Research on breeding birds in Dutch dune areas

Dune areas, including salt marshes, comprise only 1% of the land area of The Netherlands. Yet almost 80% of the 180 bird species that breed in The Netherlands, are known to breed or to have bred in dunes, which also represent valuable habitat for migratory and wintering birds. Being aware of the high natural value of the dunes and of the expected impact of a variety of threatening activities, nature conservation studies were set up by concerned volunteers and universities. Breeding birds played an important role from the beginning. It certainly contributed to the rather high nature protection status that most dunes areas currently enjoy. Furthermore these old studies provide a picture of the avifaunal value of these areas in the more pristine days. During the last decades intensive long-term monitoring of breeding bird populations has become more and more important in the Dutch dunes. In 1958 the first inventory of dune breeding birds in relation to management issues started. Its aim was to monitor the changes in species composition and numbers after the artificial infiltration of river water for drinking water production. Since then many projects of the same kind evolved in different dune areas, almost exclusively organised by volunteer bird watchers, yielding a data set which offers promising analytical possibilities. This article provides an overview of breeding bird research projects in dune habitats in relation to important actual management issues. The following issues will be dealt with: the impact of drinking water production; the impact of tall grass dominance and the ongoing growth of shrubs; the impact of the reappearance of the red fox Vulpes vulpes. The review will show that much insight has been gathered over the years concerning breeding birds and dune management but that many gaps in our knowledge still exist.