Study design for assessing the effects of knapweed control on grassland birds at Saratoga National Historical Park
Trocki CL and Paton PW. 2007. Study design for assessing the effects of knapweed control on grassland birds at Saratoga National Historical Park. Natural Resource Report: Northeast Region. 2007/015. National Park Service. Boston, MA
Recommendations for study design to measure impacts of knapweed control on grassaland birds on SARA. Assuming the Park initiates some type of integrated management scheme on a series of knapweed patches throughout park, how can impacts on grassland birds be assessed? We suggest using double-observer variable-radius point counts to assess the short- and long-term impacts of knapweed control on grassland birds. Point counts are the accepted method for monitoring birds in grassland habitats, and have been used by the National Park Service for Inventorying and Monitoring schemes and by the US Fish and Wildlife Service for long-term monitoring plans. Budgetary considerations will determine the number of experimental plots (i.e. plots where integrated invasive species control takes place). We suggest that plot locations either be randomly located on centers of grid cells (less desirable) or a generalized random tessellation stratified (GRTS) sampling (more desirable) is used to pick a spatially-balanced sample from the gird system we have established. Following a slightly modified US Fish and Wildlife Service guidelines (Appendix B), we suggest using 50-m radius point counts at both experimental plots and control plots. Plots of this size, 7,852 m2, would account for 79% of the area of 1-ha experimental and control plots.
- Type
- Published Report
- Authors
- Trocki, Carol; Paton, Peter
- Date of Issue
- 2007-08
- Publisher
- National Park Service
- Units
- NER , NETN , SARA
- Keywords
- Grassland Birds, grassland management, GRTS, knapweed, Monitoring, Point Counts, Saratoga National Historical Park, Study, Weed Control, Weed Management