A comparison of sampling methodologies for long-term monitoring of forest vegetation in the Great Lakes Network National Parks
Johnson SE, Mudrak EL, Waller DM. 2006. A comparison of sampling methodologies for long-term monitoring of forest vegetation in the Great Lakes Network National Parks. Great Lakes Network Reports. GLKN/2006/06. Great Lakes Inventory and Monitoring Network. Ashland, Wisconsin
We conducted side-by-side sampling of forested sites with the U.S. Forest Service’s Forest Inventory and Analysis (FIA) method and two more intense methods, the PEL method used by the University of Wisconsin’s Plant Ecology Laboratory and a method designed to be intermediate between the FIA and the PEL methods, the ‘Hybrid’. We compared the quantity of data returned by each method, and the statistical power of each to detect a 20% change in many plant community and population variables. Higher species richness of each forest layer was generally observed with the more intensive methods compared to FIA. The FIA method performed as well as the other two methods in attaining high power to detect changes in tree metrics though, the PEL and Hybrid methods consistently outperformed the FIA method for detecting changes in the understory. All methods had low power for detecting a 20% change in the abundance of most individual species. The smaller area sampled by the FIA method is sufficient for monitoring tree communities, but the larger areas of the PEL and Hybrid methods are more suitable for monitoring variables associated with understory communities. Also, composite variables were more powerful than population-level variables for tracking changes.
- Type
- Published Report
- Authors
- Johnson, Sarah; Mudrak, Erika; Waller, Donald
- Date of Issue
- 2006-11
- Publisher
- Great Lakes Inventory and Monitoring Network
- Units
- APIS , GLKN , PIRO
- Keywords
- Abundance (Biodiversity), composite indicators, Distribution (Biodiversity), forest inventory and analysis, Long-Term Monitoring, Observations, Plant Community, point-centered quarter, Presence (Biodiversity), Understory, Vegetation Monitor