DOI: 10.5061/dryad.0p2ngf25k
title: Fluvial geomorphic evolution and stream fish community trajectories in the Bayou Pierre, Mississippi

description: Changing environments place stresses on ecosystems, and are contributing
 to widespread losses of biodiversity and ecosystem function. Comparisons
 of historical and contemporary data offer considerable utility in
 understanding how ecosystems respond to, adapt to, or recover from
 changing environments. Stream fishes offer a particularly interesting
 study system for this topic, as streams are naturally dynamic environments
 and human needs have placed increasing pressure on aquatic systems. The
 effects of fine sediments on stream fishes and aquatic ecosystems more
 broadly have been well studied. Yet studies from fluvial geomorphology
 have resulted in models of watershed morphological evolution which
 encompass far broader processes and changes to aquatic systems. Our
 dataset integrates a fluvial geomorphic approach to characterize stream
 channel and habitat evolution over a four decade period in the Bayou
 Pierre, Mississippi, an ecological approach to study related change in
 stream fish communities in the same watershed, and analyses linking the
 two. Fluvial geomorphic processes were characterized both from remote
 sensing data sources for historic and contemporary time periods, and local
 fish habitat data for contemporary time periods. Historical fish community
 data were extracted from museum records, and contemporary fish community
 data were collected via sampling for fishes at the same localities as
 historic efforts using similar methods.
description: Fluvial geomorphic data were collected from remote sensing
 sources using QGIS (open-source) geospatial software. Measurements were
 taken from aerial imagery sources (National High Altitude Imagery Program
 1982 and National Agricultural Imagery Program 2020) and two digital
 elevation models (Mississippi Digital Earth Model, data source 1958-1980,
 and 2015/2016 Lidar-based 3DEP DEM) and exported to shapefile formats.
 Spatial sampling locations were determined by creating a 200m chain object
 using QChainage on the trunk stream and five tributaries via the NHD+ V2
 flowline files. At each sample location we digitized channel width line
 features (1982 and 2020) and extracted channel thalweg elevations (both
 DEMs). We employed visual identification of knickpoint features using
 channel profiles generated from DEMs. These measurements were processed in
 R to create csv files of measurements for further analyses. Historical
 fish community data were extracted from the University of Southern
 Mississippi Ichthyological collections, and were filtered to remove
 non-community samples, and verified by consulting original field notes.
 Contemporary fish collections were repeated at the same localities as
 historical fish collections, using similar methods. We seined all
 available habitats in three subsample plots in proportion to their
 occurrence at a site. Contemporary habitat data were collected via a
 point-transect method at each sample site.
description: Data files (csv) can be opened by either proprietary spreadsheet
 software (e.g., MS Word), any open-source spreadsheet software, or any
 software which can read csv files. R code files can be opened in any text
 editor. R code files require the R Environment for Statistical Computing
 (open-source) for running analyses.