Management of coastal grazing marshes for breeding waders: the importance of surface topography and wetness

Abstract

Coastal grazing marshes are amongst the most threatened habitats in the UK. Those in the North Kent Marshes ESA in south-east England support large breeding populations of lapwing ( Vanellus vanellus) and redshank ( Tringa totanus). Habitat preferences, feeding rates and nest site selection by lapwing and redshank were investigated to determine the importance of rills (relict saltmarsh drainage channels) and surface wetness. Studies showed that lapwing chicks and redshank preferred to feed in rills, where their feeding rates were higher than those on open turf. Feeding rates were also higher in wet rills than in dry ones. Lapwings but not redshank tended to nest closer to rills than would have been expected by chance. These findings identify a behavioural link for the relationship between the birds' distribution, rill availability and wetness. The study also showed that the settling densities of both species were highest in marshes containing rills with many branches. It is, therefore, possible to attract breeding lapwing and redshank by flooding rills during April and May to create water margin habitat for feeding. As this approach does not appear to result in extensive sward death, it is a practical alternative to extensive flooding on grazing marshes that are managed for breeding waders and livestock production.