Sommer Nathalie R, Dobson Annise M, Baker Matthew S, Trussell Geoffrey C, Schmitz Oswald J
School of the Environment, Yale University, New Haven, Connecticut, USA.
Department of Ecology & Evolutionary Biology, Yale University, New Haven, Connecticut, USA.
Glob Chang Biol. 2025 Jul;31(7):e70359. doi: 10.1111/gcb.70359.
Geographic variation in ecosystem function is often attributed to differences in climate and soil properties, with biophysical constraints assumed to dictate spatial patterns in nutrient cycling, carbon storage, and plant productivity. However, biotic interactions, particularly herbivory, also vary geographically and can generate feedbacks that influence ecosystem processes. Using a replicated three-year field experiment, we tested how population-level functional differences in a widespread arthropod herbivore mediate geographic variation in ecosystem function. Structural equation modeling revealed that herbivores exerted strong direct effects on plant biomass, soil carbon, and nitrogen mineralization, often surpassing the influence of historical conditions and geographic variation in climate. Moreover, functionally distinct herbivore populations had divergent effects on nutrient cycling and plant diversity, demonstrating that population-level differences introduce novel pathways of influence on ecosystem function. These findings challenge ecosystem models that prioritize abiotic constraints and highlight the need to incorporate consumer-driven feedbacks into ecological frameworks.
生态系统功能的地理差异通常归因于气候和土壤性质的不同，人们认为生物物理限制决定了养分循环、碳储存和植物生产力的空间格局。然而，生物相互作用，尤其是食草作用，在地理上也存在差异，并且会产生影响生态系统过程的反馈。通过一项为期三年的重复田间实验，我们测试了一种广泛分布的节肢动物食草动物在种群水平上的功能差异如何介导生态系统功能的地理差异。结构方程模型表明，食草动物对植物生物量、土壤碳和氮矿化有强烈的直接影响，其影响常常超过历史条件和气候地理差异的影响。此外，功能不同的食草动物种群对养分循环和植物多样性有不同的影响，这表明种群水平的差异引入了影响生态系统功能的新途径。这些发现挑战了优先考虑非生物限制的生态系统模型，并强调了将消费者驱动的反馈纳入生态框架的必要性。
