Dimensionality of consumer search space drives trophic interaction strengths

摘要

一个食物链中不同生物的进食习惯之间的相互作用(即营养相互作用)可以按二维或三维形式来发生，而很多群落二者皆有。本文作者发现，营养相互作用强度与身体大小之间的关系在二维中遵从“亚线性”规律，但在三维中则遵从“超线性”规律。他们还建立了一个模型，来显示这种现象何以能够解释如水生生态rn系统和陆地生态系统之间的差别，因为额外的维度提供了一个可以从中寻找资源的额外生境或机会。作为另一个例子，该模型还预测，对觅食的加拉帕戈斯岛海狮来说，它们的进食量在接近海洋表面的一个浮游区(三维环境)要比在海洋底部的一个海底区(二维环境)大近30倍。%Trophic interactions govern biomass fluxes in ecosystems, and stability in food webs. Knowledge of how trophic interaction strengths are affected by differences among habitats is crucial for understanding variation in ecological systems. Here we show how substantial variation in consumption-rate data, and hence trophic interaction strengths, arises because consumers tend to encounter resources more frequently in three dimensions (3D) (for example, arboreal and pelagic zones) than two dimensions (2D) (for example, terrestrial and benthic zones). By combining new theory with extensive data (376 species, with body masses ranging from 5.24 × 10~-(14) kg to 800 kg), we find that consumption rates scale sublinearly with consumer body mass (exponent of approximately 0.85) for 2D interactions, but superlinearly (exponent of approximately 1.06) for 3D interactions. These results contradict the currently widespread assumption of a single exponent (of approximately 0.75) in consumer-resource and food-web research. Further analysis of 2,929 consumer-resource interactions shows that dimensionality of consumer search space is probably a major driver of species coexistence, and the stability and abundance of populations.