Active farmsteads are year-round strongholds for farmland birds.
Abstract
Farmland birds have experienced substantial declines over recent decades and various conservation measures have been designed to halt their massive decrease. The effectiveness of these measures is however limited, due to inappropriate identification of crucial breeding and wintering habitats. Identification of appropriate habitats, like farmsteads, and understanding seasonal changes in species richness and abundance of farmland birds within these habitats may therefore be key for farmland bird conservation. We investigated the effect of variation in farmstead management on alpha and gamma diversity of all farmland birds and red-listed farmland birds in the Czech Republic. In particular, we evaluated the diversity of wintering and breeding birds at over 200 sites to explore: (1) differences in bird communities in three types of farmsteads and open farmland; (2) changes in species-specific habitat preferences between winter and spring; and (3) effect of landscape composition, ruderal vegetation and altitude on bird assemblages. Farmsteads with animal production harboured the highest, whereas open farmland areas had the lowest, species richness and abundance of all farmland birds and red-listed farmland birds. The decline of species richness in winter was more pronounced in farmland and abandoned farmsteads compared to farmsteads with plant and animal production. Single bird species showed different habitat preferences but the majority of species including red-listed farmland birds changed preferences towards animal farmsteads during winter. Bird species richness was negatively correlated with altitude and positively with representation of ruderal vegetation. Rarefied gamma diversity confirmed local patterns for both all species and red-listed species: the highest total species richness was observed in active animal farmsteads but differences among types were significant only during winter. Synthesis and applications. Active farmsteads are local bird diversity hotspots in agricultural landscapes, and host species of conservation concern. Our results highlight the importance of farmsteads during winter, which is a critical period for several wintering farmland species. Our research thus indicates that recent conservation measures for farmland birds should also focus on conservation within non-farmed habitats, such as actively used farmsteads.