Young Kenneth R, León Blanca
Department of Geography and the Environment, University of Texas at Austin, Austin, TX 78712, USA.
Philos Trans R Soc Lond B Biol Sci. 2007 Feb 28;362(1478):263-72. doi: 10.1098/rstb.2006.1986.
The Andes provide an extensive latitudinal and topographical framework for studying the factors that control the spatial patterns of forests (timberlines) and their species components expressed through the presence of tree growth forms (tree lines). Despite consistent overall similarities in landscape patterns, many processes must be unique, given the dramatic differences in species richness and biophysical constraints along the Andes. In all cases evaluated to date, morphological plasticity is a common trait of plant species that dominate at tree lines. In fact, many changes observed can be related to species-specific traits. Physiological limitations on tree growth form only explain species limits, while disturbances and cyclical climate fluctuations interact to affect many landscape patterns. Over long periods of time, tree lines provide unique habitats and perhaps opportunities for speciation. Understanding the spatial organization of tree-line dynamics is one viable research approach for evaluating the likely past fluxes and possible future changes.
安第斯山脉为研究控制森林（树线）空间格局及其通过树木生长形式（林线）的存在所表现出的物种组成的因素提供了广阔的纬度和地形框架。尽管景观格局总体上存在一致的相似性，但考虑到安第斯山脉沿线物种丰富度和生物物理限制的巨大差异，许多过程必定是独特的。在迄今为止评估的所有案例中，形态可塑性是在林线占主导地位的植物物种的共同特征。事实上，观察到的许多变化可能与物种特异性特征有关。树木生长形式的生理限制仅解释了物种界限，而干扰和周期性气候波动相互作用，影响了许多景观格局。在很长一段时间里，林线提供了独特的栖息地，也许还有物种形成的机会。了解林线动态的空间组织是评估过去可能的通量和未来可能变化的一种可行研究方法。
