DOI: 10.71615/bexis.32057
title: Losers and winners: Responses of grassland arthropods to land-use components for all grassland plots from 2008-2018

description: Intensified land-use in grasslands reduces biodiversity, particularly affecting arthropod populations. However, responses of individual species vary depending on their ecological traits and habitat requirements. Some species may tolerate or even benefit from intensive land-use, while others, particularly specialists or those with narrow niches, are likely to be negatively affected.&lt;br&gt;We used a quantitative niche model to evaluate species-specific responses to land-use intensity in four arthropod orders common in grasslands: Araneae, Coleoptera, Hemiptera, and Orthoptera. From 2008 to 2018, a total of 214,416 individuals across 1352 species were collected on 150 grassland plots across three regions (Schorfheide-Chorin, Hainich-Dün, and Schwäbische Alb) of Germany. The effects of mowing, fertilizing, and grazing on species occurrence and abundance were evaluated with their niche optima to identify winners, losers, and neutrals. Further abundance weighted means of the species and the respective land-use component were compared with feeding guilds, body size, and Red List statuses (categories, short-term and long term population trends).
description: Study design: For analysis, we only used adult specimens, and arthropods that were determined to species level. In total, we analyzed 214,416 individuals from 1352 species out of four arthropod orders, namely Araneae (176 species, 7078 individuals), Coleoptera (762 species, 42,248 individuals), Hemiptera (384 species, 161,171 individuals) and Orthoptera (30 species, 3919 individuals) found on all 150 grassland plots between 2008 and 2018.&lt;br&gt;Calculated niche models on basis of fertilizing, grazing and mowing intensity. Based on interview data set 26487 and publication of Vogt et al. 2019; for fertilizing and grazing the raw data from the LUI Tool (default components set, unstandardized) was used. Mowing intensity is based on the new mowing intensity index by Hartlieb et al. (2024), Dataset id: 31970. | Sampling design: From 2008 to 2018, arthropods were sampled annually on the 150 grassland plots. Sampling took place twice a year, in June and August. Herb layer arthropods were sampled by sweep netting along a 150 m transect along three plot borders, with 60 double sweeps per plot. Sweep netting was only conducted on days without rain, with low wind speed and after the morning dew had dried. All adult specimens of the orders Araneae, Coleoptera, Orthoptera and Hemiptera (only Heteroptera and Auchenorrhyncha) were sorted and identified to species level (Neff et al., 2019; Seibold et al., 2019).&lt;br&gt;To understand species’ ecological roles and predicting their responses to land-use intensification, we combined a trait-based approach with our sampled arthropod species. Therefore, we used a comprehensive trait dataset, assembled from various literature sources and validated in consultation with taxonomic experts for the respective groups (Gossner et al., 2015). We compiled the mean body size (mm) and feeding guild for all collected species of Araneae, Coleoptera, Hemiptera, and Orthoptera. Feeding guild is categorised into carnivore, herbivore, omnivore, and myceto-detritivore (which is the combination of mycetophagous, detrivore, and fungivore), each referring to the main food source during larval and adult stages of a species. Omnivores are defined as species using more than one feeding source (plants, animals, fungi, decaying plants or animals) to similar extent across larval and adult stages. All Araneae are carnivores and all sampled Auchenorrhyncha herbivores. &lt;br&gt;The inclusion of Red List data offers valuable insights into how land-use components impact species of varying conservation status. German Red List data were downloaded from the Rote Liste Zentrum website (https://www.rote-liste-zentrum.de/de/Download-Wirbellose-Tiere-1875.html, last accessed on 01/2025) (SI Table S2). For our analysis, we used Red List categories (LC = Least concern, NT = Near threatened, R = Rare, G = Threatened to an unknown extent, VU = Vulnerable, EN = Endangered, CR = Critically endangered, EX = Extinct in Germany) and the short-term (last 10-25 years) and long-term (last 50-150 years) population trends (converted in decrease, stable, increase). Non-native species are not evaluated in the German Red List and hence excluded.&lt;br&gt;For the habitat fidelity with focus on forest species, our data set was merged with the data from Dorow et al. (2019). | Data preparation: The data on land-use components are based on the responses of the respective farmers, landowners, or tenants to a standardized questionnaire on relevant management information on the type and intensity of annual land-use and agricultural practices. These surveys were carried out on an annual basis. The survey data from Vogt et al. (2019) were used to calculate individual land-use intensity values for mowing, fertilizing and grazing, from 2008 to 2018 (SI Fig. S1). We used the unstandardized raw data per year and plot for the indices of grazing and fertilizing intensity according to Blüthgen et al. (2012). Grazing (LSU d/ha) is derived by multiplying the livestock units with the duration of grazing per hectare, accounting for cattle, sheep, horses, and goats, ranging from 2 to 2500 animals for 1 to 365 days per year. Fertilizing (kgN/ha) is quantified in kilograms of nitrogen per hectare, encompassing organic or inorganic sources such as manure, slurry, biogas, mash, and nitrogen, applied from 1 to 7 times, ranging between 6 and 360 kg/ha per year. For mowing intensity, we used the mowing compound intensity index M(i) (cuts ± impact of mowing regime i.e., mowing machine, mowing height and use of conditioner per year) from Hartlieb et al. (2024). If there were missing values for one variable of the mowing index, the neutral benchmark (a chosen mean value of each component, representing a midpoint between favorable or unfavorable mowing practices affecting the biodiversity of meadow-dwelling species) was used instead (Hartlieb et al., 2024). | Data analysis: Components were averaged across the years 2008–2018, and the sampled arthropods were summed up per plot.&lt;br&gt;We employed a randomization method based on a null model. This model assumes that each species had an equal likelihood of occurring at any site from the regions where the species occurred. The null model assigned mowing, grazing, or fertilizing intensity to each species from random sites, drawing from the same total number (but not identity) of sites on which the species was found. This calculation was restricted to the specific region (Schwäbisch Alb, Hainich, Schorfheide) where the respective species was recorded, i.e., when the species only occurred in the Schorfheide, the null model only uses plot values from the 50 Schorfheide plots. We used 10,000 iterations to produce a distribution of expected 〖AWM〗_null values. We then calculated the p-values by comparing the observed data to the null distribution generated through randomizations. Species with observed AWM lower than 95% of the 〖AWM〗_null values (p < 0.05) were treated as “loser”, while those with AWM higher than 95% of the 〖AWM〗_null values (p < 0.05) were identified as “winner”. Species that did not fit into either category were classified as “neutral”.&lt;br&gt;To separate true neutral responses from those caused by species rarity, we conducted a simulation analysis using log-normal randomizations of species occurrences across plots to establish minimum occurrence thresholds required to reliably classify species as “losers” or “winners” along land-use gradients (fertilization, mowing, grazing). Fertilization required at least five occurrences for detecting losers (two for mowing/grazing), while no thresholds were needed for winners; for consistency, a conservative five-occurrence threshold was applied across all components, excluding 781 rare species. | Literature references: Blüthgen et al. (2012) A quantitative index of land-use intensity in grasslands: Integrating mowing, grazing and fertilization. Basic and Applied Ecology 13. https://doi.org/10.1016/j.baae.2012.04.001&lt;br&gt;&lt;br&gt;Vogt et al. (2019) Eleven years’ data of grassland management data in Germany. Biodiversity Data Journal 7: e36387. https://doi.org/10.3897/BDJ.7.e36387&lt;br&gt;&lt;br&gt;Ostrowski et al. (2020) Land use intensity index (LUI) calculation tool of the Biodiversity Exploratories project for grassland survey data from three different regions in Germany since 2006. Zenodo.&lt;br&gt;http://doi.org/10.5281/zenodo.3865579&lt;br&gt;&lt;br&gt;Hartlieb M, Staab M, Berger JL, Achury R, Gossner MM, Seibold S, Weisser WW, Blüthgen N (accepted): Losers and winners: Responses of grassland arthropods to land-use components. Oikos https://doi.org/10.1002/oik.11404&lt;br&gt;https://www.bexis.uni-jena.de/PUB/ShowPublication/Index/32004&lt;br&gt;&lt;br&gt;Seibold, S., Gossner, M. M., Simons, N. K., Blüthgen, N., Müller, J., Ambarlı, D., Ammer, C., Bauhus, J., Fischer, M., Habel, J. C., Linsenmair, K. E., Nauss, T., Penone, C., Prati, D., Schall, P., Schulze, E.-D., Vogt, J., Wöllauer, S., & Weisser, W. W. (2019). Arthropod decline in grasslands and forests is associated with landscape-level drivers. Nature, 574(7780), 671–674. https://doi.org/10.1038/s41586-019-1684-3&lt;br&gt;&lt;br&gt;Gossner, M. M., Simons, N. K., Achtziger, R., Blick, T., Dorow, W. H. O., Dziock, F., Köhler, F., Rabitsch, W., & Weisser, W. W. (2015). A summary of eight traits of Coleoptera, Hemiptera, Orthoptera and Araneae, occurring in grasslands in Germany. Scientific Data, 2(1), 150013. https://doi.org/10.1038/sdata.2015.&lt;br&gt;&lt;br&gt;Neff, F., Blüthgen, N., Chisté, M. N., Simons, N. K., Steckel, J., Weisser, W. W., Westphal, C., Pellissier, L., & Gossner, M. M. (2019). Cross-scale effects of land-use on the functional composition of herbivorous insect communities. Landscape Ecology, 34(8), 2001–2015. https://doi.org/10.1007/s10980-019-00872-1&lt;br&gt;&lt;br&gt;Dorow, W. H., Blick, T., Pauls, S. U., & Schneider, A. (2019). Waldbindung ausgewählter Tiergruppen Deutschlands. BfN-Skripten, 544, 388. | Data references: This dataset is based on the other datasets: &lt;br&gt;&lt;br&gt;    Weisser, Wolfgang; Goßner, Martin; Pasalic, Esther; Lange, Markus; Türke, Manfred; Gallenberger, Iris; Simons, Nadja; Staab, Michael (2024): Sweep net samples from grasslands since 2008: Araneae, Coleoptera, Hemiptera, Orthoptera. Version 13. Biodiversity Exploratories Information System. Dataset. https://www.bexis.uni-jena.de/ddm/data/Showdata/21969?version=13&lt;br&gt;   &lt;br&gt; Staab, Michael; Simons, Nadja; Goßner, Martin (2024): Body size and life-history traits of arthropod species. Version 30. Biodiversity Exploratories Information System. Dataset. https://www.bexis.uni-jena.de/ddm/data/Showdata/31122?version=30&lt;br&gt; &lt;br&gt;   Staab, Michael; Achury, Rafael (2024): Check list for species names (including synonyms) for all Arthropods Core species data. Version 21. Biodiversity Exploratories Information System. Dataset. https://www.bexis.uni-jena.de/ddm/data/Showdata/31355?version=21&lt;br&gt;  &lt;br&gt;  Staab, Michael (2025): Red List Germany status of arthropods. Version 23. Biodiversity Exploratories Information System. Dataset. https://www.bexis.uni-jena.de. Dataset ID= 31982 &lt;br&gt;&lt;br&gt;Hartlieb, Margarita (2025): M(i) - mowing intensity index for all grassland plots since 2006. Version 8. Biodiversity Exploratories Information System. Dataset. https://www.bexis.uni-jena.de. Dataset ID= 31970&lt;br&gt;&lt;br&gt;Vogt, Juliane; Schumacher, Uta; Schreiber, Christin; Lauterbach, Ralf; Franke, Anna; Ostrowski, Andreas; Miriam Teuscher (2025): Land use in grasslands: raw data of yearly owner interviews. Version 69. Biodiversity Exploratories Information System. Dataset. https://www.bexis.uni-jena.de. Dataset ID= 26487