DOI: 10.5061/dryad.ghx3ffbz9
title: Grassland nature reserves safeguard a high species richness and biomass of grasshoppers

description: In the course of land-use change, especially since the mid-20th century,
 the area of semi-natural (unimproved) grasslands has dramatically
 decreased. One way to counteract this process is to designate nature
 reserves. However, the effectiveness of nature reserves is controversial.
 The aim of our study was to evaluate the environmental drivers of species
 richness and biomass of Orthoptera (hereinafter termed ‘grasshoppers’) in
 grasslands inside nature reserves and within the intensively-used
 agriculture landscape (hereinafter termed ‘wider countryside’). For this
 purpose, we sampled the grasshoppers at the landscape scale in 45 randomly
 selected plots. Each plot had a size of 5 ha. The abundance of
 grasshoppers, as a basis for the biomass calculation, was recorded at the
 habitat scale in 20 meadow patches (500 m² each). In addition, various
 environmental parameters such as habitat diversity, mowing intensity and
 vegetation structure were determined at the landscape and habitat scale.
 Our results illustrate the importance of nature reserves for the
 conservation of grasshoppers. Control plots in the wider countryside
 harboured fewer species than plots within nature reserves. The differences
 were even clearer among threatened species. On average, plots in nature
 reserves had almost twice as many threatened species than control plots in
 the wider countryside. The comparison revealed similar patterns at the
 habitat scale: both the number of species and biomass were higher in
 nature reserves. At the landscape scale, number of species were best
 explained by the amount of wet grassland and habitat diversity. We
 identified mowing intensity and to a lower extend the degree of drainage
 as the key drivers of species richness and biomass at the habitat scale.
 Synthesis and applications: To preserve biodiversity in nature reserves,
 we recommend (i) leaving uncut refuges during mowing and (ii) blocking
 drainage to stabilize the water level. Both measures contribute to a high
 species number and abundance of grasshoppers and many other insects. An
 effective conservation measure to promote species richness in the wider
 countryside would be to increase habitat diversity. This can be done by
 creating or restoring fallow islands, field margins, fringes and
 hedgerows.
description: # Grassland nature reserves safeguard a high species richness and biomass
 of grasshoppers
 [https://doi.org/10.5061/dryad.ghx3ffbz9](https://doi.org/10.5061/dryad.ghx3ffbz9) ## Description of the data and file structure These are species (Orthoptera) and environmental data collected in the field at two spatial scales (csv. files). A detailed description of the methodology and structure of the data can be found in Poniatowski et al. (2024): Grassland nature reserves safeguard a high species richness and biomass of grasshoppers. Journal of Applied Ecology. ### Files and variables #### File: Data\_landscape\_scale.csv **Description:** **plots of 5 ha** ##### Variables * no_plot: Name (abbreviation) of the sample site - species_no_all: Number of all species detected - species_no_threatened: Number of threatened species detected - subarea: The study area was divided into six subareas according to landscape configuration - temperature: Summer temperature (°C) (long-term mean: 1991–2020) - precipitation: Annual precipitation (mm) (long-term mean: 1991–2020) - elevation: m a.s.l. - arable_land: Cover of this land-use types (%) within a radius of 200 m around each plot - forest: Cover of this land-use types (%) within a radius of 200 m around each plot - grassland: Cover of this land-use types (%) within a radius of 200 m around each plot - urban_area: Cover of this land-use types (%) within a radius of 200 m around each plot - habitat_diversity: The number and proportion of the habitat types per plot were used to calculate the Shannon index (H′) as a measure of habitat diversity - wet_grassland: Cover within each plot #### File: Data\_patch\_scale.csv **Description: meadow patches of 500 m²**  ##### Variables * no_patch: Name (abbreviation) of the sample site * species_no_all: Number of all species detected * biomass_all: To calculate biomass, we used the sampled grasshopper abundance data and the available species- and sex-specific weights (Table S5). In order to get a value for the nymphs, the mean weights of the adults were halved. The result of multiplying abundance and weight was an area-specific grasshopper biomass value (g/10 m²). * plot_type: Grassland inside or outside nature reserves * subarea: The study area was divided into six subareas according to landscape configuration. * mowing_intensity: We used the data set provided by Schwieder et al. (2022) to determine the mowing frequency within the patches. Using a special remote sensing procedure based on a combined "Sentinel-2 and Landsat 8 time series", the authors measured the intensity of land use for mown grassland in Germany between the years 2017 and 2020. The result is a raster data set (spatial resolution 10 m × 10 m) that divides the mowing frequency into seven categories (0 to 6 mowing events per year). To determine the land-use intensity within each meadow patch, the mowing data set was merged with the geometry of the patch. Afterwards, we calculated the mean mowing intensity per year for each patch. * drainage: To estimate the hydrological conditions in and around the respective patch, we measured the length of the ditches in ArcGIS 10.3.1 and determined the depth of the ditches at five random locations per ditch. A draining index was then calculated from the summed ditch length and the mean value of the ditch depth (draining index = ditch depth [m] × ditch length [m]). * height_field_layer: The vegetation height of the field layer was measured at five randomly selected points at an accuracy of 2.5 cm within the respective meadow patch and the mean value was then calculated. * cover_field_layer: We estimated the cover in steps of 5% for the entire meadow patch. * cover_sedges: We estimated the cover in steps of 5% for the entire meadow patch. * cover_mosses: We estimated the cover in steps of 5% for the entire meadow patch. * cover_litter: We estimated the cover in steps of 5% for the entire meadow patch. * cover_bare_soil: We estimated the cover in steps of 5% for the entire meadow patch. ## Code/software Excel