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DECODING RESILIENCE IN THE OREGON CASCADES: AN ANALYSIS OF HISTORICAL TRENDS OF STREAMFLOW VARIABILITY (E)

Forested watersheds in the Oregon Cascades have a long history of disturbances including floods, droughts, wildfires, and logging. As these disturbances can alter hydrological regulation capabilities in watersheds, we look for evidence of such alterations in long-term patterns of streamflow variability. We estimate spectral entropies from hydrologic time series from the H. J. Andrews Experimental forests (Oregon Cascades). Spectral entropy measures changes in Shannon’s information of natural patterns as they respond to different drivers. We analyze annual changes in streamflow variability since 1950 in eight watersheds that cover a wide range of disturbance regimes and human manipulation. We represent changes in streamflow variability by using entropy curves that have the potential to inform about system resilience. Our results show that in spite of being subject to broadly similar climatic conditions, and sharing similar annual trends in water quantity, H.J. Andrews watersheds display different patterns of streamflow variability, even during extreme droughts or in close spatial proximity. The mechanisms responsible for these different responses seem to operate at different temporal scales, from months to seasons. Regardless of the underlying mechanisms for streamflow variability, all the patterns observed in the dataset can be represented along entropy curves, depicting predictable trajectories of change under disturbance. Our results suggest that an information theory-based approach could offer a comprehensive representation of ecosystem response to disturbances and therefore help us to decipher the keys from resilience encoded in variability patterns.

Authors

Guerrero Bolano, F. J., Oregon State University, USA, francisco.guerrero@oregonstate.edu

Peñaranda-Velez, V. M., National University of Colomba, Colombia, hydroingvmpv@me.com

Hatten, J. A., Oregon State University, USA, jeff.hatten@oregonstate.edu

Details

Oral presentation

Session #:067
Date: 03/02/2017
Time: 12:15
Location: 323 A

Presentation is given by student: Yes