76 research outputs found
07. The Effects of Seed Mix Diversity on Soil Conditions and Nesting of Bees in Prairie Restorations
With the goal of conserving native bees, current recommendations for improving habitats include increasing available floral resources by planting diverse seed mixes. However, these recommendations only account for the nutritional needs of bees while the availability of equally important nesting resources is often ignored. Here we used a novel system to investigate the effects of seed mix diversity on abiotic factors previously associated with nest sites of ground-nesting beesâavailable bare ground and soil temperature, moisture, and compactionâand on the occurrence of nests. We used standard bee-collecting techniques and a newer method using soil emergence tents (E-tents) to assess how seed mix diversity affects the distribution of bees. Plots planted with the highest-diversity seed mixes had the greatest amount of available bare ground and the highest soil temperatures at the surface and depths commonly associated with bee nests. The observed changes suggest these areas should be preferred by ground-nesting bees, but nest occurrence did not vary significantly among treatments. However, foraging bee species richness and abundance was greatest in plots planted with the highest-diversity seed mixes. Failure to detect a response in nest occurrence to seed mix diversity may be the result of low bee nest density, manifested in only a few nests being detected and low statistical power. We conclude that the current recommendation of planting highly diverse seed mixes provides adequate nutritional resources and improves some of the key abiotic factors associated with selection of nest sites by ground-nesting bees
The Effects of Forest Management Practices on Wild Bee Abundance and Functional Traits
Both wild and managed bees are in decline due to the combined and interactive effects of anthropogenic disturbances such as habitat loss and pesticide use. This is concerning because bees are important not only for the pollination of agricultural lands, but also for plants in both natural and managed landscapes. North America is home to about 4000 native species of bees, all of which can be further classified by various characteristics such as body size, nesting strategy, diet breadth, and sociality. These traits are considered functional traits because they can impact the function â pollination â bees contribute to an ecosystem. The way we manage lands can impact bees, but these disturbances do not affect bee functional traits consistently. Some forest management practices, including prescribed fire and thinning, can help maintain and restore forests. While some research shows positive impacts of forest management on bees in general, results vary when looking at bee functional traits. Our main objectives were to assess how prescribed fire, thinning, and the combination of the two affect both bee abundance and body size
Neonicotinoid contamination in conservation areas affects bees more sharply than beetles
The neurotoxic insecticide class of neonicotinoids has become one of the most widely used groups of pesticides globally. Their long half-lives and high water solubility increase their potential to linger and affect numerous organisms long after application. A prominent concern associated with residual contamination is the negative impact that neonicotinoids can have on beneficial arthropods such as bees and certain groups of beetles. Many studies have looked at the effects neonicotinoids have on arthropod communities in lab settings; however, comparatively few studies have looked at these groups in neonicotinoid-contaminated restored prairie habitats. These habitats are often restored from or located near agriculture and are almost ubiquitously contaminated with neonicotinoids. Our one-year manipulated field study compared native bee nesting rates and beetle community assemblages between paired clothianidin-contaminated and non-contaminated restored prairie plots. Native bee nesting probability and nesting abundance increased by 46% and 172%, respectively, in sites contaminated with clothianidin. Conversely, we observed no significant differences in beetle family assemblages, abundance, or richness between clothianidin-contaminated and control sites. These results suggest that neonicotinoid contamination of natural habitats can have numerous environmental consequences for arthropods and that these effects are not always consistent between taxa. Understanding how neonicotinoid contamination affects beneficial groups such as bees and arthropod community assemblages is crucial for characterizing the risks these chemicals pose to ecologically imperative taxa
Testing models of bee foraging behavior through the analysis of pollen loads and floral density data
The composition of social bees' corbicular pollen loads contains information about both the bees' foraging behavior and the surrounding floral landscape. There have been, however, few attempts to integrate pollen composition and floral landscape to test hypotheses about foraging behavior. Here, we present an individual-based model that generates the species composition of pollen loads given a foraging model and a spatial distribution of floral resources. We apply this model to an existing dataset of inflorescence counts and bumble bee pollen loads sampled at different field sites in California. For two out of three sites, a foraging model consisting in correlated random walks with constant preferences for each plant species provides a plausible fit for the observed distribution of pollen load content. Pollen load compositions at the third site could be explained by an extension of the model, where different preferences apply to the choice of an initial foraging patch and subsequent foraging steps. Since this model describes the expected level of pollen load differentiation due solely to the spatial clustering of conspecific plants, it provides a null hypothesis against which more complex descriptions of behavior (e.g. flower constancy) can be tested
Habitat restoration benefits wild bees: A metaâanalysis
Pollinator conservation is of increasing interest in the light of managed honeybee (Apis mellifera) declines, and declines in some species of wild bees. Much work has gone into understanding the effects of habitat enhancements in agricultural systems on wild bee abundance, richness and pollination services. However, the effects of ecological restoration targeting ânaturalâ ecological endpoints (e.g. restoring former agricultural fields to historic vegetation types or improving degraded natural lands) on wild bees have received relatively little attention, despite their potential importance for countering habitat loss.We conducted a metaâanalysis to evaluate the effects of ecological restoration on wild bee abundance and richness, focusing on unmanaged bee communities in lands restored and managed to increase habitat availability and quality. Specifically, we assessed bee abundance and/or richness across studies comparing restored vs. unrestored treatments and studies investigating effects of specific habitat restoration techniques, such as burning, grazing, invasive plant removal and seeding.We analysed 28 studies that met our selection criteria: these represented 11 habitat types and 7 restoration techniques. Nearly all restorations associated with these studies were performed without explicit consideration of habitat needs for bees or other pollinators. The majority of restorations targeted plant community goals, which could potentially have ancillary benefits for bees.Restoration had overall positive effects on wild bee abundance and richness across multiple habitat types. Specific restoration actions, tested independently, also tended to have positive effects on wild bee richness and abundance.Synthesis and applications. We found strong evidence that ecological restoration advances wild bee conservation. This is important given that habitat loss is recognized as a leading factor in pollinator decline. Pollinator responses to land management are rarely evaluated in nonâagricultural settings and so support for wild bees may be an underappreciated benefit of botanically focused management. Future restoration projects that explicitly consider the needs of wild bees could be more effective at providing nesting, foraging and other habitat resources. We encourage land managers to design and evaluate restoration projects with the habitat needs of wild bee species in mind.We found strong evidence that ecological restoration advances wild bee conservation. This is important given that habitat loss is recognized as a leading factor in pollinator decline. Pollinator responses to land management are rarely evaluated in nonâagricultural settings and so support for wild bees may be an underappreciated benefit of botanically focused management. Future restoration projects that explicitly consider the needs of wild bees could be more effective at providing nesting, foraging and other habitat resources. We encourage land managers to design and evaluate restoration projects with the habitat needs of wild bee species in mind.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142557/1/jpe13012-sup-0001-FigS1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142557/2/jpe13012.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142557/3/jpe13012_am.pd
âNot in their front yardâ The opportunities and challenges of introducing perennial urban meadows: A local authority stakeholder perspective
© 2017 The Authors The growing evidence base for the benefits for people and wildlife of nature-based solutions to managing urban green infrastructure lacks research investigating land manager perspectives on their implementation. To address this gap, we explored UK local authority manager perceptions of the challenges and opportunities of introducing perennial urban meadows to prioritise biodiversity and aesthetics. This was co-produced as an experiment in urban greenspaces with Luton Parks Service and Bedford Borough Council 2013â15. We conducted semi-structured interviews with the eight stakeholder managers involved to identify key factors impacting on the perceived feasibility of future urban meadow establishment in other areas. All managers identified three dominant factors (aesthetics and public reaction, locational context, and human resources and economic sustainability). Additional factors (local politics, communication, biodiversity and existing habitat and physical factors) varied in importance according to personal values and managerial role. Support for future meadow introduction and a desire to overcome the economic challenge of the disposal of meadow arisings were related to manager biocentricity. Managers were aware of changing public values leading to increasing acceptance of a messier urban aesthetic. They perceived perennial meadows as a realistic alternative to amenity mown grass that in specific contexts could increase local biodiversity and enhance aesthetics if implemented in consultation with the public and local councillors. Our findings have relevance for the wider implementation of such nature-based solutions to urban GI management: Changes in management practice such as the introduction of perennial meadows have significant political, strategic, economic and practical implications and cannot be viewed purely as a technical challenge
Risks to pollinators and pollination from invasive alien species
Invasive alien species modify pollinator biodiversity and the services they provide that underpin ecosystem function and human well-being. Building on the Intergovernmental Science-Policy Platform for Biodiversity and Ecosystem Services (IPBES) global assessment of pollinators and pollination, we synthesize current understanding of invasive alien impacts on pollinators and pollination. Invasive alien species create risks and opportunities for pollinator nutrition, re-organize species interactions to affect native pollination and community stability, and spread and select for virulent diseases. Risks are complex but substantial, and depend greatly on the ecological function and evolutionary history of both the invader and the recipient ecosystem. We highlight evolutionary implications for pollination from invasive alien species, and identify future research directions, key messages and options for decision-making
The Comparison of Pollen Limitation in Non-Native and Native Plant Species
Mentor: Tiffany Knight
From the Washington University Undergraduate Research Digest: WUURD, Volume 2, Issue 1, Fall 2006. Published by the Office of Undergraduate Research.
Henry Biggs, Director of Undergraduate Research and Associate Dean in the College of Arts & Sciences; Joy Zalis Kiefer, Undergraduate Research Coordinator, Editor, and Assistant Dean in the College of Arts & Sciences
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