Large isolated trees are keystone structures that can help maintain biodiversity in fragmented landscapes, with evidence that open areas with isolated trees may support similar levels of taxonomic diversity to nearby patches of habitat. However, it is not clear if isolated trees can support the same diversity of ecological functions as trees in habitat patches. We compared species richness, community composition, and functional diversity of birds in trees at forest edges and isolated trees. Twenty isolated trees and ten edge trees of American muskwood (Guarea guidonia) were selected, and sampled on 11 occasions, each of 20 min, over four months. All individual birds that landed at trees were recorded using a standardized protocol. Species richness was, on average, almost twice as high at edge trees than at isolated trees. Taxonomic composition differed between edge and isolated trees, with many forest‐dependent birds restricted to edge trees, and some open‐area birds restricted to isolated trees. Overall functional diversity was similar at edge and isolated trees, but some ecological functions (e.g., frugivory) were less frequent, while others (e.g., granivory) were more frequent at isolated compared with edge trees. Isolated trees are important for supporting many ecological functions in modified areas. However, the maintenance of forest patches is essential to complement the provision of such functions in modified landscapes.

中文翻译：

---

与栖息地中的树木相比，孤立的树木支持的鸟类分类学丰富度较低，但功能多样性相似

大型孤立的树木是关键的结构，可以帮助维持分散的景观中的生物多样性，证据表明，孤立的树木的空旷地区可能支持与附近生境斑块相似的分类学多样性。但是，目前尚不清楚离群的树木是否可以支持与栖息地斑块的树木相同的生态功能多样性。我们比较了森林边缘和孤立树木中树木的鸟类物种丰富度，群落组成和功能多样性。美国麝香树（Guarea guidonia）的二十棵孤立的树和十棵边缘树），并在四个月中的11次（每次20分钟）中取样。使用标准化协议记录着陆在树上的所有鸟类。平均而言，边缘树木的物种丰富度几乎是孤立树木的两倍。边缘树木和孤立树木之间的分类学组成有所不同，许多依赖森林的鸟类仅限于边缘树木，而一些开放区域鸟类则仅限于孤立树木。与边缘树相比，边缘树和孤立树的总体功能多样性相似，但是某些生态功能（例如，节食）的频率较低，而其他一些生态功能（例如，食草）的频率更高。隔离的树木对于支持修改区域的许多生态功能非常重要。然而，