A trait-based framework for assessing vulnerability to habitat fragmentation

Abstract

Habitat fragmentation and the loss of quality habitat are major drivers of biodiversity loss across the globe. For many impacted systems, research and management activities often occur reactively, after the loss of habitat has caused significant declines. This has resulted in a substantial body of literature identifying the impacts of habitat loss and fragmentation and linking species’ traits with persistence in fragmentated habitats. Unifying information on the biological and ecological traits which impact a species’ ability to resist habitat change with the broadly available spatial data on habitat fragmentation may enable us to predict responses before irreversible damage is done. Here, we adapt climate change vulnerability assessment, which evaluates risk proactively, to develop a framework to predict the vulnerability of species to habitat alteration. This novel application focuses on key species-level metrics related to sensitivity and adaptive capacity including body size, habitat breadth, genetic diversity, and fecundity, as well as the extrinsic pressures from exposure to habitat pressures, to estimate species-level vulnerability to habitat fragmentation and loss. As a case study, we applied this framework to the grassland-associated small mammal community of the southern Great Plains, a habitat which has undergone significant loss and fragmentation. We leverage existing data on species’ traits to characterize relative sensitivity and adaptive capacity for an assemblage of small, terrestrial mammals, and evaluate exposure to habitat fragmentation and loss across their historical range in the state of Oklahoma. Our approach identified both known at-risk species as well as several additional species which are potentially vulnerable across our study area. Although some of the species identified as vulnerable in our framework have been previously considered to be Least Concern across their range, the combination of extrinsic pressures due to high levels of habitat alteration and intrinsic sensitivity to fragmentation pressures suggest they may be at risk for decline. Proactively identifying at-risk species within an assemblage can provide important guidance for monitoring, assessment needs, and regional economic planning.