Managing coastal grasslands for an endangered wader species can give a positive result only when expanding the area of open landscape

Abstract

1) The rapid loss of wetlands has caused a severe decline in the biota associated with these habitats. In Europe, the loss of wet grasslands has seriously affected breeding waders, whose numbers have halved in past 50 years and remaining populations are facing fragmented, low quality habitats. To improve the remaining sites as breeding grounds for these birds, exact species’ habitat requirements need to be known. Our study was carried out in Boreal Baltic coastal meadows where the main reason behind waders’ population declines in the past decades has been land abandonment. Hence, we focus on partially overgrown meadows, aiming to ascertain habitat characteristics determining the breeding site selection of meadow birds, especially Southern Dunlin (Calidris alpina schinzii) – an endangered subspecies characteristic to Baltic coastal meadows. 2) We studied the breeding territory selection of four wader species (Southern Dunlin, Common Redshank (Tringa totanus), Northern Lapwing (Vanellus vanellus) and Common Snipe (Gallinago gallinago)) in 23 coastal meadows over two consecutive years. We analysed seven habitat characteristics which could influence the breeding habitat selection of these species. 3) Our study demonstrates that breeding probability of all wader species rises when the nesting site is located at least 200-500 m from woodland, up to 20-50 m from wet areas and 130-190 m from coastline. Also, the height of the ground level has an impact on breeding probability, with lower areas (around 0.8 m) favoured. Concerning the Southern Dunlin, our results show that on meadows where the species was absent, suitable nesting sites, regarding the distance from woodland edge, were lacking. Thus, reforestation of meadows may be the key reason behind its poor population status. We also demonstrated, for the first time, that proximity of reed beds did not influence the nesting site selection of waders – result which contradicts with current meadow management suggestions. 4) Synthesis and applications. Expanding the open landscape, maintaining a high proportion of wet features and preventing overgrowth of the coastline and lower parts of the meadow, makes the habitat optimal for breeding waders. Concerning the growth of population size and spatial distribution of Southern Dunlin, removal of woodlands adjacent to meadows is crucial.