Synthesis of Regional Wildlife and Vegetation Field Studies to Guide Management of Standing and Down Dead Trees
We used novel methods for combining information from wildlife and vegetation field studies to develop guidelines for managing dead wood for wildlife and biodiversity. The DecAID Decayed Wood Advisor presents data on wildlife use of standing and down dead trees (snags and down wood) and summaries of regional vegetation plot data depicting dead wood conditions, for forests across the Pacific Northwest United States. We combined data on wildlife use by snag diameter and density and by down wood diameter and cover, across studies, using parametric techniques of meta-analysis. We calculated tolerance intervals, which represent the percentage of each species' population that uses particular sizes or amounts of snags and down wood, and rank-ordered the species into cumulative species curves. We combined data on snags and down wood from >16,000 field plots from three regional forest inventories and calculated distribution-free tolerance intervals compatible with those compiled for wildlife to facilitate integrated analysis. We illustrate our methods using an example for one vegetation condition. The statistical summaries in DecAID use a probabilistic approach, which works well in a risk analysis and management framework, rather than a deterministic approach. Our methods may prove useful to others faced with similar problems of combining information across studies in other regions or for other data types.