A trait-based demographic approach to predict population response to anthropogenic threats

Biodiversity is in decline, with important consequences for ecosystem stability. Efforts to reverse these trends require an understanding of how populations respond to direct and indirect human threats. To date, conservationists have relied on empirical data to identify which species are most at risk of extinction, and by which threats. However, these data are subject to strong taxonomic and geographic biases that limit our ability to implement accurate prioritizations for biodiversity management. Given the current rate and scale of biodiversity loss, removing such biases by conventional methods is infeasible. Modelling approaches present a promising solution to fill gaps in empirical data.
Trait-based models aim to predict species' vulnerability to anthropogenic threats by finding relationships between species traits and present patterns of endangerment. Correlations to a variety of species traits have been used to infer population response to present and future threats6,7,8. However, current models do not offer mechanistic insight behind population response and rarely differentiate between the impacts of distinct threat types. This lack of specificity highly constrains the use of trait-based approaches in practical management and the resolution of vulnerability predictions.

In this project I will enhance the realism of demographic models to reflect real threats, enabling the unification of trait-based analysis with demography to develop a predictive model of vertebrate population response to global threats. In objective 1, I will compile existing demographic data across literature and conduct an expert survey to develop the first database of vital rate response (adult/juvenile survival, growth, and reproduction) to distinct threat types across ertebrate species. In objective 2, I will use this data to parameterise demographic models to project how population growth rates change in response to different threat types across species. I will apply trait based comparative methods to projected population trajectories to build a predictive model of threat response as a function of species' life history traits. In objectives 3 and 4, I will explore how the interactions of threats influence population response, and explore the consequences of predicted population declines on the functional diversity of key global ecosystems.