Response of Avian communities to edges of tropical montane forests: Implications for the future of endemic habitat specialists

Tropical montane landscapes harbor diverse flora and fauna, and many species there are ecological specialists with narrow elevational distributions, limited geographic ranges, and small global populations. Along elevational gradients, environmental conditions and community composition change dramatically over small spatial scales. As forests are disturbed and edges formed with modified habitat, natural communities could be affected differently across elevations by the many physical and biotic changes at edges. We asked whether forest edges produced altered patterns of avian species composition along a cloud forest - dry forest gradient on the Pacific slope of the Tilarán mountains in Monteverde, Costa Rica. A strong moisture gradient produces cloud forests near the ridgetops, with a concentration of species endemic to the Costa Rica – Panama highlands that are habitat specialists. We conducted 552 point counts across 110 locations from 1100 to 1800 m elevation, yielding 6586 detections ...

热带山地景观孕育着多样的动植物群落，其中许多物种为生态特化种（ecological specialists），具有狭窄的海拔分布范围、有限的地理分布区及较小的全球种群规模。沿海拔梯度，环境条件与群落组成在小空间尺度上发生剧烈变化。随着森林受到干扰、边缘地带形成经改造的生境，边缘处的诸多物理与生物变化可能会对不同海拔的自然群落产生差异化影响。我们探究了在哥斯达黎加蒙特维尔德的蒂拉兰山脉太平洋坡地，沿云雾林（cloud forest）-干旱林梯度，森林边缘是否会改变鸟类物种组成模式。强烈的湿度梯度在山脊附近形成云雾林，这里聚集着哥斯达黎加-巴拿马高地特有的物种，这些物种均为生境特化种（habitat specialists）。我们在海拔1100至1800米的110个点位开展了552次点计数（point counts）调查，共记录到6586次物种探测结果……