Landtype Associations for Wyoming

This dataset is the result of a contract between the Bureau of Land
Management (BLM) and the University of Wyoming Dept. of Botany to
delineate a hierarchical set of landunits for Wyoming. These results
will also contribute to a multi-agency effort to develop a common
ecological map of the United States. The purpose of these units is
ultimately to provide a framework for organizing data for resource
management by ecological units instead of political units.

This dataset is a scientifically based, hierarchical system of map
units for Wyoming that incorporates ecological principles and
processes across a range of scales.
These units are a mapping of terrain features having similar
terrain configuration, ecological properties and management implications
within which situational landscape-ecosystems can logically and
conveniently be defined. The units are hierarchically nested into the
structure of
the ECOMAP (1993) national hierarchy of ecological units. The data-set
includes Landtype Associations as well as higher hierarchical units in
which Landtype Associations are imbedded. Landtype Associations are
defined by ECOMAP (1993) as units at the landscape scale as follows:
groupings of Landtypes or subdivisions of Subsections based upon
similarities in geomorphic process, geological rock types, soil complexes,
stream types, lakes, wetlands, and series, subseries, or plant association
vegetation communities. Repeatable patterns of soil complexes and plant
communities are useful in delineating map units at this level. Names of
Landtype Associations are often derived from geomorphic history and
vegetation community. Mountainous terrain was delineated only at
the higher subsection level as finer sub-divisions are the purview of the
U.S. Forest Service.

The dataset is available in four different regions of Wyoming, compiled during
different time periods and using different methods. Southeast Wyoming was
compiled in 1996. Southwest Wyoming and a portion of Northeast Wyoming was
compiled in 1997. In 1999, two more regions were compiled (Northwest
and Buffalo Resource Area, NorthCentral) using different methods.
Landtype associations delineated in 1996 and 1997 were based on a subjective
process. The subsequent mapping of northwest
Wyoming and the Buffalo Resource area was based on a different
delineation process, using a terrain characterization process based on
empirical analysis modified from Hammond (1964). Details of methods
used are provided in the report:

W.A. Reiners, Axtmann E.V., and R.C. Thurston. 1999. Delineations of Landtype
Associations for Northwest Wyoming and the Buffalo Resource Area. Bureau of
Land
Management/University of Wyoming.