Landscape fragmentation and exotic species invasions are two modern‐day forces that have strong and largely irreversible effects on native diversity worldwide. The spatial arrangement of habitat fragments is critical in affecting movement of individuals through a landscape, but little is known about how invasive species respond to landscape configuration relative to native species. This information is crucial for managing the...

The young‐of‐the‐year (YOY) fish community in Oder‐Havel‐Kanal, a navigable canal in the German lowlands, assessed from May to October 1999, was dominated by tolerant species especially roach Rutilus rutilus and perch Perca fluviatilis . Roach dominance was high in May and June and low during the rest of the sampling period. The dominance pattern of perch was inversely related to that of roach. Significantly higher densities o...