Rapid morphological change in a small mammal species after habitat fragmentation over the past half-century

Study Aim: To compare the rapid shifts in body size of mainland and island populations of a native rodent and examine the mechanisms underlying these changes. Location: Thousand Island Lake, China, which was created in 1959 when the Xin’anjiang Dam was constructed for generating hydroelectricity. Taxon: The Chinese white-bellied rat, Niviventer confucianus. Methods: Field surveys were conducted from 2015 to 2018 to collect data on body size of the rodents from a set of islands and nearby mainland sites. We constructed multiple linear models to examine the relationships between body size (length and mass) of rodents and biological variables (predators, interspecific and intraspecific competitors, and food availability). We also conducted structural equation modeling (SEM) by constructing models via confirmatory path analysis. Results: All island populations of N. confucianus had significantly larger body size (both body mass and body length) than their mainland counterparts. ...研究目的：比较本土啮齿类大陆种群与岛屿种群的体型快速变化，并探究此类体型变化背后的潜在机制。 研究区域：中国千岛湖（Thousand Island Lake），该水域于1959年因修建新安江大坝（Xin’anjiang Dam）以开展水力发电工程而形成。 研究类群：中国白腹鼠（Niviventer confucianus）。 研究方法：于2015年至2018年间开展野外调查，从多个岛屿及邻近的大陆样点采集该啮齿类的体型数据。构建多元线性模型，以分析啮齿类体型（体长与体质量）与各类生物变量（捕食者、种间竞争者、种内竞争者以及食物可获得性）之间的关联；同时通过验证性路径分析构建结构方程模型（SEM）开展相关分析。 研究结果：中国白腹鼠的所有岛屿种群，其体型（体质量与体长）均显著大于对应的大陆种群。……