Landscape and Regional Stream Ecology
Due to the directional flow of water, the study of streams is an inherently spatial undertaking. Since early in its emergence, stream research has emphasized the connection between the ecology of channels and the valleys they drain, as well as the connections between small headwaters and the larger rivers they become. Stream ecology has thus connected and contributed intermittently to spatial concepts derived from ecology in general. In this chapter, we consider three broad connections between streams and landscapes. First, streams are spatial systems in and of themselves, potentially conceptualized, both as gradients and as mosaics of distinct patches, at scales ranging from individual reaches to whole river networks and basins. Second, streams play distinct roles within the landscapes, serving as habitat and corridors for biota, and as locations for transformations of pollutants and other chemicals. Third, the ecological character of river networks varies dramatically across regions and continents, due to variation in climate, geology, and terrestrial vegetation, but increasingly due to regional patterns of alteration by human society.
