Assessing the potential impacts of anthropogenic disturbance on seabirds: A case study from Alderney



Warwick-Evans, VC
(2016) Assessing the potential impacts of anthropogenic disturbance on seabirds: A case study from Alderney. PhD thesis, University of Liverpool.

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Abstract

Seabirds are threatened by multiple anthropogenic pressures in the marine environment. These pressures may be short- or long- term and impacts may be either direct or indirect and affect reproduction or survival. Marine Renewable Energy Installations (MREIs) provide a relevant, and spatially explicit, example of such pressures. However, there is currently very little empirical evidence as to how MREIs will impact seabirds. Studies have shown that potential impacts are likely to be species and device specific, temporary or long term, and both positive and negative. Current approaches to predict and assess these impacts from MREIs rely on understanding the species- specific risk of devices (e.g. by making predictions based on the ecology of the seabird), the occurrence of individual species at-sea (e.g. from boat-based surveys), and demographic studies of breeding populations (e.g. through long-term ringing studies). However, these approaches are limited in their ability to detect changes in the distribution of seabirds at-sea and at breeding colonies. They may omit the impacts on non-breeding birds, and overlook the cumulative impacts of multiple pressures on specific populations when predicting potential impacts. Alderney in the English Channel hosts internationally and nationally important seabird colonies, in addition to providing a suitable environment for the installation of tidal turbines. Additionally, the home range area of the colony of Northern gannets Morus bassanus breeding just offshore of Alderney overlaps with nine sites proposed for the development of MREIs, thus Alderney provides an ideal site for this type of study. This thesis explores simple approaches to predict and assess the impacts of proposed MREIs on seabirds, and demonstrates how the large amount of existing seabird tracking data can be used to predict the colony specific impacts of spatial change on seabirds. These approaches are developed at our Alderney study site but are broadly applicable elsewhere. Overall our results suggest that the MREIs proposed for development around Alderney and the English Channel are unlikely to cause population level impacts to the seabirds breeding on, and around, Alderney. With ever increasing human pressures on the marine environment it is vital that we identify robust approaches with which to predict and monitor the impacts of these pressures. This thesis provides simple, robust and cost-effective approaches to predict and assess the potential impacts of spatial change on seabirds, and could be easily adapted for other sites, and for alternative types of spatial change.

Item Type: Thesis (PhD)
Divisions: Faculty of Science and Engineering > School of Engineering
Depositing User: Symplectic Admin
Date Deposited: 16 Aug 2016 09:36
Last Modified: 19 Jan 2023 07:35
DOI: 10.17638/03001637
Supervisors:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3001637