Mesopredators in forest edges

Abstract

Fragments and edges account for most remaining forest habitats globally. Apex predators and megaherbivores often decline in these degraded habitats while smaller generalist omnivores can persist or thrive in forest edges, especially if they can utilize nonnative resources (“cross‐boundary food subsidies”). Outcomes for small‐medium carnivores (mesopredators) remain unclear or idiosyncratic. We tested responses of a widespread and common forest mesopredator to edges and the composition of the adjacent nonforested areas using 91 camera trapping surveys in Southeast Asia. Leopard cats ( Prionailurus bengalensis and Prionailurus javanensis ) showed a hump‐shaped relationship with forest cover and a positive association with oil palm plantations, but they did not increase near other types of nonnative land cover. Leopard cats' success in edges appears due to their hunting abundant rodent prey inside oil palm plantations, providing natural pest management for farmers. Abundant leopard cats also hunt and suppress native small vertebrates, which may trigger negative ecological cascades and suppress biodiversity in forest edges. 全球大部分残留的森林栖息地都是破碎化和边缘性的。在生境退化的栖息地中，顶级捕食者和大型草食动物种群数量通常会减少，而普适性的杂食动物则可以在森林边缘地带生存或持续发展，尤其是当这些杂食动物可以利用非本土资源（称为“跨界食物补充”）时。而中小型食肉动物（中级捕食者）在这些区域的种群趋势尚不明确或因种而异。我们在东南亚利用91 个自动相机监测位点，检验了一种常见的广泛分布的森林中级捕食者对于边缘地区以及邻近非森林区域复合景观的反应。豹猫（ Prionailurus bengalensis and P. javanensis ）丰富度与森林覆盖率呈单峰形关系，与油棕榈种植园呈正相关，然而，在其他非原生植被覆盖的生境附近，豹猫的数量并没有增加。豹猫在森林边缘地带的成功分布是因为它们在油棕榈种植园内捕食大量的啮齿类猎物，这起到帮助农民管理自然害兽的作用。豹猫还捕食并抑制了本地小型脊椎动物，这可能会引发生物多样性的级联效应。 The rise of native mesopredators in forest edges provides pest control ecosystem services by regulating rodent proliferation in cultivated lands and natural forest edges, benefiting people and conservation. Native mesopredators can be managed by farmers (e.g., oil palm plantation managers) through the retention of natural forest patches and the selective cultivation of preferred microhabitats (e.g., shade trees and understory vegetation). Abundant mesopredators may impose unnaturally high predation pressure on small native vertebrate species and undermine conservation in forest edges. The trade‐offs associated with mesopredators in forest edges can be elucidated through mesopredator diet studies spanning different habitats.