Vegetation composition, nutrient, and sediment dynamics along a floodplain landscape

River Systems
By: , and 

Links

Abstract

Forested floodplains are important landscape features for retaining river nutrients and sediment loads but there is uncertainty in how vegetation influences nutrient and sediment retention. In order to understand the role of vegetation in nutrient and sediment trapping, we quantified species composition and the uptake of nutrients in plant material relative to landscape position and ecosystem attributes in an urban, Piedmont watershed in Virginia, USA. We investigated in situ interactions among vegetative composition, abundance, carbon (C), nitrogen (N) and phosphorus (P) fluxes and ecosystem attributes such as water level, shading, soil nutrient mineralization, and sediment deposition. This study revealed strong associations between vegetation and nutrient and sediment cycling processes at the plot scale and in the longitudinal dimension, but there were few strong patterns between these aspects at the scale of geomorphic features (levee, backswamp, and toe-slope). Patterns reflected the nature of the valley setting rather than a simple downstream continuum. Plant nutrient uptake and sediment trapping were greatest at downstream sites with the widest floodplain and lowest gradient where the hydrologic connection between the floodplain and stream is greater. Sediment trapping increased in association with higher herbaceous plant coverage and lower tree canopy density that, in turn, was associated with a more water tolerant tree community found in the lower watershed but not at the most downstream site in the watershed. Despite urbanization effects on the hydrology, this floodplain functioned as an efficient nutrient trap. N and P flux rates of herbaceous biomass and total litterfall more than accounted for the N and P mineralization flux rate, indicating that vegetation incorporated nearly all mineralized nutrients into biomass.

Publication type Article
Publication Subtype Journal Article
Title Vegetation composition, nutrient, and sediment dynamics along a floodplain landscape
Series title River Systems
DOI 10.1127/rs/2015/0097
Volume 21
Issue 2-3
Year Published 2015
Language English
Publisher E. Schweizerbart’sche Verlagsbuchhandlung
Contributing office(s) National Research Program - Eastern Branch
Description 15 p.
First page 109
Last page 123
Country United States
State Virginia
Google Analytic Metrics Metrics page
Additional publication details