Article

The influence of immigration on demography of sympatric voles

Acta theriologica (impact factor: 0.89). 04/2012; 50(3):323-342. DOI:10.1007/BF03192629 pp.323-342

ABSTRACT We studied the influence of immigration on the dynamics ofMicrotus ochrogaster Wagner, 1842 andM. pennsylvanicus Ord, 1815 populations in alfalfa, bluegrass, and tallgrass prairie in east-central Illinois for 25 years. The numbers of
immigrants in a site were positively correlated with overall population densities of the species in the vicinity of the study
sites and within the study site. Population density of the other species was not correlated with immigration of either species.
Immigrants did not differ significantly from residents with respect to sex-ratio and reproductive condition. Persistence of
immigrantM. pennsylvanicus was lower than that of resident adults in all three habitats, while that of immigrantM. ochrogaster was lower than that of resident adults in alfalfa, where the species was most abundant. Neither the absolute number of immigrants
nor the proportion of the population composed of immigrants indicated an effect of immigrants on among- and within-habitat
differences in demography and population fluctuations of either species. Immigrants may have been an important factor in maintenance
ofM. pennsylvanicus in alfalfa, a low-quality habitat, but the influence of immigration on the dynamics of populations inhabiting other habitats
was insubstantial.

Key wordsdemography-immigration-meadow vole-
Microtus ochrogaster
-
Microtus pennsylvanicus
-population dynamics-prairie vole

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Keywords

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Persistence
 
population densities
 
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