Ecological restoration can be defined as the process of assisting the recovery of an ecosystem that has been degraded, damaged or destroyed; and as an attempt to return an ecosystem to its historic trajectory (SERI 2004). As urbanization rapidly transforms landscapes across the globe, urban ecological restoration becomes an increasingly common approach to restore functioning and biodiversity to remnant and regenerating habitat patches. Is the historic trajectory an attainable goal in these heterogeneous, highly fragmented, warmed, invaded, paved, polluted and frequently human-disturbed sites? Trajectories of community development – ecological succession, or vegetation dynamics – are driven by the interplay of available sites for establishment and growth, available species, and species performance. How are these factors shaped by urbanization? This presentation explores the usefulness of a vegetation dynamics framework for selection of targets and gauging success in urban ecological restoration. Findings from long-term studies evaluating ecological restoration of urban forest patches in New York City will be discussed in this light. In these park forests, woody invasive plant species were removed beginning in the mid-1980s. Data presented compare these early restorations, similar sites where no restoration has occurred, and longitudinal study sites restored since 2010.
Results/Conclusions
Comparison of sites restored starting in the mid-1980s and similarly invaded sites that were unrestored in 2010 indicates that after 15-20 years, restored sites had a more complex forest structure, greater cover by native species, more native trees, and reduced abundance of exotic invasive species that were removed. Re-sampling of sites that remained unrestored and sites that received restoration treatment between 2010 and 2015 found that forest patches dominated by woody invasive plants remained dominated by these species following major storm events, while restored sites had increased diversity and abundance of native species. Species composition and regeneration indicate novel future forest assemblages. These trends indicate that trajectories in urban forest patches are and will continue to be shaped by urban influences on vegetation dynamics.