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Alison J, Botham M, Maskell LC, Garbutt A, Seaton FM, Skates J, Smart SM, Thomas ARC, Tordoff G, Williams BL, Wood CM, Emmett BA. Woodland, cropland and hedgerows promote pollinator abundance in intensive grassland landscapes, with saturating benefits of flower cover. J Appl Ecol 2021. [DOI: 10.1111/1365-2664.14058] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jamie Alison
- UK Centre for Ecology & Hydrology Bangor UK
- Department of Ecoscience Aarhus University Aarhus Denmark
| | - Marc Botham
- UK Centre for Ecology & Hydrology Wallingford UK
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Scheper J, Bukovinszky T, Huigens ME, Kleijn D. Attractiveness of sown wildflower strips to flower-visiting insects depends on seed mixture and establishment success. Basic Appl Ecol 2021. [DOI: 10.1016/j.baae.2021.08.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Rasmussen C, Dupont YL, Madsen HB, Bogusch P, Goulson D, Herbertsson L, Maia KP, Nielsen A, Olesen JM, Potts SG, Roberts SPM, Sydenham MAK, Kryger P. Evaluating competition for forage plants between honey bees and wild bees in Denmark. PLoS One 2021; 16:e0250056. [PMID: 33909661 PMCID: PMC8081269 DOI: 10.1371/journal.pone.0250056] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/31/2021] [Indexed: 11/23/2022] Open
Abstract
A recurrent concern in nature conservation is the potential competition for forage plants between wild bees and managed honey bees. Specifically, that the highly sophisticated system of recruitment and large perennial colonies of honey bees quickly exhaust forage resources leading to the local extirpation of wild bees. However, different species of bees show different preferences for forage plants. We here summarize known forage plants for honey bees and wild bee species at national scale in Denmark. Our focus is on floral resources shared by honey bees and wild bees, with an emphasis on both threatened wild bee species and foraging specialist species. Across all 292 known bee species from Denmark, a total of 410 plant genera were recorded as forage plants. These included 294 plant genera visited by honey bees and 292 plant genera visited by different species of wild bees. Honey bees and wild bees share 176 plant genera in Denmark. Comparing the pairwise niche overlap for individual bee species, no significant relationship was found between their overlap and forage specialization or conservation status. Network analysis of the bee-plant interactions placed honey bees aside from most other bee species, specifically the module containing the honey bee had fewer links to any other modules, while the remaining modules were more highly inter-connected. Despite the lack of predictive relationship from the pairwise niche overlap, data for individual species could be summarized. Consequently, we have identified a set of operational parameters that, based on a high foraging overlap (>70%) and unfavorable conservation status (Vulnerable+Endangered+Critically Endangered), can guide both conservation actions and land management decisions in proximity to known or suspected populations of these species.
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Affiliation(s)
- Claus Rasmussen
- Department of Agroecology, Aarhus University, Tjele, Denmark
- * E-mail:
| | - Yoko L. Dupont
- Department of Bioscience, Aarhus University, Kalø, Denmark
| | | | - Petr Bogusch
- Faculty of Science, University of Hradec Králové, Hradec Králové, Czech Republic
| | - Dave Goulson
- School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Lina Herbertsson
- Centre for Environmental and Climate Research, Lund University, Lund, Sweden
| | - Kate Pereira Maia
- Institute of Biosciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Anders Nielsen
- Norwegian Institute of Bioeconomy Research (NIBIO), Ås, Norway and Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Jens M. Olesen
- Department of Biology, Aarhus University, Aarhus, Denmark
| | - Simon G. Potts
- Centre for Agri-Environmental Research, School of Agriculture, Policy and Development, University of Reading, Reading, United Kingdom
| | - Stuart P. M. Roberts
- Centre for Agri-Environmental Research, School of Agriculture, Policy and Development, University of Reading, Reading, United Kingdom
| | | | - Per Kryger
- Department of Agroecology, Entomology and Plant Pathology, Aarhus University, Slagelse, Denmark
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Wignall VR, Brolly M, Uthoff C, Norton KE, Chipperfield HM, Balfour NJ, Ratnieks FLW. Exploitative competition and displacement mediated by eusocial bees: experimental evidence in a wild pollinator community. Behav Ecol Sociobiol 2020. [DOI: 10.1007/s00265-020-02924-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Abstract
Eusocial bees are likely to be ecologically important competitors for floral resources, although competitive effects can be difficult to quantify in wild pollinator communities. To investigate this, we excluded honeybees (HBE treatment), bumblebees (BBE) or both (HB&BBE) from wild-growing patches of bramble, Rubus fruticosus L. agg., flowers in two eight-day field trials at separate locations, with complementary mapping of per-site local floral resource availability. Exclusions increased per-flower volume of nectar and visitation rates of non-excluded bees, compared to control patches with no bee exclusions (CON). There was a large increase in average nectar standing crop volume both at Site 1 (+ 172%) and Site 2 (+ 137%) in HB&BBE patch flowers, and no significant change in HBE or BBE, compared to CON patches. Foraging bee responses to exclusion treatments were more pronounced at Site 2, which may be due to lower local floral resource availability, since this is likely to increase the degree of exploitative competition present. Notably, at Site 2, there was a 447% increase in larger-bodied solitary (non-Apis/Bombus) bees visiting HB&BBE patches, suggesting ecological release from competition. Hoverflies showed no response to bee removals. Numbers of other non-bee insect groups were very small and also showed no clear response to exclusions. Our findings reveal patterns of competitive exclusion between pollinator groups, mediated by resource depletion by eusocial bees. Possible long-term implications of displacement from preferred flowers, particularly where alternative forage is reduced, are discussed.
Significance statement
Understanding patterns of exploitative competition and displacement is necessary for pollinator conservation, particularly for vulnerable or threatened species. In this research, experimental methods reveal underlying patterns of resource competition exerted by eusocial bees in a wild pollinator community. We show that honeybees and bumblebees competitively displace each other and particularly solitary (non-Apis/Bombus) bees from bramble, an important native nectar and pollen source. Effects were stronger where local floral resource availability was identified to be limited. Notably, following experimental exclusion of both honey- and bumblebees from flowers, visitation by solitary bees increased by up to 447%, strongly suggesting ecological release from competition. These results highlight the need for informed landscape management for pollinator wellbeing, including appropriate honeybee stocking densities and improved floral resource availability.
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Sawe T, Eldegard K, Totland Ø, Macrice S, Nielsen A. Enhancing pollination is more effective than increased conventional agriculture inputs for improving watermelon yields. Ecol Evol 2020; 10:5343-5353. [PMID: 32607157 PMCID: PMC7319119 DOI: 10.1002/ece3.6278] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 03/11/2020] [Accepted: 03/23/2020] [Indexed: 11/28/2022] Open
Abstract
Agricultural practices to improve yields in small-scale farms in Africa usually focus on improving growing conditions for the crops by applying fertilizers, irrigation, and/or pesticides. This may, however, have limited effect on yield if the availability of effective pollinators is too low. In this study, we established an experiment to test whether soil fertility, soil moisture, and/or pollination was limiting watermelon (Citrullus lanatus) yields in Northern Tanzania. We subjected the experimental field to common farming practices while we treated selected plants with extrafertilizer applications, increased irrigation and/or extra pollination in a three-way factorial experiment. One week before harvest, we assessed yield from each plant, quantified as the number of mature fruits and their weights. We also assessed fruit shape since this may affect the market price. For the first fruit ripening on each plant, we also assessed sugar content (brix) and flesh color as measures of fruit quality for human consumption. Extra pollination significantly increased the probability of a plant producing a second fruit of a size the farmer could sell at the market, and also the fruit sugar content, whereas additional fertilizer applications or increased irrigation did not improve yields. In addition, we did not find significant effects of increased fertilizer or watering on fruit sugar, weight, or color. We concluded that, insufficient pollination is limiting watermelon yields in our experiment and we suggest that this may be a common situation in sub-Saharan Africa. It is therefore critically important that small-scale farmers understand the role of pollinators and understand their importance for agricultural production. Agricultural policies to improve yields in developing countries should therefore also include measures to improve pollination services by giving education and advisory services to farmers on how to develop pollinator-friendly habitats in agricultural landscapes.
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Affiliation(s)
- Thomas Sawe
- Faculty of Environmental Sciences and Natural Resource ManagementNorwegian University of Life SciencesÅsNorway
| | - Katrine Eldegard
- Faculty of Environmental Sciences and Natural Resource ManagementNorwegian University of Life SciencesÅsNorway
| | - Ørjan Totland
- Department of Biological SciencesUniversity of BergenBergenNorway
| | - Samora Macrice
- Department of Ecosystems and ConservationSokoine University of AgricultureMorogoroTanzania
| | - Anders Nielsen
- Department of Landscape and BiodiversityNorwegian Institute of Bioeconomy Research (NIBIO)ÅsNorway
- Department of BiosciencesCentre for Ecological and Evolutionary Synthesis (CEES)University of OsloOsloNorway
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Gaba S, Cheviron N, Perrot T, Piutti S, Gautier JL, Bretagnolle V. Weeds Enhance Multifunctionality in Arable Lands in South-West of France. Front Sustain Food Syst 2020. [DOI: 10.3389/fsufs.2020.00071] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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Mccune F, Normandin É, Mazerolle MJ, Fournier V. Response of wild bee communities to beekeeping, urbanization, and flower availability. Urban Ecosyst 2020; 23:39-54. [DOI: 10.1007/s11252-019-00909-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Santos JD, Varassin IG, Muschner VC. Effects of neighborhood on pollination and seed dispersal of a threatened palm. Acta Oecologica 2018. [DOI: 10.1016/j.actao.2018.08.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Neokosmidis L, Tscheulin T, Devalez J, Petanidou T. Landscape spatial configuration is a key driver of wild bee demographics. Insect Sci 2018; 25:172-182. [PMID: 27512960 DOI: 10.1111/1744-7917.12383] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 06/23/2016] [Accepted: 07/17/2016] [Indexed: 06/06/2023]
Abstract
The majority of studies investigating the effects of landscape composition and configuration on bee populations have been conducted in regions of intensive agricultural production, ignoring regions which are dominated by seminatural habitats, such as the islands of the Aegean Archipelago. In addition, research so far has focused on the landscape impacts on bees sampled in cropped fields while the landscape effects on bees inhabiting seminatural habitats are understudied. Here, we investigate the impact of the landscape on wild bee assemblages in 66 phryganic (low scrubland) communities on 8 Aegean islands. We computed landscape metrics (total area and total perimeter-area ratio) in 4 concentric circles (250, 500, 750, and 1000 m) around the center of each bee sampling site including 3 habitat groups (namely phrygana, cultivated land, and natural forests). We further measured the local flower cover in 25 quadrats distributed randomly at the center of each sampling site. We found that the landscape scale is more important than the local scale in shaping abundance and species richness of bees. Furthermore, habitat configuration was more important than the total area of habitats, probably because it affects bees' movement across the landscape. Phrygana and natural forests had a positive effect on bee demographics, while cultivated land had a negative effect. This demonstrates that phryganic specialists drive bee assemblages in these seminatural landscapes. This finding, together with the shown importance of landscape scale, should be considered for the management of wild bees with special emphasis placed on the spatial configuration of seminatural habitats.
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Affiliation(s)
- Lazaros Neokosmidis
- Laboratory of Biogeography and Ecology, Department of Geography, University of the Aegean, University Hill, Mytilene, Greece
| | - Thomas Tscheulin
- Laboratory of Biogeography and Ecology, Department of Geography, University of the Aegean, University Hill, Mytilene, Greece
| | - Jelle Devalez
- Laboratory of Biogeography and Ecology, Department of Geography, University of the Aegean, University Hill, Mytilene, Greece
| | - Theodora Petanidou
- Laboratory of Biogeography and Ecology, Department of Geography, University of the Aegean, University Hill, Mytilene, Greece
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Reitan T, Nielsen A. Do Not Divide Count Data with Count Data; A Story from Pollination Ecology with Implications Beyond. PLoS One 2016; 11:e0149129. [PMID: 26872136 PMCID: PMC4752487 DOI: 10.1371/journal.pone.0149129] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 01/27/2016] [Indexed: 11/18/2022] Open
Abstract
Studies in ecology are often describing observed variations in a certain ecological phenomenon by use of environmental explanatory variables. A common problem is that the numerical nature of the ecological phenomenon does not always fit the assumptions underlying traditional statistical tests. A text book example comes from pollination ecology where flower visits are normally reported as frequencies; number of visits per flower per unit time. Using visitation frequencies in statistical analyses comes with two major caveats: the lack of knowledge on its error distribution and that it does not include all information found in the data; 10 flower visits in 20 flowers is treated the same as recording 100 visits in 200 flowers. We simulated datasets with various "flower visitation distributions" over various numbers of flowers observed (exposure) and with different types of effects inducing variation in the data. The different datasets were then analyzed first with the traditional approach using number of visits per flower and then by using count data models. The analysis of count data gave a much better chance of detecting effects than the traditionally used frequency approach. We conclude that if the data structure, statistical analyses and interpretations of results are mixed up, valuable information can be lost.
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Affiliation(s)
- Trond Reitan
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, NO-0316 Oslo, Norway
- * E-mail:
| | - Anders Nielsen
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, NO-0316 Oslo, Norway
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Somme L, Mayer C, Jacquemart AL. Multilevel spatial structure impacts on the pollination services of Comarum palustre (Rosaceae). PLoS One 2014; 9:e99295. [PMID: 24915450 PMCID: PMC4051681 DOI: 10.1371/journal.pone.0099295] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 05/12/2014] [Indexed: 11/18/2022] Open
Abstract
Habitat destruction and fragmentation accelerate pollinator decline, consequently disrupting ecosystem processes such as pollination. To date, the impacts of multilevel spatial structure on pollination services have rarely been addressed. We focused on the effects of population spatial structure on the pollination services of Comarum palustre at three levels (i.e. within-population, between-populations and landscape). For three years, we investigated 14 Belgian populations, which differed in their within-population flower density, population surface, closure (i.e. proportion of the population edge that consisted of woody elements) and isolation (i.e. percentage of woody area cover within a 500 m radius from the population centre). We tested whether these spatial characteristics impact on pollinator abundance and visitation rate and thus, reproductive success of C. palustre. Insects were observed in 15 randomly-chosen plots in each population. We tested for pollen limitation with supplemental hand-cross pollination. Bumble bees and solitary bees were the major pollinators through all populations. Within populations, plots with high flower densities attracted high numbers of bumble bees and other insects. High bumble bee and solitary bee abundance was observed in populations presenting high proportions of woody edges and in populations within landscapes presenting high proportions of woody areas. Seed set resulting from open pollination varied with bumble bee and solitary bee visitation rate, leading to increased pollen limitation when pollinators were scarce. Since the reproductive success depended on the visitation rate of the main pollinators, which depended on multilevel spatial structure, wetland management plans should pay special attention to favour a mosaic of biotopes, including nesting sites and food resources for insects. This study particularly supports the relevance of a mix wetlands and woody habitats to bees.
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Affiliation(s)
- Laurent Somme
- Earth and Life Institute-Agronomy, Research Team Genetics, Reproduction, Populations, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
- * E-mail:
| | - Carolin Mayer
- Earth and Life Institute-Agronomy, Research Team Genetics, Reproduction, Populations, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Anne-Laure Jacquemart
- Earth and Life Institute-Agronomy, Research Team Genetics, Reproduction, Populations, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
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Bennett JA, Gensler GC, Cahill JF. Small-scale bee patch use is affected equally by flower availability and local habitat configuration. Basic Appl Ecol 2014. [DOI: 10.1016/j.baae.2014.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Affiliation(s)
- Stein J. Hegland
- Norwegian Red deer Centre N‐6914 Svanøybukt Norway
- Faculty of Science University College of Sogn and Fjordane P.O. Box 133N‐5801 Sogndal Norway
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