Garden Pollinators and the Potential for Ecosystem Service Flow to Urban and Peri-Urban Agriculture

Abstract

Hedgerows, flowering strips, and natural areas that are adjacent to agricultural land have been shown to benefit crop production, via the provision of insect pollinators that pollinate crops. However, we do not yet know the extent to which bee habitat in the form of urban gardens might contribute to pollination services in surrounding crops. We explored whether gardens might provision pollinators to adjacent agricultural areas by sampling bees from gardens in the Portland, Oregon metropolitan area, and estimating typical foraging distances in the context of commercialand residential-scale pollination-dependent crops up to 1000 m from garden study sites. We estimate that garden bees could forage outside of the garden in which they were collected, and that when pollination-dependent crops (commercial-scale or residential-scale) are nearby, 30-50% of the garden bee community could potentially provide pollination services to adjacent crops, if urban bees readily cross boundaries and forage among habitat types. Urban gardens might thus be well-positioned to provision neighboring farms and food gardens with pollination services, or could serve as a refuge for pollinators when forage is scarce or crop management practices are inhospitable. The actual capacity of gardens to serve as a refuge for pollinators from agricultural fields depends upon the extent to which bees forage across habitat types. However, relatively little is known about the degree to which bees move among habitat patches in heterogeneous landscapes. We thus propose a research agenda that can document the extent to which gardens contribute to pollinator health and pollination services at the interface of urban, peri-urban, and rural landscapes. In particular, more data is needed on how landscape context impedes or promotes garden bee movement between habitat types.

Income Vulnerability of West African Farming Households to Losses in Pollination Services: A Case Study from Ouagadougou, Burkina Faso

“…Within West African countries urban growth and agricultural intensification can trigger changes in biodiversity leading to either a homogenization or a reduction of important insect communities affecting the ecosystem service of pollination [35][36][37][38][39]. The fact that urban farming households in Ouagadougou were highly specialized in the cultivation and marketing of crops which often rely substantially upon insect pollination and from which they earn most of their total household income, made these households vulnerable to loss of pollination services by insects.…”

Domestic Gardens Mitigate Risk of Exposure of Pollinators to Pesticides—An Urban-Rural Case Study Using a Red Mason Bee Species for Biomonitoring

“…Earlier research highlighted the potential of urban green spaces in terms of providing diverse nesting and forage sources to pollinators, which have decreased in rural areas [5,12]. On the other hand, the production of crops in peri-urban and urban areas may benefit from a pollination ecosystem service flow from these green refugia [13,15,54]. We add new findings on the potential of gardens to provide an enhanced quality of forage resources for pollinators [18,49].…”

“…Though not recognized by gardeners as a priority, protecting the environment also includes protecting pollinator communities and the pollination ecosystem service to their crops [8,91]. Our findings contribute to a broader understanding of how urban gardening generates valuable environmental and social outputs in the cities [12][13][14][15][16]53,54].…”

“…Bees spread from urban refugia to forage in peri-urban agricultural land, where they may contribute to crop production by pollination [11,13]. Their pollination service is also important for yields of urban crops, mainly in view of the expanding field of urban agriculture and increased demand for local and sustainable food in cities [13][14][15][16].…”

“…Domestic gardens are defined as an area adjacent to a domestic dwelling [51]. Aside from the benefits in terms of human health and well-being, air cooling or support of biodiversity [12,13,[52][53][54], the misuse of fertilizers and pesticides in domestic gardens [55], out of any institutional control, may pose a risk to pollinators. On the other hand, a lower intensity of agrochemicals use in gardens than in the agricultural landscape could be expected on the basis of earlier research [18,49].…”