DOI: 10.5061/dryad.6mn67g0
title: Data from: Emerging reservoir delta-backwaters: biophysical dynamics and riparian biodiversity

description: Deltas and backwater-affected bottomlands are forming along tributary and
 mainstem confluences in reservoirs worldwide. Emergence of prograding
 deltas, along with related upstream hydrogeomorphic changes to river
 bottomlands in the backwater fluctuation zones of reservoirs, signals the
 development of new and dynamic riparian and wetland habitats. This study
 was conducted along the regulated Missouri River, USA to examine
 delta-backwater formation and describe vegetation response to its
 development and dynamics. Our research focused specifically on the
 delta-backwater forming at the confluence of the White River tributary and
 Lake Francis Case reservoir. Objectives of the research were to: (1)
 describe and analyze the process of delta-backwater formation over space
 and time; (2) determine by field sampling and GIS mapping how vegetation
 has responded to development of the delta-backwater; and (3) compare the
 woody plant communities of the delta-backwater to those along free-flowing
 and regulated remnant river reaches. In response to base level changes
 caused by reservoir filling, the thalweg of the lower 31 km of the
 original White River channel and adjacent floodplain aggraded by up to 12
 m between 1954 and 2011. The overall channel slope flattened from 0.70
 m/km to 0.29 m/km. Riparian Populus-Salix forests increased in area by
 nearly 50 percent during the post-dam period by colonizing new deltaic and
 floodplain deposits. Many of the native woody species found along natural
 and regulated river reaches were also found on the delta-backwater. Woody
 species sorted along a fluvial to delta gradient; wetland-affiliated
 species (Salix spp., Typha spp.) dominated the delta-backwater near the
 reservoir while riparian species (Populus, Fraxinus) dominated in upstream
 portions of the delta-backwater. This habitat complex supports young
 stands of native riparian vegetation now in decline in remnant reaches
 protected from flooding.
description: Stand-locations-and-boundaries-shapefileAn ArcMap shapefile with all stand sampling locations and boundaries.Cottonwood-and-willow-seedling-sapling-densityDensity values for cottonwood and willow seedlings and saplings in each sampled stand. A README file is provided on the first worksheet.Cross-sections-for-Lake-Francis-Case-and-White-RiverGeomorphic cross section data for the lower White River and Lake Francis Case (Missouri River) from the U.S. Army Corps of Engineers. A README file is provided on the first worksheet.Delta-backwater-Missouri-River-species-presence-comparisonWoody species presence on the White River delta-backwater and the Garrison and Gavins Point remnant reaches of the Missouri River. A README file is provided on the first worksheet.GIS-woodland-age-area-distribution-by-yearRiparian woodland age-area distribution by year on the White River delta-backwater, based on GIS analysis of historic aerial photos. A README file is provided on the first worksheet.Lake-Francis-Case-Water-Surface-Elevation-1989-2013Water Surface Elevations of Lake Francis Case, 1989-2013. Data were derived from the US Geological Survey Gage 06442996 at Chamberlain, South Dakota. A README file is provided on the first worksheet.Liana-presence-absenceLiana (woody vine) species presence/absence in sampled stands. A README file is provided on the first worksheet.List-of-woody-plant-species-sampledA complete list of the woody species sampled. A README file is provided on the first worksheet.Overstory-species-composition-structureOverstory tree species composition and structure across the study site. A README file is provided on the first worksheet.Overstory-tree-dbhOverstory tree species diameter at breast height (dbh) for each tree in the sample. A README file is provided on the first worksheet.Sapling-species-composition-structureSapling species composition and structure across the study site. A README file is provided on the first worksheet.Seedling-species-composition-structureSeedling species composition and structure across the study site. A README file is provided on the first worksheet.Stand-characteristicsCharacteristics of the 35 stands sampled along the lower White River and its delta-backwater in South Dakota. A README file is provided on the first worksheet.Tree-ring-age-dataStand location, species, diameter, and age of each tree cored along the lower White River and on the White River delta-backwater in South Dakota. A README file is provided on the first worksheet.README-Methods-for-vegetation-data-summarization-analysisA description of the methods used to summarize and analyze vegetation composition and structure.