the roles of connectivity and recovery
JANSSON, R., NILSSON, C. and MALMQVIST, B. (2007), Restoring freshwater ecosystems in riverine landscapes: the roles of connectivity and recovery processes. Freshwater Biology, 52: 589–596. doi: 10.1111/j.1365-2427.2007.01737.x
The authors present key messages from papers originating from the 2004 International Symposium on Riverine landscapes. The paper provides an excellent summary of the role of connectivity and recovery processes in restoring freshwater rivers.
The authors emphasized the importance of matching the spatial scale of restoration to scale at which ecological processes are occurring. For instance, if the life history of a particular species includes a larger scale than the restoration, the restoration may be unsuccessful. In addition, the authors emphasize that the return of target species cannot be assumed to recolonize spontaneously. Increasing connectivity may initiate recolonization or active revegetation may be necessary. However, connectivity (lateral, longitudinal, vertical) may have unwanted consequences such as invasive species encroachment. The authors suggest that construction of migration barriers might be necessary in extreme cases.
Further, the authors state that the choice of whether or not to restore something should be weighed on whether the ecological condition of will stream improve. For instance, in the urban stream, if broader catchment management strategies are not employed , such as identifying areas to recharge ground water, flush pollutants, and sewage before entering creek, than the restoration may not be successful. The authors emphasize the need to assess restoration to determine whether ecosystems have recovered (and objectives have been met). Lastly, despite mentioning that close cooperation between practitioners and scientists would be beneficial in river restoration, the authors did not include participation from restoration practitioners in the paper content.