Effects of grass field margin management on food availability for Black-tailed Godwit chicks

Abstract

Over the last six decades, populations of wader species like the Black-tailed Godwit (Limosa limosa) have sharply decreased in the Netherlands. Agricultural intensification has led to reduced habitat quality for meadow birds. As a consequence, reproductive success has declined. One of the main drivers of this decline in reproductive success is reduced food availability for meadow bird chicks. Agri-environment schemes (AES), designed to halt this decline, have so far been insufficient. Most of these AES focus on entire fields, but recent research suggests that differences in suitability exist within fields. Grass field margins may be more suitable for meadow bird chicks than the center of intensively managed grass lands. To improve existing meadow bird AES it could be beneficial to implement additional management in field margins of intensively managed grass fields. An already existing type of field margin AES with additional management is the botanical field margin. Here, we evaluate four different types of field margin management, including botanical field margins, focusing on aerial insects (an important part of the diet of Black-tailed Godwit chicks and Redshank chicks) in field centers and margins. Grass field margins contained more large aerial insects than field centers and, more importantly, additional management of the grass field margin increased the number of aerial insects in the margin. We conclude that combining meadow bird AES and botanical field margin management may enhance meadow bird food availability and improve the efficacy of AES.