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Abstract
Biodiversity loss is occurring globally with intensifying human-driven land-use change. Effective conservation planning with increasing anthropogenic pressure requires knowledge of: (1) species’ responses to habitat modification, including their ability to persist in, and their relative susceptibility to, human modified environments, and (2) species’ traits that facilitate persistence in these landscapes. This information is critical for predicting extinction risk and mitigating species declines. As one of the most threatened yet understudied vertebrate taxa, amphibians are promising candidates to broaden understanding of biodiversity responses to habitat change and identify conservation options.
This thesis examines species’ responses to anthropogenic habitat modification and explores how species’ ecology, behaviour and life history may influence persistence in these environments, with a focus on frogs. I use a multi-scale approach, combining taxonomically broad analyses of citizen science data (landscape scale) with targeted species-specific fieldwork (local and regional scale). Chapter 1 reviews current knowledge of species’ responses to habitat modification, highlights research priorities and outlines my research approach. Chapter 2 integrates continental citizen science data with a global human modification index to quantify frog species’ tolerance of habitat modification and to identify broad trait-based associations. Chapter 3 uses this data to assess if and how habitat modification influences frog breeding phenology and call acoustics. Chapter 4 explores underexamined genetic threats to species in modified landscapes, with evidence from two sympatric frog species, the threatened Booroolong frog (Litoria booroolongensis) and the non-declining eastern stony creek frog (L. wilcoxii). Chapter 5 considers how species’ behaviours may influence vulnerability to habitat modification, drawing on movement and habitat use data gained from radiotracking these two species. Chapter 6 synthesises these findings, discusses implications for conservation management and outlines future research avenues.
Overall, this thesis offers insight into why some species persist whilst others decline in modified landscapes, and the capacity of frogs to cope with habitat modification. I show how integrating big data with field studies can improve knowledge of species’ traits and species-environment relationships at multiple scales, with broad conservation implications.
