现的复杂反应表明，未来的气候变化将以不同的方式影响营养级及其相互作用，使得从单个物种的反应和从一个生态系统到另一个生态系统进行推断变得非常困难。
