Conservation demography: demographic and life-history based frameworks for assessing extinction risk

The biodiversity crisis demands urgent identification of at-risk species, to ensure timely and focused conservation intervention. Demographic modelling contributes to understanding population responses to threats such as over-exploitation and environmental change, but is hindered by incomplete and biased data and limited understanding of how life cycle processes and life history shape demographic responses. Here, I explore barriers to and opportunities for effective conservation demography, using core life history and modelling principles to address limitations and opportunities presented by existing demographic data sets and by relating demographic responses to life history. I focus on long-lived birds, which include many highly threatened species and may present challenges for modelling because of missing stage-specific data due to aspects of their life cycle and habitat use. In Chapter 2, I develop a two-sex model for monogamous species to explore whether including pairing and divorce processes influences insights from classical conservation analyses. When divorce costs take the form of loss of reproductive output, population dynamics in slow-lived species were largely insensitive to pairing and divorce. In Chapter 3, I use phylogenetic imputation to reconstruct vital rates of survival, growth, and reproduction in avian demographic data for use in conservation analyses. Certain vital rates, such as adult survival, could be imputed relatively accurately based on vital rate covariation, with phylogeny and auxiliary trait data improving estimates in some cases. However, demographic metrics such as generation time were sensitive to the accuracy of imputed vital rates. In Chapter 4, I explore the use of pace of life indicators to assess responses to mortality impacts in seabirds. Pace of life indicators could help to assess risk to seabirds from extrinsic threats, reducing dependency on classical vital rates required to parameterise demographic models. Finally, in Chapter 5, I review the literature on demographic responses to climate in mammals to highlight data gaps and limitations for exploring species’ responses to environmental change, revealing geographic and taxonomic biases in missing data and complex demographic responses to climate.