Abstract Estimating population density and identifying those areas where is changing through time are central to prioritizing conservation management strategies. Obtaining reliable estimates of trends can be challenging, however, especially for long‐lived species that rare, have broad geographic distributions, difficult detect reliably during field surveys. We developed a hierarchical model dis...

The spatial spread of invading organisms is a major contemporary concern. We focus here on invasions in inherently fragmented habitats, such as freshwater systems, and explore the usefulness of metapopulation models in this context. Maximum-likelihood methods allow the estimation of colonization and extinction rates, as functions of habitat patch sizes and positions, from time series of presenc...