Data from: Applying ecological site concepts and state-and-transition models to a grazed riparian rangeland

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.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