Relative Abundance, Nest Site Characteristics, and Nest Dynamics of Sonoma Tree Voles on Managed Timberlands in Coastal Northwest California

Red-tree vole habitat suitability modeling: Implications for conservation and management

“…The association of RTV with late-seral forest conditions is evidenced from univariate differences (e.g., large downed wood, basal area of trees >90 cm dbh, mean dbh of Douglas fir, SD dbh of conifers) found between plots with and without nests (Table 1). However, not all RTV nests were detected within plots containing late-seral/oldgrowth habitat, as consistent with other RTV studies (Taylor, 1915;Howell, 1926;Benson and Borell, 1931;Maser, 1966;Carey, 1991;Thompson and Diller, 2002;Swingle, 2005).…”

“…2) relationship between Po and maximum tree diameter adds further support to the contention that RTVs are associated with late-seral and oldgrowth forests. Other researchers reported that the number of RTV nests per tree increased with tree dbh (Carey, 1991;Gillesberg and Carey, 1991), and that nest densities increased with dbh (Jones, 2003) and stand age (Biswell and Forsman, 1999;Thompson and Diller, 2002). Huff et al (1992) found 67% of tree vole nests in stands >300 years of age, with a range from 62 to 525 years.…”

“…However, Swingle (2005) and Maser (1965) reported finding many occupied RTV nests in young forests in Oregon. Similarly, Thompson and Diller (2002) evaluated A. pomo abundance in redwood-dominated forests under intensive, private, timber management in coastal northwestern California. Their study area contained little-to-no old-growth forests, yet tree voles were found in all but the youngest stands (10-19 years) and tree vole nest density increased with stand age (Thompson and Diller, 2002).…”

“…Similarly, Thompson and Diller (2002) evaluated A. pomo abundance in redwood-dominated forests under intensive, private, timber management in coastal northwestern California. Their study area contained little-to-no old-growth forests, yet tree voles were found in all but the youngest stands (10-19 years) and tree vole nest density increased with stand age (Thompson and Diller, 2002). During our study, RTV were found in forests with varying structures, but RTV's disproportionately selected areas with older forest characteristics.…”

“…Tree voles: (1) live in conifer forests and forage on conifer leaves (Taylor, 1915;Howell, 1926;Benson and Borell, 1931); (2) have exceptionally long gestation periods, small litters, and slow juvenile growth rates (Hamilton, 1962); (3) have a relatively small geographic range (Johnson and George, 1991); (4) have limited dispersal abilities (Biswell et al, 2000;Swingle, 2005). Although tree voles do occur in young forests (Taylor, 1915;Howell, 1926;Benson and Borell, 1931;Maser, 1966;Thompson and Diller, 2002;Swingle, 2005), many researchers have suggested that they are habitat specialists primarily associated with mature and old forests (Corn and Bury, 1986;Raphael, 1988;Carey, 1989;Aubry et al, 1991;Gilbert and Allwine, 1991;Ruggiero et al, 1991;Gomez and Anthony, 1998;Biswell and Forsman, 1999;Jones, 2003). Carey (1991) and Huff et al (1992) suggested that tree vole populations in young forests were not self-sustaining, and that such habitats were population sinks.…”