生态学代谢理论:基于个体新陈代谢过程解释物种多样性的地理格局

Metabolic theory of ecology: an explanation for species richness patterns based on the metabolic processes of organisms

新陈代谢是生物的基本生理过程。生态学代谢理论(metabolic theory of ecology)基于生物个体大小和环境温度对个体新陈代谢过程的影响,使用尺度推移(scaling)的方法来解释多种生态学格局和过程。James Borwn等将这一理论用于解释物种多样性的大尺度格局,并从机制上解释了物种多样性与环境温度的关系。这一理论提出了两个明确的预测:(1)物种多样性的对数与绝对温度的倒数之间呈线性关系;(2)这一线性关系的斜率为–0.6至–0.7。这一理论自提出以来,饱受争议,经过了正反两方面经验数据的检验,目前仍未形成一致的结论。虽然这一理论仍面临着一些有待解决的问题,但它以崭新的思路和方法有别于以往的基于统计学方法的研究。人们过去对该理论的实证检验忽略了两个重要的约束条件,即除温度以外的环境条件处于理想状态和群落处于平衡状态,而这两个约束条件是理解该理论的基础。本文对生态学代谢理论的理论框架、预测和含义,以及以往的检验结果进行阐述,在此基础上提出了作者对该理论的若干认识和未来研究中应考虑的若干问题。

Metabolisms are fundamental processes of organisms. The recently-proposed Metabolic Theory of Ecology （MTE） seeks to explain ecological patterns and processes in terms of the effects of body size and temperature on the metabolic processes of organisms and using the scaling approach. James Brown and his colleagues extended the MTE to explain large-scale patterns of species diversity, and proposed a potential mechanism for species richness-temperature relationships, which predicted that the number of species increases exponentially with increasing environmental temperature. More quantitatively, they predicted that （1） log-transformed number of species varies linearly with the reciprocal of absolute temperature, and （2） the slope of the relationship ranges between -0.70 and -0.60. The MTE has generated widespread attention and controversy and has been tested by a number of empirical observations, but no agreement has yet been reached. Although several issues need to be resolved, the theory is quite different from conventional regression-based methods because of its biological mechanism-sound approach. Previous empirical tests of the theory may ignore two important assumptions （i.e. unconstrained environments except temperature and equilibrium communities） that are the basis for understanding the MTE. This article reviews the frame-work, predictions, and biological meanings of the MTE and examines previous empirical tests of the theory. We also comment on criticisms raised by previous studies and prospect some aspects for the further study.