**2.3 Implement on lower level ecosystem classification in western Utah of the United States**

At Domain, Division, and Province levels, Ecoregions of the United States had been examined by Bailey. The first case study we used for the lower level was accomplished with the upper four levels for the project in a 4.5-million-hectare area centered in western Utah of the United States. National Hierarchy of Ecological Unit (NHEU) had been referenced as the coarsest boundaries in Utah, the United States. This study area was on 300 Dry dominant divisions and had bounders intersecting with 340 Temperate Desert Division and M340 Temperate Desert Regime Mountains Divisions. Three interesting provinces are 342 Intermountain Semi-Desert Province, M341 Nevada-Utah Mountains Semi-desert Coniferous Forest Alpine Province, and 341 Intermountain Semi-Desert and Desert Province. In addition, four sections were intersected in the study area: Bonneville Basin Section, Central Great Basin Section and Northeastern Great Basin Section, and Northwestern Basin and Range Section, shown in **Figure 2**, **Table 2** in [14].

"Bolson" is used as a term in the lower level of ecosystem classification, described the terrain, having entire area from surrounding mountains to mountain slopes, reduced with distance from ridgelines, to the centre of either a river valley or terminal lake basins, or reaching nearly all the study area. DEM data (30 m) was used in the model (**Figure 3A** and **B**) and generated 60 bolson segments.

**Figure 2.** *Upper four levels of ECLs overlaid and intersected in the study area.*


#### **Table 2.**

*Summaries of the implemented ecosystem classification in western Utah.*

#### *2.3.1 Macrotterain units*

In the study area, the 60 bolson segments were subdivided into different macroterrain units. The algorithm to determine macroterrain units employed elevation and relative change in apparent elevation (slope) from adjacent 30 m DEM cells. It had classified the cells as upslope of equal or higher slope position. Thus, most "mixed" macroterrain unit cells will have "erosional" cells upslope and "depositional" cells downslope depended on their positions. This principle of "superposition" was enforced by the application of the macroterrain class using watershed functions.

*Implement and Analysis on Current Ecosystem Classification in Western Utah of the United… DOI: http://dx.doi.org/10.5772/intechopen.100557*
