DOI: 10.5061/dryad.tdz08kpws
title: Data from: The relative importance of green infrastructure as refuge habitat for pollinators increases with local land-use intensity

description: 1. Agricultural expansion and intensification have resulted in strong
 declines in farmland biodiversity across Europe. In many intensively
 farmed landscapes, linear landscape elements such as field boundaries,
 road verges and ditch banks are the main remaining green infrastructures
 providing refuge for biodiversity, and as such play a pivotal role in
 agri-environmental policies aiming at mitigating biodiversity loss. Yet,
 while we have a fairly good understanding of how agricultural
 intensification influences biodiversity on farmland, little is known about
 whether and how local land-use intensity affects biodiversity in nearby
 linear landscape elements and how this affects their role as biodiversity
 refuge. 2. Focussing on pollinating insects, we examined the effects of
 local land-use intensity on biodiversity in agricultural fields and
 adjacent green infrastructures. In an intensively farmed area in
 South-Western France, we selected 23 agricultural grasslands and nearby
 field boundaries along a gradient in grassland cutting frequency which
 acted as a proxy for land-use intensity. We analysed how grassland cutting
 frequency affects species richness, abundance and community composition of
 wild bees and hoverflies in the grasslands and neighbouring field
 boundaries, and whether these effects differ across habitat types and
 species groups. 3. Grassland cutting frequency negatively affected
 pollinator species richness and abundance in the grasslands, whereas
 pollinators in the neighbouring field boundaries were unaffected. These
 responses reflected the effects of cutting frequency on floral resources,
 with flower cover and richness decreasing in grasslands but not in field
 boundaries. As a result, the proportion of the local pollinator community
 supported by field boundaries increased with the increasing cutting
 frequency of the adjacent grassland. 4. Common and rare pollinator species
 generally showed similar responses. Furthermore, communities of plants and
 pollinators in field boundaries next to intensively farmed grasslands were
 fairly similar to those next to extensively farmed ones. 5. Synthesis and
 applications. Our results suggest that, as nearby land-use intensifies,
 flower-rich field boundaries become increasingly important as pollinator
 refuge habitats. Conserving field boundaries and other green
 infrastructures, and maintaining or enhancing their quality, therefore
 constitute important tools to conserve and promote pollinators in
 intensively farmed landscapes.
description: Data was collected in the Long Term Socio-economic and Ecosystem
 Research Platform Zone Atelier “Plaine & Val de Sèvre” in
 south-western France. We surveyed wild bees, hoverflies and flowers
 twenty-three sites, each consisting of a grassland and a nearby field
 boundary. The survey was conducted in four separate rounds from June to
 August in 2015 using standardized transect walks. Data on cutting
 frequency of grasslands in 2015 was collected through interviews conducted
 with farmers in early 2016. Arable land cover and semi-natural habitat
 cover in 2015 within radii of 500 m and 1 km of each grassland-field
 boundary pair was calculated based on yearly land-use monitoring at the
 field scale over the study area. Species richness and
 abundance data of pollinators and flowers were aggregated over the two
 transects per habitat at each site. We classified wild bee and hoverfly
 species into rare and common species according to their proportional
 abundance in this study. Species accounting for less than 1.0% of the
 total number of individuals were classified as rare species, the other
 species were considered as common species. We
 calculated Bray-Curtis community similarity index of wild bees, hoverflies
 and flowers based on abundance data of each species in each habitat per
 site (aggregated over the two transects and four rounds). The reference
 grassland was randomly selected from those with the lowest cutting
 frequency (once a year). The field boundary adjacent this reference
 grassland was considered as the reference field boundary. We calculated
 similarity indexes for three comparisons: (a) between each field boundary
 and the reference field boundary; (b) between each grassland and the
 reference grassland; (c) between each grassland and its adjacent field
 boundary.
description: Only the pollinator individuals identified to species level were
 included in classifying species classes (common and rare species) and
 calculating similarity indexes. Two sites were not included when we
 calculated similarity indexes because they were surveyed less than four
 rounds.