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Hederström V, Ekroos J, Friberg M, Krausl T, Opedal ØH, Persson AS, Petrén H, Quan Y, Smith HG, Clough Y. Pollinator-mediated effects of landscape-scale land use on grassland plant community composition and ecosystem functioning - seven hypotheses. Biol Rev Camb Philos Soc 2024; 99:675-698. [PMID: 38118437 DOI: 10.1111/brv.13040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/05/2023] [Accepted: 12/07/2023] [Indexed: 12/22/2023]
Abstract
Environmental change is disrupting mutualisms between organisms worldwide. Reported declines in insect populations and changes in pollinator community compositions in response to land use and other environmental drivers have put the spotlight on the need to conserve pollinators. While this is often motivated by their role in supporting crop yields, the role of pollinators for reproduction and resulting taxonomic and functional assembly in wild plant communities has received less attention. Recent findings suggest that observed and experimental gradients in pollinator availability can affect plant community composition, but we know little about when such shifts are to be expected, or the impact they have on ecosystem functioning. Correlations between plant traits related to pollination and plant traits related to other important ecosystem functions, such as productivity, nitrogen uptake or palatability to herbivores, lead us to expect non-random shifts in ecosystem functioning in response to changes in pollinator communities. At the same time, ecological and evolutionary processes may counteract these effects of pollinator declines, limiting changes in plant community composition, and in ecosystem functioning. Despite calls to investigate community- and ecosystem-level impacts of reduced pollination, the study of pollinator effects on plants has largely been confined to impacts on plant individuals or single-species populations. With this review we aim to break new ground by bringing together aspects of landscape ecology, ecological and evolutionary plant-insect interactions, and biodiversity-ecosystem functioning research, to generate new ideas and hypotheses about the ecosystem-level consequences of pollinator declines in response to land-use change, using grasslands as a focal system. Based on an integrated set of seven hypotheses, we call for more research investigating the putative pollinator-mediated links between landscape-scale land use and ecosystem functioning. In particular, future research should use combinations of experimental and observational approaches to assess the effects of changes in pollinator communities over multiple years and across species on plant communities and on trait distributions both within and among species.
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Affiliation(s)
- Veronica Hederström
- Centre for Environmental and Climate Science, Lund University, Sölvegatan 37, Lund, 223 62, Sweden
| | - Johan Ekroos
- Centre for Environmental and Climate Science, Lund University, Sölvegatan 37, Lund, 223 62, Sweden
| | - Magne Friberg
- Department of Biology, Lund University, Sölvegatan 37, Lund, 223 62, Sweden
| | - Theresia Krausl
- Centre for Environmental and Climate Science, Lund University, Sölvegatan 37, Lund, 223 62, Sweden
| | - Øystein H Opedal
- Department of Biology, Lund University, Sölvegatan 37, Lund, 223 62, Sweden
| | - Anna S Persson
- Centre for Environmental and Climate Science, Lund University, Sölvegatan 37, Lund, 223 62, Sweden
| | - Hampus Petrén
- Department of Biology, Lund University, Sölvegatan 37, Lund, 223 62, Sweden
| | - Yuanyuan Quan
- Centre for Environmental and Climate Science, Lund University, Sölvegatan 37, Lund, 223 62, Sweden
| | - Henrik G Smith
- Centre for Environmental and Climate Science, Lund University, Sölvegatan 37, Lund, 223 62, Sweden
- Department of Biology, Lund University, Sölvegatan 37, Lund, 223 62, Sweden
| | - Yann Clough
- Centre for Environmental and Climate Science, Lund University, Sölvegatan 37, Lund, 223 62, Sweden
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Neacă AM, Meis J, Knight T, Rakosy D. Intensive pasture management alters the composition and structure of plant-pollinator interactions in Sibiu, Romania. PeerJ 2024; 12:e16900. [PMID: 38435994 PMCID: PMC10909354 DOI: 10.7717/peerj.16900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 01/16/2024] [Indexed: 03/05/2024] Open
Abstract
Background Land management change towards intensive grazing has been shown to alter plant and pollinator communities and the structure of plant-pollinator interactions in different ways across the world. Land-use intensification in Eastern Europe is shifting highly diverse, traditionally managed hay meadows towards intensive pastures, but few studies have examined how this influences plant-pollinator networks. We hypothesized that the effects of intensive grazing on networks will depend on how plant communities and their floral traits change. Methods We investigated plant and pollinator diversity and composition and the structure of plant-pollinator interactions near Sibiu, Romania at sites that were traditionally managed as hay meadows or intensive pastures. We quantified the identity and abundance of flowering plants, and used transect walks to observe pollinator genera interacting with flowering plant species. We evaluated the effects of management on diversity, composition and several indices of network structure. Results Pollinator but not plant diversity declined in pastures and both plant and pollinator taxonomic composition shifted. Functional diversity and composition remained unchanged, with rather specialized flowers having been found to dominate in both hay meadows and pastures. Apis mellifera was found to be the most abundant pollinator. Its foraging preferences played a crucial role in shaping plant-pollinator network structure. Apis mellifera thus preferred the highly abundant Dorycnium herbaceum in hay meadows, leading to hay meadows networks with lower Shannon diversity and interaction evenness. In pastures, however, it preferred less abundant and more generalized flower resources. With pollinators being overall less abundant and more generalized in pastures, we found that niche overlap between plants was higher. Discussion With both hay meadows and pastures being dominated by plant species with similar floral traits, shifts in pollinator preferences seem to have driven the observed changes in plant-pollinator interaction networks. We thus conclude that the effects of grazing on pollinators and their interactions are likely to depend on the traits of plant species present in different management types as well as on the effects of grazing on plant community composition. We thereby highlight the need for better understanding how floral abundance shapes pollinator visitation rates and how floral traits may influence this relationship.
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Affiliation(s)
- Ana-Maria Neacă
- Faculty of Biology and Geology, Babeș-Bolyai University, Cluj-Napoca, Romania
| | - Julia Meis
- Institute of Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
- Helmholtz Centre for Environmental Research–UFZ, Leipzig, Germany
| | - Tiffany Knight
- Institute of Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
- Department Species Interaction Ecology, German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
- Department Species Interaction Ecology, Helmholtz Centre for Environmental Research–UFZ, Leipzig, Germany
| | - Demetra Rakosy
- Department Species Interaction Ecology, German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
- Department Species Interaction Ecology, Helmholtz Centre for Environmental Research–UFZ, Leipzig, Germany
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Kasiske T, Dauber J, Harpke A, Klimek S, Kühn E, Settele J, Musche M. Livestock density affects species richness and community composition of butterflies: A nationwide study. ECOLOGICAL INDICATORS 2023; 146:109866. [PMID: 36777177 PMCID: PMC9904221 DOI: 10.1016/j.ecolind.2023.109866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 12/19/2022] [Accepted: 01/02/2023] [Indexed: 06/18/2023]
Abstract
Extensively managed grasslands are globally recognized for their high biodiversity value. Over the past century, a continuous loss and degradation of grassland habitats has been observed across Europe that is mainly attributable to agricultural intensification and land abandonment. Particularly insects have suffered from the loss of grassland habitats due to land-use change and the decrease in habitat quality, either due to an increase in livestock density, higher mowing frequency, and an increase in nitrogen fertilization, or by abandonment. However, only a few studies have used nationwide datasets to analyse the effects of land cover and land-use intensity on insects. It further remains largely unexplored how these effects are modulated by species traits, i.e. habitat specialisation and mobility. Using nationwide butterfly data originating from the German Butterfly Monitoring Scheme, we investigated the effect of three indicators related to land cover and agricultural land-use intensity on species richness as well as trait composition of butterfly communities. Based on agricultural census data at the municipality scale, we calculated the share of permanent grasslands (measure of habitat availability), the total livestock density (proxy for organic fertilization) and the livestock density of domestic herbivores (proxy for management intensity in grasslands) within a 2 km buffer surrounding each butterfly transect. To analyse the relationships between butterflies and indicators of land cover and land-use intensity, we applied generalised linear mixed effect models. We found a negative relationship between butterfly species richness and the livestock density of domestic herbivores. Further, the ratio of butterfly generalist to specialist species shifted towards generalists and the size of butterflies increased with higher herbivore livestock density, indicating a shift in communities towards mobile habitat generalists. Our results are in accordance with previous studies carried out across smaller geographic extents, highlighting the importance of low herbivore livestock densities to halt the loss of pollinating insects and safeguard biodiversity and associated ecosystem services in agricultural landscapes. We here demonstrate that indicators based on livestock distribution data at the municipality scale can provide insights into processes and spatial diversity patterns of butterflies at the national level. Further, we highlight potentials and limitations of using agricultural census data to quantify and assess effects of land cover and land-use intensity on butterflies, and make recommendations for further research needs.
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Affiliation(s)
- Toni Kasiske
- Thünen-Institute of Biodiversity, Braunschweig, Germany
- Biodiversity of Agricultural Landscapes, Institute of Geoecology, Technische Universität Braunschweig, Germany
| | - Jens Dauber
- Thünen-Institute of Biodiversity, Braunschweig, Germany
- Biodiversity of Agricultural Landscapes, Institute of Geoecology, Technische Universität Braunschweig, Germany
| | - Alexander Harpke
- Department of Community Ecology, Helmholtz Centre for Environmental Research - UFZ, Halle, Germany
- Department of Conservation Biology and Social-Ecological Systems, Helmholtz Centre for Environmental Research - UFZ, Halle, Germany
| | | | - Elisabeth Kühn
- Department of Conservation Biology and Social-Ecological Systems, Helmholtz Centre for Environmental Research - UFZ, Halle, Germany
| | - Josef Settele
- Department of Conservation Biology and Social-Ecological Systems, Helmholtz Centre for Environmental Research - UFZ, Halle, Germany
- iDiv - German Centre for Integrative Biodiversity Research, Leipzig, Germany
- Institute of Biological Sciences, University of the Philippines Los Baños, College, Laguna, Philippines
| | - Martin Musche
- Department of Conservation Biology and Social-Ecological Systems, Helmholtz Centre for Environmental Research - UFZ, Halle, Germany
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