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Intraspecific variation in environmental and geographic space use: insights from individual movement data 10.17863/CAM.22826 Bonnet-Lebrun, Anne-Sophie 000000027587615X Manica, Andrea 000000031895450X Rodrigues, Ana Sofia Luis Species’ ranges arise from the interplay between environmental preferences, biotic and abiotic environmental conditions, and accessibility. Understanding of – and predictive models on – species distributions often build from the assumption that these factors apply homogenously within each species, but there is growing evidence for individual variation. Here, I use movement data to investigate individual-level decisions and compromises regarding the different costs and benefits influencing individuals’ geographic locations, and the species-level spatial patterns that emerge from these. I first developed a new method that uses tracking data to quantify individual specialisation in geographic space (site fidelity) or in environmental space (environmental specialisation). Applying it to two species of albatrosses, I found evidence of site fidelity but weak environmental specialisation. My results have implications for how limited research efforts are best-targeted: if animals are generalists, effort are best spent by understanding in depth individual patterns, i.e., better to track fewer individuals for long periods of time; whereas if animals tend to be specialists, efforts should be dedicated to tracking as many individuals as possible, even if for shorter periods. I then investigated individual migratory strategies and their drivers in nine North American bird species, using ringing/recovery data. I found latitudinal redistribution of individuals within the breeding and non-breeding ranges that generally did not follow textbook patterns (‘chain migration’ or ‘leapfrog migration’). Migratory individuals tend to trade off the benefits of migration (better tracking of climatic niche; better access to resources) and its costs (increasing with migratory distance). I found that birds are more likely to remain as residents in areas with warmer winter temperatures, higher summer resource surpluses and higher human population densities (presumably because of a buffering effect of urban areas). Overall, my results highlight the importance of considering individual variation to understanding the ecological processes underpinning species’ spatial patterns. University of Cambridge 2018-03-05 Thesis Doctoral Doctor of Philosophy (PhD) en St John's College Benefactors' Scholarship Cambridge Philosophical Society https://www.repository.cam.ac.uk/handle/1810/275584 https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/7f67c0c8-121e-453a-9a0f-96c2d537fb5a/download 87eda9de84448d1f82354d60eee3eb5f https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/489a5264-18ce-4c93-8d43-9401fe13ea60/download d115b9782c2933bff1704422e2d80f1a https://www.rioxx.net/licenses/all-rights-reserved/ migration birds individual variability foraging strategies space use individual specialisation site fidelity residency migration patterns tracking data ringing data movement ecology