Ecological Scale and Forest Development: Squirrels, Dietary Fungi, and Vascular Plants in Managed and Unmanaged Forests
Andrew B. Carey, Janet Kershner, Brian Biswell, Laura Domínguez de Toledo
Format: PDF / Kindle (mobi) / ePub
Abstract: Understandingecological processes and their spatial scales is key to managing ecosystems for
biodiversity, especially for species associated with late-seral forest. We focused on 2 species of squirrel (Sci-
uridae: northern flying squirrel, Glaucomys sabrinus, and Townsend's chipmunk,Tamias townsendii) in a
cross-sectional survey of managed and naturalstandsin southwestern Oregon during 1985-89.
We measured vegetation and abundances of squirrelsat >2,000 pointsin 19 stands in 3 seral stages.We described the diets of the squirrels in the stands. We analyzed data at point, stand, and stage scales to identify key processes contributing to biodiversity and scales at which emergent properties (synergistic effects) appeared.
use subject to JSTOR Terms and Conditions 29 WILDLIFE MONOGRAPHS 30 C X Or"-17 1-L1 I OG22 OG20 1 /7 OG23 NU4Z ND44 [ I , .; IfI I! i :I..i....o...... cover(%) Midstory Fig.6. Continued. This content downloaded from 220.127.116.11 on Thu, 21 Mar 2013 23:45:25 PM All use subject to JSTOR Terms and Conditions SCALE AND HABITAT-Carey et al. 31 D CE64 0 I ... I .:: }i 64 cover(%) Midstory Fig.6. Continued. conifersand hardwoods) inverselyrelated to canopy closure. Thus,
home ranges) used by Townsend's chip- 19 significantregressionswith 71 coeffimunksin 16 stands. Patch size did not dif- cients and explained an average of 20% of fer between young and old animals the variance in CPUE's. Understoryveg(Mann-Whitney tests; significant, P < etation had positive coefficients in 11 0.05, in only2 of 16 stands) or among seral stands and coarse woody debris in 12 stages (Kruskal-Wallis tests, x2 = 0.78, 2 stands; measures of stem exclusion had df, P = 0.69 for males; x2
composition generated 4 orthogonal factorsand a set of vegetation site types. The factors(1) accounted for63% of variance in vegetationstructure,(2) separated realized habitatfrompotentialhabitatwith an accuracy of 60-66%, but (3) explained only 14-20% of variance in within-stand activityand 11-14% of variance in activity among points across stands. Squirrels did not appear to select any small subset of site types for their activities.Point values differedmarkedlywithinstands for many variables,
Conditions SCALE AND HABITAT-Carey progress. One incorporates variable-density thinning,legacy retention,and introduction of top-rotin trees throughcavity creationand inoculationof decay fungi;results from 3 years posttreatmentare encouraging (Carey et al. 1996b). Another (C. A. Harrington,U.S. For. Serv., Olympia, Wash. and A. B. Carey, coauthor,unpubl. data) incorporates variable-density thinningand creation of coarse woody debris structuresfromsmall-dbhtrees felled during thinning;this
often were a second age class (cohort) composed of -1 species of shade-toleranttrees. We measured nested plots at 2,107 grid points. All percent covers were estimated by eye and recorded on an octave scale with midpointsof 0, 2, 4, 8, 16, 32, and 64% and categoryranges of 0, trace-2.9, 3.05.9, 6.0-11.9, 12.0-23.9, 24.0-47.9, and -48.0%. Preston (1981) reportedthe ecological relevance of the octave scale in studies of commonness and rarityof species. We chose the octave scale also to (1) allow