Evaluating potential impacts to riparian/wetland areas caused by changes in functionality or invasive species establishment focuses on resource management actions that (1) cause surface disturbances or limit the impacts for surface disturbances, and (2) are substantially different among the proposed alternatives. Estimates of projected surface disturbances are used as the primary metric for determining the relative level of potential indirect impact to riparian/wetland areas.

Surface disturbances generally increase the potential for accelerated sediment loading to streams.

Surface disturbances generally increase surface runoff to streams due to an increase in impervious surface, changes in water routing, and loss of vegetation.

Surface disturbance, transportation networks, ungulate use, and recreation increase the likelihood of invasive species introduction and spread in an area.

The greater the amount of surface disturbance in a watershed, the greater the probability that excess surface runoff and sediment will enter the stream and contribute to the loss of riparian/wetland functionality.

Placing salt and mineral supplements outside of riparian/wetland communities is one tool that can reduce wildlife and livestock use of riparian/wetland areas.

Surface runoff to streams generally increases as livestock stocking rates increase. This is not a linear relationship. For example, low stocking rates typically have no measurable impact on surface runoff, moderate stocking rates typically have a negligible impact on surface runoff, high stocking rates have a measurable impact on surface runoff, and consecutive years of high stocking rates have the highest potential for increasing surface runoff to streams.

Herbivory use is typically disproportionately higher in riparian/wetland communities than in upland communities. Improper or unmanaged herbivory can adversely impact these areas throughout the year, but surface impacts (due to hoof action) are generally greater in the spring and early summer, when soils are wet and, therefore, more vulnerable to compaction and stream banks are more vulnerable to sloughing. Livestock, especially cattle, tend to congregate in these communities during the hot season (mid to late summer). While stocking rates for an allotment or pasture may be low to moderate, the utilization levels in riparian/wetland areas can be high.

Riparian areas are evaluated during application of the Standards for Healthy Rangelands and Guidelines for Livestock Grazing Management for the Public Lands Administered by the BLM in the State of Wyoming (Appendix N).

Grazing practices can maintain, improve, or degrade rangeland health. The Standards for Healthy Rangelands and Guidelines for Livestock Grazing Management for the Public Lands Administered by the BLM in the State of Wyoming (Appendix N) are designed to maintain or improve rangeland health. Approximately 10 percent of the public land in the Planning Area is evaluated annually for rangeland health.

Riparian/wetland areas, except for laterally unstable cobble substrate-based streams, possess the ability to recharge and rebound faster than other vegetative areas in the Planning Area.

All riparian/wetland areas are evaluated per the Wyoming Standards for Healthy Rangelands (Appendix N) and managed toward proper functioning condition (PFC). Management toward DPC is assumed to exceed the requirements of managing toward desited future condition (DFC), which is assumed to exceed the requirements of managing toward PFC.