Influence of local demographic processes on the regional dynamics of a yellow-bellied marmot metapopulation

The dynamics of spatially structured populations are determined by the local demographic processes, and by the interactions among local populations. We investigated the dynamics of a spatially structured population of the yellow-bellied marmot in Colorado, USA using data collected from 17 local populations over 43 years. Using a vec-permutation matrix approach, we developed a matrix metapopulation model and investigated the relative influence of local demographic rates and the dispersal rate on metapopulation dynamics.

Prospective elasticity analysis revealed that the metapopulation growth rate was most sensitive to survival of the reproductive adults, followed by that of the two younger age classes. The potential influence of dispersal on the metapopulation growth rate was lower than that of the aforementioned demographic rates. The dynamics of the yellow-bellied marmot metapopulation depended heavily on a small number of good quality colony sites, and the metapopulation growth rate was highly sensitive to the changes in the demographic rates of these sites. These results underscore the need for the explicit consideration of the local demographic processes for understanding the dynamics and persistence of demographically and spatially structured populations.