Volunteer urban environmental stewardship: An effective way to manage plant communities in city parks

Background/Question/Methods

Urban areas are increasingly viewed as diverse ecosystems that provide a wide array of valuable ecosystem services. Many cities rely on programs that recruit and train volunteer citizens to perform environmental stewardship work. The extent to which these programs are ecologically successful, however, is rarely assessed. The Urban EcoStewards program is an initiative of a group of Pittsburgh, PA nonprofits, coordinated by the Pittsburgh Parks Conservancy, with the goal of “building sustainable urban ecosystems through citizen stewardship.” The objective of this project was to assess the success of the Urban EcoStewards program in encouraging diverse, native communities of plants in Pittsburgh’s urban parks. Volunteer-reported data were analyzed for trends in invasive species presence/absence with management duration and plant functional traits. Additional plant community surveys were performed in a subset of EcoSteward plots during the summer of 2010, spanning a management gradient measured in years of stewardship. This data was used to answer the following questions: Does volunteer stewardship of portions of urban parkland in Pittsburgh, PA: (1) reduce the prevalence of invasive plant species?, (2) increase native plant species diversity? And (3) is small-scale invasive species removal more successful for some species than others?

Results/Conclusions

The Urban EcoStewards program significantly reduces the prevalence of invasive plant species in managed plots, based on an analysis of data collected from volunteer annual monitoring forms. The average number of reported invasive species in plots decreased significantly after one year of EcoSteward management. There was no additional change seen with additional years of management. Resurveys of a subset of plots showed a consistent increasing trend, however, in native species diversity in plots with additional years of management. Species varied in their response to management, but when this variation was compared to functional traits (life form, dispersal mode, seed size, ability to reproduce clonally), no strong patterns were detected. Assessing the ecological results of environmental stewardship programs is an important and often over-looked component of stewardship groups’ efforts, due to time, money, and expertise limitations. However, these findings suggest that when these programs are assessed, substantial potential to improve urban ecosystems through such management effort is indicated.