Abstract from BTO Research Report No. 451:

G.E. Austin, N.H.K. Burton & M.M. Rehfisch (2006)

Newport Wetlands Reserve: Assessment of the SPA Established Wetland 2000/1 to 2005/06 ISBN 978-1-906204-00-6

EXECUTIVE SUMMARY

1. The Newport Wetlands Reserve was established in March 2000 as part of the compensation measures arising from the impoundment of Cardiff Bay. It was asked to meet two “bird targets” within five years of its establishment. Firstly, to ensure appropriate compensation to the scale of loss of the bird populations from Cardiff Bay, the reserve should support at least two species of wintering waterbird in nationally (GB) important numbers. Secondly, that within five years it would have the potential to qualify for Special Protection Area (SPA) status alongside or within an extended Severn Estuary SPA boundary.
2. This report analyses waterbird counts collected as part of the Wetland Bird Survey (WeBS) together
   with additional counts supplied by CCW with the aim of assessing whether either or both of these targets have been met.
3. Generally, in the UK, a site is considered to be nationally important for a given species when numbers exceed a level of at least 1% of the estimated national population – the 1% National Threshold. For wintering waterbirds, numbers on a site are generally quantified by taking the five-year average of the peak winter counts – the five-year peak mean.
4. Under this criterion and when using all available data, two waterbird species, Shoveler and Blacktailed
   Godwit, have attained the 1% National Threshold across the entire reserve during the first five years (winters 2000/01 to 2004/05) following establishment of the reserve. Black-tailed Godwit has also attained the 1% National Threshold on the newly created habitat alone. proportion of 1% National Threshold attained new habitat inland of the sea wall entire reserve standard counts all available data standard counts all available data
   Shoveler 0.72 0.78 0.91 1.06
   Black-tailed Godwit 0.79 1.09 0.93 1.19
5. Given that the reserve substantially comprises newly created habitat, it is possible that some species are still going through a period of colonisation. While generally, five-year peak means are used to determine if qualifying thresholds have been met, other methods may be acceptable when defensible. Accordingly, annual peak counts were also considered. Aside from the two species that have already surpassed their 1% National thresholds, the annual peaks of Shelduck and Little Grebe have come close to, but have not yet reached, this Threshold. The annual peak for Pintail exceeded the Threshold during the first winter but has declined sharply since.
6. Furthermore, significant upward trends (P<0.05) in annual peak counts were found for five species.
   Thus if numbers do not reach carrying capacity (upper limit of numbers that can be supported by available resources) in the foreseeable future and these trends continue, then Little Grebe is likely to attain this Threshold in the next two years. None of the other species are likely to attain this level in the immediate future although the annual peak numbers of Gadwall and Wigeon have the potential to do so within the next six years if current trends were to be maintained.
7. It is reasonable to assume that, since it was established, the reserve has become a functional component of the Severn Estuary SPA. Consequently an extension of the boundaries of the Severn Estuary SPA to encompass the newly created habitats within the reserve boundary would be warranted.
8. Underpinning this, an argument could be made for the extension and re-notification for waterbird interest, of the existing Gwent Levels SSSIs complex, of which part of the reserve is already a component, to include all newly established habitat within the reserve inland of the seawall, based on numbers of Black-tailed Godwit, Shoveler and potentially Little Grebe.

Back to Research Reports 345 onwards