Here are notes from Lecture 19's additional reading, "Meeting Ecological and Societal Needs for Freshwater," by Baron et al.
Humans have traditionally overlooked the value of freshwater for supporting ecosystems. However, freshwater ecosystems provide a variety of ecosystem services, ranging from drinking water, food supply, flood control , and purification of wastes, that are costly and perhaps impossible to replace. Current water management practices are inadequate so we need to find a new way to appropriately allocate resources between ecosystem needs and societal needs.
The authors describe five key dynamic environmental drivers regulate much of the structure and function of all aquatic ecosystems:
- Flow regime
- Sediment and organic material inputs
- Thermal and light characteristics
- Chemical and nutrient characteristics
- Biotic assemblage
They suggest several steps to help restore freshwater ecosystems:
- Setting management targets for temporal streamflow variability so as to simulate traditional flow variability
- Minimizing non-point sources of agricultural runoff through best management practices for controlling erosion and minimizing fertilizer and pesticide use.
- More stringent controls on emissions from transportation and energy generation so as to reduce atmospheric deposition into freshwater ecosystems.
Some key challenges to effective management of freshwater ecosystems are identified. To be successful, freshwater ecosystem health must be addressed in an integrated fashion - focusing on specific symptoms is unlikely to change the overall picture. Politically, this means that broad coalitions of water users need to be involved in water management decisions but in many places the best opportunities to form such coalitions has already passed. Another challenge is that the long term ecological consequences of human impacts on freshwater ecosystems often aren't immediately apparent, and in some cases, the changes aren't noticed until a key threshold has been passed and it is too late to implement more stringent protections.
The authors conclude with six recommendations for how water should be viewed and managed:
- Freshwater ecosystem needs should be incorporated into national and regional water management policies
- Water resources should be viewed within the context of the watershed so as to better illustrate linkages between terrestrial and aquatic ecosystems
- More interdisciplinary training is needed for future water-related professionals, especially engineers, hydrologists, economists, and ecologists
- Efforts to restore lakes, wetlands, and river ecosystems should be accelerated and must be informed by ecological principles
- The remaining minimally-impaired freshwater ecosystems should be maintained and protected
- Broader public understanding of the ecosystem concept and human impacts on ecosystems is necessary for long—term successful management of freshwater ecosystems.