Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
Am Nat. 2012 Oct;180(4):E110-26. doi: 10.1086/667577. Epub 2012 Aug 24.
Understanding biodiversity gradients is a long-standing challenge, and progress requires theory unifying ecology and evolution. Here, we unify concepts related to the speed of evolution, the influence of species richness on diversification, and niche-based coexistence. We focus on the dynamics, through evolutionary time, of community invasibility and species richness across a broad thermal gradient. In our framework, the evolution of body size influences the ecological structure and dynamics of a trophic network, and organismal metabolism ties temperature to eco-evolutionary processes. The framework distinguishes ecological invasibility (governed by ecological interactions) from evolutionary invasibility (governed by local ecology and constraints imposed by small phenotypic effects of mutation). The model yields four primary predictions: (1) ecological invasibility declines through time and with increasing temperature; (2) average evolutionary invasibility across communities increases and then decreases through time as the richness-temperature gradient flattens; (3) in the early stages of diversification, richness and evolutionary invasibility both increase with increasing temperature; and (4) at equilibrium, richness does not vary with temperature, yet evolutionary invasibility decreases with increasing temperature. These predictions emerge from the "evolutionary-speed" hypothesis, which attempts to account for latitudinal species richness gradients by invoking faster biological rates in warmer, tropical regions. The model contrasts with predictions from other richness-gradient hypotheses, such as "niche conservatism" and "species energy." Empirically testing our model's predictions should help distinguish among these hypotheses.
理解生物多样性梯度是一个长期存在的挑战，需要理论将生态学和进化学统一起来才能取得进展。在这里，我们统一了与进化速度、物种丰富度对多样化的影响以及基于生态位的共存相关的概念。我们关注的是在广泛的温度梯度上，通过进化时间，群落可入侵性和物种丰富度的动态。在我们的框架中，体型的进化影响着营养网络的生态结构和动态，而生物体的新陈代谢将温度与生态进化过程联系起来。该框架将生态可入侵性（受生态相互作用控制）与进化可入侵性（受局部生态和由突变引起的小表型效应造成的约束控制）区分开来。该模型产生了四个主要预测：（1）随着时间的推移和温度的升高，生态可入侵性下降；（2）随着丰富度-温度梯度变平，群落之间的平均进化可入侵性随着时间的推移而增加，然后减少；（3）在多样化的早期阶段，丰富度和进化可入侵性都随着温度的升高而增加；（4）在平衡状态下，丰富度不随温度变化，但进化可入侵性随温度升高而降低。这些预测源于“进化速度”假说，该假说试图通过在温暖的热带地区更快的生物率来解释纬度物种丰富度梯度。该模型与其他丰富度梯度假说（如“生态位保守主义”和“物种能量”）的预测形成对比。实证检验我们模型的预测应该有助于区分这些假说。
