URPP GCB Seminar Series

March 24, 2014

Dr. Kate A. Brauman

Institute on the Environment, University of Minnesota

Hydrologic Ecosystem Services: Managing Landscapes for Water, Nature, and People

Dr. Brauman’s talk focused on her research in Hawai’i cloud forests and perceived reduced water supply due to development. In this work, Dr. Brauman measured rain and fog water throughfall in forest and in pastures and found that denser forests had higher throughfall. This was likely due to increased cloud interception by increased vegetation surface area.

This example was used to discuss how the Ecosystem Services framework is useful in forming questions about land use and trade-offs.

The potential effect of land use change in the watershed on water supply was a local concern. Although water supply might be affected by location, quality or timing, the relevant factor in this case was quantity. A number of ecosystem processes might affect the quantity of water available and but in this system the processes that needed to be measured were local climate interactions and water use by plants.

By identifying the final service at the point of use helps to identify the specific problem and therefore frame a question - in this case how does land use affect water throughfall and the water supply? This also allows for predictive and realistic change scenarios, for example, conversion of dense forest to timber or timber forest to pasture. The trade-offs between increased water supply, increased timber supply and increased biodiversity could then be evaluated. Dr. Brauman emphasized that there is a clear need to be very specific about the services being studied and the realistic transitions that might take place under different scenarios. It is also important to be clear about the location of the effects and the change at which change occurs.

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