School of Life Sciences/State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou 510275, People's Republic of China.
Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
Proc Biol Sci. 2018 Apr 11;285(1876). doi: 10.1098/rspb.2017.2878.
Why tropical forests harbour an exceptional number of species with striking differences in abundances remains an open question. We propose a theoretical framework to address this question in which rare species may have different extirpation risks depending on species ranks in tree growth and sensitivities to neighbourhood interactions. To evaluate the framework, we studied tree growth and its responses to neighbourhood dissimilarity (ND) in traits and phylogeny for 146 species in a neotropical forest. We found that tree growth was positively related to ND, and common species were more strongly affected by ND than rare species, which may help delay dominance of common species. Rare species grew more slowly at the community-wide average ND than common species. But rare species grew faster when common species tended to dominate locally, which may help reduce extirpation risk of rare species. Our study highlights that tree growth rank among species depends on their responses to neighbourhood interactions, which can be important in fostering diversity maintenance in tropical forests.
为什么热带森林中存在如此多具有显著差异的物种，这仍然是一个悬而未决的问题。我们提出了一个理论框架来解决这个问题，其中稀有物种可能由于其在树木生长中的种级和对邻域相互作用的敏感性而具有不同的灭绝风险。为了评估该框架，我们研究了 146 种新热带森林树种的生长及其对性状和系统发育上的邻域差异（ND）的响应。我们发现，树木生长与 ND 呈正相关，常见物种比稀有物种更容易受到 ND 的影响，这可能有助于延迟常见物种的优势地位。稀有物种在整个社区平均 ND 处的生长速度比常见物种慢。但是，当常见物种趋于在局部地区占主导地位时，稀有物种的生长速度会更快，这可能有助于降低稀有物种的灭绝风险。我们的研究强调了物种之间的树木生长等级取决于它们对邻域相互作用的响应，这在促进热带森林的多样性维持方面可能很重要。
