Forest Ecology and Conservation Group, Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB3 2EA, UK.
Philos Trans R Soc Lond B Biol Sci. 2010 May 12;365(1545):1437-47. doi: 10.1098/rstb.2009.0298.
Understanding successional trends in energy and matter exchange across the ecosystem-atmosphere boundary layer is an essential focus in ecological research; however, a general theory describing the observed pattern remains elusive. This paper examines whether the principle of maximum entropy production could provide the solution. A general framework is developed for calculating entropy production using data from terrestrial eddy covariance and micrometeorological studies. We apply this framework to data from eight tropical forest and pasture flux sites in the Amazon Basin and show that forest sites had consistently higher entropy production rates than pasture sites (0.461 versus 0.422 W m(-2) K(-1), respectively). It is suggested that during development, changes in canopy structure minimize surface albedo, and development of deeper root systems optimizes access to soil water and thus potential transpiration, resulting in lower surface temperatures and increased entropy production. We discuss our results in the context of a theoretical model of entropy production versus ecosystem developmental stage. We conclude that, although further work is required, entropy production could potentially provide a much-needed theoretical basis for understanding the effects of deforestation and land-use change on the land-surface energy balance.
理解生态系统-大气边界层能量和物质交换的演替趋势是生态研究的一个重要焦点；然而，一个能够描述所观察到的模式的一般理论仍然难以捉摸。本文探讨了最大熵产生原理是否可以提供解决方案。使用来自陆地涡度协方差和微气象学研究的数据，为计算熵产生开发了一个通用框架。我们将该框架应用于亚马逊盆地八个热带森林和牧场通量站点的数据，结果表明森林站点的熵产生率始终高于牧场站点（分别为 0.461 与 0.422 W m(-2) K(-1)）。有人认为，在发育过程中，冠层结构的变化使地表反照率最小化，而较深根系的发育则优化了对土壤水分的利用，从而潜在蒸腾作用增强，导致地表温度降低和熵产生增加。我们根据熵产生与生态系统发育阶段的理论模型来讨论我们的结果。我们得出结论，尽管还需要进一步的工作，但熵产生可能为理解森林砍伐和土地利用变化对陆面能量平衡的影响提供一个急需的理论基础。
