Browsing by Person "Grass, Ingo"

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Biomonitoring via DNA metabarcoding and light microscopy of bee pollen in rainforest transformation landscapes of Sumatra
(2022) Carneiro de Melo Moura, Carina; Setyaningsih, Christina A.; Li, Kevin; Merk, Miryam Sarah; Schulze, Sonja; Raffiudin, Rika; Grass, Ingo; Behling, Hermann; Tscharntke, Teja; Westphal, Catrin; Gailing, Oliver; Carneiro de Melo Moura, Carina; Department of Forest Genetics and Forest Tree Breeding, University of Göttingen, Göttingen, Germany; Setyaningsih, Christina A.; Department of Palynology and Climate Dynamics, Albrecht-von-Haller-Institute for Plant Sciences, University of Göttingen, Göttingen, Germany; Li, Kevin; Agroecology, Department of Crop Sciences, University of Göttingen, Göttingen, Germany; Merk, Miryam Sarah; Statistics and Econometrics, University of Göttingen, Göttingen, Germany; Schulze, Sonja; Agroecology, Department of Crop Sciences, University of Göttingen, Göttingen, Germany; Raffiudin, Rika; Department of Biology, IPB University ID, Bogor, Indonesia; Grass, Ingo; Department of Ecology of Tropical Agricultural Systems, University of Hohenheim, Stuttgart, Germany; Behling, Hermann; Department of Palynology and Climate Dynamics, Albrecht-von-Haller-Institute for Plant Sciences, University of Göttingen, Göttingen, Germany; Tscharntke, Teja; Agroecology, Department of Crop Sciences, University of Göttingen, Göttingen, Germany; Westphal, Catrin; Functional Agrobiodiversity, Department of Crop Sciences, University of Göttingen, Göttingen, Germany; Gailing, Oliver; Centre of Biodiversity and Sustainable Land Use, University of Göttingen, Göttingen, Germany
Background: Intense conversion of tropical forests into agricultural systems contributes to habitat loss and the decline of ecosystem functions. Plant-pollinator interactions buffer the process of forest fragmentation, ensuring gene flow across isolated patches of forests by pollen transfer. In this study, we identified the composition of pollen grains stored in pot-pollen of stingless bees, Tetragonula laeviceps , via dual-locus DNA metabarcoding (ITS2 and rbcL ) and light microscopy, and compared the taxonomic coverage of pollen sampled in distinct land-use systems categorized in four levels of management intensity (forest, shrub, rubber, and oil palm) for landscape characterization. Results: Plant composition differed significantly between DNA metabarcoding and light microscopy. The overlap in the plant families identified via light microscopy and DNA metabarcoding techniques was low and ranged from 22.6 to 27.8%. Taxonomic assignments showed a dominance of pollen from bee-pollinated plants, including oil-bearing crops such as the introduced species Elaeis guineensis (Arecaceae) as one of the predominant taxa in the pollen samples across all four land-use types. Native plant families Moraceae, Euphorbiaceae, and Cannabaceae appeared in high proportion in the analyzed pollen material. One-way ANOVA (p > 0.05), PERMANOVA (R² values range from 0.14003 to 0.17684, for all tests p-value > 0.5), and NMDS (stress values ranging from 0.1515 to 0.1859) indicated a lack of differentiation between the species composition and diversity of pollen type in the four distinct land-use types, supporting the influx of pollen from adjacent areas. Conclusions: Stingless bees collected pollen from a variety of agricultural crops, weeds, and wild plants. Plant composition detected at the family level from the pollen samples likely reflects the plant composition at the landscape level rather than the plot level. In our study, the plant diversity in pollen from colonies installed in land-use systems with distinct levels of forest transformation was highly homogeneous, reflecting a large influx of pollen transported by stingless bees through distinct land-use types. Dual-locus approach applied in metabarcoding studies and visual pollen identification showed great differences in the detection of the plant community, therefore a combination of both methods is recommended for performing biodiversity assessments via pollen identification.
Insect conservation in agricultural landscapes needs both high crop heterogeneity and semi-natural habitats
(2024) Tassoni, Sara; Becker, David; Kasten, Marit Kinga; Moriníere, Jérôme; Grass, Ingo
Identifying landscapes that are suitable for both biodiversity conservation and agricultural production is a major challenge. Traditionally, much research has focused on biodiversity conservation outside of agricultural production areas, e.g., in semi-natural habitats. In contrast, recent research has mainly focused on the potential of crop heterogeneity. This includes both compositional (crop diversity) and configurational heterogeneity (field border density). However, if and how crop heterogeneity, and semi-natural habitats interact to shape insect diversity in agricultural landscapes remains poorly understood. Here we investigated the combined effects of crop diversity, field border density, and semi-natural habitats (i.e., grassland proportion, hedge density) on insect diversity. We sampled insect communities from 14 – 17 June 2021 with pan traps in 27 study landscapes (500 m x 500 m) covering independent gradients of these landscape variables and identified a total of 587 insect species with DNA metabarcoding. We found that field border density mediated the effects of crop diversity, grassland proportion, and hedge density on insect richness. At low levels of field border density (i.e., landscapes with mostly large fields), effects were either neutral (crop diversity), negative (grassland proportion) or weakly positive (hedge density). By contrast, at high levels of field border density, crop diversity, grassland proportion, and hedge density all exerted positive effects on insect richness. Responses to crop heterogeneity and semi-natural habitat differed among trophic groups of insects (decomposers, herbivores, parasitoids, predators). While variation in richness of herbivorous insects followed the patterns of the overall richness, decomposer richness was not related to any of the investigated variables. Predator richness increased with hedge density in landscapes, whereas parasitoid richness increased when high levels of field border density and grassland proportion coincided. Our study shows that increasing crop heterogeneity is a viable strategy for promoting insect diversity in agricultural landscapes. However, the effects of the amount of remaining semi-natural habitats, such as grassland or hedges, are mediated by configurational heterogeneity, and vary between trophic groups. Efforts to conserve insects in agricultural landscapes must therefore focus on both increasing the heterogeneity of the crop matrix by promoting crop diversity and increasing the density of field borders, while also maintaining or restoring semi-natural habitats as important source habitats for insect species.
Trophic level and specialization moderate effects of habitat loss and landscape diversity on cavity‐nesting bees, wasps and their parasitoids
(2024) Klaus, Felix; Tscharntke, Teja; Grass, Ingo
1. Habitat loss is a primary driver of biodiversity decline, but differences in species responses to habitat loss from local to landscape scales are poorly understood. 2. Trophic level, food and habitat specialization have been suggested to be important predictors of species responses to habitat loss, landscape diversity and landscape scale. 3. Using cavity-nesting communities of bees, wasps and their parasitoids on calcareous grasslands as a model system allowed us to compare responses of species differing regarding their trophic level, and degree of specialization on habitat and food. 4. We found that species from higher trophic levels experienced semi-natural habitat at larger spatial scales than those of lower trophic levels, but only, when they were generalists (abundance of bees, 150 m radius, vs. wasps feeding on herbivores, 450 m radius), not specialists (bees, 150 m, vs. bee parasitoids, 150 m). 5. Parasitoids, which are typically more specialized regarding their food resources (hosts), compared to predators such as predatory wasps, responded to habitat loss at the same spatial scales as their hosts, suggesting strong bottom-up effects of resource availability, that is, host availability driving parasitoid abundance. 6. Bees were mostly habitat specialists of calcareous grasslands and mainly driven by local habitat loss, whereas wasps as habitat generalists were mostly affected by landscape diversity. 7. Our study highlights the need to consider the different spatial scales contingent on trophic level and specialization of target species groups, maintaining or restoring both local habitat and landscape diversity, as this is needed for their successful conservation.
Urbanization alters the spatiotemporal dynamics of plant–pollinator networks in a tropical megacity
(2023) Marcacci, Gabriel; Westphal, Catrin; Rao, Vikas S.; Kumar S., Shabarish; Tharini, K. B.; Belavadi, Vasuki V.; Nölke, Nils; Tscharntke, Teja; Grass, Ingo
Urbanization is a major driver of biodiversity change but how it interacts with spatial and temporal gradients to influence the dynamics of plant–pollinator networks is poorly understood, especially in tropical urbanization hotspots. Here, we analysed the drivers of environmental, spatial and temporal turnover of plant–pollinator interactions (interaction β-diversity) along an urbanization gradient in Bengaluru, a South Indian megacity. The compositional turnover of plant–pollinator interactions differed more between seasons and with local urbanization intensity than with spatial distance, suggesting that seasonality and environmental filtering were more important than dispersal limitation for explaining plant–pollinator interaction β-diversity. Furthermore, urbanization amplified the seasonal dynamics of plant–pollinator interactions, with stronger temporal turnover in urban compared to rural sites, driven by greater turnover of native non-crop plant species (not managed by people). Our study demonstrates that environmental, spatial and temporal gradients interact to shape the dynamics of plant–pollinator networks and urbanization can strongly amplify these dynamics.
Win-win opportunities combining high yields with high multi-taxa biodiversity in tropical agroforestry
(2022) Wurz, Annemarie; Tscharntke, Teja; Martin, Dominic Andreas; Osen, Kristina; Rakotomalala, Anjaharinony A. N. A.; Raveloaritiana, Estelle; Andrianisaina, Fanilo; Dröge, Saskia; Fulgence, Thio Rosin; Soazafy, Marie Rolande; Andriafanomezantsoa, Rouvah; Andrianarimisa, Aristide; Babarezoto, Fenohaja Soavita; Barkmann, Jan; Hänke, Hendrik; Hölscher, Dirk; Kreft, Holger; Rakouth, Bakolimalala; Guerrero-Ramírez, Nathaly R.; Ranarijaona, Hery Lisy Tiana; Randriamanantena, Romual; Ratsoavina, Fanomezana Mihaja; Raveloson Ravaomanarivo, Lala Harivelo; Grass, Ingo; Wurz, Annemarie; Conservation Ecology, Department of Biology, Philipps-University Marburg, Marburg, Germany; Tscharntke, Teja; Centre for Biodiversity and Sustainable Land Use (CBL), University of Göttingen, Göttingen, Germany; Martin, Dominic Andreas; Department of Geography, University of Zurich, Zürich, Switzerland; Osen, Kristina; Tropical Silviculture and Forest Ecology, University of Göttingen, Göttingen, Germany; Rakotomalala, Anjaharinony A. N. A.; Entomology Department Faculty of Science, University of Antananarivo, Antananarivo, Madagascar; Raveloaritiana, Estelle; Plant Biology and Ecology Department, University of Antananarivo, University of Antananarivo, Antananarivo, Madagascar; Andrianisaina, Fanilo; Department of Tropical Agriculture and Sustainable Development, Higher School of Agronomic Science,University of Antananarivo, Antananarivo, Madagascar; Dröge, Saskia; Division of Forest, Nature and Landscape, KU Leuven, Leuven, Belgium; Fulgence, Thio Rosin; Natural and Environmental Sciences, Regional University Centre of the SAVA Region (CURSA), Antalaha, Madagascar; Soazafy, Marie Rolande; Doctoral School of Natural Ecosystems (EDEN), University of Mahajanga, Mahajanga, Madagascar; Andriafanomezantsoa, Rouvah; Zoology and Animal Biodiversity, Faculty of Sciences, University of Antananarivo, Antananarivo, Madagascar; Andrianarimisa, Aristide; Zoology and Animal Biodiversity, Faculty of Sciences, University of Antananarivo, Antananarivo, Madagascar; Babarezoto, Fenohaja Soavita; Diversity Turn in Land Use Science, coordination office, Sambava, Madagascar; Barkmann, Jan; Department of Agricultural Economics and Rural Development, Research Unit Environmental- and Resource Economics, University of Göttingen, Göttingen, Germany; Hänke, Hendrik; Department of Agricultural Economics and Rural Development, Research Unit Environmental- and Resource Economics, University of Göttingen, Göttingen, Germany; Hölscher, Dirk; Tropical Silviculture and Forest Ecology, University of Göttingen, Göttingen, Germany; Kreft, Holger; Biodiversity, Macroecology and Biogeography, University of Göttingen, Göttingen, Germany; Rakouth, Bakolimalala; Plant Biology and Ecology Department, University of Antananarivo, University of Antananarivo, Antananarivo, Madagascar; Guerrero-Ramírez, Nathaly R.; Biodiversity, Macroecology and Biogeography, University of Göttingen, Göttingen, Germany; Ranarijaona, Hery Lisy Tiana; Doctoral School of Natural Ecosystems (EDEN), University of Mahajanga, Mahajanga, Madagascar; Randriamanantena, Romual; Natural and Environmental Sciences, Regional University Centre of the SAVA Region (CURSA), Antalaha, Madagascar; Ratsoavina, Fanomezana Mihaja; Zoology and Animal Biodiversity, Faculty of Sciences, University of Antananarivo, Antananarivo, Madagascar; Raveloson Ravaomanarivo, Lala Harivelo; Entomology Department Faculty of Science, University of Antananarivo, Antananarivo, Madagascar; Grass, Ingo; Ecology of Tropical Agricultural Systems, University of Hohenheim, Stuttgart, Germany
Resolving ecological-economic trade-offs between biodiversity and yields is a key challenge when addressing the biodiversity crisis in tropical agricultural landscapes. Here, we focused on the relation between seven different taxa (trees, herbaceous plants, birds, amphibians, reptiles, butterflies, and ants) and yields in vanilla agroforests in Madagascar. Agroforests established in forests supported overall 23% fewer species and 47% fewer endemic species than old-growth forests, and 14% fewer endemic species than forest fragments. In contrast, agroforests established on fallows had overall 12% more species and 38% more endemic species than fallows. While yields increased with vanilla vine density and length, non-yield related variables largely determined biodiversity. Nonetheless, trade-offs existed between yields and butterflies as well as reptiles. Vanilla yields were generally unrelated to richness of trees, herbaceous plants, birds, amphibians, reptiles, and ants, opening up possibilities for conservation outside of protected areas and restoring degraded land to benefit farmers and biodiversity alike.