Closing in on meadow birds. Coping with a changing landscape in the Netherlands

Abstract

A major part of the Netherlands consists of meadows used for dairy farming. These meadows are relatively wet and are the main habitat for a group of bird species, known as ‘meadow birds’. They are defined as bird species of which the population that occurs in the Netherlands is largely dependent on agriculturally used grasslands as a breeding site. Meadow birds are typically Dutch because nowhere else in the world does this assemblage of species breed together in the same habitat. The Netherlands is especially important for the Black-tailed Godwit (Limosa limosa) of which circa 50% of the European population breeds in Dutch meadows. Because of a recent decline of meadow bird species, various studies into many life characteristics have been started. It was found that the decline must be attributed to changes during the breeding season, especially to agricultural intensification resulting in a lowered breeding success. This thesis however focuses on nest site selection of meadow bird breeding pairs early in the season. Three habitat requirements are important then: land use, groundwater level and landscape openness. When quantifying the relative importance of these three requirements, landscape openness is found to be the most important, followed by land use and groundwater level. Similarly, an open landscape has been shown to be important in many other habitats characterized by openness like deserts, tundras, coasts, bogs and marshes. Predator visibility is the main reason for the importance of openness: meadow birds want to visually locate their potential predators and deter it from the breeding site. This is only possible in an open landscape setting with few landscape elements. A literature review confirms that meadow birds select nest sites at a distance from landscape elements. Apart from view-obstructing elements (like forest or buildings), also flat elements (like roads) result in disturbance distances. Human-used elements cause the largest disturbance distances, but elements that are not used by human beings also still do. Furthermore, occupied predator nests result in a surrounding area with lowered densities of meadow birds, irrespective whether the predator’s nest is situated in an open or closed landscape. For Black-tailed Godwit, five core breeding areas in lowland Netherlands were identified where it still breeds in the Netherlands in 2020. These core areas are all open meadow landscapes with high water levels, resulting in an agricultural management that can sustain a healthy godwit population. The five core areas are not officially designated as reserves and, also, two of them are located in the western provinces where the largest pressure of landscape clutter, especially due to urbanization, occurs. For the conservation of the relevant flyway population of the Black-tailed Godwit, EU member states can appoint Special Protection Areas (SPAs). However, the Netherlands did not formally appoint SPAs for its breeding population, but only for the period outside the breeding season when the SPAs function as post-breeding staging areas. Connectivity between SPAs and core breeding areas was however found to be not optimal, resulting in a bottleneck in the protection of Black-tailed Godwit