.|  Baltimore Ecosystem Study
Biodiversity Research on Pollinators

Research led by BES collaborator Gail Langellotto at Fordham University focuses on developing a thorough understanding of the potential of developed landscapes (urban and suburban areas) to conserve insect pollinators and promote the ecosystem service of pollination. The success of these investigations hinges on the support and active involvement of various stakeholders (both public and private). Thus, outreach, extension and education are inherently coupled with our research program. Currently, our studies are conducted in the New York City metropolitan area. We are now expanding our research program into the Baltimore area.

The Potential for Pollinator Conservatories within Developed Landscapes
  • Gail Langellotto, Fordham University

Due to the decline of the European honey bee, coupled with an increased awareness of the utility and necessity of alternative pollinators, federal and non-profit organizations have begun to promote the protection of native pollinators and the ecosystem service (i.e. pollination) that they provide. The importance of gardeners to the conservation of insect pollinators is recognized by non-profit organizations such as the Xerxes Society and federal agencies such as EPA and USDA. All of these agencies have highlighted the contributions that homeowners can make to pollinator conservation efforts. That ecosystem services can be conserved in developed landscapes may seem counterintuitive, since the prevalence of suburban and urban neighborhoods in many areas of the United States has generally had adverse affects on biodiversity. However, the proliferation of ornamental, flowering plants within urban/suburban gardens and parks suggests that these habitats may provide beneficial resources to native pollinators. A diversity of nectar-producing flowering plants can be found in many urban community and suburban private gardens. The abundance and diversity of these plants may promote a diverse and abundant pollinator assemblage.

Consideration of within-garden characteristics (such as plant diversity and abundance) on pollinator abundance is not enough. In suburban and urban neighborhoods, individual gardens are embedded within a mosaic of habitats which provide favorable and unfavorable conditions in which pollinators must survive and navigate. Pollinator-conservation recommendations have focused primarily upon local, within-garden interactions among pollinators and plants. However, the effectiveness of these recommendations has yet to be rigorously tested and the impact of landscape-level development has not been fully considered.

Our Current Research Program

Despite the ubiquity and potential ecological importance of urban and suburban gardens, a thorough understanding of the basic biology and ecology associated with such habitats is completely lacking. My lab group at Fordham has been sampling urban community gardens in East Harlem and the Bronx, and suburban private gardens in Westchester County, New York since 2004. Our study sites are unique in their locations within some of the most impoverished and polluted urban areas (East Harlem and the Bronx, NY), and one of the most affluent suburbs (Westchester County, NY) in the United States. As a result, we have conducted our research in close cooperation with local stakeholders from a variety of ethnic, educational and economic backgrounds.

In urban gardens, a total of 49 species of bees (in the superfamily Apoidea), representing 18 genera, have been found. Thus far, a total of 46 species of bees, representing 18 genera, have been identified from suburban gardens. From the urban gardens, the species within a single recalcitrant genus (Dialictus) await identification from an expert systematist. More specimens await processing and identification in the suburban gardens.

In urban gardens, we have found that bee diversity significantly increases as a function of within-garden characteristics such as floral abundance, floral diversity and sunlight. We have also found a non-significant trend towards increasing pollinator diversity as a function of landscape level greenspace surrounding gardens. Curiously, we have found no significant relationship between floral abundance and pollinator diversity in suburban gardens. Analysis of the relationship between landscape level greenspace and pollinator diversity is forthcoming. Nonetheless, results from our urban gardens suggest that community groups and private citizens can conserve pollinator populations by simply maintaining a garden. Furthermore, urban planners may be able to contribute to the conservation of insect pollinators by incorporating more greenspace into developed landscapes. Given that much of the land in the United States is privately owned, it is wise to consider the role that the general public can play in conserving ecosystem services.

Ultimately, our lab intends to pursue a greater understanding of how developed landscapes may influence the ecosystem service of pollination. A more abundant and diverse pollinator community in the local area of a garden doesn't necessarily translate into increased fruit/vegetable yield in gardens and improved native plant fitness in the vicinity of gardens. In fact, preliminary results from our lab suggest that cucumber yield is depressed within gardens that host a diverse pollinator assemblage, perhaps due to an increased deposition of heterospecific pollen on cucumber stigmas. Future research will focus on developing an understanding of how different garden configurations may impact fruit/vegetable yield, and how gardens may impact the fitness of native plants in adjacent habitats.