Global comparison of habitat intactness models for predicting extinction risk in terrestrial mammals

The effects of habitat condition on biodiversity have primarily been investigated using discrete (patch-matrix) habitat models, which consider habitat fragments as islands embedded in an inhospitable matrix. Recently, continuum habitat models, which focus on ecological gradients without defining habitat or matrix, have emerged. However, no formal comparison between patch-matrix, continuum, and hybrid habitat models (which combine characteristics of both) has been undertaken globally. Here, we compared the ability of patch-matrix, continuum, and hybrid models of habitat intactness to explain the risk of extinction for terrestrial mammals on a global scale. We found that hybrid models consistently outperform both patch-matrix and continuum models of habitat intactness in predicting extinction risk, regardless of a species' habitat specialization. Moreover, the magnitude of the relationship between habitat intactness and extinction risk was strongest when using hybrid habitat models. Our results suggest that combining discrete habitat patches with gradients of habitat condition, influenced by the surrounding matrix, can improve extinction risk analyses and provide valuable insights for conservation efforts.