Pollinators and Heavy Metals

Can a legacy of heavy metal contamination influence the survivorship, fitness and/or behavior of bees in cities? 

Cleveland OH’s formerly densely-populated inner-city neighborhoods now contain over 27,000 vacant lots as a result of protracted economic decline and the recent home foreclosure crisis. Currently, there are over 250 urban agroecosystems established on formerly vacant land across Cleveland. The sustainability of urban agriculture requires reliable ecosystem services, including pollination. A landscape legacy of heavy metal (HM) soil contamination represents a key threat to pollinators. This research program is examining the impact of HM contamination on bee foraging behavior, bumblebee colony health, and pollination.

This is a new research project and we recently completed our first study , documenting the impact of growing agricultural crops in Pb contaminated soil on bee visitation (see papers section for full results). We found that honey bees and bumble bees were just as likely to visit sunflowers growing in Pb contaminated soil, but spent less time per visit. This could influence the quality of the pollination service provided by the bees as well as the efficiency of their provision collection, influencing reproduction and survivorship. Currently experiments are underway examining the effects of Cd contamination on bee behavior at sunflowers. This study will be conducted by Rachel McLaughlin, and OSU Honors Undergraduate as her Senior Thesis project.

Undergraduate Rachel McLaughlin in our new greenhouse with sunflowers growing in Cd contaminated and uncontaminated potting mix.

Mary  and Rachel  mix Cd into potting soil in a mixer.

 

 

 

 

 

 

 

 

 

What impact can this research have?

This project focuses on a key unknown: understanding how a legacy of HM contamination influences pollinators and the services that they provide in urban agroecosystems. Although our study will focus on one urban area, HM contamination is widespread throughout U.S. cities, and potentially under recognized as a threat to urban ecosystems. For example, a 14-month USA TODAY investigation focusing on Pb in cities’ soils found evidence of smelting at more than 230 previously unrecognized sites in 25 states including OH (Young and Eisler 2012). Reporters performed soil tests in 21 neighborhoods around the country and found that 80% had median soil Pb levels above the standard set by California as hazardous to children (Young & Eisler 2012). Our work will also illustrate how varying levels of contamination can influence the sustainability of food production within a given location by documenting the impacts of HM contamination on bees and pollination. This will provide key information to growers seeking to establish farming sites. Further, measuring the impacts of HMs on important urban biota as proposed herein will inform policy regarding threshold HM levels requiring remediation.

This project is lead by Frances Sivakoff, who is a postdoctoral researcher in the Gardiner Lab. Frances is originally from Maryland and received her PhD from University of California, Davis. 


This material is based upon work supported by the USDA NIFA Grant Number

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the USDA NIFA