Untangling the role of a novel agroecosystem as a habitat for declining farmland birds

Abstract

As a result of agricultural industrialisation, traditionally managed habitats have dramatically declined throughout Europe. As a result, farmland specialists across several taxa have become increasingly threatened. Concurrently, altered farming practices have also contributed to the emergence of novel agricultural habitats, such as Christmas tree plantations, but knowledge of their impact on biodiversity is still scarce. In the following study, we analysed the drivers behind the territory selection of four declining farmland birds—Common linnet (Linaria cannabina), Tree pipit (Anthus trivialis), Woodlark (Lullula arborea) and Yellowhammer (Emberiza citrinella)—in a landscape dominated by Christmas tree plantations. Our study suggests that Christmas tree plantations provide well‐suited breeding conditions for the species and thus may represent important refuges in human‐modified landscapes. We found that all four species favoured young Christmas tree plantations (<6 years) for territory establishment. In particular, the territories of Tree pipit and Woodlark were characterised by a high proportion of young plantations, which provide open habitat structures rich in bare ground. However, older plantations (>6 years) were also of high importance for some of the model organisms, especially for Common linnet and Yellowhammer. The territory establishment of Yellowhammer was additionally favoured by brushwood plantations, clear‐cut/fringe vegetation and low‐growing shrubland. We attribute the high value of Christmas tree plantations mainly to the coexistence of open habitat structures rich in bare ground and less intensively managed stands, which both represent important foraging sites for the model organisms. At least in intensively used agricultural areas, Christmas tree plantations may represent important refuges for declining farmland birds. Therefore, further measures aiming to promote habitat quality while reducing the use of herbicides in the plantations should be addressed.

Local and regional‐scale effects of hedgerows on grassland‐ and forest‐associated bird populations within agroecosystems

“…Retaining native habitat along the edges of fields provides foraging and nesting opportunities for species that require forest and shrub habitats in landscapes dominated by large agricultural fields (Fonderflick et al, 2013; Wilson et al, 2017). LWFs also often provide a buffer zone between the woody vegetation and planted crops that represents less frequently disturbed transitional habitat of grasses and forbs that may provide grassland species with suitable foraging and ground‐nesting sites, particularly for species that are less restricted by grass height or proximity to edge habitat (Kämpfer et al, 2022). This may explain the positive effect on some grassland species, such as vesper sparrow ( Pooecetes gramineus ), which tend to nest along field edges and fence lines (Jones & Cornely, 2020).…”

Vegetation management shapes arthropod and bird communities in an African savanna

“…This enhanced catchability could explain why Lilac‐breasted Rollers characterized summer mow habitats where they fed on potentially easy‐to‐detect arthropods due to low herbaceous vegetation cover (K. Stears, personal observations). Although interactive effects have been observed between the prey abundance and prey catchability hypotheses for some predators (Smith et al, 2020), numerous predators, including insectivorous birds, prefer to hunt in habitats where it is easier to catch their prey and not necessarily where prey are more abundant (Kämpfer et al, 2022; Kämpfer & Fartmann, 2019; Nkwabi et al, 2011). Our results support the prey catchability hypothesis because tree density (i.e., perching locations for hunting), and not arthropod abundance, was the overriding driver of insectivorous bird abundance and richness across our treatments.…”

Urban rooftops near sports pitches provide a safe haven for a declining shorebird

“…breeding or feeding adults, alarming birds and pairs at potential nesting sites) were recorded with their location during each survey. In order to separate the territories of different birds in close proximity, particular attention was paid to simultaneous observations of territorial behaviour 52 . If birds showing territorial behaviour were detected at potential nesting sites during at least two of the four surveys, breeding was assumed 51 .…”