The impact of land-use change on birds and their contribution to ecosystem function
File(s)
Author(s)
Weeks, Thomas
Type
Thesis
Abstract
Land-use change and habitat fragmentation are major threats to biodiversity. However, not all species react to these pressures in similar ways. Better understanding of how fragmentation and land-use change impact species and associated functions, is essential to ensure the maintenance of key ecosystem processes. The functional role of a species is dictated by the make-up of intrinsic traits which underpin how they interact with and respond to their environment. Thus, functional trait databases allow us to analyse how fragmentation and land-use changes affect assemblage function and stability at unprecedented resolution. Birds provide an unparalleled system to study these research gaps at large spatial scales because they have the most comprehensive functional trait database and are widely surveyed. I collated intrinsic trait data for all birds and integrate these with a global distribution of avian surveys. I find that dispersal limited, specialist species are disproportionately affected by forest fragmentation and land-use change. I provide evidence that more tolerant trait syndromes at northerly latitudes are shaped predominantly by climatic seasonality, rather than previously proposed extinction filters. Using traits linked to ecological functions, I also show that variation in species responses to land-use change has important implications for the current and future function of bird assemblages. Substantial erosion of functional trait diversity (FD) in human-modified habitats is associated with underappreciated declines in redundancy, particularly in tropical biomes. Post-hoc analyses reveal that this erosion of redundancy destabilizes future ecosystem functions as relatively few additional extinctions will lead to major FD losses. Thus, encouraging conservation practices which limit redundancy losses in sedentary specialist species – such as improving connectivity through habitat corridors - is key to ensuring the future stability of essential ecosystem processes.
Version
Open Access
Date Issued
2023-09-12
Date Awarded
01/02/2024
License URL
Advisor
Tobias, Joseph
Purvis, Andy
Sponsor
Natural Environment Research Council (Great Britain)
Grant Number
NE/I028068/1
Publisher Department
Life Sciences
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)