Identifying drivers of Cape vulture (Gyps coprotheres) space use in southern Africa

Phipps, W.L., 2015. Identifying drivers of Cape vulture (Gyps coprotheres) space use in southern Africa. PhD, Nottingham Trent University.

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Abstract

The decline of worldwide vulture populations due to multiple anthropogenic threats is recognised as one of the most important issues in avian conservation due to the loss of the important ecosystem services that they provide. The Cape vulture (Gyps coprotheres) is endemic to southern Africa and is listed as Vulnerable by the International Union for Conservation of Nature due to declines across its range largely attributed to poisoning and fatal interactions with the expanding power line network. In this thesis I provide a first insight into the factors that drive the space use patterns of Cape vultures in an effort to inform future conservation strategies. I deployed Global Positioning System (GPS) tracking units attached to vultures caught from the wild in the main breeding range of the species in northern South Africa, and in north central Namibia where the species has recently been declared extinct as a breeding species but a small population remains. Tracking units were also deployed on three Cape vultures released in Namibia as part of a pilot reintroduction program. The GPS tracking data were used to delineate the size and extent of the vulture home ranges and to identify key factors influencing their movement patterns. Their relative use of unprotected and protected areas was assessed, as well as the influence of vegetation characteristics. Finally, I present the first approximation of the spatial niche of Cape vultures using ecological niche modelling methods and provide a first assessment of the potential impacts of climate change on their future occurrence. Immature individuals and two of the reintroduced vultures traversed extensive ranges (maximum home range >975,000 km2) and regularly crossed international borders, while wild-caught adult vultures tended to show a higher degree of site fidelity while foraging across more restricted ranges (maximum home range <150,000 km2) closer to known breeding colonies. The vultures tracked from South Africa regularly used transmission line towers as roost and perch sites which has allowed them to extend their foraging range beyond their historical distribution into areas previously devoid of suitable perches. Although some adults often roosted at breeding colonies inside officially protected areas, all of the vultures foraged primarily on unprotected or privately managed land. The vultures generally tended to forage in more open habitats. The ecological niche models indicated that bioclimatic variables such as precipitation seasonality were the key factors that influenced the space use of the tracked vultures. The models predicted that climate change could potentially result in significant pole-wards shifts of up to 333 km in Cape vulture occurrence patterns, putting the core breeding colonies in the north of their range under threat. This study has provided a first insight into the ranging patterns of Cape vultures using GPS tracking methods and has identified that their extensive ranges, frequent use of unprotected land and close association with power lines puts them at serious risk from multiple threats during their regular foraging activity. The findings of this study confirm for the first time that the threat of climate change to Cape vultures should be seriously considered when planning future conservation measures. This research has demonstrated the ability of GPS tracking methods to identify new threats and key areas for the implementation of conservation measures.

Item Type: Thesis
Creators: Phipps, W.L.
Date: July 2015
Rights: This work is the intellectual property of the author. You may copy up to 5% of this work for private study, or personal, non-commercial research. Any re-use of the information contained within this document should be fully referenced, quoting the author, title, university, degree level and pagination. Queries or requests for any other use, or if a more substantial copy is required, should be directed in the owner(s) of the Intellectual Property Rights.
Divisions: Schools > School of Animal, Rural and Environmental Sciences
Depositing User: Linda Sullivan
Date Added: 25 May 2016 15:42
Last Modified: 25 May 2016 15:42
URI: http://irep.ntu.ac.uk/id/eprint/27887

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