Although landscape ecology is generally considered a terrestrial discipline, ecologists working on streams and rivers have long been interested in the spatial relations and geographical distribution of aquatic organisms and their habitats. In fact, if a landscape is defined as a spatially heterogeneous area, and landscape ecology as the study of its structure, function, and change (Turner, 1989), then landscape ecology has the potential to be an important force in the appropriate management of streams and rivers. The application of landscape ecology to riverine management is particularly well suited to three classes of activities: conservation of biodiversity, fisheries management, and restoration/ rehabilitation of biological integrity.
In this chapter we review relevant stream-ecology concepts that encompass a landscape perspective and link these concepts to current management practices. We argue, with examples, that scale-dependent processes that are valuable to society underlie biotic patterns in streams. We show how recent evidence links certain land-use activities with altered stream condition, and attempt to present the underlying mechanisms responsible. To show the integration of landscape principles with practical management, we present examples related to stream restoration, recreational fishing, and a case study of an ongoing project to prioritize the conservation of aquatic biodiversity on a regional basis.
Landscape elements of stream ecology
Several categories of concepts have been developed to explain how streams function in the context of the landscape (Ward, 1989; Lorenz et al., 1997): concepts that focus on longitudinal changes of the biota; concepts emphasizing lateral interactions; concepts that integrate longitudinal, lateral, and vertical dimensions of streams; and concepts emphasizing spatial hierarchies and temporal changes.