COS 115-5 - Using the generalized random tessellation (GRTS) survey design for monitoring and assessment of terrestrial plant communities at local, regional and ecoregional scales

Thursday, August 11, 2011: 2:50 PM
12B, Austin Convention Center
Constance E. Hausman, Terry L. Robison and John J. Mack Jr., Division of Natural Resources, Cleveland Metroparks, Fairview Park, OH

Cleveland Metroparks (CM) initiated the Plant Community Assessment Program (PCAP) as a method for evaluating terrestrial habitats and for measuring change associated with disturbance and management activities.  We used a probabilistic survey design to develop nested sets of random plot locations that allowed community condition assessment at park unit, park system, county, region and ecoregional scales.  Initial data collection efforts focused on park unit and park system scales.  Plot locations were selected using the Generalized Random Tessellation Stratified (GRTS) survey design developed by U.S. EPA’s EMAP program.  This method, which provides a spatially balanced, random sample, has typically been used for aquatic resource monitoring.  The PCAP design represents one of the first implementations of GRTS for upland terrestrial habitats and provides a framework for addressing ecosystem process questions at multiple scales.

The five year sample event includes ~100 plots sampled for 4 consecutive years (400 plots total) with a fifth year for analysis and writing.  In 2010, the first 100 permanent plots were sampled using methods from the Carolina Vegetation Survey.  Habitat quality and community condition were determined using floristic quality assessment index (FQAI) and a modified Vegetation Index of Biotic Integrity (VIBI) for upland communities. 


Plots sampled in 2010 reflected current cover types in the park as determined by NatureServe cover mapping indicating that the GRTS design effectively sampled habitat differences across CM property.  Across 14 park units sampled, ten major plant community types were identified that included a variety of upland forests, floodplain forests, wetlands and successional communities.  Large variability in average FQAI and VIBI scores was found across reservations (VIBIscores 34-51).  However, greater variability in community condition occurred within park units reflecting presence of high quality habitat (VIBI 55-74) as well as poor quality habitat (VIBI 0-29).  Lower VIBI scores indicate highly disturbed and/or depauperate areas with communities composed mainly of tolerant/ruderal species.

In addition, U.S. Forest Service’s iTree-Eco program was used to assess forest condition and ecosystem services.  Carbon sequestration was estimated at >10,000 metric tons/year with a value of ~$200,000.  Forest infrastructure is currently compromised with threats imposed by forests pests and pathogens including the emerald ash borer.  We estimated that 6.3% of Cleveland Metroparks trees are ash species (89,000 trees). 

Results will be used to assess management, wildlife, invasive species, and the surrounding urban matrix on the Park District’s natural infrastructure to prioritize future conservation and restoration programs.

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