Understanding and predicting the impacts of land use and climate change on riparian ecosystems requires information on expected shifts in species’ distributions.  A metapopulation approach is appropriate for modeling the spatial population dynamics of riparian species, as colonization and extinction processes should respond to the dominant hydrologic and geomorphic forces affected by environmental change.
   Here we present the results of preliminary work using common Western U.S. riparian species (Populus, Salix, Tamarix, Elaeagnus, etc.) to parameterize a simple, spatially explicit network of reach-scale patches in a single watershed. We explore how different network configurations (e.g. highly branched vs. lattice-like) and dispersal modes (e.g. hydrochory vs. anemochory) affect overall persistence time and whether particular patches contribute disproportionately to metapopulation persistence.
   By combining metapopulation models with future surveys for both native and invasive riparian plants, we aim to refine theories of spatial population dynamics in river networks. Further considerations include exploring appropriate patch networks at a regional, multi-watershed scale; incorporating geomorphic controls on habitat availability; interspecific interactions in multi-species models; and combining these models with flow regime scenarios under climate change and dam operation alternatives.