Environmental Impacts on Native Bumble Bee Pollinators in an Agricultural Landscape of Western Oregon PDF Download

Author: Kimberly M. Skyrm
Publisher:
ISBN:
Category : Bumblebees
Languages : en
Pages : 151

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Book Description
Bumble bees provide vital pollination services in both native and agricultural landscapes. However, in recent years, bumble bee populations have experienced global population declines. The primary causes of these declines have been attributed to the environmental impacts of pathogens, pesticide use and habitat fragmentation. While research has examined the impacts of pathogens, there is limited information on the effects of pesticides and habitat fragmentation on native bumble bees. Hence, the objectives of my dissertation research were to: 1) assess the toxicological impacts of pesticides used in two important bee-pollinated crops on queens and workers; 2) determine the impacts of forage resource availability on bumble bee colonies; 3) examine pollen foraging behavior of bumble bees in a late season mass-flowering agricultural landscape; and 4) document observations on trends towards bivoltinism in three western North American bumble bees. This research was conducted in the lab using wild and lab reared colonies, and in an agricultural landscape in the Willamette Valley of Western Oregon. In pesticide bioassays the impacts of residual toxicity of five classes of pesticides used in highbush blueberry and red clover cropping systems, were tested on queen and worker bumble bees, respectively. The results indicated variation in responses to the same insecticide by queens and workers, and to the same class of compounds by workers. Also, toxic effects were documented for both queens and workers to pesticides considered to be "safe" for bees. The impacts of forage resource availability were evaluated by exposing bumble bee colonies to four quantities of pollen, four quantities of nectar and three feeding frequencies of pollen. The study documented an inverse relationship between larvae and workers to resource type and availability. In addition, the type of larval mortality displayed by colonies, larval ejection or within clump mortality, was dependent on worker mortality. The individual and colony-level pollen foraging behavior of bumble bees was examined by placing colonies in red clover. Observations in the field on forager abundance, and at the colony-level on the duration and number of pollen trips and weight of stored pollen documented that red clover is an important resource for bumble bees. Pollen analysis revealed that in addition to red clover, Himalayan blackberry was also a key forage resource for bumble bees. Red clover resources at the end of the season may also benefit bumble bees by allowing for the creation of a second generation. Observations on both field and lab-reared queens document a trend towards bivoltinism in three species of western North American bumble bees. Agricultural habitats are vital for sustaining bumble bee populations. However, given the potential for pesticide impacts and temporal availability of flowering plants, these landscapes must be managed to provide maximum benefit to bumble bees. Results from this research should assist growers and researchers in developing landscape management and production practices geared toward the conservation and enhancement of native Bombus spp. populations in western Oregon.

Author: The Xerces Society
Publisher: Storey Publishing, LLC
ISBN: 1603427473
Category : Technology & Engineering
Languages : en
Pages : 385

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Book Description
With the recent decline of the European honey bee, it is more important than ever to encourage the activity of other native pollinators to keep your flowers beautiful and your grains and produce plentiful. In Attracting Native Pollinators, you’ll find ideas for building nesting structures and creating a welcoming habitat for an array of diverse pollinators that includes not only bees, but butterflies, moths, and more. Take action and protect North America’s food supply for the future, while at the same time enjoying a happily bustling landscape.

Author: Sarah A. Maxfield-Taylor
Publisher:
ISBN:
Category : Bumblebees
Languages : en
Pages : 112

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Book Description
Bumble bees (Hymenoptera: Apidae) are important native pollinators in wild and agricultural systems, and are one of the few groups of native bees commercially bred for use in the pollination of a range of crops. In recent years, declines in bumble bees have been reported globally. One factor implicated in these declines, believed to affect bumble bee colonies in the wild and during rearing, is natural enemies. A diversity of fungi, protozoa, nematodes, and parasitoids has been reported to affect bumble bees, to varying extents, in different parts of the world. In contrast to reports of decline elsewhere, bumble bees have been thriving in Oregon on the West Coast of the U.S.A. In particular, the agriculturally rich Willamette Valley in the western part of the state appears to be fostering several species. Little is known, however, about the natural enemies of bumble bees in this region. The objectives of this thesis were to: (1) identify pathogens and parasites in (a) bumble bees from the wild, and (b) bumble bees reared in captivity and (2) examine the effects of disease on bee hosts. Bumble bee queens and workers were collected from diverse locations in the Willamette Valley, in spring and summer. Bombus mixtus, Bombus nevadensis, and Bombus vosnesenskii collected from the wild were dissected and examined for pathogens and parasites, and these organisms were identified using morphological and molecular characteristics. Queens of Bombus griseocollis, Bombus nevadensis, and Bombus vosnesenskii were reared in captivity, and those that died or did not initiate nests were also examined for pathogens and parasites. In addition, the immune responses of healthy and infected bees were compared, to examine the effects of a common bumble bee gut pathogen Crithidia bombi (Kinetoplastida: Trypanosomatidae) on its host. This thesis reports that wild bumble bees in western Oregon are infected with the protozoa Apicystis bombi (Neogregarinida: Ophrocystidae) and Crithidia bombi, the fungus/microsporidian Nosema bombi (Microsporidia: Nosematidae), the nematode Sphaerularia bombi (Nematoda: Tylenchida), and two dipteran parasitoids, one unknown and one belonging to the family Conopidae (Diptera: Conopidae). In addition, this research presents the first ever report of infection by the larval pathogen Ascosphaera apis (Ascomycota: Ascosphaerales), in reared bumble bee adults. New host and distribution records are also presented for C. bombi, N. bombi, and S. bombi. The study found that bumble bees infected with C. bombi had lower activated levels of immune responses than healthy bees. The thesis discusses the long-term implications of study findings, and addresses the threat that bumble bee diseases pose to bee pollinators through shared environments.

Author: National Research Council
Publisher: National Academies Press
ISBN: 0309102898
Category : Technology & Engineering
Languages : en
Pages : 327

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Book Description
Pollinators-insects, birds, bats, and other animals that carry pollen from the male to the female parts of flowers for plant reproduction-are an essential part of natural and agricultural ecosystems throughout North America. For example, most fruit, vegetable, and seed crops and some crops that provide fiber, drugs, and fuel depend on animals for pollination. This report provides evidence for the decline of some pollinator species in North America, including America's most important managed pollinator, the honey bee, as well as some butterflies, bats, and hummingbirds. For most managed and wild pollinator species, however, population trends have not been assessed because populations have not been monitored over time. In addition, for wild species with demonstrated declines, it is often difficult to determine the causes or consequences of their decline. This report outlines priorities for research and monitoring that are needed to improve information on the status of pollinators and establishes a framework for conservation and restoration of pollinator species and communities.

Author: Elena Gratton
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Bumble bees (Bombus spp) are critical pollinators contributing to native ecosystems as well as agricultural production. At least half of the studied bumble bee species in North America are experiencing population declines and range contractions due to interacting factors such as habitat loss, climate change, invasive species, and pathogens. Pathogens can cause disease, reduce fitness, and shorten lifespans. Moreover, infection rates are increased in bee populations that are stressed by poor nutrition or exposure to pesticides, and thus pathogen prevalence can serve as a broader bioindicator of poor conditions. Given the myriad of factors impacting bumble bees, a comprehensive approach is needed to assess which biotic and abiotic factors are most important for determining the health of bees across diverse landscapes. Through multi-state and multi-year analysis, I examine how environmental conditions affect bumble bee pathogen levels and communities at different spatial scales. First, I assess whether levels of four bumble bee pathogens and distributions of bumble bee species are driven by variation in habitat at a local scale by leveraging the replicated hill and valley system in Central Pennsylvania. I then evaluate if associations between pathogen levels, bumble bee species, and environmental conditions observed in Pennsylvania are also found in North Carolina. In Pennsylvania, I found that different communities of both pathogens and bumble bees were found between forested hills and developed valleys, with viral loads higher in valleys and loads of one pathogen, Crithidia bombi, higher in forests. Valley habitats were dominated by Bombus impatiens, a disturbance resilient bee, while the forest habitats hosted more diverse bumble bee communities. Through DNA barcoding I found that there has been significant misidentification of B. sandersoni as B. vagans or B. perplexus, all of which are found primarily in forested landscapes. The North Carolina data, consistent with data from Pennsylvania as well as other studies in the United States, demonstrate that bumble bee pathogen loads are higher in areas with more honey bees and developed land. However, across the broader datasets, there were variable effects of floral resources and bee community composition on pathogen loads. For example, areas with more floral resources were associated with decreased viral loads in honey bees in North Carolina and in bumble bees in Pennsylvania; but were associated with increased viral loads in North Carolina bumble bees. Moreover, these data show more floral resources support more diverse bumble bee communities, but more diverse communities may facilitate increased loads of some pathogens (e.g., Crithidia) for which some bumble bee species are more susceptible. Ultimately this thesis highlights several outstanding research issues and provides management recommendations. Pathogen transmission and prevalence can clearly be influenced by habitat type but the complexity of landscapes, changing bumble bee communities, and variable susceptibility of different bumble bee species means there is not a single, simple solution to reducing the effects or loads of pathogens for bumble bees. Generally, the presence of honey bees and increased disturbance lead to increased pathogen prevalence. Thus, management efforts should be targeted to improving habitat quality through increased floral and nesting resource quality, which reduces pathogen levels in both honey bees and bumble bees. Higher quality habitat can improve bumble bee community diversity, which can potentially reduce transmission rates, though this depends on the specific species involved. Future studies should focus on species showing declines, to better understand the disease dynamics. While there was partitioning of pathogens at a local scale, the overall loads of pathogens shift over larger regional scales, highlighting the value of examining effects from local to broader landscape scales.

Author: Charles Duncan Michener
Publisher: Smithsonian Books (DC)
ISBN:
Category : Nature
Languages : en
Pages : 232

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Book Description
"The first identification key to cover all bees in the whole of the New World north of the equator. Parallel columns of English and Spanish text, and 500 drawing and photographs detail the distinguishing features of 169 genera and provide additional information such as range, number of species and subgenera, and references to any revisionist studies. Includes a guide to using the key. Field tested. Annotation c. by Book News, Inc., Portland, Or." -- PUBLISHER.

Author: The Xerces Society
Publisher: Storey Publishing
ISBN: 1612127010
Category : Nature
Languages : en
Pages : 241

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Book Description
The international bee crisis is threatening our global food supply, but this user-friendly field guide shows what you can do to help protect our pollinators. The Xerces Society for Invertebrate Conservation offers browsable profiles of 100 common flowers, herbs, shrubs, and trees that support bees, butterflies, moths, and hummingbirds. The recommendations are simple: pick the right plants for pollinators, protect them from pesticides, and provide abundant blooms throughout the growing season by mixing perennials with herbs and annuals! 100 Plants to Feed the Bees will empower homeowners, landscapers, apartment dwellers — anyone with a scrap of yard or a window box — to protect our pollinators.

Author: Chiho Kimoto
Publisher:
ISBN:
Category : Bees
Languages : en
Pages : 135

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Book Description
Native bees play an important role as pollinators of natural vegetation and agricultural crops. Yet many pollinators, including some native bees, are declining in numbers. Some of the potential causes of these declines are habitat destruction and degradation by various human land uses, including urban development and sprawl, construction of roadways, and habitat conversion to agriculture such as crop production and livestock grazing. Livestock grazing is one of the most common land uses in western North America and it can impact floral and nesting resources that are important to native bees. These effects are likely manifested through grazing's effect on vegetation and soil characteristics. However, few studies have investigated how livestock grazing impacts native bees in North America. As a result, the overall goal of this research was to determine how a gradient of livestock grazing intensities impacts native bee communities in a threatened and poorly studied grassland of western North America, the Pacific Northwest Bunchgrass Prairie. Because no studies have examined the bee fauna of this grassland habitat, our study had two objectives: 1) describe the native bee community in the Zumwalt Prairie in northeastern Oregon, which is one of the largest remaining remnants of this unique grassland type, and how it changes through time, and 2) investigate how livestock grazing affects that native bee fauna. To address these objectives, we sampled pollinators during the summer of 2007 and 2008 in 16 40-ha pastures on a plateau in the Zumwalt Prairie using blue vane traps. Each pasture was assigned one of four cattle stocking rates (high, medium low, and no cattle), and grazing intensity was quantified by measuring utilization. Grazing treatments were applied in the early summer for two years. We measured soil and vegetation characteristics that related to floral and nesting resources of bees as well as several metrics of the bee community, including diversity, richness, abundance, and community composition. We found 92 species and 119 morphospecies of native bees in 27 genera. This diverse community of native bees showed strong interseasonal and interannual variation that appears to be related to weather and plant phenology. We also found that even after exposure to just two years of grazing, some effects on vegetation and soils were evident. For example, increased grazing intensity significantly reduced vegetation structure, the abundance of certain blooming plants, surface soil stability, and the amount of soil surface covered by herbaceous litter. In addition, increased grazing intensity significantly increased soil compaction and the amount of bare ground. Native bee communities responded grazing intensity through changes in abundance, richness, diversity and community composition. Different bee taxa responded to grazing intensity differently and this response varied temporally. For example, bumble bees were sensitive to grazing intensity early in the season, showing reduced abundance, diversity, and/or richness with increased grazing intensity. In contrast, halictid bees did not respond to grazing intensity in any season. However, even within a genus or family, different species responded to grazing intensity in different manners, potentially because of variation in life histories. This research suggests that maintaining land with a mixture of livestock grazing intensities may be the best way to conserve this important and diverse pollinator group in the Pacific Northwest Bunchgrass Prairie.

Author: Dave Goulson
Publisher: Oxford University Press on Demand
ISBN: 0199553068
Category : Nature
Languages : en
Pages : 330

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Book Description
This book provides a concise and readable summary of the ecology and behaviour of bumblebees, with a particular focus on practical issues such as conservation strategies, management of bumblebees for crop pollination, and the possible impacts of bumblebees as non-native invasive species.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 460

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