Report 344
UK inshore Special Protection Areas: a methodological evaluation of site selection and definition of the extent of an interest feature using line transect data.
(2005)
McSorley, C.A, Webb, A, Dean, B.J, Reid, J,B
A methodological evaluation of site selection and definition of the extent of an interest feature using line transect data.

Introduction

 

Although the UK's SPA network currently is mostly limited to the terrestrial, freshwater, and the estuarine environments (Stroud et al. 2001), Article 4 of the Birds Directive states that protection of these bird species should take place "in the geographical sea and land area" (79/409/EEC). Therefore, the Joint Nature Conservation Committee (JNCC), in collaboration with the four statutory country agencies; English Nature (EN); Scottish Natural Heritage (SNH); Countryside Council for Wales (CCW); and the Environment and Heritage Service (Northern Ireland; EHS), is undertaking to provide advice on protection of birds found in the marine environment. Initial work on the implementation of the Birds Directive in the marine environment has been reported in Johnston et al. (2002). Three strands of work have been identified:

 
 i.      seaward extensions of existing seabird breeding colony SPA boundaries beyond the low water mark;
 ii.      inshore feeding areas used by concentrations of birds (e.g. seaducks, divers and grebes) in the non-breeding season; and
 iii.      offshore areas used by marine birds, probably for feeding but also for other purposes.
 
Other aggregations not captured in the former three strands may also be identified.
 
The methodological basis for identifying inshore marine SPAs for seaducks, divers and grebes under strand ii) is discussed in this report.
 
Many seabird species form important wintering aggregations in UK inshore marine waters (Dean et al. 2003). This report presents the current scientific methodological basis for site selection and defining the extent of the interest feature (a natural or semi-natural feature for which a site has been selected) with a view to providing guidelines for setting appropriate marine SPA seaward boundaries for inshore aggregations of divers Gaviidae, grebes Podicipedidae, and seaducks Anatidae outwith the breeding season.
 
In order to assess whether an area qualifies for SPA status, a basic requirement is to know the local population size and bird distribution within that area. Usually it is impossible to count all individuals in a population or to survey all areas, so representative samples are measured to enable estimation of the local population size and likely distribution. This report describes the analytical techniques used for (a) generating total estimated population sizes to aid in marine SPA site selection, and (b) defining the extent of each interest feature, including some consideration of site boundary location. Aerial and boat-based survey count data from Carmarthen Bay, Wales (Webb et al. 2004); the outer Tay area, Scotland (McSorley et al. in prep.); and Liverpool Bay, England and Wales (Webb et al. in prep.) are used as case studies for illustrative purposes.
 
 
 
 
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ISSN 0963 8901
 
Please cite as: McSorley, C.A, Webb, A, Dean, B.J, Reid, J,B, (2005), UK inshore Special Protection Areas: a methodological evaluation of site selection and definition of the extent of an interest feature using line transect data., JNCC Report 344, ISSN 0963 8901