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Patch Connectivity & Directionality

Image: Patch Connectivity. Figure is drawn from the perspective of a lake. A patch = a lake.Individual ecosystems are connected within the freshwater landscape by hydrologic flowpaths through both surface water and groundwater. These flowpaths define the movement of materials, such as dissolved ions, nutrients and sediments, and organisms among ecosystems and display a strong directionality in connectivity that must be explicitly considered (e.g., Kling et al. 2000).

The location of an ecosystem along the hydrologic flowpath defined by the freshwater landscape explains spatial heterogeneity in a range of physical, biological and chemical properties. For streams, the River Continuum Concept (RCC) of Vannote et al. (1980) was the first to conceptualize a longitudinal pattern in attributes and processes from headwaters to lowland reaches. For lakes and wetlands, Kratz et al. (1997) and Winter et al. (1991) developed frameworks conceptualizing analogous longitudinal patterns. In this example, in general, a headwater lake (A) would have a smaller surface area, lower conductivity, and fewer fish species than a lowland lake (B).

Figures are drawn from the perspective of a lake. A patch = a lake.