Vertical Stratification of Activity of Two Peromyscus Species: An Experimental Analysis

Abstract

The importance of competitive interactions in maintaining the vertical microhabitat segregation of two ecologically similar Peromyscus species was evaluated by reciprocal species-removal experiments during a year of peak density. The white-footed mouse, Peromyscus leucopus noveboracensis, and cloudland deer mouse, Peromyscus maniculatus nubiterrae, are syntopic in southwest Virginia and are commonly trapped aboveground in mixed deciduous forest. Patterns of arboreal habitat use and levels of arboreal activity were determined for both species before the removal experiments. During the summer and fall of 1981, six live-trapping grids, equipped with both ground and aboveground traps, were randomly allocated as control, leucopus removal, or maniculatus removal grids. On all grids, maniculatus used arboreal habitat more extensively than leucopus. Overall, 48% of 1357 maniculatus captures, but only 24% of 2270 leucopus captures, were in aboveground traps. Before removals, both species occupied structurally similar arboreal habitat, and following removals we detected no shifts in arboreal habitat use that would indicate competitive release by the unmanipulated species. Removals also had no effect on the degree of individual arboreal activity shown by the remaining species.Both before and after removals, maniculatus consistently showed more arboreal activity than leucopus for all treatments. While maniculatus significantly increased the number of arboreal sites occupied in the absence of leucopus, and encroached substantially on arboreal habitat formerly used by its congener, this expanded arboreal habitat use occurred in the absence of any numerical increase or change in activity levels. We attribute it to the greater arboreal orientation of maniculatus and opportunistic use of arboreal habitat in areas of former range overlap with leucopus. The experiments suggest that differential use of arboreal habitat by these species results from differences in their behavioral responses to vertical habitat, and is independent of dynamic competitive interactions.

Small Mammals and Stand Structure in Young Pine, Seed-Tree, and Old-Growth Forest, Southwest Canada

“…Thus, although structural richness appeared low in the oldgrowth stands, species diversity of coniferous trees and provision of snags for cavity-using wildlife species was high (Thomas et al 1979, Neitro et al 1985. There tends to be a positive relationship between foliage height diversity and species richness of various taxa, particularly birds (MacArthur and MacArthur 1961, Aber 1979, Hunter 1990) and small mammals (Adler 1987, Harney andDueser 1987). In particular, canopy tree retention after forest harvesting benefits many bird species (Hansen et al 1995b, Hansen and Hounihan 1996, Chambers and McComb 1997, Norton and Hannon 1997.…”

Founder takes more: Interspecific competition affects range expansion of North American mammals into deglaciated areas

“…occupying meadow vs. forest; Anich & Hadly, ), microhabitat (e.g. occupying different vertical strata; Harney & Dueser, ), or specializing on different diets (Buzzard, ). For example M. longicaudus and M. montanus coexist throughout a large portion of their ranges via habitat partitioning, maintained by asymmetric competition (Anich & Hadly, ).…”

An Experimental Examination of Nest‐Site Segregation by Two Peromyscus Species

“…Probably not. Harney and Dueser (1987) found that differential use of arboreal habitat during a year of high density (1981) could not be attributed to ongoing competition or implicated in the continued coexistence of these congeners. Further, based on a multivariate analysis of variance comparing the microhabitats occupied by these species, R. Dueser and J. Porter (personal observation) found that P. leucopus and P. maniculatus exhibited no detectable differences in microhabitat structure in years of high (1981), intermediate (1982), or low (1983) densities.…”

“…The morphological and ecological similarity of these species, combined with their apparently stable coexistence in a relatively homogeneous habitat, predispose them to an experimental investigation of interspecific competition. Similarly, Harney and Dueser (1987) found neither significant partitioning of arboreal habitat between species nor competitive release in removal experiments. Wolff et al (1985) found no differences in diet.…”

“…Porter (personal observation) found only minor indications of habitat segregation. Similarly, Harney and Dueser (1987) found neither significant partitioning of arboreal habitat between species nor competitive release in removal experiments. Wolffet al (1983) and Wolff (1985) observed that neither species was effectively excluding the other from home range space; rather individuals of both species tended to exclude other same-sex intruders from home range areas regardless of species.…”