Connectivity is defined as the maintenance of lateral, longitudinal, and vertical pathways for biological, hydrological, and physical processes (Annear, 2004). It refers to the flow, exchange, and pathways that move organisms, energy, and matter throughout the watershed. The most obvious example of connectivity may be the free flow of water downstream in a river and the passage of fish upstream. The construction of a high dam across a stream is a vivid and obvious illustration of fragmentation or the loss of connectivity.
This exchange of energy, nutrients and material does not stop at the water's edge, it can be observed at many scales throughout the surrounding landscape. Complex, interdependent processes are continuously present throughout the watershed landscape and are required to maintain the ecological health of the system as a whole.
There are four dimensions of connectivity between a river and its contributing watershed. These are longitudinal, lateral, vertical and temporal.
For the river system, this continuum of hydrologic, biological, and chemical interactions and connections is described along the same four dimensions used to describe the hydrologic system.
- Longitudinal (upstream and downstream)
- Lateral (midchannel to floodplain)
- Vertical (underground, in the sediment surrounding the channel)
- Temporal (continuity over time) (Annear, 2004).
Explore the Connectivity Health Scores to see a series of index values that show health trends in the connectivity of ecological systems in Minnesota.