Source: UNIVERSITY OF CALIFORNIA, DAVIS submitted to NRP
ASSESSING AND ENHANCING THE CONTRIBUTIONS OF NATIVE BEES TO AGRICULTURAL POLLINATION
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
1004910
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Nov 28, 2014
Project End Date
Sep 30, 2019
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
UNIVERSITY OF CALIFORNIA, DAVIS
410 MRAK HALL
DAVIS,CA 95616-8671
Performing Department
Entomology and Nematology
Non Technical Summary
Bee pollination is critical to the production of much of the world's food crops. In North America, managed honeybees provide most of the agricultural pollination valued at over $15 billion annually. Parasitic mites and recently Colony Collapse Disorder have exposed the vulnerability of U.S. crop production because of its heavy reliance on this single pollinator. Native bees can also provide important pollination to numerous crops when their habitat and resource needs are met. Indeed under favorable farm management and in landscapes with sufficient habitat native bees alone can provide adequate pollination. We know little about how wild bee communities respond to farm and landscape quality. We also lack data on how reliable native bees are compared to managed honey bees and what growers might do to promote reliable pollination. Responses of native bees to intensive agriculture suggest that enhancing floral resources within agricultural landscapes is a key to promoting native pollinators. Recently the role of limited nesting sites has also been raised as a cause for changes in bee communities under human land transformation. Methods are needed to identify plant species that are most important to bees and that would be top candidates for enhancing bee resources. Testing the importance of candidate plant species for bees in agricultural settings is a critical first step toward increasing the amount of habitat for pollinators. Approaches are also needed that provide robust characterization and assessment of nesting substrates for ground-nesting native bees. I propose a series of studies to (1) quantify the effects of farm habitat quality and landscape context on the bee communities and pollination in agricultural landscapes and (2) to determine strategies to enhance habitat quality for pollinators and crop pollination.To separate the effects of local farm-scale habitat and landscape context on pollination by native bees, I will compare reliability of pollination of specific specialty crops by native bees and honey bees on farms differing in farm management and located in more or less intensively managed landscapes. To assess reliability of pollination over time, I will measure pollination at each site multiple times within and among seasons. Results from these studies will determine the importance of habitat quality on farms for enhancing pollination by native bees in different landscape. This information is critical for growers because they have greatest control over management of pollinators and habitat within their farms, but little control over the quality of the landscape.To promote habitat enhancement for pollinators within agricultural landscapes, I will use a combination of analytical and field-based approaches to identify and test native plant species that support native bees and honeybees and are well suited to restoration of pollinator habitat. Native plants are ideal because they are adapted to the local climate, are known to support bees in general, and are great interest resource and biodiversity conservation. One result of this work will be an analytical framework for ranking best plants to support pollinators that can be applied within our region, as well as more broadly throughout North America. The results of field tests will be used to provide guidelines for pollinator habitat restoration and specific recommendations for plant species that can be used to enhance pollinators for agriculture.
Animal Health Component
55%
Research Effort Categories
Basic
30%
Applied
55%
Developmental
15%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1363085107020%
1367310107010%
1360850107030%
1361212107010%
1361499107010%
1363010107020%
Knowledge Area
136 - Conservation of Biological Diversity;

Subject Of Investigation
1499 - Vegetables, general/other; 1212 - Almond; 0850 - Wildlife habitats; 7310 - Experimental design and statistical methods; 3010 - Honey bees; 3085 - Other bees (non-Apis bees) - All bees except Apis cerana; includes Bombas, Alfalfa leaf-cutter;

Field Of Science
1070 - Ecology;
Goals / Objectives
Bee pollination is a critical input to the production of most of the world's food crops. In North America, the managed honey bee (Apis mellifera) provides much of the agricultural pollination with an estimated annual value exceeding $15 billion. Domesticated honey bee stocks have declined by 59% in the USA over the past 58 years, and feral colonies are rare, due to infestation by parasitic mites (Varroa destructor) and other causes [3]. Atop already reduced numbers of managed colonies, North American bee-keepers continue to lose roughly a third of their honey bee colonies annually. These challenges highlight the risk of relying solely on honey bee colonies to provide California's agricultural pollination. Native wild bees can also provide important pollination to numerous crops when their habitat and resource needs are met. However, their populations also are threatened by intensification of agriculture and our understanding of how wild bee species and communities respond to habitat and landscape quality remains limited. A key driver behind the loss of wild pollinators within intensive agricultural landscapes is likely to be the lack of sufficient floral resources throughout the flight season of the bees. Although certain flowering crops offer resources pulses, there are few flowers to maintain bees between these flowering bonanzas. Restoration of habitat containing diverse native flowering plant communities can help to bolster native pollinators and increase the level of pollination they provide to crops. These same plantings may also enhance honeybee health by providing a more diverse diet and reducing nutritional stress of the colony. In addition to insufficient forage resources, wild bee species may also be limited by insufficient nesting substrates. The classic question in ecology about the relative importance of multiple resources also has critical practical relevance. Bolstering forage for bees where populations are limited by nesting opportunities would have little impact. Although research has begun on wildflower plantings to benefit pollinators, little is known about how these planting can provide nesting resources.This project thus has a series of interconnected objectives that revolve round the goal of supporting robust populations of wild bees that can be integrated with healthy honey bee populations to provide reliable pollination for California agriculture.Objective 1: Quantify the reliability and stability of wild bee and honey bee pollination, and the role of pollinator biodiversity in stabilizing pollination services over multiple spatial and temporal scales.Objective 2: Identify the roles of forage (floral) resources and nesting habitat in determining native bee abundance and diversity in association with pollinator habitat plantings.Objective 3: Identify native wildflower species that best support wild bees and honey bees in agricultural contexts and can be used to enhance habitat quality for pollinators.Objective 4: Determine effective strategies for cultivation of native plants (so called pollinator habitat) in different agricultural contexts.
Project Methods
Objective 1: Quantify the reliability and stability of wild bee and honey bee pollination, and the role of pollinator biodiversity in stabilizing pollination services over multiple spatial and temporal scales. I will select a set of farms with different combinations of landscape and local site quality. For each farm, I will quantify various aspects of site quality and use Geographic Information Systems (GIS) to quantify the landscape context. I will then measure the diversity and abundance of bees visiting a target crop (watermelon, which I also used in previous work) and quantify the contributions of wild bees and managed honeybees to pollination based on visitation rates per flower and pollen deposition per visit. These measures of bees and pollination will be made multiple times within a season and among seasons. The resulting hierarchically-structured data will allow me to relate variation in pollination at different temporal and spatial scales to bee diversity at the site, farm characteristics and landscape context. In addition I will explicitly test the roles of abundance and diversity of wild bees on pollination by using a new analytical tool, the Price Equation Partition. The method, borrowed from evolutionary biology, can, I hope, be used successfully to disentangle effects of bee abundance, diversity and species identity on variation in pollination. Results of these studies will help growers to promote sustainable pollination with native species.Objective 2: Roles of forage (floral) resources and nesting habitat in determining native bee abundance and diversity. I will use three distinct approaches to address this objective, one uses a manipulative field experiment, the second uses field surveys of different habitat areas and the third implements a predictive spatial model. For the first, I focus on a subset of species that nest above ground. I will set up a fully-blocked field design using new and existing pollinator plantings and control areas that lack augmented floral resources. Sites will be matched for landscape context by assessing surrounding landscapes using (GIS). At half of the sites of each type, I will add nesting resources for above-ground-nesting bees. Over the subsequent three seasons, I will monitor the abundance of above-ground-nesting species at flowers at each site and compare abundances among the four treatment types. I use flower-based monitoring because it is independent of the nesting augmentation. Comparisons among treatments will be made using GLMM. For the second approach, I will focus on identifying habitats and types of management that enhance ground-nesting bees. Understanding soil and other microsite characteristics that determine nest site selection and success of ground-nesting bee species is a critical unknown for promoting native bee populations and their contribution to crop pollination. I will use existing pollinator plantings and unenhanced crop field boundaries (controls) within agricultural landscapes. At each location I will deploy 30 emergence traps (0.5 m2 area) at dusk on each of three dates between May and August. Traps are left over night and collect active ground-nesting bees as they emerge following morning. I will characterize soil and ground cover attributes beneath each trap to provide information on microsites. I will use incidence of bees among traps to test the ability of habitat enhancements to augment nesting opportunities for wild bees and determine microsite characteristics associated with nesting of different species. Data on incidence among the different habitats will also be used to inform spatially explicit models. For the third approach I will work with spatially explicit models to assess where bees are most likley limited by nesting versus forage availability. The basis for these approaches was developed in previous collaboration (Lonsdorf et al 2009; Annals of Botany). These models include information on nesting and forage quality among habitats types to predict relative population/ community abundance of bees. I propose to partition the nesting and forage components to consider sensitivity of predictions to the two resource types across test landscapes. I will then use data from ongoing monitoring on bee groups that have distinct resource requirements, (e.g., ground versus soil nesting guilds) to validate the model.Objective 3: I will use multiple approaches to identify and test native plant species that support native bees and honeybees and are well suited for restoration of pollinator habitat.Existing and new data on native plant visitation and pollen collection by bees will be used as input for this objective. I will develop a set of robust analytical methods to identify plant species that are most frequently used and most preferred by native bees. The methods will account for differences in use related to plant abundance and assess the degree of reliance by various bee species at different times of year. It also will incorporate data on flowering time, so that we can determine mixes of plants that provide resources throughout the season. I will field test the importance of identified plants and plant mixes by measuring the abundance and diversity of bees visiting each species at multiple sites. These data will be combined with estimates of flower density to assess the value of different species on a per flower basis.Objective 4: We have begun testing different approaches for establishment of wildflower-based pollinator habitat. This work will be extended to new agricultural contexts, specifically orchard crops, which rely heavily on bee pollination. To test different strategies for planting and management of pollinator habitat, I will select mixes of plants determined to be most important for supporting bee diversity and abundance based on our previous research and will establish replicated plots at multiple sites. I will compare different planting and irrigation schemes that are likely to affect plant establishment, ease of management and flower densities within restorations. For each scheme I will record data on plant establishment, stem density, and floral densities throughout the year.

Progress 11/28/14 to 09/30/19

Outputs
Target Audience:During its five-year period the project targeted (1) California fruit, nut growers and vegetable growers, including those focused on fresh market fruits and those in the seed industry; (2) Conservation practitioners, including Federal, State and County levels and NGO organizations engaged in pollinator health and biodiversity conservation efforts and (3) beekeepers of California and elsewhere who are involved in almond pollination. As part of our work on Objectives 3 & 4 we worked with California beekeepers through collaboration with Project Apis m (PAm). We focused on almond growers in Southern, Central and Northern growing regions. The almond grower/ industry organization (ABC) has been instrumental in promoting pollinator health and the industry is now embracing the importance of diversifying the forage resources available to manage honeybees and also the potential for other species of bees to contribute to pollination. Our work with NGOs and state agencies involved controlled studies providing data to parameterize models that aid the design of regional seed mixes for pollinator plantings and continued work on best management strategies for maintaining habitat plantings for beneficial insects including pollinators. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Ola Lundin (postdoc) - received individual mentoring throughout the project on field research design and coordination. He also led his own team for which he was given nearly full control to manage. This built his skill set toward obtaining a position in academics. He finished in the lab in Nov. 2016 and is a senior postdoc in agroecology at The Swedish Agricultural University, Uppsala. Visiting Scholar Maj Rundlof (Lund University) joined our project and worked on different aspects. She was mentored in grant development, field data collection. She successfully obtained two research grants and returned to Sweden to begin these projects in 2019. Tina Harrison (postdoc) received mentoring throughout the project on field research design and coordination. She also led model development for integration of pest and pollinator data. She presented the results at the 2018 National Entomology Meeting. These activites are building her skill set toward obtaining a faculty position. Kimiora Ward (Project specialist; SRAIII supervisor) coordinated research testing the attractiveness and growth of wildflower mixes to bolster native and managed pollinators. She was provided training in and then presented work at regional workshops building her skill set in outreach components of our project. Graduate students John Mola, Maureen Page, Rei Scampavia and Clara Stuligross were mentored on activities associated with this project. Logan Rowe (Junior Specialist, UCD), received individual mentoring in running a research team. He oversaw parts of the bee nesting project. Mike Epperly (Junior Specialist, UCD), received individual mentoring in running a research team. He oversaw parts of the bee monitoring projects in almond landscapes and will take over management of a new project examining impacts of pollinator plantings on other beneficial insects. Katherine Bolte (Junior Specialist, UCD), received individual mentoring in managing field crews and working with growers. She has coordinated management of over 15 restoration sites across northern California. 5 postgraduate research technicians also worked on the projects and received mentoring in field methods for pollination biology, insect surveying and plant surveying. They also received training on lab based protocols, including insect identification and in project management. Williams updated course in Pollination Ecology in Fall 2017. As part of this course he led field trips to study sites associated with the project. This provided exposure to field methods used in objectives 3 and 4. Two undergraduate students from this course joined the lab group where they trained on insect identification, data summary and management and worked on data related to the optimization of seed mixes as well as pollination in almond landscapes. How have the results been disseminated to communities of interest?Throughout the project I and my lab group continued to disseminate results from the work through publications and presentations to stakeholder groups. Results from Objective 2, 3 and 4 have been most widely disseminated to communities of interest through a combination of field day presentation, outreach publications and talks to commodity groups and bee keeper organizations throughout the state. I presented summary or results and recommendations on plant materials to support bee health to members of the California Department of Agriculture and leading beekeeper and almond board of California representatives in at CDFA. I also spoke at 2015, 2017& 2018 Almond Conference research symposia on practices to promote bee forage and bee health. In addition, I lectured in the UC seed production course in 2016-2019 which reached 50-75 production specialists each year from around the world. I and others in my group presented talks and round table discussion at the 2015, 2016 & 2017 Bee Symposia at UC Davis attended by 150-200 stakeholders each year. In each spring of 2015, 2017, 2018 and 2019 I presented at field days for almond and seed growers, these reach 30-65 individuals, including growers, PCAs, and conservation land managers. Some specifically targeted elements of Objective 3 and 4 on habitat design the others were more generally about pollinators and pollination. I presented and discussed plant selection guidelines to two different bee keeper groups San Mateo Bee Guild and the Sacramento Area Beekeepers Association. Both groups were enthusiastic about the information. SABA provided support to develop the on-line database. I presented ideas for farming to support bees and the 2016 Bee Audacious conference in Marin County California and led 3 days of facilitated discussion around bee health and pollination. I developed an archived presentation for eXtension on establishing pollinator habitat. And Collaborated on guidelines for establishing and managing wild flower plantings for almond and California row crops. These specific materials were also shared with government and NGO agencies who are involved in designing plant mixes (specifically, CDFA, NRCS and Farm Services Agency). What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? This project involved a series of interconnected objectives that revolve round the goal of supporting robust populations of wild bees that can be integrated with healthy honey bee populations to provide reliable pollination for California agriculture. I outline accomplishments with reference to these. Objective 1: Quantify the reliability and stability of wild bee pollination of specialty crops, and the role of pollinator biodiversity in stabilizing pollination services over multiple spatial and temporal scales. Objective 2: Identify the roles of forage (floral) resources and nesting habitat in determining native bee abundance and diversity in association with pollinator habitat plantings. Objective 3: Identify native wildflower species that best support wild bees and honey bees in agricultural contexts and can be used to enhance habitat quality for pollinators. Objective 4: Determine effective strategies for cultivation of native plants (so called pollinator habitat) in different agricultural contexts. We successfully gathered data completed analysis for parts of Objective 1 in row crop (watermelon, was the target) and almond orchard systems. Data were collected over 3 years for each system to provide robust estimates over time. I am preparing manuscripts from this work on row crops and almond. I worked with collaborators to explicitly test the roles of abundance and diversity of wild bees on pollination by using a new analytical tool, the Price Equation Partition and understanding how the need for diversity scales with increasing numbers of sites (Winfree et al. 2018). The method, borrowed from evolutionary biology, disentangled the effects of bee abundance, diversity and species identity on variation in pollination. The approach has now been adopted by other research groups and who are using it in their own systems. Results of these studies will help target audiences to better design actions to promote sustainable pollination with native species and conservation. For example the ability to identify key species that provide the bulk of crop pollination may allow for more streamlined design of habitat. The importance of turnover of dominant pollinators across regions supports the role of maintaining diverse farm landscapes regionally. I also worked with collaborators to develop a national level spatial analysis of wild bee abundance and pollination demand identifying regions of pollinator deficit. I contributed data from our California studies to validate model predictions. With visiting scientist Dr. Ouin (Toulouse) we used multi-year data sets on bee visitors to watermelon and surround farm lands to make an assessment of pollinator stability over time. On Objective 2, we gathered three years of data on ground-nesting bees at forage plantings. Results from this work have been drafted to a manuscript for submission (Williams et al in prep). In addition we assessed the potential of hedgerow sites to provide important forage resources for a community of "above-ground" nesting species. Data revealed that wildflower plantings along field borders increased nesting over un-enhanced margins. Surprisingly, however, pollen collected by bees nesting there was most often collected elsewhere in the landscape. There is a manuscript under revision from this work. We published a second paper revealing the role of nesting habit as an ecological filter of bee communities on agricultural lands. Nest location was a dominant trait in determine species response to agriculture in general regardless of whether management was organic or conventional. Graduate student Rae Scampavia additionally revealed the role of specific management (irrigation, tillage, and compaction) on nest site preferences of soil-nesting bees. Finally, we published a manuscript (Lundin et al 2017) documenting that wildflower border plantings associated with almond do not compete with orchards for pollination service. For Objective 3. We developed an optimization model to help further refine plant mixes for different goals (e.g., biodiversity conservation, crop pollination). I published a paper from this work (Williams Lonsdorf 2018) and have presented results at multiple stakeholder and professional meetings. We also applied our optimization model to help refine existing plant mixes from throughout different regions of North America. For this extension of our approach, the models were updated to account for compensatory changes in seeding density with the reduction in mix diversity - with fewer species practitioners often add more seed of the remaining species to avoid leaving too much bare ground. This allowed us to more appropriately apply an optimization model that included true seed costs. I and colleagues presented results at multiple stakeholder and professional meetings. We also expanded our studies to use a new type of field data collected over multiple seasons. Here we collected data on phenology and floral visitation for 43 drought tolerant California native plant species. Along with data on floral visitors (pollinating bees/flies) we also collected data on herbivore species and parasitic wasps associated with the plants. This expansion allows us to much more comprehensively consider the benefits and liabilities of plant choices for use in proposed mixes (Lundin et al. 2019). We are now working to integrate the field data with different models to assess trade-off among different plant choices and mixes. For Objective 4 we continue to refine methods for cultivating native plants. We have begun a new component of our project to test differences in establishment and plant performance of a range of plant mixes across various diversity and seeding density treatments. These variables are of ecological interest and also have particular applied relevance. The two, in additional to species identity, are the main elements that can be adjusted by practitioners to change the cost of seed mixes to promote pollinators and other conservation/ sustainable agriculture goals. This portion of the project will move forward during our next AES proposal.

Publications

  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Sgolastra, F., Hinarejos, S., Pitts-Singer, T.L., Boyle, N., Joseph, T., Luckmann, J., Raine, N. E., Singh, R., Williams, N. M. and J. Bosch. (2018). Pesticide exposure assessment paradigm for solitary bees. Environ. Entomol.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Lundin, O.*, Ward, K. L., & Williams, N. M. (2019). Identifying native plants for coordinated habitat management of arthropod pollinators, herbivores and natural enemies. Journal of Applied Ecology, 56(3), 665-676
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Sponsler, D. B., Grozinger, C. M., Hitaj, C., Rundl�f, M., Bot�as, C., Code, A, Thogmartin, W. E., Smith, D.J., Suryanarayanan, S., Williams, N. M., Zhang, M., Douglass, M.R.. (2019). Pesticides and pollinators: A socioecological synthesis. Science of the Total Environment. 662:1012-1027
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Malfi, R.L., Crone, E.E., Williams, N. M. (2019). Demographic benefits of early season resources for bumble bee (B. vosnesenskii) colonies. Oecologia 191: 377-388


Progress 10/01/17 to 09/30/18

Outputs
Target Audience:During the reporting period the project targets (1) California fruit, nut growers and vegetable growers, including those focused on fresh market fruits and those in the seed industry; (2) Conservation practitioners, including Federal, State and County levels and NGO organizations engaged in pollinator health and biodiversity conservation efforts and (3) beekeepers of California and elsewhere who are involved in almond pollination. As part of our work on Objectives 3 &4 in 2017 we worked increasingly with California beekeepers through collaboration with Project Apis m (Pam). We focused on almond growers in and Northern parts of the Central Valley. The almond grower/ industry organization (ABC) has been instrumental in promoting pollinator health and the industry is now embracing the importance of diversifying the forage resources available to managed honeybees and also the potential for other species of bees to contribute to pollination. Our work with NGOs and conservation involved controlled studies providing data to parameterize optimization models for the design of regional seed mixes for pollinator plantings and continued work on best management strategies for maintaining habitat plants for beneficial insects including pollinators. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Visiting Scholar Maj Rundlof (Lund University) joined our project and has worked on different aspects. She was mentored in grant development, field data collection. She successfully obtained two research grants and will return to Sweden to begin these projects in 2019. Tina Harrison (postdoc) received mentoring throughout the project on field research design and coordination. She also led model development for integration of pest and pollinator data. She presented the results at the 2018 National Entomology Meeting. These activites are building her skill set toward obtaining a faculty position Kimiora Ward (Project specialist; SRAIII supervisor) coordinated research testing the attractiveness and growth of wildflower mixes to bolster native and managed pollinators. She was provided training in and then presented work at regional workshops building her skill set in outreach components of our project. Graduate students John Mola, Maureen Page and Clara Stuligross were mentored on activities associated with this project. Two undergraduate students from this course joined the lab group where they trained on insect identification, data summary and management and have been working on data related to the optimization of seed mixes as well as pollination in almond landscapes. 5 postgraduate research technicians also worked on the projects and received mentoring in field methods for pollination biology, insect surveying and plant surveying. They also received training on lab based protocols, including insect identification and in project management. How have the results been disseminated to communities of interest?Results from Objective 3 and 4 have been most widely disseminated to communities of interest through a combination of field day presentation, outreach publications and talks to commodity groups and bee keeper organizations throughout the state and webinars (eXtension). I presented summary and recommendations on plant materials to support bee health to leading beekeeper and almond board of California representatives at presentation. Williams also spoke at 2017 Almond Conference research symposium on best practices to promote bee forage and bee health. Postgraduate assistants also presented a poster on specific research related to almond pollination. In additional I presented a Specialty seed groups courses held in spring at UC Davis (120 attending). I and others in my group presented talks and round table discussion at the 2017 Bee Symposium at UC Davis (150 attendees). Finally we gave presentations at grower and other stakeholder field days over the 2018 season. These specifically targeted elements of Objective 3 and 4 on habitat design the others were more generally about pollinators and pollination. What do you plan to do during the next reporting period to accomplish the goals?For Objective 1. I will complete research on native bee/ honey bee contributions to pollination of almond in CA and will be contributing to a national synthesis paper native bee contributions to specialty crop pollination. We also are expanding the exploration from habitats along field borders to covercrop plantings. For Objective 2, I will continue work on different types of management that enhance ground-nesting bees. Understanding soil and other microsite characteristics that determine nest site selection and success of ground-nesting bee species is a critical unknown for promoting native bee populations and their contribution to crop pollination. I will complete field study of habitat restorations role to support native bee and managed bee pollinators in almond. Complete a BMP guide for almond and a journal article on multiple benefits of these plantings in agricultural lands. I will add preliminary study of orchard cover crops as alternative farm scape enhancement for these systems. For Objective 3. With optimization model complete and applied to multiple data sets. I will work collaboratively improve the tool incorporating shifting seed densities. I will also work with postdoc Tina Harrison to develop the integration of pest information into the plant selection process. I will complete manuscripts examining the potential impacts of plantings for supporting pollination and pest damage as well as pest control in two contrasting crop systems.This will be complemented by continued trials of a broader array of plant species that could be used to support managed and wild pollinator populations. We have set up additional test plots at the a collaborating seed production farm and will gather a second season of data from single species plots that can be used to inform plant choices. Objective 4. I will initiate trials of the impacts of seed density and diversity on the performance on habitat plantings in working agricultural lands.

Impacts
What was accomplished under these goals? This project has a series of interconnected objectives that revolve round the goal of supporting robust populations of wild bees that can be integrated with healthy honey bee populations to provide reliable pollination for California agriculture. I outline accomplishments with reference to these. Objective 1: Quantify the reliability and stability of wild bee pollination of specialty crops, and the role of pollinator biodiversity in stabilizing pollination services over multiple spatial and temporal scales. Objective 2: Identify the roles of forage (floral) resources and nesting habitat in determining native bee abundance and diversity in association with pollinator habitat plantings. Objective 3: Identify native wildflower species that best support wild bees and honey bees in agricultural contexts and can be used to enhance habitat quality for pollinators. Objective 4: Determine effective strategies for cultivation of native plants (so called pollinator habitat) in different agricultural contexts. We successfully completed data gathering and analysis for parts of Objective 1 and I am preparing manuscripts from this work on row crops. I worked with collaborators to explicitly test the roles of abundance and diversity of wild bees on pollination by using a new analytical tool, the Price Equation Partition and understanding how the need for diversity scales with increasing numbers of sites (Winfree et al. 2018). Results of these studies will help target audiences to better design actions to promote sustainable pollination with native species and conservation. For example the ability to identify key species that provide the bulk of crop pollination may allow for more streamlined design of habitat. The importance of turnover of dominant pollinators across regions supports the role of maintaining diverse farm landscapes regionally. On Objective 2, we gathered a third season of data on ground-nesting bees at forage plantings. Results from this work have been drafted to a manuscript for submission (Williams et al in prep). In addition we assessed the potential of hedgerow sites to provide important forage resources for a community of "above-ground" nesting species. Data revealed that wildflower plantgins along field borders increased nesting over un-enhanced margins. Surprisingly, however, pollen collected by bees nesting there was most often collected elsewhere in the landscape. There is a manuscript under revision from this work. For Objective 3, We also applied our an optimization model to further refine existing plant mixes from throughout different regions of North America building on our new paper, Williams Lonsdorf 2018. The models were updated to account compensatory changes in seeding density with the reduction in mix diversity. This allowed us to more appropriately apply an optimization model that included seed costs. I and colleagues presented results at multiple stakeholder and professional meetings. results were also shared with government and NGO agencies who are involved in designing plant mixes (e.g., NRCS, Farm Services Agency). We also expanded our studies to use a new type of field data collected over multiple seasons. Here we collected data on phenology and floral visitation for 43 drought tolerant California native plant species. Along with data on floral visitors (pollinating bees/flies) we also collected data on herbivore species and parasitic wasps associated with the plants. This expansion allows us to much more comprehensively consider the benefits and liabilities of plant choices for use in proposed mixes. We have a first manuscript accepted in Journal of Applied Ecology. We are now working to integrate the field data with different models to assess trade-off among different plant choices and mixes. For Objective 4.We continue to refine methods for cultivating native plants as proposed in Objective 4. We have begun a new component of our project to test differences in establishment and plant performance of a range of plant mixes that vary in diversity and seeding density. These variables are of ecological interest and also have particular applied relevance. The two in additional to species identity are the main elements that can be adjusted (and are adjusted by practitioners) to change the cost of seed mixes to promote pollinators and other conservation/ sustainable agriculture goals.

Publications

  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Lichtenberg, E. M., C. M. Kennedy, C. Kremen, P. Batáry, F. Berendse, R. Bommarco, N. A. Bosque?Pérez, L. G. Carvalheiro, W. E. Snyder, N. M. Williams, et al. (2017). A global synthesis of the effects of diversified farming systems on arthropod diversity within fields and across agricultural landscapes. Global Change Biology. 23:4946-4957
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Williams, N. M., & Lonsdorf, E. V. (2018). Selecting cost-effective plant mixes to support pollinators. Biological Conservation, 217:195-202
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Winfree, R., Reily, J.R., Bartomeus, I, Cariveau, D.P., Williams, N.M., Gibbs, J. (2018) Species turnover promotes the importance of bee diversity for crop pollination at regional scales. Science
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Iles, D.T., Williams, N.M. Crone, E.E. (2018). Source-sink dynamics of bumble bees in rapidly changing landscapes. Journal of Applied Ecology.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Boyle, N.K., Pitts-Singer, T.L., Abbott, J., Alix, A., Cox-Foster, D.L., Hinarejos, S., Lehmann, D.M., Morandin, L., ONeill, B., Raine, N.E., Singh, R., Thompson, H.M., Williams, N.M. and T. Steeger. (2018). Workshop on pesticide exposure assessment paradigm for non-Apis bees: foundation and summaries. Environ. Entomol


Progress 10/01/16 to 09/30/17

Outputs
Target Audience:During the reporting period the project targets (1) California fruit, nut growers and vegetable growers, including those focused on fresh market fruits and those in the seed industry; (2) Conservation practitioners, including Federal, State and County levels and NGO organizations engaged in pollinator health and biodiversity conservation efforts and (3) beekeepers of California and elsewhere who are involved in almond pollination. As part of our work on Objectives 3 &4 in 2017 we worked increasingly with California beekeepers through collaboration with Project Apis m (Pam). We focused on almond growers in and Northern parts of the Central Valley. The almond grower/ industry organization (ABC) has been instrumental in promoting pollinator health and the industry is now embracing the importance of diversifying the forage resources available to managed honeybees and also the potential for other species of bees to contribute to pollination. Our work with NGOs and conservation involved controlled studies providing data to parameterize optimization models for the design of regional seed mixes for pollinator plantings and continued work on best management strategies for maintaining habitat plants for beneficial insects including pollinators. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Ola Lundin (postdoc) received mentoring throughout the project on field research design and coordination. He also led his own team for which he was given nearly full control to manage. This is building his skill set toward obtaining a position in academics. Kimiora Ward (Project specialist; SRAIII supervisor) coordinated research testing the attractiveness and growth of wildflower mixes to bolster native and managed pollinators. She was provided training in and then presented work at regional workshops building her skill set in outreach components of our project. Katherine Bolte (Junior Specialist) received training on implementation and management of plantings for pollinator restoration. Graduate students John Mola, Rei Scampavia, Maureen Page and Clara Stuligross were mentored on activities associated with this project. Scampavia successfully completed her doctorate. Williams updated course in Pollination Ecology in Fall 2017. As part of this course he led field trips to study sites associated with the project. This provided exposure to field methods used in objectives 3 and 4. Two undergraduate students from this course joined the lab group where they trained on insect identification, data summary and management and have been working on data related to the optimization of seed mixes as well as pollination in almond landscapes. 4 postgraduate research technicians also worked on the projects and received mentoring in field methods for pollination biology, insect surveying and plant surveying. They also received training on lab based protocols, including insect identification and in project management. How have the results been disseminated to communities of interest?Results from Objective 3 and 4 have been most widely disseminated to communities of interest through a combination of field day presentation, outreach publications and talks to commodity groups and bee keeper organizations throughout the state and webinars (eXtension). I presented summary and recommendations on plant materials to support bee health to leading beekeeper and almond board of California representatives at presentation. Williams also spoke at 2017 Almond Conference research symposium on best practices to promote bee forage and bee health. Postgraduate assistants also presented a poster on specific research related to almond pollination. In additional I presented a Specialty seed groups courses held in spring at UC Davis (120 attending). I presented and discussed plant selection guidelines to two different bee keeper groups Sacramento Area Beekeepers Association. The group was enthusiastic about the information. SABA provided support to develop the on-line database. I and others in my group presented talks and round table discussion at the 2017 Western Apicultural Society Meeting (150 attendees) and Bee Symposium at UC Davis (150 attendees). Finally we gave presentations at four grower and other stakeholder field days over the 2017 season. Two of these specifically targets elements of Objective 3 and 4 on habitat design the others were more generally about pollinators and pollination. What do you plan to do during the next reporting period to accomplish the goals?For Objective 1. I will complete research on native bee/ honey bee contributions to pollination of almond in CA and will be contributing to a national synthesis paper native bee contributions to specialty crop pollination. For Objective 2, I will continue work on different types of management that enhance ground-nesting bees. Understanding soil and other microsite characteristics that determine nest site selection and success of ground-nesting bee species is a critical unknown for promoting native bee populations and their contribution to crop pollination. I will complete field study of habitat restorations role to support native bee and managed bee pollinators in almond. Complete a BMP guide for almond and a journal article on multiple benefits of these plantings in agricultural lands. I will add preliminary study of orchard cover crops as alternative farmscape enhancement for these systems. For Objective 3. With optimization model complete, the next period will be dedicated to demonstrating its ability using multiple data sets. I also will work collaboratively to use the tool to help inform plant selection decisions. This will be complemented by continued trials of a broader array of plant species that could be used to support managed and wild pollinator populations. We have set up test plots at the UC Davis Laidlaw bee biology Facility and will gather a second season of data from single species plots that can be used to inform plant choices. I also will complete the on-line Honey Plants of California and searchable database plants for bees database. Objective 4. I will initiate trials of the impacts of seed density and diversity on the performance on habitat plantings in working agricultural lands.

Impacts
What was accomplished under these goals? This project has a series of interconnected objectives that revolve round the goal of supporting robust populations of wild bees that can be integrated with healthy honey bee populations to provide reliable pollination for California agriculture. I outline accomplishments with reference to these. Objective 1: Quantify the reliability and stability of wild bee pollination of specialty crops, and the role of pollinator biodiversity in stabilizing pollination services over multiple spatial and temporal scales. Objective 2: Identify the roles of forage (floral) resources and nesting habitat in determining native bee abundance and diversity in association with pollinator habitat plantings. Objective 3: Identify native wildflower species that best support wild bees and honey bees in agricultural contexts and can be used to enhance habitat quality for pollinators. Objective 4: Determine effective strategies for cultivation of native plants (so called pollinator habitat) in different agricultural contexts. We successfully completed data gathering and analysis for parts of Objective 1 and I am preparing manuscripts from this work on row crops. I worked with collaborators to explicitly test the roles of abundance and diversity of wild bees on pollination by using a new analytical tool, the Price Equation Partition (Citation) and understanding how the need for diversity scales with increasing numbers of sites (citation). Results of these studies will help target audiences to better design actions to promote sustainable pollination with native species and conservation. For example the ability to identify key species that provide the bulk of crop pollination may allow for more streamlined design of habitat. The importance of turnover of dominant pollinators across regions supports the role of maintaining diverse farm landscapes regionally. On Objective 2, we gathered a third season of data on ground-nesting bees at forage plantings. Results from this work have been drafted to a manuscript for submission (Williams et al in prep) and were presented at two national meetings (Entomology Society and Ecological Societies of America. Additionally. Rae Scampavia successfully complete her doctorate that included work revealing the role of specific management (irrigation, tillage, and compaction) on nest site preferences of soil-nesting bees. In addition we assessed the potential of hedgerow sites to provide important forage resources for a community of "above-ground" nesting species. Data revealed that hedgerows along field borders increased nesting over un-enhanced margins. Surprisingly, however, pollen collected by bees nesting there was most often collected elsewhere in the landscape. There is a manuscript under revision from this work. Finally, we published a manuscript (Lundin et al 2017) documenting that wildflower border plantings associated with almond do not compete with orchards for pollination service. For Objective 3, We also developed an optimization model to help further refine plant mixes for different goals (e.g., biodiversity conservation, crop pollination. I published a paper from this work, Williams Lonsdorf 2018) and have presented results at multiple stakeholder and professional meetings. This approach is being applied broadly to pollinator mixes statewide and nationally in the coming year We continue to refine methods for cultivating native plants as proposed in Objective 4. We published a guide to Establishing Wildflower Habitat to Support Pollinators of California Row Crops (http://icpbees.org/wp-content/uploads/2014/05/CA-Row-Crops-Habitat-Guide-FINAL-1.pdf).

Publications

  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Isaacs, R., Williams, N., Ellis, J., Pitts-Singer, T. L., Bommarco, R., & Vaughan, M. (2017). Integrated Crop Pollination: Combining strategies to ensure stable and sustainable yields of pollination-dependent crops. Basic and Applied Ecology 22:44-60
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Lundin, O., Ward, K. L., Artz, D. R., Boyle, N. K., Pitts-Singer, T. L., & Williams, N. M. (2017). Wildflower plantings do not compete with neighboring almond orchards for pollinator visits. Environmental Entomology, 46(3), 559-564
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Schaeffer, R. N., Vannette, R. L., Brittain, C., Williams, N. M., & Fukami, T. (2017). Non?target effects of fungicides on nectar?inhabiting fungi of almond flowers. Environmental microbiology reports 9: 79-84
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Genung, M. A., Fox, J., Williams, N. M., Kremen, C., Ascher, J. Gibbs, J. and R. Winfree. (2017) Pollinator abundance, rather than species richness, drives the temporal variability of pollination services. Ecology 98:1807-1816
  • Type: Other Status: Published Year Published: 2017 Citation: May, E. , Ward, K. Williams, N. et al. 2017. ESTABLISHING WILDFLOWER HABITAT TO SUPPORT POLLINATORS OF CALIFORNIA ROW CROPS, Guidelines for Establishing Pollinator Habitat on California Farms. University of California, Xerces Society for Invertebrate Conservation.
  • Type: Other Status: Published Year Published: 2017 Citation: Ullmann, K., Isaacs, R., Vaughan, M., May, E., Ellis, J. , Williams, N., et al. 2017. Guide to Integrated Crop Pollination. Project ICP & Xerces Society for Invertebrate Conservation.


Progress 10/01/15 to 09/30/16

Outputs
Target Audience:During the reporting period the project targeted (1) California fruit, nut growers and vegetable growers, including those focused on fresh market fruits and those in the seed industry; (2) Conservation practitioners, including Federal, State and County levels and NGO organizations engaged in pollinator health and biodiversity conservation efforts and (3) beekeepers of California and elsewhere who are involved in almond pollination. As part of our work on Objectives 3 &4 in 2016 we worked increasingly with California beekeepers through collaboration with Project Apis m (Pam), and direct engagement at bee keepers associations. We targeted almond growers in South Central and Northern parts of the Central Valley. The almond grower/ industry organization (ABC) has been instrumental in promoting pollinator health and the industry is now embracing the importance of diversifying the forage resources available to managed honeybees and also the potential for other species of bees to contribute to pollination. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Ola Lundin (postdoc) - has received individual mentoring throughout the project on field research design and coordination. He also led his own team for which he was given nearly full control to manage. This is building his skill set toward obtaining a position in academics. Dr. Lundin finished his postdoc in Nov 2016 and has a new position at the Swedish Agricultural University. Kimiora Ward - Project specialist (SRA) coordinated research testing the attractiveness and growth of wildflower mixes to bolster native and managed pollinators. She was provided training in and then presented work at regional workshops building her skill set in outreach components of our project. Ms. Ward also took a leading role in developing a Specialty Crop grant pre-proposal this has for full submission. Mike Epperly (Junior Specialist, UCD), received individual mentoring in running a research team. He oversaw parts of the bee monitoring projects in almond landscapes and will take over management of a new project examining impacts of pollinator plantings on other beneficial insects. Katherine Bolte (Junior Specialist, UCD), received individual mentoring in managing field crews and working with growers. She has coordinated management of over 15 restoration sites across northern California. Graduate students Maureen Page and Rei Scampavia are being mentored on activities associated with this project. Williams update his course in Pollination Ecology. As part of this course he led field trips to study sites associated with the project. This provided exposure to field methods used in objectives 3 and 4. One student from this course joined the lab group where he trained on insect identification, data summary and management. Three additional undergraduate students and 5 postgraduate research technicians also worked on the projects and received mentoring in field methods for pollination biology, insect surveying and plant surveying. They also received training on lab based protocols, including insect identification and in project management. How have the results been disseminated to communities of interest?Results from Objective 3 and 4 have been most widely disseminated to communities of interest through a combination of field day presentation (2 in almond in spring 2016), outreach publications (ICP news letters) and talks to commodity groups (Almond Conference, Seed Production Meeting, UC Davis) and bee keeper organizations throughout the state. I presented a poster at the Almond Conference research bee forage and bee health. I and others in my group presented talks and round table discussion at the 2016 Bee Symposium at UC Davis attended by of 200 stakeholders. In additional I presented plant selection guidelines to two different land grant Universities (Penn State, Iowa State). I presented ideas for farming to support bees and the 2016 Bee Audacious conference in Marin County California and led 3 days of facilitated discussion around bee health and pollination. Groups were enthusiastic about the information. Finally we gave presentations at three grower and other stakeholder field days over the 2016 season. Two of these specifically targets elements of Objective 3 and 4 on habitat design the others were more generally about pollinators and pollination. We began preparing guidelines for best management for wild flowers for bees in almond and California row crops. Objective 2 information on the role of nesting habitat was presented a Summer 2016 scientific and public pollinator meeting at Penn State University. What do you plan to do during the next reporting period to accomplish the goals?In the next reporting period I will continue work in each objective For Objective 1. I will complete research on native bee contributions to pollination of watermelon and summarize data on impacts of native bees to almond pollination. I will contribute to a two national synthesis papers of data exploring this question. I will present a Extension Webinar on the role of native bees for watermelon pollination and approaches to bolster their populations using wildflower habitats. For Objective 2, I will complete an additional year of surveys to identify habitats and types of management that enhance ground-nesting bees. Understanding soil and other microsite characteristics that determine nest site selection and success of ground-nesting bee species is a critical unknown for promoting native bee populations and their contribution to crop pollination. For Objective 3. With optimization model complete, the next period will be dedicated to demonstrating its ability using multiple data sets. I also will work collaboratively to use the tool to help inform plant selection decisions. This will be complemented by continued trials of a broader array of plant species that could be used to support managed and wild pollinator populations. We have set up test plots at the UC Davis Laidlaw Bee Biology Facility and will gather another season of data from single species plots that can be used to inform plant choices. I also will complete the on-line Honey Plants of California and searchable database plants for bees database.

Impacts
What was accomplished under these goals? We successfully completed data gathering and analysis for parts of Objective 1 focusing on almond and following on previous years' work with vegetable row crops. We will continue with almond study in the next year. Data from row crops were combined with other data from across the nation to complete a national assessment of the contributions of wild bees to pollination of specialty crops in different contexts. I also worked with collaborators to develop a national level spatial analysis of wild be abundance and pollination demand identifying regions of pollinator deficit. I contributed data from our California studies to validate model predictions. With visiting scientist Dr. Ouin we are using multi-year data sets on bee visitors to watermelon and surround farm lands to make an assessment of pollinator stability over time. On Objective 2, we completed analysis of the data set on ground-nesting bees at forage plantings. I am drafting a paper on the impact of wildflower plantings on native bee nesting and well as protocols for surveying of soil nesting bees and wasps. Results indicate a significant benefit from plantings. This activity has also been a chance to collaborate with a postgraduate research technician, building his ability in preparing data for a paper. Student Rae Scampavia additionally revealed the role of specific management (irrigation, tillage, and compaction) on nest site preferences of soil-nesting bees. She and I are preparing also a review paper on the topic. For Objective 3, We continued to develop the optimization model to help further refine plant mixes for different goals (e.g., biodiversity conservation, crop pollination). Collaborator E. Lonsdorf and I have completed a paper on the model and on mix optimization submitted to Conservation Biology. The model will be applied in the coming grant period to several data set. We continue to refine methods for cultivating native plants as proposed in Objective 4. One new paper published with collaborators explored differences in seeding density and this complemented a second paper that considered species diversity. We extended our work to a new set of plant species and contexts focusing on almond landscapes. We are preparing for assessment of the impacts of these planting on almond pollination in the coming month.

Publications

  • Type: Journal Articles Status: Published Year Published: 2016 Citation: M'Gonigle, L. K., Williams, N. M., Lonsdorf, E., and C. Kremen. (2016) A tool for selecting plants when restoring habitat for pollinators. Conservation Letters 1-7. DOI:�10.1111/conl.12261
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Koh, I., Lonsdorf, E.V., Williams, N. M., Brittain, C.*, Isaacs, R., Gibbs, J., and T.H. Ricketts. (2015) Modeling the status, trends, and impacts of wild bee abundance in the United States. Proceedings of the National Academy of Sciences. 113:140-145.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Crone, E. E., and N. M. Williams. (2016) Bumble bee colony dynamics: quantifying the importance of land use and floral resources for colony growth and queen production. Ecology Letters. 19:460-468.
  • Type: Journal Articles Status: Submitted Year Published: 2017 Citation: Williams, N.M. and E. Lonsdorf. Selecting cost-effective plant mixes to support pollinators. Conservation Biology.


Progress 11/28/14 to 09/30/15

Outputs
Target Audience:During the reporting period the project targets (1) California fruit, nut growers and vegetable growers, including those focused on fresh market fruits and those in the seed industry; (2) Conservation practitioners, including Federal, State and County levels and NGO organizations engaged in pollinator health and biodiversity conservation efforts and (3) beekeepers of California and elsewhere who are involved in almond pollination. As part of our work on Objectives 3 &4 in 2015 we worked increasingly with California beekeepers through collaboration with Project Apism (Pam), and direct engagement at bee keepers associations. We are targeting almond growers in South Central and Northern parts of the Central Valley. The almond grower/ industry organization (ABC) has been instrumental in promoting pollinator health and the industry is now embracing the importance of diversifying the forage resources available to managed honeybees and also the potential for other species of bees to contribute to pollination. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Ola Lundin (Postdoc) - has received individual mentoring throughout the project on field research design and coordination. He also led his own team for which he was given nearly full control to manage. This is building his skill set toward obtaining a position in academics. Kimiora Ward - Project specialist (SRA) coordinated research testing the attractiveness and growth of wildflower mixes to bolster native and managed pollinators. She was provided training in and then presented work at regional workshops building her skill set in outreach components of our project. Logan Rowe (Junior Specialist, UCD), received individual mentoring in running a research team. He oversaw parts of the bee nesting project. Graduate students John Mola and Rei Scampavia are being mentors on activities associated with this project. Williams designed a new course in Pollination Ecology in Spring 2015. As part of this course he led field trips to study sites associated with the project. This provided exposure to field methods used in objectives 3 and 4. One student from this course joined the lab group where he trained on insect identification, data summary and management. Three additional undergraduate students and 4 postgraduate research technicians also worked on the projects and received mentoring in field methods for pollination biology, insect surveying and plant surveying. They also received training on lab based protocols, including insect identification and in project management. How have the results been disseminated to communities of interest?Results from Objective 3 and 4 have been most widely disseminated to communities of interest through a combination of field day presentation, outreach publications and talks to commodity groups and bee keeper organizations throughout the state. I presented summary and recommendations on plant materials to support bee health to members of the California Department of Agriculture and leading beekeeper and almond board of California representatives in at CDFA. I also spoke at 2015 Almond Conference research symposium on best practices to promote bee forage and bee health. In additional I presented and discussed plant selection guidelines to two different bee keeper groups San Metao Bee Guild and the Sacramento Area Beekeepers Association. Both groups were enthusiastic about the information. SABA provided support to develop the on-line database. I and others in my group presented talks and round table discussion at the 2015 Bee Symposium at UC Davis attended by of 200 stakeholders. Finally we gave presentations at four grower and other stakeholder field days over the 2015 season. Two of these specifically targets elements of Objective 3 and 4 on habitat design the others were more generally about pollinators and pollination. What do you plan to do during the next reporting period to accomplish the goals?In the next reporting period I will continue work in each objective For Objective 1. I will complete research on native bee contributions to pollination of watermelon. I will contribute to a national synthesis of data exploring this question. For Objective 2, I will focus on identifying habitats and types of management that enhance ground-nesting bees. Understanding soil and other micro-site characteristics that determine nest site selection and success of ground-nesting bee species is a critical unknown for promoting native bee populations and their contribution to crop pollination. For Objective 3. With optimization model complete, the next period will be dedicated to demonstrating its ability using multiple data sets. I also will work collaboratively to use the tool to help inform plant selection decisions. This will be complemented by continued trials of a broader array of plant species that could be used to support managed and wild pollinator populations. We have set up test plots at the UC Davis Laidlaw Bee Biology Facility and will gather a second season of data from single species plots that can be used to inform plant choices. I also will complete the on-line Honey Plants of California and searchable database plants for bees database.

Impacts
What was accomplished under these goals? This project has a series of interconnected objectives that revolve round the goal of supporting robust populations of wild bees that can be integrated with healthy honey bee populations to provide reliable pollination for California agriculture. I outline accomplishments with reference to these. Objective 1: Quantify the reliability and stability of wild bee pollination of specialty crops, and the role of pollinator biodiversity in stabilizing pollination services over multiple spatial and temporal scales. Objective 2: Identify the roles of forage (floral) resources and nesting habitat in determining native bee abundance and diversity in association with pollinator habitat plantings. Objective 3: Identify native wildflower species that best support wild bees and honey bees in agricultural contexts and can be used to enhance habitat quality for pollinators. Objective 4: Determine effective strategies for cultivation of native plants (so called pollinator habitat) in different agricultural contexts. We successfully completed data gathering and analysis for parts of Objective 1 and will continue with it in the next year. I worked with collaborators to explicitly test the roles of abundance and diversity of wild bees on pollination by using a new analytical tool, the Price Equation Partition. The method, borrowed from evolutionary biology, disentangled the effects of bee abundance, diversity and species identity on variation in pollination. Results of these studies will help target audiences to better design actions to promote sustainable pollination with native species and conservation. For example the ability to identify key species that provide the bulk of crop pollination may allow for more streamlined design of habitat. Alternatively if the goal is biodiversity conservation a different action might be pursued. On Objective 2, we gathered a second season of data on ground-nesting bees at forage plantings. These data will form the basis of a paper on the impact of wildflower plantings on native bee nesting and well as protocols for surveying of soil nesting bees and wasps. Student Rae Scampavia additionally revealed the role of specific management (irrigation, tillage, and compaction) on nest site preferences of soil-nesting bees. In addition we assessed the potential of hedgerow sites to provide important forage resources for a community of "above-ground" nesting species. Data revealed that hedgerows along field borders increased nesting over un-enhanced margins. Surprisingly, however, pollen collected by bees nesting there was most often collected elsewhere in the landscape. Finally we published a paper revealing the role of nesting habit as an ecological filter of bee communities on agricultural lands. Nest location was a dominant trait in determine species response to agriculture in general regardless of whether management was organic or conventional. For Objective 3, I published the first North American paper quantifying the role of different wildflower mixes to support bees. We also developed an optimization model to help further refine plant mixes for different goals (e.g., biodiversity conservation, crop pollination). This will be applied in the coming grant period. We continue to refine methods for cultivating native plants as proposed in Objective 4. One new paper published with collaborators explored differences in seeding density and this complemented a second paper that considered species diversity.

Publications

  • Type: Journal Articles Status: Published Year Published: 2015 Citation: J.R.K. Forrest*, R.W. Thorp, C. Kremen, and N.M. Williams. 2015. Contrasting patterns in species and functional-trait diversity of bees in an agricultural landscape, Journal of Applied Ecology 52: 706-715
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Williams, N. M., Ward, K. L.*, Pope, N.*, Isaacs, R. Wilson, J., May, E. A., Ellis, J., Daniels, J., Pence, A., Ullmann, K. Peters, J. (2015) Native wildflower plantings support wild bee abundance and diversity in agricultural landscapes across the United States. Ecological Applications
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Kleijn, D, Scheper, J, Winfree, R. (2015) Delivery of crop pollination services is an insufficient argument for wild pollinator conservation. Nature Communications, 6:7414
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Winfree, R., J. W. Fox, N. M. Williams, J. R. Reilly, and D. P. Cariveau. (2015) Abundance of common species, not species richness, drives delivery of a real-world ecosystem service. Ecology Letters. doi: 10.1111/ele.12424
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Wilkerson, M. L., Ward, K. L.*, Williams, N. M., Ullmann, K. S.*, Young, T. P. (2014) Diminishing returns from higher density restoration seedings suggest tradeoffs in pollinator seed mixes. Restoration Ecology