Palmquist, Emily , Ralston, Barbara , Merritt, David , Shafroth, Patrick .
Landscape-scale processes influence riparian plant composition along a regulated river.
It is important to consider both landscape-scale factors (elevation, geography, climate) and local scale factors (hydrology, channel geomorphology, microhabitat) when trying to explain and predict patterns of vegetation in riparian areas. In areas with steep environmental gradients and high habitat heterogeneity, riparian vegetation turnover can be high along a river’s course. To assess how landscape-scale factors change the structure of riparian vegetation, we determine if riparian vegetation composition substantially changes along the Colorado River through Grand Canyon, determine which factors more likely explain the change, identify how richness and functional diversity change, and identify the implications of these changes to river management.
We identified three divergent floristic groups that are distributed longitudinally along the river. These groups correlated with changes in elevation, temperature and seasonal precipitation, but not with annual precipitation or site-scale factors. Species richness decreased as a function of distance downstream, and functional composition differed among floristic groups, showing that changing landscape-scale factors result in changes to these ecosystem characteristics and functioning. Although riparian vegetation location and amount is closely tied to river regulation, the composition remains closely linked to seasonal precipitation and temperature and will therefore change over time in response to climate change, independent of climate effects on streamflow. These patterns and changes in floristic composition inform present day management and provide insights into potential changes in riparian ecosystems as a result of climate change and flow management.
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1 - USGS, Grand Canyon Monitoring and Research Center, 2255 N Gemini Dr, Flagstaff, AZ, 86001, USA
2 - UNITED STATES GEOLOGICAL SURVEY, GCMRC, 2255 N. GEMINI DR, Flagstaff, AZ, 86001, USA
3 - USDA Forest Service, Watershed, Fish, Wildlife, Air, and Rare Plants Staff, 2150 Centre Ave., Bldg A., Suite 368, Fort Collins, CO, 80526, USA
4 - USGS, Fort Collins Science Center, 2150 Center Ave., Bldg. C, Fort Collins, CO, 80526, USA
Plant species composition
Plant community analysis
Landscape-scale vegetation change.
Presentation Type: Oral Paper
Candidate for Awards:None