Data from: Farmland biodiversity benefits from small woody features
Abstract
Although positive effects on biodiversity of woody features in agricultural landscapes are widely recognized, questions remain on where to prioritize their implementation and in which proportion. To investigate the response of farmland biodiversity to small woody features (SWF) density in different landscape compositions (cropland, grassland, mixed), we analyzed fine-resolution data from standardized monitoring schemes on 111 common birds, 22 bats, and 25 bush crickets species, at national scale (relying on 3772, 834, and 727 monitoring points). We used Generalized Additive Mixed Models to model population and community responses, through different metrics (i.e., abundance, species diversity, and functional composition). We found that the three taxa exhibited a positive response to SWFs, and more especially in cropland, where the SWF density is the lowest relative to grassland and mixed landscapes. Also, our results suggested a non-linear response common to the three taxa, with an increased benefit up to at least 6% of SWF density in cropland, and beyond for most of the metrics but to a lesser extent (e.g., maximum abundance reached at 7-12% SWF). We note, however, that some particular species among farmland bird specialists do not benefit from these SWFs. Overall, we emphasize the benefits to promote woody features in agricultural landscapes, notably in cropland, to support farmland biodiversity and its associated ecosystem functions. Our study results provide crucial empirical evidence to the recommendations of previous studies and the relevance of the EU Biodiversity Strategy for 2030 to dedicate at least 10% of farmland to high-diversity landscape features.
https://doi.org/10.5061/dryad.6wwpzgn3v
======================================================================================
DATA-SPECIFIC INFORMATION (Data.zip file)
This folder (Data.zip) contains the .RData dataframes used to run the Generalized Additive Mixed Models (GAMMs) in the study. The file names follow a standardized structure describing their content:
- Taxa:
STOC(Birds),CHIROPTERA(Bats), orORTHOPTERA(Bush-crickets).- For bird abundance, files are split by ecological guilds where applicable:
GENERALIST,FORESTIERS(Forest),AGRICOLES(Farmland), orBATIS(Urban).
- For bird abundance, files are split by ecological guilds where applicable:
- Analysis Level:
LONGDATAFRAME(Population-level / multi-species format) orSHORTDATAFRAME(Community-level format). - SWF Buffer Size: The landscape resolution buffer considered (
100m,300m,500m,1km,5km, or10km).
Note: The suffixes _NOTWEEDIE or _TWEEDIE in the filenames indicate the family distribution family used in the corresponding models.
Note on Bird (STOC) Datafiles structure: Please note that the number of variables retained varies depending on the specific model requirements for each STOC file: SHORTDATAFRAME_NOTWEEDIE files contain all 11 variables listed below, LONGDATAFRAME_TWEEDIE files contain 6 variables, and guild-specific files (e.g., forestiers, agricoles) contain 7 variables.
Variable Definitions
1. Response Variables
Simpson: Simpson diversity index (dimensionless).Abundance: Total count/abundance per species (used for Birds).log_Abundance: Log-transformed activity/abundance index (used for Bats and Bush-crickets).CSI: Community Specialization Index (used for Birds and Bats).CTrI: Community Thermal Index (used for Birds).SBI: Community Body-Length Index (used for Bush-crickets).
2. Explanatory Variables Common to All Taxa
Haies: Percentage of Woody Linear Features (SWF) density within the considered buffer.LM: Landscape composition categories.- For Bats & Bush-crickets:
C= Cropland,G= Grassland,Mixte= Mixed. - For Birds:
C= Cropland, Cg = Cropland with minor grassland dominance,G= Grassland,Gc= Grassland with minor cropland dominance,Mixte= Mixed.
- For Bats & Bush-crickets:
tmp_spring: Mean spring temperature (°C) at a 10 km resolution, extracted from the European climate rasters (E-OBS, ECA&D) using the R packageclimateExtract.precip_spring: Total spring precipitation (mm/day) at a 10 km resolution, extracted from the European climate rasters (E-OBS, ECA&D) using the R packageclimateExtract.
3. Explanatory Variables Specific to Bird Models (STOC)
carre: ID of the 2x2 km monitoring plot (random effect; points are nested within plots).id_point: ID of the specific monitoring point (random effect).annee.x: Year of the survey (random effect).Urban: Percentage of urban cover within the buffer (used exclusively as a covariate in the Bird Simpson model).
4. Explanatory Variables Specific to Bat & Bush-cricket Models
Julian_day: Julian day of the survey (continuous seasonal covariate).tg_day: Mean temperature of the specific survey day (°C).annee: Year of the survey (random effect).Species: Species scientific name (used as a random effect in population-levelLONGDATAFRAMEmodels).
5. Explanatory Variable Exclusive to Bat Models (CHIROPTERA)
dist_min_water: Log-transformed minimum distance to the nearest water body (meters).
======================================================================================
CODE MAIN INFORMATION. (Code.zip file)
1 - Run GAMM model.R --> script used to fit the GAMM model with settings (buffer size where % SWF density computed, response metrics and taxa) can be change to retrive all models fitted in article.
2 - Calculate breakpoint and maximal value.R --> script used to calculate breakpoint value and maximal value from the fitted model with script 1.
We used R logiciel (4.1.1) and packages described in main manuscript and appendix B.
