DOI: 10.5061/dryad.vhhmgqnqx
title: Similarity between agricultural and natural land covers shapes how biodiversity responds to agricultural expansion at landscape scales

description: The impact of agriculture on biodiversity depends on the extent and types
 of agriculture and the degree to which agricultural land contrasts with
 the natural ecosystem. Most research on the latter comes from studies on
 the influence of different agricultural types within a single ecosystem
 with far less study on how the natural ecosystem context shapes the
 response of biodiversity to agricultural production. We used citizen
 science data from agricultural areas in Canada’s Eastern Hardwood-Boreal
 (forest ecosystem, n=108 landscapes) and Prairie Pothole (prairie
 ecosystem, n=99) regions to examine how ecosystem context shapes the
 response of avian species diversity, functional diversity and abundance to
 the amount of arable crop and pastoral agriculture at landscape scales.
 Avian surveys were conducted along 8km transects of Breeding Bird Survey
 routes with land cover assembled within a 20km2 landscape around each
 transect. The amount of agriculture at which species diversity peaked
 differed between the forest (15%) and prairie (51%) ecosystems, indicating
 that fewer species tolerated the expansion of agriculture in the former.
 In both ecosystems, functional diversity initially increased with
 agriculture and peaked at higher amounts (forest: 42%, prairie: 77 %) than
 species diversity suggesting that functional redundancy was lost first as
 agriculture increased. Species turnover with increasing agriculture was
 primarily among functional groups in forest where a shift from a low to a
 high agriculture landscape led to a decline in the percent of the
 community represented by Neotropical migrants, insectivores, upper foliage
 gleaners and bark foragers, and an increase in the percent of the
 community represented by short-distance migrants, granivores, omnivores
 and ground gleaners. There were few distinct shifts in the percent of the
 community represented by different functional groups in the prairie
 ecosystem. Total abundance was the least sensitive measure examined in
 both ecosystems and indicated that species losses with agriculture are
 likely followed by numerical compensation from agriculture tolerant
 species. Our results highlight the importance of ecosystem context for
 understanding how biodiversity is affected by agricultural production with
 declines in diversity occurring at lower agricultural extents in
 ecosystems with lower similarity between natural and agricultural land
 covers. These findings allow for more specific conservation
 recommendations including managing for species intolerant to agriculture
 in prairie ecosystems and limiting the expansion of high contrast
 agriculture and the loss of semi-natural habitat, such as hedge rows, in
 historically forested ecosystems.
description: Avian data is based on citizen science surveys collected during
 the North American Breeding Bird Survey. Land cover data is based on
 Agriculture and Agri-Food Canada crop mapping data which integrates
 remotely sensed and other sources of information to generate a 30m
 resolution spatial layer of natural and agricultural land covers. These
 datasets were combined to examine avian diversity and abundance along
 sections of BBS routes (i.e. transects) in relation to extent of
 agricultural land cover in the Eastern Hardwoods and Prairie ecosystems in
 Canada.
description: All cells contain data where a row is a transect and columns
 specify information about the transect, avian data and land cover
 measurements.