Riverine Thermal Regimes: Natural Patterns and Effects of Human Disturbance Part 1

Riverine communities are in great part regulated by water temperature.  Natural freshwater thermal regimes display variability over both space and time.  Phenology and fitness of freshwater fishes may depend on particular facets of these natural thermal regimes.  For example, thermal shifts in spring may act as cues for smolt outmigration or the magnitude of daily fluctuations in water temperature during winter may contribute to the phenology of salmon fry emergence.  Essential elements of the thermal landscape such as the biological significance of fluctuations over time or the spatial distribution of cool water habitat patches are only beginning to be understood; yet, human activities such as dams, land-use, and climate change as well as natural disturbances such as wildfire are altering these thermal patterns in both predictable and unpredictable ways.  Effective management of aquatic systems requires attention to the complexities of natural thermal regimes as well as a better understanding of how disturbances have and are likely to continue to change stream and river thermal landscapes in the future.  The goal of this session is address two primary questions: (1) How can we best measure, model, and predict natural thermal regimes? (2) What are the potential effects of disturbance on natural thermal regimes?  The understanding of current and future thermal regimes that emerges from this session can help guide our understanding of how to protect, restore, and manage freshwater ecosystems and the many species that depend on them.