Small mammals reduce distance-dependence and increase seed predation risk in tropical rainforest fragments

Seed predation and reduced predation risk with distance from conspecific trees are important influences on tree regeneration in tropical forests. Shifts in animal communities, such as an increase in rodents and other small mammals due to forest fragmentation, could alter patterns of seed predation and affect tree regeneration and community dynamics in forest fragments. We performed a field experiment on four native rainforest tree species in the Western Ghats, India, to test whether fragmentation increases seed predation by mammals and alters the distance-dependence of seed predation. We monitored seed predation within open and mammal-exclosure plots, near and far from the canopies of conspecific trees, in contiguous and fragmented forests. Seed predation of Cullenia exarillata, Ormosia travancorica, and Syzygium rubicundum was markedly higher in forest fragments, and more so within open plots than exclosures, while the predominantly insect-predated Acronychia pedunculata e...

热带森林中，种子捕食以及随与同种树木距离增加而降低的捕食风险，是影响树木更新的关键因素。动物群落的变化——例如森林破碎化导致啮齿类与其他小型哺乳动物种群扩张——可能会改变种子捕食模式，并进而影响森林破碎化斑块内的树木更新与群落动态。我们在印度西高止山脉（Western Ghats）的四种本土雨林树种中开展了野外实验，以验证森林破碎化是否会提升哺乳动物介导的种子捕食强度，并改变种子捕食的距离依赖性格局。我们在连续森林与破碎化森林中，于靠近和远离同种树木冠层的开放式样地及哺乳动物排除样地内开展了种子捕食监测。针对Cullenia exarillata、Ormosia travancorica与Syzygium rubicundum三个树种，森林破碎化区域内的种子捕食率显著更高，且开放式样地的捕食率高于哺乳动物排除样地；而主要受昆虫捕食的Acronychia pedunculata……