Effectiveness of spatial mosaic management for grassland breeding shorebirds

Since 2000, a new management technique has been introduced to stop the rapid decline of grassland breeding shorebirds in the Netherlands, called 'mosaic management'. The most important difference from earlier Agri-Environment Schemes is that the mosaic management is conducted at a landscape scale (150-650 ha) rather than an individual farm scale (50-60 ha) and that there is purposeful planning of the spatial distribution and layout of management measures within a local area. We tested the effectiveness of the mosaic management by analysing breeding population trends of Northern Lapwing (Vanellus vanellus), Black-tailed Godwit (Limosa limosa), Redshank (Tringa totanus) and Oystercatcher (Haematopus ostralegus) in comparison with three other management types: individual management, regular farmland and nature reserves. After the introduction of mosaic management, populations of Black-tailed Godwit and Redshank stabilised and Northern Lapwing populations increased. Oystercatcher decreased, but this was also due to reduced winter survival. Populations in the mosaic management areas showed a greater annual improvement of 0-18% compared to other management types. The mosaic areas did not appear to be 'sink' areas as productivity in the mosaic areas seemed to be sufficient to support the observed densities. However, with the exception of Northern Lapwing, the change of trend was not greater in the mosaic areas than in the other management types. So, for the species other than Northern Lapwing, the good performance cannot be attributed to the mosaic management. The mosaic areas were good breeding habitats beforehand and continue to be so. It is possible that the mosaic management is part of the success, but not exclusively so. Our results show that modern farming can still be combined with grassland breeding shorebird management. However, further study of success factors is urgently needed for the conservation of the remaining good habitats on farmland and restoration of lost ones.