Approach
Variable precipitation and warming is predicted to affect the growing season water balance and may resulting in chronic or permanent water limited dry conditions, particularly in the late-growing season. Limited water is of particular concern for habitats and food webs sensitive to altered timing and quantity of available water, such as aquatic species dependent on ecological flows for survival. Repeated drought pressures can influence species assemblages, and habitat function negatively affecting forests unlikely to adjust to drier conditions. Management that anticipates drier conditions in long-term watershed planning can capitalize on a system’s inherent elasticity to lessen habitat degradation and enhance systems to persist under a range of conditions. Management responses to help systems cope with limited water may require innovation like selecting drought tolerant species and genotypes from drier habitats, reducing stocking levels, and modifying infrastructure and facilities to maximize water capture and storage. However, some treatments can further diminish water supply or may negatively affecting other ecosystem services (e.g. water quality, nutrient cycling and wildlife habitat). Therefore management decisions require careful attention to site conditions and characteristics to critically evaluate trade-offs.
Tactics
- Reducing leaf area by thinning, and favoring a diversity of native species and age classes that consume less water, such as xeric tree species that may be drought tolerant and less vulnerable to insect outbreaks.
- Use seedlings and saplings to increase tree survival after planting, for example saplings grown in gravel, and nursery containerized stock.
- Planting or enhancing colonization of native vegetation on new shorelines exposed to lower water levels.
- Improve stream-crossings to reduce aquatic habitat fragmentation during periods of low water levels and remove in-stream flow modifications such as dams and agricultural drain tiles that may exacerbate low water levels.
- Control invasive species and/or establish desirable native species on newly exposed soil due to lower water levels in formally inundated areas (such as wetlands), or along shorelines and floodplains.
- Manage gaps and forest openings to increase snow catch accumulation, and use techniques to shade snow such as mulching with wood chips to extend the retention of snowpack and enhance water availability during the growing season.
Strategy
Strategy Text
This strategy aims to help ecosystems adjust in response to fundamental changes in hydrologic processes altered by a changing climate. The timing, form, and spatial distribution of precipitation is changing with the climate, with cascading effects on forest hydrologic cycles that affect water yield and water quality. Forest species assemblage, structure, and habitat quality will shift with changes in the nature and timing of water availability. Anticipating potential impacts to water levels and quality in management planning may help managers reduce risks and take advantage of opportunities to sustain hydrologic function. Broadly considering climate related alterations to the hydrologic cycle along with site-level responses and potential land-use changes is likely to provide the most complete picture of risks and opportunities.
Shannon, P.D.; Swanston, C.W.; Janowiak, M.K.; Handler, S.D.; Schmitt, K.M.; Brandt, L.A.; Butler-Leopold, P.R.; Ontl, T.A. (in review). Adaptation Strategies and Approaches for Forested Watersheds. Ecological Applications.,