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Marcacci G, Westphal C, Rao VS, Kumar S S, Tharini KB, Belavadi VV, Nölke N, Tscharntke T, Grass I. Urbanization alters the spatiotemporal dynamics of plant-pollinator networks in a tropical megacity. Ecol Lett 2023; 26:1951-1962. [PMID: 37858984 DOI: 10.1111/ele.14324] [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: 02/13/2023] [Accepted: 09/01/2023] [Indexed: 10/21/2023]
Abstract
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.
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Affiliation(s)
- Gabriel Marcacci
- Functional Agrobiodiversity, University of Göttingen, Göttingen, Germany
- Swiss Ornithological Institute, Sempach, Switzerland
| | - Catrin Westphal
- Functional Agrobiodiversity, University of Göttingen, Göttingen, Germany
- Centre of Biodiversity and Sustainable Land Use (CBL), University of Göttingen, Göttingen, Germany
| | - Vikas S Rao
- Agricultural Entomology, University of Agricultural Sciences, GKVK, Bangalore, India
| | - Shabarish Kumar S
- Department of Apiculture, University of Agricultural Sciences, GKVK, Bangalore, India
| | - K B Tharini
- Agricultural Entomology, University of Agricultural Sciences, GKVK, Bangalore, India
| | - Vasuki V Belavadi
- Agricultural Entomology, University of Agricultural Sciences, GKVK, Bangalore, India
| | - Nils Nölke
- Forest Inventory and Remote Sensing, Faculty of Forest Sciences and Forest Ecology, University of Göttingen, Göttingen, Germany
| | - Teja Tscharntke
- Centre of Biodiversity and Sustainable Land Use (CBL), University of Göttingen, Göttingen, Germany
- Agroecology, University of Göttingen, Göttingen, Germany
| | - Ingo Grass
- Ecology of Tropical Agricultural Systems, University of Hohenheim, Stuttgart, Germany
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Côte J, Poulet N, Blanc L, Grenouillet G. Disentangling the effects of different human disturbances on multifaceted biodiversity indices in freshwater fish. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2023; 33:e2845. [PMID: 36922403 DOI: 10.1002/eap.2845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 11/29/2022] [Accepted: 12/15/2022] [Indexed: 06/02/2023]
Abstract
Evaluating the effects of anthropogenic pressures on several biodiversity metrics can inform the management and monitoring of biodiversity loss. However, the type of disturbances can lead to different responses in different metrics. In this study, we aimed at disentangling the effects of different types of anthropogenic disturbances on freshwater fish communities. We calculated diversity indices for 1109 stream fish communities across France by computing richness and evenness components for ecological, morphological, and phylogenetic diversity, and used null models to estimate standardized effect sizes. We used generalized linear mixed models to assess the relative effects of environmental and anthropogenic drivers in driving those diversity indices. Our results demonstrated that all diversity indices exhibited significant responses to both climatic conditions and anthropogenic disturbances. While we observed a decrease of ecological and phylogenetic richness with the intensity of disturbance, a weak increase in morphological richness and evenness was apparent. Overall, our results demonstrated the importance of disentangling various types of disturbances when assessing human-induced ecological impacts and highlighted that different facets of diversity are not impacted identically by anthropogenic disturbances in stream fish communities. This calls for further work seeking to integrate biodiversity responses to human disturbances into a multifaceted framework, and could have beneficial implications when planning conservation action in freshwater ecosystems.
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Affiliation(s)
- Jessica Côte
- Laboratoire Evolution et Diversité Biologique (EDB), UMR5174, Université de Toulouse, CNRS, IRD, Université Toulouse III - Paul Sabatier, Toulouse, France
| | - Nicolas Poulet
- Pôle Ecohydraulique, Office Français de La Biodiversité, Institut des Mécaniques des Fluides, Toulouse, France
| | - Laurence Blanc
- Office français de la biodiversité, Direction régionale Occitanie, Toulouse, France
| | - Gaël Grenouillet
- Laboratoire Evolution et Diversité Biologique (EDB), UMR5174, Université de Toulouse, CNRS, IRD, Université Toulouse III - Paul Sabatier, Toulouse, France
- Institut Universitaire de France, Paris, France
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Dzekashu FF, Pirk CWW, Yusuf AA, Classen A, Kiatoko N, Steffan‐Dewenter I, Peters MK, Lattorff HMG. Seasonal and elevational changes of plant-pollinator interaction networks in East African mountains. Ecol Evol 2023; 13:e10060. [PMID: 37187966 PMCID: PMC10175727 DOI: 10.1002/ece3.10060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 03/06/2023] [Accepted: 04/22/2023] [Indexed: 05/17/2023] Open
Abstract
Across an elevation gradient, several biotic and abiotic factors influence community assemblages of interacting species leading to a shift in species distribution, functioning, and ultimately topologies of species interaction networks. However, empirical studies of climate-driven seasonal and elevational changes in plant-pollinator networks are rare, particularly in tropical ecosystems. Eastern Afromontane Biodiversity Hotspots in Kenya, East Africa. We recorded plant-bee interactions at 50 study sites between 515 and 2600 m asl for a full year, following all four major seasons in this region. We analysed elevational and seasonal network patterns using generalised additive models (GAMs) and quantified the influence of climate, floral resource availability, and bee diversity on network structures using a multimodel inference framework. We recorded 16,741 interactions among 186 bee and 314 plant species of which a majority involved interactions with honeybees. We found that nestedness and bee species specialisation of plant-bee interaction networks increased with elevation and that the relationships were consistent in the cold-dry and warm-wet seasons respectively. Link rewiring increased in the warm-wet season with elevation but remained indifferent in the cold-dry seasons. Conversely, network modularity and plant species were more specialised at lower elevations during both the cold-dry and warm-wet seasons, with higher values observed during the warm-wet seasons. We found flower and bee species diversity and abundance rather than direct effects of climate variables to best predict modularity, specialisation, and link rewiring in plant-bee-interaction networks. This study highlights changes in network architectures with elevation suggesting a potential sensitivity of plant-bee interactions with climate warming and changes in rainfall patterns along the elevation gradients of the Eastern Afromontane Biodiversity Hotspot.
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Affiliation(s)
- Fairo F. Dzekashu
- International Centre of Insect Physiology and Ecology (icipe)NairobiKenya
- Social Insects Research Group, Department of Zoology and EntomologyUniversity of PretoriaPretoriaSouth Africa
| | - Christian W. W. Pirk
- Social Insects Research Group, Department of Zoology and EntomologyUniversity of PretoriaPretoriaSouth Africa
| | - Abdullahi A. Yusuf
- Social Insects Research Group, Department of Zoology and EntomologyUniversity of PretoriaPretoriaSouth Africa
| | - Alice Classen
- Department of Animal Ecology and Tropical Biology, BiocenterUniversity of WürzburgWürzburgGermany
| | - Nkoba Kiatoko
- International Centre of Insect Physiology and Ecology (icipe)NairobiKenya
| | - Ingolf Steffan‐Dewenter
- Department of Animal Ecology and Tropical Biology, BiocenterUniversity of WürzburgWürzburgGermany
| | - Marcell K. Peters
- Department of Animal Ecology and Tropical Biology, BiocenterUniversity of WürzburgWürzburgGermany
| | - H. Michael G. Lattorff
- International Centre of Insect Physiology and Ecology (icipe)NairobiKenya
- Present address:
Department of ChemistryUniversity of NairobiNairobiKenya
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Ojija F, Adam LS, Nicholaus R, Mwakalapa EB. Insect-pollinators and their interactions with plants differ in disturbed and semi-natural areas: Tanzania's Southern Highlands case study. Sci Prog 2023; 106:368504231184035. [PMID: 37358485 PMCID: PMC10358636 DOI: 10.1177/00368504231184035] [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] [Indexed: 06/27/2023]
Abstract
Due to inadequate insect-pollinator data, particularly in sub-Saharan African countries like Tanzania, it is difficult to manage and protect these species in disturbed and semi-natural areas. Field surveys were conducted to assess insect-pollinator abundance and diversity and their interactions with plants in disturbed and semi-natural areas in Tanzania's Southern Highlands using pan traps, sweep netting, transect counts, and timed observations techniques. We found that species diversity and richness of insect-pollinators were high in semi-natural areas, and there was 14.29% more abundance than in disturbed areas. The highest plant-pollinator interactions were recorded in semi-natural areas. In these areas, the total number of visits by Hymenoptera was more than three times that of Coleoptera, while that of Lepidoptera and Diptera was more than 237 and 12 times, respectively. Hymenoptera pollinators had twice the total number of visits of Lepidoptera, and threefold of Coleoptera, and five times more visits than Diptera in disturbed habitats. Although disturbed areas had fewer insect-pollinators and fewer plant-insect-pollinator interactions, our findings indicate that both disturbed and semi-natural areas are potential habitats for insect-pollinators. The study revealed that the over-dominant species Apis mellifera could influence diversity indices and network-level metrics in the study areas. When A. mellifera was excluded from the analysis, the number of interactions differed significantly between insect orders in the study areas. Also, Diptera pollinators interacted with the most flowering plants in both study areas compared to Hymenopterans. Though A. mellifera was excluded in the analysis, we found a high number of species in semi-natural areas compared to disturbed areas. Conclusively, we recommend that more studies be conducted in these areas across sub-Saharan Africa to unveil their potential for protecting insect-pollinators and how ongoing anthropogenic changes threaten them.
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Affiliation(s)
- Fredrick Ojija
- Department of Earth Sciences, College of Science and Technical Education, Mbeya University of Science and Technology, Mbeya, Tanzania
| | - Lusekelo S Adam
- Department of Natural Resources Conservation, Social Health and Environment Management Organization, Mbamba Bay, Nyasa, Ruvuma
| | - Regan Nicholaus
- Department of Natural Sciences, College of Science and Technical Education, Mbeya University of Science and Technology, Mbeya, Tanzania
| | - Eliezer B Mwakalapa
- Department of Natural Sciences, College of Science and Technical Education, Mbeya University of Science and Technology, Mbeya, Tanzania
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Dzekashu FF, Yusuf AA, Pirk CWW, Steffan‐Dewenter I, Lattorff HMG, Peters MK. Floral turnover and climate drive seasonal bee diversity along a tropical elevation gradient. Ecosphere 2022. [DOI: 10.1002/ecs2.3964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Affiliation(s)
- Fairo F. Dzekashu
- International Centre of Insect Physiology and Ecology (ICIPE) Nairobi Kenya
- Social Insects Research Group, Department of Zoology and Entomology University of Pretoria Pretoria South Africa
| | - Abdullahi A. Yusuf
- Social Insects Research Group, Department of Zoology and Entomology University of Pretoria Pretoria South Africa
| | - Christian W. W. Pirk
- Social Insects Research Group, Department of Zoology and Entomology University of Pretoria Pretoria South Africa
| | - Ingolf Steffan‐Dewenter
- Department of Animal Ecology and Tropical Biology, Biocenter University of Würzburg Würzburg Germany
| | | | - Marcell K. Peters
- Department of Animal Ecology and Tropical Biology, Biocenter University of Würzburg Würzburg Germany
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