This section describes impacts related to the 18 existing, existing with proposed expansion, and new proposed ACECs in the Planning Area (see Table 4-18). The BLM manages ACECs to provide special management for relevant and important values, resources, natural systems, and natural hazards (referred to here as values of concern). This section also addresses impacts related to two other Management Areas (the Craig Thomas Little Mountain SMA and the Chapman Bench Management Area) closely related to the existing and proposed ACECs. Section 4.4.6 Wildlife describes the impacts of the Absaroka Front Management Area; Section 4.2.5 Leasable Minerals - Oil and Gas describes impacts from Oil and Gas Management Areas.

The discussion of ACECs and other Management Areas considers impacts in two ways: (1) the impacts of management in these special designations to other resources and resource uses and (2) the impacts of management to the protection of the values of concern for which the BLM proposes that designation. Most of the values of concern are resources in their own right and are further discussed and analyzed by alternative in the corresponding sections of this chapter. For example, this section describes impacts to paleontological values of concern in the Big Cedar Ridge ACEC, but Section 4.5.2 Paleontological Resources describes overall impacts to paleontology from management under the alternatives. The impacts analysis in this section focuses on high-level comparisons of potential adverse and beneficial impacts among the alternatives. While simply designating an ACEC would not produce effects that can be analyzed, the management prescriptions applied to the ACEC would result in effects.