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|Title: ||Rarity and coexistence of a small hibernator, Zapus hudsonius, with fluctuating populations of Microtus pennsylvanicus in the grasslands of Southern Ontario|
|Authors: ||Boonstra, Rudy|
Hoyle, James A.
|Issue Date: ||1986|
|Publisher: ||British Ecological Society|
|Citation: ||Journal of Animal Ecology, Vol. 55, No. 3. (Oct., 1986), pp. 773-784.|
|Abstract: ||(1) The meadow jumping mouse (Zapus hudsonius) and the meadow vole (Microtus pennsylvanicus) are sympatric over most of the northern half of North America and occur in the same habitats. We tested the hypothesis that these species compete directly for space by examining the response of the Zapus to experimental manipulations of Microtus numbers from 1978 to 1982. (2) Zapus populations reached maximum densities (28.6-37.1 per ha) after a 2-year time-lag on a grid where all resident Microtus were removed, intermediate densities (11.4-20.0 per ha) on grids where either male or female Microtus were removed and low densities (1.4-5.7 per ha) on control grids. (3) Zapus used the same habitats on the grids as Microtus but avoided traps visited by Microtus. Thus, avoidance was temporal rather than spatial. (4) Because of low trappability of Zapus, clear differences among grids in most other demographic variables were not found. Transiency rate was highest on the control grids and lowest on the grids with lowest Microtus density. Most between-grid movements of Zapus (68%) were towards the Microtus removal grid. (5) These results indicate that in southern Ontario, Zapus populations compete with, and are perennially low because of Microtus populations. We suggest that this is the case throughout the range of Zapus because of the lag times caused by peculiarities of Zapus life-history traits (hibernation and one or two litters per year) and because of short periods when Microtus populations are declining or low.|
|Appears in Collections:||Biology|
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