DOI: 10.5061/dryad.6jc55mn
title: Data from: Applying ecological site concepts and state-and-transition models to a grazed riparian rangeland

description: Ecological sites and state-and-transition models are useful tools for
 generating and testing hypotheses about drivers of vegetation composition
 in rangeland systems. These models have been widely implemented in upland
 rangelands, but comparatively little attention has been given to
 developing ecological site concepts for rangeland riparian areas, and
 additional environmental criteria may be necessary to classify riparian
 ecological sites. Between 2013 and 2016, fifteen study reaches on five
 creeks were studied at Tejon Ranch in southern California. Data were
 collected to describe the relationship between riparian vegetation
 composition, environmental variables, and livestock management; and to
 explore the utility of ecological sites and state-and-transition models
 for describing riparian vegetation communities and for creating hypotheses
 about drivers of vegetation change. Hierarchical cluster analysis was used
 to classify the environmental and vegetation data (15 stream reaches 4
 years) into two ecological sites and eight community phases that comprised
 three vegetation states. Classification and regression tree (CART)
 analysis was used to determine the influence of abiotic site variables,
 annual precipitation, and cattle activity on vegetation clusters. Channel
 slope explained the greatest amount of variation in vegetation clusters;
 however, soil texture, geology, watershed size, and elevation were also
 selected as important predictors of vegetation composition. The
 classification tree built with this limited set of abiotic predictor
 variables explained 90% of the observed vegetation clusters. Cattle
 grazing and annual precipitation were not linked to qualitative
 differences in vegetation. Abiotic variables explained almost all of the
 observed riparian vegetation dynamics—and the divisions in the CART
 analysis corresponded roughly to the ecological sites—suggesting that
 ecological sites are well-suited for understanding and predicting change
 in this highly variable system. These findings support continued
 development of riparian ecological site concepts and state-and-transition
 models to aid decision making for conservation and management of rangeland
 riparian areas.
description: Cluster Analysis
 Data_herbaceous sqrtThis file contains the
 vegetation data from 15 riparian study reaches at Tejon Ranch, California.
 Reaches were sampled annually between 2013 and 2016. Columns are species,
 and rows are the plot_years. Values reported are absolute cover. All
 species in the "herbaceous canopy" (those not followed by
 "_Shrub" or "_Tree") have had their cover values
 square-root transformed. Definitions and attributes of of species codes
 are in the "Supporting Information" file.Environmental
 Data_Plot_YearsThis file contains
 environmental attributes data for each of the study reaches. It contains
 attributes that do not change between years (geology, elevation, etc.) and
 also attributes that change between years (Cattle Exclosure and Annual
 Precipitation). Columns are the environmental criteria, rows are the
 individual plot_years.Environmental Data_for
 ESDThis file contains the
 environmental attributes of each plot that did not change between the
 years of sampling. It was used in the Ecological Site cluster analysis to
 create the Ecological Site classification.R Code for Riparian
 ESD:STM paperThis is the R code used
 to produce all the analyses in the paper (cluster analyses, indicator
 species analysis, CART analysis, and summary statistics). It requires that
 you install the packages loaded at the beginning of the script. If you
 don't want to run the code in R, but you do want to see the code and
 output, you can also look at the accompanying html file of the same
 name.Supporting
 InformationThis supporting
 information document links all the plant species codes used in the
 analysis with the full species names. It also includes attribute
 information for each of the species in the analysis (family, wetland
 status, etc.).R Code for Riparian
 ESD:STM paper.nbThis is the html output
 of the R script. It shows the code and the outputs from each step of the
 analysis.