Water, water everywhere: subtle shifts in soil saturation drive ecological function in coastal rain forests

Abstract

New research reveals how topography, soil temperature, and subtle shifts in soil drainage are key drivers in ecosystem function in the coastal temperate rain forests of southeast Alaska and British Columbia. These studies, by Dave D'Amore and his colleagues, provide a better understanding of the influence of soil hydrology on dissolved organic carbon export and the interplay between soil saturation and tree species' response to varying soil conditions. More refined techniques for identifying hydric soils are making wetland delineation in southeast Alaska quicker, easier, and more accurate. Identifying wetlands has been particularly tricky in these areas because southeast Alaska is relatively moist year-round. This means that wetland delineation is based on more subtle indicators. One study provides new information about how soil color can be used as an indicator of soil saturation and reduced oxidation, thus streamlining and increasing the accuracy of wetland identification. Scientists also have developed models that, based on long-term position of the water table and soil drainage, project the types of vegetation that will occur in specific landscapes. This information is proving useful for climate change adaptation planning. Other studies explore the influence of soil hydrology on the release of dissolved organic carbon into the Gulf of Alaska.

Citation

Oliver, Marie; D’Amore, Dave. 2015. Water, water everywhere: subtle shifts in soil saturation drive ecological function in coastal rain forests. Science Findings 180. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 5 p.