Field Guide to the Wetland and Riparian Plant Associations of Colorado


Land managers, land owners, consultants, and academics now have a single comprehensive source of information about wetland and riparian plant associations of Colorado. The Colorado Natural Heritage Program has just published the Field Guide to the Wetland and Riparian Plant Associations of Colorado.

This guide uses the relatively broad US Fish & Wildlife Service definition of wetland which requires the presence of one or more of three key attributes: dominance by water-loving plants, predominantly hydric soil, and periodic saturation by water. Thus, the guide includes some plant communities that most people would consider more riparian than wetland. In addition, some of the plant communities are not “jurisdictional wetlands” within the meaning of Section 404 of the Clean Water Act.

The basic unit of classification in the guide is the plant association, which is defined with reference to its diagnostic plant species. The guide includes 184 plant associations. The associations are based on floristic data from 4527 samples that were collected by a number of field researchers, most of whom were associated with the Colorado Natural Heritage Association. In spite of this large number of samples, the guide does not cover aquatic plant associations due to lack of sufficient data.

In order to use the guide, one can either thumb through the pages to find the plant association(s) of interest or use a dichotomous key. When using the key, one first uses a short key to determine the physiognomic group that the plant association is found within. Then one uses a more detailed key for a particular physiognomic group to find the plant association of interest. This type of organization is commonly found in botanical field guides.

Each plant association covered in the guide has a two-page description printed on facing pages. The description includes a color photograph, a range map, state and global Heritage ranks, and hydrogeomorphic method (HGM) subclass. There is also a general description of the plant community; a vegetation description, including common and Latin plant names; and a short summary of ecological processes that influence to association. Each description has a table of the more common plant species ranked in order of percent cover. Most of the plant associations have line drawings of key plant species.

The appendices contain additional useful information, including a list of plant associations by HGM subclass, a glossary to terms, references, a summary of Natural Heritage methodology, and an index of plant association names and illustrations.

Those of you who attended last fall’s CRA annual conference in Steamboat Springs heard Kathy Carsey describe the forthcoming field guide. It was immediately apparent that this guide will be extremely valuable as a field and desk reference for many people. It is available at no charge at the Colorado Natural Heritage Program’s web site at However, for ease of use we recommend that CRA members purchase a hard copy of the guide. A full-color, coil bound edition is available for only $25 post paid from CRA. This is a terrific deal, and it is not clear if and when additional copies will be available once our current stock of copies is exhausted. Please send your check for $25 payable to Colorado Riparian Association and mail it to Colorado Riparian Association, Attention Gwen Kittel, 2400 Spruce Street, Suite 201, Boulder, CO 80302. Note that the CRA mailing address has changed, so change your records accordingly.