Abstract
Recent international initiatives have promoted a number of different approaches to identify marine Important Bird and biodiversity Areas (IBAs), which are important areas for foraging, migrating or over-wintering seabirds. The ‘Foraging Radius Approach’ is one of these and uses known foraging range and habitat preferences to predict the size and location of foraging areas around breeding colonies. Here we assess the performance of the Foraging Radius Approach using GPS tracking data from six seabird species with a variety of foraging modes. For each species we compared the population home-range areas of our six study species with the home-range areas defined using the Foraging Radius Approach. We also assessed whether basic information on depth preferences from tracking data could improve these home-range area estimates. Foraging Radius Approach home-range areas based on maximum foraging radii encompassed the entire population home-range of five out of six of our study species but overestimated the size of the population home-range area in every case. The mean maximum foraging radius overestimated the population home-range areas by a factor of 4–14 for five of the six species whilst the mean foraging radius overestimated the population home-range area for half of the species and underestimated for the rest. In the absence of other data, the Foraging Radius Approach appears to provide a reasonable basis for preliminary marine IBA identification. We suggest that using the mean value of all previously reported maximum foraging radii, informed by basic depth preferences provides the most appropriate prediction, balancing the needs of seabirds with efficient use of marine space.
Highlights
In an effort to identify sites of most value to protect and conserve avian populations, Birdlife International has defined over 12,000 Important Bird and Biodiversity Areas (IBAs) worldwide (BirdLife International 2014)
Reported maximum, mean maximum and mean foraging radii reported for each of the study species can be seen in Table 2, along with the maximum and mean foraging radii recorded from this study
The Foraging Radius Approach is advocated as a simple way for marine planners to predict the distribution of foraging seabirds around important colonies in the absence of tracking or at-sea survey data (BirdLife, 2010; Thaxter et al, 2012), and should avoid the need for complex modelling procedures or dependence on the availability and processing of oceanographic variables
Summary
In an effort to identify sites of most value to protect and conserve avian populations, Birdlife International has defined over 12,000 Important Bird and Biodiversity Areas (IBAs) worldwide (BirdLife International 2014). These are selected based on the following criteria: (i) sites holding globally threatened species on a regular basis; (ii). Whilst the designation of an IBA has no legal standing, they have been used to both raise the profile of a site and to provide justification for protected area management by relevant local statutory authorities and NGOs (BirdLife International, 2010, Heath et al, 2000).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
