Decourtye A.,ACTA |
Mader E.,Xerces Society for Invertebrate Conservation |
Mader E.,University of Minnesota |
Desneux N.,French National Institute for Agricultural Research
Apidologie | Year: 2010
Honey bee populations have experienced serious losses in Europe and North America. These losses highlight the potential risk to our agricultural systems that could result from loss of pollination. These losses include direct economic repercussions to multiple industries (beekeeping, fruit, vegetable, forage seed, oil seed and biofuel crops), and corresponding threats to human nutrition. Reasons for the losses are varied but include a lack of diverse nectar and pollen resources within intensively farmed agricultural landscapes. Focusing primarily on Europe and the USA, we review the potential approaches to provide and maintain diverse floral resources for honey bees, giving particular consideration to herbaceous plants ("forbs"). These approaches include the cultivation and maintenance of "bee pastures", consisting of diverse native or non-native flower-rich plantings maintained in fallow areas, field margins, and conservation buffer strips to sustain bee populations, support honey bee health, and aid beekeeping activities. Within this review we examine specific governmental policy initiatives to support these efforts in the USA and Europe. © 2010 INRA/DIB-AGIB/EDP Sciences.
Black S.H.,Xerces Society for Invertebrate Conservation |
Kulakowski D.,Clark University |
Noon B.R.,Colorado State University |
Dellasala D.A.,Geos Institute
Natural Areas Journal | Year: 2013
Appropriate response to recent, widespread bark beetle (Dendroctonus spp.) outbreaks in the western United States has been the subject of much debate in scientific and policy circles. Among the proposed responses have been landscape-level mechanical treatments to prevent the further spread of outbreaks and to reduce the fire risk that is believed to be associated with insect-killed trees. We review the literature on the efficacy of silvicutural practices to control outbreaks and on fire risk following bark beetle outbreaks in several forest types. While research is ongoing and important questions remain unresolved, to date most available evidence indicates that bark beetle outbreaks do not substantially increase the risk of active crown fire in lodgepole pine (Pinus contorta) and spruce (Picea engelmannii)-fir (Abies spp.) forests under most conditions. Instead, active crown fires in these forest types are primarily contingent on dry conditions rather than variations in stand structure, such as those brought about by outbreaks. Preemptive thinning may reduce susceptibility to small outbreaks but is unlikely to reduce susceptibility to large, landscape-scale epidemics. Once beetle populations reach widespread epidemic levels, silvicultural strategies aimed at stopping them are not likely to reduce forest susceptibility to outbreaks. Furthermore, such silvicultural treatments could have substantial, unintended short- and long-term ecological costs associated with road access and an overall degradation of natural areas.
Gilgert W.,U.S. Department of Agriculture |
Vaughan M.,Xerces Society for Invertebrate Conservation
Rangelands | Year: 2011
Wendell Gilgert and Mace Vaughan examine the value of pollinators and pollinator habitat to rangelands, focusing on connections among pollinators, insects, plant communities, fish, and wildlife. Native pollinating bees are a vital component of the biologically diverse plant and animal community which is critical to healthy, ecologically functional range landscapes. Managing rangelands to enhance life requisites for native pollinators likely will require adjusting current practices. Many bumble bee species also nest under or on the ground, but instead of digging narrow underground tunnels, they utilize existing cavities, such as those left behind by burrowing mammals. A diversity and abundance of plants that produce nectar and pollen used by insects, combined with a variety of standing or downed dead wood, bare ground, and overgrown vegetation, are the hallmarks of rich heterogeneous pollinator habitat. Similarly, diverse rangeland plant communities support diverse assemblages of grasshoppers, crickets, and other orthopterans, with the interesting side effect of mitigating or preventing outbreaks.
Fowler J.,Xerces Society for Invertebrate Conservation
Northeastern Naturalist | Year: 2016
Habitat conservation is performed in North America to support populations of managed and wild pollinators. The current recommended plant selections for northeastern pollinator habitats primarily provide resources for common or generalist pollinators. However, such plants may not benefit uncommon or rare northeastern specialist pollinators, whose populations are susceptible to harm from anthropogenic threats. This manuscript presents the first catalog of native specialist bees and associated host plants for the Northeast. Approximately 15% of northeastern native bee species are pollen specialists, represented by 6 families, 15 genera, and 61 species of bees that restrict pollen foraging to 23 families, 33 genera, and 201 possible species of native host plants. Specialist bees are associated with non-graminoid forbs and non-coniferous woody plants in nearly all major northeastern terrestrial and wetland habitats. Herein, I identify and discuss vulnerable bee-plant associations and suggest greater emphasis on research and restoration efforts. I recommend that northeastern pollinator-conservation practice specifically target specialist bees.
Kremen C.,University of California at Berkeley |
Ullman K.S.,Xerces Society for Invertebrate Conservation |
Ullman K.S.,University of California at Davis |
Thorp R.W.,University of California at Davis
Conservation Biology | Year: 2011
Concerns about pollinator declines have grown in recent years, yet the ability to detect changes in abundance, taxonomic richness, and composition of pollinator communities is hampered severely by the lack of data over space and time. Citizen scientists may be able to extend the spatial and temporal extent of pollinator monitoring programs. We developed a citizen-science monitoring protocol in which we trained 13 citizen scientists to observe and classify floral visitors at the resolution of orders or super families (e.g., bee, wasp, fly) and at finer resolution within bees (superfamily Apoidea) only. We evaluated the protocol by comparing data collected simultaneously at 17 sites by citizen scientists (observational data set) and by professionals (specimen-based data set). The sites differed with respect to the presence and age of hedgerows planted to improve habitat quality for pollinators. We found significant, positive correlations among the two data sets for higher level taxonomic composition, honey bee (Apis mellifera) abundance, non-Apis bee abundance, bee richness, and bee community similarity. Results for both data sets also showed similar trends (or lack thereof) in these metrics among sites differing in the presence and age of hedgerows. Nevertheless, citizen scientists did not observe approximately half of the bee groups collected by professional scientists at the same sites. Thus, the utility of citizen-science observational data may be restricted to detection of community-level changes in abundance, richness, or similarity over space and time, and citizen-science observations may not reliably reflect the abundance or frequency of occurrence of specific pollinator species or groups. ©2011 Society for Conservation Biology.