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The structure of the herpetofaunal assemblage in the Douglas-fir/hardwood forests of northwestern California and southwestern Oregon

Informally Refereed
Download (PDF 1.37 MB): https://research.fs.usda.gov/download/treesearch/3711.pdf

Abstract

Terrestrial and aquatic herpetofauna were sampled by three methods, time-constrained searches, pitfall traps, and areaconstrained searches from 1984 to 1986 in northwestern California and southwestern Oregon. The 54 terrestrial and 39 aquatic study sites were in Douglas-fir/hardwood forest stands that ranged in age from 30 to 560 years. Results of these surveys are presented in terms of species richness, equitability, relative abundance, relative biomass, and macrohabitat and microhabitat associations. Although species richness did not differ among forest ageclasses, the composition of the herpetofauna was notably different. Old and wet sites had proportionately more amphibian species, and young and dry sites had proportionately more reptile species. Terrestrial salamanders were more abundant on old-growth than on young sites. We also found that structural components associated with older forests were the best predictors of increased numbers of salamanders. Analyses of microhabitat associations indicated that large, welldecayed logs were the most heavily used woody debris, though use of particular size- and decay-classes varied among salamander species. Harvesting forests without immediately affecting herpetofauna is probably not possible; however, strategies can be developed to minimize long-term adverse effects. We provide a summary of management recommendations designed to assure long-term viablity of herpetofauna in areas subject to logging.

Citation

Welsh, Hartwell H., Jr.; Lind, A.J. 1991. The structure of the herpetofaunal assemblage in the Douglas-fir/hardwood forests of northwestern California and southwestern Oregon. Pages 394-413 in: Ruggerio, L.F.; Aubry, K.B.; Carey, A.B.; Huff, M., tech. corrds., Wildlife and Vegetation of Unmanaged Douglas-fir Forests. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. Gen. Tech. Rep. PNW-GTR-285
Citations