Trait-explicit approaches cast new light of fragmentation effects on biodiversity

While the negative effects of landscape fragmentation on biodiversity are well documented, recent evidence shows that positive or neutral effects may also be common. Understanding the mechanisms underlying these contrasting outcomes requires evaluating how species traits mediate their responses to landscape and patch characteristics. Here, we show that three key elements can improve predictions of fragmentation effects on biodiversity across scales: (1) the trait distribution of the regional species pool; (2) the relationship between taxonomic and trait diversity; and (3) the influence of the landscape matrix on the distribution of species traits. To demonstrate how these hypotheses can be tested at multiple spatial scales, we present a fully reproducible framework that integrates survey data from global datasets, remote‐sensing products, and analytical tools. As a proof of concept, we analyzed 120 fragmented landscapes in forest ecoregions spanning several biomes. We focused on forest‐dependent plant and bird species using survey data from 410 plots and species lists extracted from eBird and sPlot. Our results show that variation in the trait diversity of regional species pools across regions and ecosystems explains both the direction and magnitude of fragmentation effects on functional and taxonomic diversity. Notably, the relationship between taxonomic and functional diversity determines whether different facets of biodiversity show convergent or divergent responses to fragmentation. When functional diversity saturates rapidly with increasing taxonomic diversity, species assemblages show a narrow range of responses to fragmentation. In these cases, few species are able to colonize small patches or exploit resources in the landscape matrix, resulting in assemblages with low species richness and reduced trait diversity. Depending on the spatial scale and the region considered, fragmentation effects can be positive, neutral, or negative for species with different traits related to dispersal, life history, and resource acquisition. The implementation of our framework will support the development of generalizable hypotheses about the consequences of fragmentation across diverse taxonomic groups and regions, with broad implications for ecology and conservation.