The EU Birds Directive provides a
legislative framework for the protection, management and control of
naturally occurring wild birds within the EU. As part of the
implementation of the Birds Directive in the UK, JNCC is currently
undertaking work to identify the most suitable sites to be put
forward as Special Protection Areas (SPAs) for birds in the marine
environment.
The identification of potential SPAs
in the marine environment is particularly difficult. The UK coastal
and offshore area is large (over 750,000 km2 ); there are no
obvious boundaries that can be used; and data on seabird
distributions at sea are sparse. To date, the UK has classified 253
sites as SPAs, but only three of these sites stretch below the
low-water mark.
As part of our work to identify
suitable marine SPAs, JNCC is working to identify offshore areas
with important aggregations of seabirds, using the European
Seabirds at Sea database (ESAS). With over 2 million records, ESAS
is the most comprehensive source of at-sea seabird distribution
data. Nevertheless, it provides only an irregular grid of data
points, with gaps in spatial coverage.
To fill in the gaps between the
known data points, we’re using a statistical interpolation method
called kriging. Based on the
idea that data points which are close together are more similar
than data points further apart, it estimates data at unknown
locations using known distances and values of known locations.This
technique is producing continuous maps of bird densities. Further
statistical techniques will then be used to help us identify
important areas for these species. Whether the areas identified are
suitable for classification as SPAs will depend on several
criteria, such as the numbers of species and individuals regularly
using the areas, and the geographical representation of the species
distributions.The first bird density maps were produced in October
2007, and the density mapping work should be completed for all
species for which this approach is feasible within the next 6-12
months.