Classification Of Riparian Communities On The Bighorn National Forest

This classification of riparian and wetland plant communities in the Shoshone National Forest was a cooperative project between the Wyoming Natural Diversity Database (WYNDD) of The Nature Conservancy and the Shoshone National Forest. This project identifies groups of plant species that commonly occur together in particular environmental settings, Each such group of species, or plant community type, is identified by the structure of the vegetation and by the species contributing the most canopy cover. The classification identifies physiognomic types based on the amounts of trees, tall shrubs, low shrubs, and herbaceous plants; and dominance types within each physiognomic type. The term "community type" is used in a broad sense to mean both seral or successional vegetation types and potential or climax vegetation types.

An approach for synthesizing the results of ecological research pertinent to land management is the analysis of the historic range of variability (HRV) for key ecosystem variables that are affected by management activities. This report provides an HRV analysis for the upland vegetation of the Bighorn National Forest in northcentral Wyoming. The variables include live tree density, dead tree (snag) density, canopy cover, abundance of coarse woody debris, species diversity, fire return intervals, the abundance of various diseases, the proportion of the landscape in different land cover types, and the degree of patchiness in the landscape. The variables were examined at the stand and landscape scales, using information available in the literature and USFS databases. High-elevation landscapes were considered separately from low-elevation landscapes. Much of the report pertains to forests dominated by lodge-pole pine, subalpine fir, and Engelmann spruce at high elevations, and by ponderosa pine, aspen, and Douglas-fir at lower elevations. We defined the HRV reference period for the BNF as approximately 1600 to 1890.

This field guide was designed for people with minimal botanical training. It is an identification aid to plant species that have ecological indicator value, are on sensitive species lists, or are considered noxious weeds. It contains illustrations and simplified taxonomic descriptions.