Urban pollinators: their ecology and conservation

There are two schools of thought concerning the effect of urbanization on pollinating insects. On one hand, urbanization is considered to be one of the major causes of insect decline, in particular through the alteration of ecological features important to pollinators, such as food and nesting sites. On the other hand, some urban habitats are remarkably good for pollinators: 35% of hoverfly species known from the UK were recorded in a single garden in Leicester, and urban habitats are one of the few habitats where bumblebees are not declining. Our research will start by asking where pollinators are found in the UK landscape, by comparing pollinator diversity in three habitats: cities, farmland and nature reserves. Rather than just counting species though, we will use a systems approach to study the network of interactions between plants and their pollinators, as these interactions have a profound impact on a community's response to species loss, stress and ecological restoration. In the second stage of the proposed research, we will look in detail at the pollinator fauna of four cities (Bristol, Reading, Leeds and Edinburgh), with the aim of quantifying the value for pollinators of various city habitats. While ecologists know a little about the value of urban gardens for pollinators, practically nothing is known about the value of industrial estates, school grounds, allotments, graveyards and the many other habitats found in cities. Our pilot data suggest that some habitats can be remarkably good for pollinators, or can be managed to be so. Again a network approach will be used, and the impact of change will be predicted using an entirely new mathematical tool - one which combines data on the network of interactions linking pollinators to flowers with data on meta-community ecology (how the whole system of local pollination networks responds to species loss and species dispersal). In the final stage of our proposed research, we ask whether we can improve conditions for urban pollinators. We will use a large-scale field experiment, replicated in four cities, in which we will manipulate pollinator food supplies by introducing an urban version of the field margins sown with 'nectar flower mixtures' on farmland to conserve pollinators. Our plant mixes will be chosen to provide pollinator food, be low-maintenance, and look attractive to the human eye. Working with local professional conservation practitioners in each city (seven of these are named collaborators on the proposal), treatments will be implemented in a bold experimental design in four cities. As can be seen from the letters of support, our project will provide the exact data that practitioners need for evidence-based conservation management of pollinators. Moreover, The Natural Environment and Rural Communities Act 2006 states that public authorities must have regard to conserving biodiversity. Evidence-based urban planning offers considerable promise for pollinator conservation. By using our data to understand the value and spatial properties of the urban habitat mosaic, Local Authorities will be able to integrate pollinator conservation into the 9% of land that comprises urban areas in the UK. Members of the proposed research team have the skills, experience and wherewithal to improve pollinator conservation significantly in the UK. Led by Memmott, the team consists of university-based pollination ecologists, taxonomists to identify the many hundreds of species that will be found, and conservation ecologists, with long-term interests and influence in urban areas, to implement the changes needed to conserve both the pollinators and the ecosystem services they provide. Our research proposal is exciting, timely, pioneering and ambitious. It is also very feasible, as a clear management structure is in place. We will provide both scientific excellence and immediate conservation impact.

In this project a multidisciplinary team of ecologists, conservation practitioners and taxonomists will use a systems approach to study the impact of land use change on pollinators. The mathematics that predicts the system's response to change are models that predict the robustness of the community to environmental change. There are three stages to our research programme: STAGE 1: While there is a growing appreciation of the value of urban habitats to pollinators, in reality we do not know their worth in comparison to other habitats. Here, we will sample replicate urban habitats, agro-ecosystems and nature reserves for pollinators and their interactions with plants. Our replicate networks will be used to identify the factors and processes that act as filters following land use changes due to urbanization. STAGE 2: We will identify the hot spots of pollinator abundance and diversity in urban habitats by constructing spatially explicit plant-pollinator networks for four cities. We will combine these data with estimates of pollinator dispersal from the literature, this providing us with plant-pollinator meta-communities. We will then simulate the effect of habitat loss on these meta-communities. STAGE 3: Working closely with our practitioner collaborators, we will add urban equivalents of the nectar mixes used in agri-environmental schemes to the four cities as pollinator conservation measure. We will use a stratified, randomized design with urban margins added to increasingly urbanized zones. Memmott will lead the project overall. Other PIs are based in Bristol, Reading, Leeds and Edinburgh and each will supervise the project staff based in their city. Good communication between the groups will be ensured by timetabled meetings. In summary, the research will provide scientific excellence and real impact to pollinator conservation.

The users and beneficiaries of our research, outside the academic community, are listed below. Our research will have an immediate impact on pollinators via the conservation practitioners. and our city field sites will enable us to showcase the importance of pollinators to a large swathe of the general public. 1) CONSERVATION PRACTITIONERS: Our research provides the exact type of data that conservation practitioners working in urban habitats require to manage pollinator biodiversity. Thus, the project will give the Wildlife Trusts and other conservation organisations practical assistance in making decisions for urban conservation and land and wildlife management, in the face of rapid development (see e.g. letters of support from Rogers, Fieldhouse, Hall & Smithson). Moreover it will broaden the practitioners' knowledge base of each city's pollinator diversity, and allow the possibility of designating particularly species-rich sites as Local Biodiversity Sites (see letter of support from Fraser). Seven practitioners are collaborators on our project, making it simple to keep them informed of the projects, progress, results and recommendations. We will convey our results to the rest of the UK conservation practitioner community via a Practitioners' Conference. Memmott will organise this Conference and invite the following people to attend: the staff member responsible for reserve management from each of the Wildlife Trusts (n = 47), the County Ecologist (or equivalent) from each UK City (n = 66), PhD students and PDRAs from each of the four Universities involved (n=28). These combined with the academic team of staff (n = 11) leads to 152 delegates. We will cover the costs of conference attendance, as funds to work on biodiversity tend to be very limited for conservation practitioners, and we want guaranteed participation to achieve a guaranteed impact. The conference (see full impact plan for schedule) will spread the ethos, methods, results and recommendations of our research to the very people who have the wherewithal to implement our recommendations in the UK. Moreover, our long-term plan is to implement a country-wide roll out phase of the urban margins as a testable experiment, and the conference will facilitate this process by identifying future project partners. After the conference, we will submit articles about the project to the publications to which many practitioners subscribe, e.g. British Wildlife, ECOS - a review of conservation, and Conservation Management. 2) SCHOOL-CHILDREN AND THE GENERAL PUBLIC: Two approaches will be used to put our research and data into the public arena: a) A 'Meet a Bee' event will be run in eight schools in each city. We will run these in collaboration with the Wildlife Trusts, who will provide contacts and ready access to schools in cities. b) We will use notice boards at all our urban field margins (n=64) to showcase the importance of pollinators and to explain our research. Our field sites are in four large cities, which are home to millions of people. IMPACT PLAN COSTING: Our impact plan is ambitious but effective and the costs are very reasonable when weighed against the likely impact: implementation of our recommendations throughout the UK.