Impacts of climate change on the structure and function of global bird diversity
File(s)
Author(s)
Rabeau, Alexandre Jean Claude
Type
Thesis or dissertation
Abstract
Climate change poses a major threat to global biodiversity, disrupting ecosystems that human societies depend on. Predicting its impacts requires accurate estimates of species’ climate niches—the range of climatic conditions a species can tolerate. In this PhD project, I developed a global dataset of avian climate niches and assessed how different methods affect niche estimates. I found that approaches using range maps versus point localities, and variations in spatial and temporal resolution, produced significantly different results. Temporal resolution—whether climate data were averaged monthly, seasonally, or annually—was especially influential. I then examined how well climate niches and local environmental variables predict recent bird population trends. Local factors, such as climate variability and change rates, were more predictive than species-level niche estimates, suggesting that species may respond to environmental shifts before reaching climatic thresholds. To understand broader ecological impacts, I constructed frugivory interaction networks using bird and plant trait data across the Americas and projected their responses to future climate change. Simulations indicated a likely decline in the average number of bird-plant interactions per species, but also showed potential for "interaction rewiring"—particularly in tropical regions with high trait diversity—buffering some negative effects. The findings presented in this thesis contribute significantly to the fields of macroecology and global change biology, offering new insights into species responses to climate change and the complex dynamics of ecological networks under future climatic conditions.
Version
Open Access
Date Issued
2024-11-13
Date Awarded
2025-08-01
Copyright Statement
Attribution-NonCommercial 4.0 International Licence (CC BY-NC)
License URL
Advisor
Tobias, Joseph
Pigot, Alex
Publisher Department
Department of Life Sciences
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)