Department of Ecological Science - Animal Ecology, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.
Integrative Ecology Lab, Center for Biodiversity, Department of Biology, Temple University, Philadelphia, Pennsylvania.
Glob Chang Biol. 2018 Oct;24(10):4784-4796. doi: 10.1111/gcb.14334. Epub 2018 Jun 27.
Human land use causes major changes in species abundance and composition, yet native and exotic species can exhibit different responses to land use change. Native populations generally decline in human-impacted habitats while exotic species often benefit. In this study, we assessed the effects of human land use on exotic and native reptile diversity, including functional diversity, which relates to the range of habitat use strategies in biotic communities. We surveyed 114 reptile communities from localities that varied in habitat structure and human impact level on two Caribbean islands, and calculated species richness, overall abundance, and evenness for every plot. Functional diversity indices were calculated using published trait data, which enabled us to detect signs of trait filtering associated with impacted habitats. Our results show that environmental variation among sampling plots was explained by two Principal Component Analysis (PCA) ordination axes related to habitat structure (i.e., forest or nonforest) and human impact level (i.e., addition of man-made constructions such as roads and buildings). Several diversity indices were significantly correlated with the two PCA axes, but exotic and native species showed opposing responses. Native species reached the highest abundance in forests, while exotic species were absent in this habitat. Human impact was associated with an increase in exotic abundance and species richness, while native species showed no significant associations. Functional diversity was highest in nonforested environments on both islands, and further increased on St. Martin with the establishment of functionally unique exotic species in nonforested habitat. Habitat structure, rather than human impact, proved to be an important agent for environmental filtering of traits, causing divergent functional trait values across forested and nonforested environments. Our results illustrate the importance of considering various elements of land use when studying its impact on species diversity and the establishment and spread of exotic species.
人类土地利用导致物种丰富度和组成发生重大变化，但本地和外来物种对土地利用变化的反应可能不同。在受人类影响的生境中，本地种群通常会减少，而外来物种通常会受益。在这项研究中，我们评估了人类土地利用对外来和本地爬行动物多样性的影响，包括与生物群落中栖息地利用策略范围相关的功能多样性。我们在两个加勒比岛屿上的不同生境结构和人类影响水平的地点调查了 114 个爬行动物群落，并为每个样方计算了物种丰富度、总丰度和均匀度。功能多样性指数是使用已发表的特征数据计算得出的，这使我们能够检测与受影响生境相关的特征过滤迹象。我们的结果表明，采样样方之间的环境变化由与生境结构（即森林或非森林）和人类影响水平（即道路和建筑物等人为建筑的增加）相关的两个主成分分析（PCA）排序轴来解释。几个多样性指数与两个 PCA 轴显著相关，但外来和本地物种表现出相反的反应。本地物种在森林中丰度最高，而外来物种在这种生境中不存在。人类影响与外来物种丰度和物种丰富度的增加有关，而本地物种没有表现出显著的相关性。在两个岛屿的非森林环境中，功能多样性最高，在圣马丁岛，由于在非森林生境中建立了具有独特功能的外来物种，功能多样性进一步增加。生境结构而不是人类影响被证明是对特征进行环境过滤的重要因素，导致森林和非森林环境之间出现不同的功能特征值。我们的结果表明，在研究土地利用对物种多样性的影响以及外来物种的建立和传播时，考虑土地利用的各个方面非常重要。
