BUSHY-TAILED WOODRAT ABUNDANCE IN DRY FORESTS OF EASTERN WASHINGTON

• Published in: Journal of mammalogy Vol. 87; no. 2; pp. 371 - 379
• Main Authors: Lehmkuhl, John F., Kistler, Keith D., Begley, James S.
• Format: Journal Article
• Language: English
• Published: Provo, UT American Society of Mammalogists 01.04.2006; Brigham Young University, Department of Zoology; Oxford University Press
• Subjects: Animal and plant ecology; Animal populations; Animal, plant and microbial ecology; Animals; Biological and medical sciences; bushy-tailed woodrat; Cascade Range; Coniferous forests; Coniferous trees; Demecology; Density; Density estimation; dry forest; Dry forests; Forest cover; Forest ecology; Forest habitats; Forest service; Forest stands; Forests; fuel management; Fundamental and applied biological sciences. Psychology; Habitats; Mammalia; Mixed forests; Neotoma cinerea; Owls; Pine trees; Pinus ponderosa; Population density; Rodents; Santalales; Sex ratio; Survival; Timber; Vertebrata; Washington; United States; North America; America; United States > US; Washington (state); Dry forest; density; Rodentia; Neotoma cinerea; survival; Abundance; Washington; bushy-tailed woodrat; Vertebrata; Mammalia; Cascade Range; fuel management; Muridae; Population dynamics; Population density; Field study
• ISSN: 0022-2372; 1545-1542
• DOI: 10.1644/05-MAMM-A-053R1.1

We studied bushy-tailed woodrats (Neotoma cinerea occidentalis) in the eastern Washington Cascade Range to estimate their density and survival in 3 typical dry forest cover types. We predicted woodrat density to be high, moderate, and low in mature mixed-conifer forests, young mixed-conifer forests, and open ponderosa pine forests, respectively. We livetrapped on 8 × 8 grids (280 m) over an 8-day period each autumn for 4 years to obtain Huggins mark–recapture estimates of woodrat density. We captured woodrats 617 times and marked 193 individual woodrats in 12 sample stands during 42,165 trap nights. The sex ratio of captures was 62% female and 38% male. Adults made up 79% of captures. Woodrat density averaged 0.49 animals/ha among all cover types and years; woodrat density did not differ among types. Regardless of cover type, stands fell into 4 woodrat-density groups, with densities ranging from 0.13 to 0.93 woodrats/ha. Classification tree analysis revealed that woodrat-density groups could be predicted well (proportional reduction in error = 0.73 to 0.89) by the type and amount of cover provided by large snags, mistletoe brooms, and soft downed logs. Over the 4-year period, woodrat density ranged from 0.28 animals/ha to 0.87 animals/ha, increasing each year at a rate of λ = 1.8 consistently among cover types. A moderate (r = 0.55) density-dependent response in per capita rate of increase was detected. The apparent annual survival rate was a low 0.14. Management to reduce woody fuels and to restore low-intensity high-frequency fire regimes in ponderosa pine and dry Douglas-fir forest likely will reduce bushy-tailed woodrat populations unless prescriptions can mitigate the loss of snag, mistletoe, and downed log cover.