Data from: Ecological, evolutionary and human-mediated determinants of poeciliid species richness on Caribbean islands

Aim: The theory of island biogeography provides a predictive framework relating species richness to island size and distance from the mainland. However, the theory as originally formulated does not necessarily scale to large islands and continental landmasses that are capable of generating species through in situ speciation (rather than entirely by colonization), nor does it necessarily account for how human introduction of species alters traditional biogeographical patterns. Here, we examine the ecological (colonization and extinction), evolutionary (in situ speciation) and human-mediated (deliberate introductions) determinants of species richness in a taxonomic group that has undergone a radiation on Caribbean islands: live-bearing fishes of the family Poeciliidae. Location: The Caribbean. Methods: We created a database of both native and introduced poeciliid species occurrence on Caribbean islands through literature review, and estimated the number of colonizations versus speciation events on each island using a molecular phylogeny. Linear regression and other statistical tests were used to explore species–area and species–isolation relationships. Results: Species richness on small islands results entirely from colonization and does not significantly increase with island area, whereas on larger islands species richness increases dramatically as a function of area due primarily to in situ speciation. Poeciliid fishes have been introduced widely, both as a by-product of their popularity in the aquarium hobby and as a means of mosquito control. We show that such establishments have occurred disproportionately on islands depauperate in native species, and that introduced species richness is positively correlated with economic interconnectedness (shipping traffic) and human population size. Main conclusions: On large Caribbean islands in situ speciation has elevated the number of poeciliid species beyond that predicted from ecological processes alone. Introduced species significantly alter biogeographical patterns.

研究目的：岛屿生物地理学理论（theory of island biogeography）为物种丰富度与岛屿面积、距大陆距离之间的关联提供了预测框架。然而，该理论的原始表述未必适用于可通过原地物种形成（而非完全依赖殖民事件）产生新物种的大型岛屿与大陆陆块，也未能解释人类引入物种如何改变传统生物地理格局。本研究以在加勒比群岛经历辐射演化的分类群——花鳉科（Poeciliidae）胎生鱼类为研究对象，探讨了物种丰富度的三类驱动因素：生态过程（殖民与灭绝）、进化过程（原地物种形成）以及人类介导的人为刻意引入。研究区域：加勒比海域。方法：本研究通过文献综述构建了加勒比群岛土著与引入花鳉科鱼类的物种出现记录数据库，并利用分子系统发育树估算了各岛屿的殖民事件与物种形成事件数量。采用线性回归及其他统计方法探究物种-面积关系与物种-隔离关系。结果：小型岛屿的物种丰富度完全源自殖民事件，且未随岛屿面积显著提升；而大型岛屿的物种丰富度则随面积显著增加，这一现象主要源于原地物种形成过程。花鳉科鱼类已被广泛引入，一方面得益于其在水族观赏领域的高人气，另一方面则被用于蚊虫防控。本研究发现，此类成功建立种群的引入物种多集中在土著物种匮乏的岛屿，且引入物种丰富度与经济连通性（航运流量）及人类人口规模呈正相关。主要结论：加勒比大型岛屿的原地物种形成过程使花鳉科鱼类的物种丰富度远超仅由生态过程预测的水平。人类引入的物种显著改变了岛屿生物地理格局。