Changes in Community-Level Riparian Plant Traits over Inundation Gradients, Colorado River, Grand Canyon

• Published in: Wetlands (Wilmington, N.C.) Vol. 37; no. 4; pp. 635 - 646
• Main Authors: McCoy-Sulentic, Miles E., Kolb, Thomas E., Merritt, David M., Palmquist, Emily, Ralston, Barbara E., Sarr, Daniel A., Shafroth, Patrick B.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.08.2017; Springer Nature B.V
• Subjects: Adaptation; Assembly; Biomedical and Life Sciences; Canyons; Coastal Sciences; Dams; Density; Drought; Ecology; Ecosystems; Environmental gradient; Environmental Management; Flooding; Floods; Flowers & plants; Freshwater & Marine Ecology; Functionally gradient materials; Hydrogeology; Hydrologic regime; Landscape Ecology; Leaf area; Life Sciences; Original Research; Plant communities; Plants (botany); Riparian ecology; Rivers; Seeds; Shorelines; Specific gravity; Stream flow; Submergence; Vegetation; Vegetation cover; Glen Canyon Dam; Grand Canyon; Colorado River; Regulated river; Stream flow; Seed mass; Riparian; Plant functional trait; Stem specific gravity; Wood density; C4 photosynthesis; Specific leaf area
• ISSN: 0277-5212; 1943-6246
• DOI: 10.1007/s13157-017-0895-3

Comparisons of community-level functional traits across environmental gradients have potential for identifying links among plant characteristics, adaptations to stress and disturbance, and community assembly. We investigated community-level variation in specific leaf area (SLA), plant mature height, seed mass, stem specific gravity (SSG), relative cover of C4 species, and total plant cover over hydrologic zones and gradients in years 2013 and 2014 in the riparian plant community along the Colorado River in the Grand Canyon. Vegetation cover was lowest in the frequently inundated active channel zone, indicating constraints on plant establishment and production by flood disturbance and anaerobic stress. Changes in trait values over hydrologic zones and inundation gradients indicate that frequently inundated plots exhibit a community-level ruderal strategy with adaptation to submergence (high SLA and low SSG, height, seed mass, C4 relative cover), whereas less frequently inundated plots exhibit adaptation to drought and infrequent flood disturbance (low SLA and high SSG, height, seed mass, C4 relative cover). Variation in traits not associated with inundation suggests niche differentiation and multiple modes of community assembly. The results enhance understanding of future responses of riparian communities of the Grand Canyon to anticipated drying and changes in hydrologic regime.