Authors: Danielle K. Walkup, Brandon C. Bowers, Toby J. Hibbitts, Paul S. Crump, A. Michelle Lawing, and Wade A. Ryberg.
The Houston toad Anaxyrus houstonensis, an amphibian endemic to eastern-central Texas, was one of the first amphibians to be listed as federally endangered in the USA. Despite ongoing conservation efforts, the species continues to face declining populations from habitat degradation, loss, and fragmentation, along with compounding effects of climate change and increased drought severity. This study aimed to develop robust habitat suitability models for A. houstonensis using ensemble habitat suitability modeling (EHSM) to inform conservation strategies. We generated multiple EHSMs to identify suitable habitats, potential survey sites, and reintroduction areas, integrating occurrence data from various sources with environmental and climatic variables. We also conducted connectivity modeling to highlight essential habitat corridors that could enhance population dispersal and interconnectivity. Our models indicate that deep sandy soils, forest cover, and maximum precipitation in March are critical factors associated with use by A. houstonensis, reinforcing prior understanding of A. houstonensis habitat needs. Our model projections showed there has been a loss of 23% of the top-quality habitat between 2004 and 2021. However, the lack of connectivity among the core patches suggests that restoring the historical species connectivity is an unlikely event, and that we should focus on increasing connectivity within the large core patches. These findings provide crucial guidance for targeted habitat conservation, restoration efforts, and land management practices. Moving forward, these models will be instrumental in refining recovery plans, engaging stakeholders, and identifying target areas for priority conservation actions, outlined in the 2022 A. houstonensis recovery plan.
Suggested Citation
Walkup, D.K., B.C. Bowers, T.J. Hibbitts, P.S. Crump, A.M. Lawing, and W.A. Ryberg. 2025. Integrating ensemble habitat suitability models to guide conservation strategies for the endangered Houston toad Anaxyrus houstonensis. Endangered Species Research 57:299-312.
