River Connectivity and Biological Complexity
Wednesday, May 13, 2020
1:00 pm Eastern Time
USDA Forest Service, Pacific Northwest Research Station
Abstract/ Session Description:
River systems have been extensively modified by anthropogenic development of uplands and alterations in flow regimes including river connectivity. These changes reduce the capacity of river floodplains to absorb natural geophysical and environmental changes and directly affect life history adaptations that have developed over the millennia for native aquatic species. For example, in western North America changes in upslope processes (i.e. fire regimes, forest harvest and associated managements) work in concert with alterations in natural flow and thermal regimes through dams, levees, and floodplain development to change recovery trajectories of river systems and their biota. Existing phenotypic adaptation by native fishes to environmental conditions may not be compatible with alterations to flow and thermal regimes. Climate change may compound this issue by further reducing variability in environmental conditions, both directly and indirectly, thereby inhibiting the full expression of life history diversity present in current populations. Further, movement among and within habitats, sometimes over vast distances, is a strong adaptation by many species of migratory fish in response to dynamic landscape conditions. Movement constraints have altered the capacity of native fishes to respond to anthropogenic and natural disturbance processes resulting in modifications in the composition and complexity of biological communities throughout river systems. To explore these concepts, this webinar will focus on fishes in the Pacific Northwest and will include a review of habitat connectivity research focused on Pacific salmon. Riverscape genetics will also be explored as a lens through which to consider the long-term implications of passage constraints. Visualization techniques that display patterns of temperature and discharge in rivers altered by dams will also be shared to consider the current and future adaptive capacity of native fishes.
Dr. Rebecca Flitcroft is a Research Fish Biologist with the United States Forest Service at the Pacific Northwest Research Station, Oregon, USA. She received her PhD in Fisheries and MS in Natural Resource Geography from Oregon State University.
Rebecca’s research explores holistic approaches to catchment analysis and management. She uses both statistical and physical representations of stream networks in analysis and monitoring to more realistically represent stream complexity and connectivity for aquatic species.