Hu Guang, Wilson Maxwell C, Wu Jianguo, Yu Jingjing, Yu Mingjian
School of Civil Engineering and Architecture, Zhejiang Sci-Tech University, Hangzhou, China.
School of Life Sciences, Arizona State University, Tempe, AZ, USA.
PeerJ. 2019 Apr 10;7:e6714. doi: 10.7717/peerj.6714. eCollection 2019.
How habitat fragmentation affects the relationship between local richness and the variation in community composition across space is important to both ecology and conservation biology, but this effect remains poorly understood.
Here, we present an empirical study to address this topic in a fragmented landscape, the Thousand Island Lake (TIL), an artificial land-bridge island system with more than 1,000 islands, which provides an "experimental" fragmented landscape with a homogeneous matrix and similar successional history. We measured species composition and plant functional type (PFT) on 29 islands, and tested the effects of island area and isolation on the relationship between α- and β-diversity. General Linear Models were applied to test the impact of habitat fragmentation. In addition, variation partitioning was used to decouple α-diversity dependent and α-diversity independent spatial turnover in β-diversity of the plant community and across different PFTs.
We found habitat fragmentation influences β-diversity of plants primarily by modifying local α-diversity, not spatial turnover in the TIL system. We also found area-dependent environmental filtering and differential plant responses across functional types were the most likely underlying driving mechanisms.
These results highlight the importance of hierarchical linkages between components of biodiversity across scales in fragmented landscapes, and have practical conservation implications.
栖息地破碎化如何影响局部物种丰富度与群落组成空间变异之间的关系，这对生态学和保护生物学都很重要，但这种影响仍知之甚少。
在此，我们开展了一项实证研究，以解决千岛湖中这一破碎景观中的该主题。千岛湖是一个拥有1000多个岛屿的人工陆桥岛系统，它提供了一个具有同质基质和相似演替历史的“实验性”破碎景观。我们测量了29个岛屿上的物种组成和植物功能类型（PFT），并测试了岛屿面积和隔离度对α多样性与β多样性之间关系的影响。应用一般线性模型来测试栖息地破碎化的影响。此外，采用变异分解法来分离植物群落β多样性中依赖α多样性和不依赖α多样性的空间周转率，以及不同植物功能类型间的空间周转率。
我们发现，在千岛湖系统中，栖息地破碎化主要通过改变局部α多样性而非空间周转率来影响植物的β多样性。我们还发现，依赖面积的环境过滤作用以及不同功能类型植物的不同响应是最可能的潜在驱动机制。
这些结果凸显了破碎景观中跨尺度生物多样性组成部分之间层次联系的重要性，并具有实际的保护意义。
