Populations of many species are spatially structured in matrilines, and their dynamics may be determined by matriline specific demographic processes. We examined whether the isolation of habitat patches (i.e. interpatch distance) affected the demography of matrilines in 14 experimentally fragmented populations of the root vole. Matrilines inhabiting the most isolated patches decreased in size over the breeding season, while matrilines in less isolated patches increased. The survival rate of adult females was the main factor underlying the variation in growth rates among matrilines. Low survival when patches were isolated seemed to be due to long-distance interpatch movements exposing females to increased predation rate.
The differential success of matrilines in patchy populations with variable interpatch distances acted to decrease the matrilineal diversity at the population level. Furthermore, isolated patches may function as sinks. Thus spatially explicit landscape features may affect both population demography and genetics.