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Population matrix models are routinely used to study the demography of wild populations and to guide management choices. When vital rates are unknown for a specific population or life history stage, researchers often replace them with estimates from other populations of the same species. Such 'hybrid' matrices might ignore among-population life history variation and lead to incorrect inferences. In this study, we examined the real-world effect of using hybrid matrices on demographic inference and management decisions, using a large dataset on yellow-bellied toad (Bombina variegata) populations, an amphibian species whose life history depends on human land use. We estimated stage-specific survival and recruitment for 18 populations across different habitat types. We then assessed how estimated population growth rates and elasticities changed when population-specific vital rates were replaced by estimates from other populations, chosen randomly or based on habitat, demographic or geographic proximity. The use of hybrid matrices mixing demographic estimates from different populations and habitats biased predictions. The mean bias was relatively minor even when sampling randomly across all populations, because our large dataset represented the whole range of life histories and errors cancelled out on average. However, borrowing estimates from geographically close or demographically similar populations substantially reduced the risk of extreme errors. Borrowing from populations from similar habitat types could also reduce bias, but results varied depending on the exact habitat types concerned. Our study illustrates how habitat-specific among-population variation in life history affects the reliability of population matrices commonly used in evolutionary demography, ecology and conservation. When the use of hybrid population matrices cannot be avoided, their creation can be informed by additional information about ecological or demographic patterns, helping reduce bias. When such information is not available, we recommend that studies should consider the whole space of parameter estimates (the complete range of estimates available), thus transparently describing the true uncertainty surrounding demographic estimates., (© 2025 The Author(s). Journal of Animal Ecology © 2025 British Ecological Society.)

Habitat anthropization is a major driver of global biodiversity decline. Although most species are negatively affected, some benefit from anthropogenic habitat modifications by showing intriguing life-history responses. For instance, increased recruitment through higher allocation to reproduction or improved performance during early-life stages could compensate for reduced adult survival, corresponding to "compensatory recruitment". To date, evidence of compensatory recruitment in response to habitat modification is restricted to plants, limiting understanding of its importance as a response to global change. We used the yellow-bellied toad ( Bombina variegata ), an amphibian occupying a broad range of natural and anthropogenic habitats, as a model species to test for and to quantify compensatory recruitment. Using an exceptional capture-recapture dataset composed of 21,714 individuals from 67 populations across Europe, we showed that adult survival was lower, lifespan was shorter, and actuarial senescence was higher in anthropogenic habitats, especially those affected by intense human activities. Increased recruitment in anthropogenic habitats fully offset reductions in adult survival, with the consequence that population growth rate in both habitat types was similar. Our findings indicate that compensatory recruitment allows toad populations to remain viable in human-dominated habitats and might facilitate the persistence of other animal populations in such environments.