Restoration Initiatives
Assessing landscape-scale tamarisk invasion characteristics
Tamarisk is prevalent in riparian areas and desert washes across the Kane and Two Mile Ranches. Our volunteers have mapped tamarisk throughout the House Rock Valley, and in the sections of Kanab Creek and the Paria River that flow through the Kane Ranch allotments. We are using this information to help the Forest Service and BLM prioritize sites and develop strategies for future tamarisk control work.
Introduction
Tamarisk are prevalent in riparian areas and desert washes across the Kane and Two Mile Ranches. Tamarisk impacts riparian ecosystems by altering soil nutrients and groundwater availability, and by displacing native vegetation following disturbances such as flooding or drought. The high competitive and reproductive success of tamarisk often results in dense, monotypic stands, reducing the diversity of other plants and wildlife species, increasing fire hazard, and altering surface and groundwater hydrology. As a result, restoration efforts are increasingly focused on controlling these species.
Approach
Following the baseline ecological assessment in 2005, Kanab Creek, the Paria River, and the washes in House Rock Valley were identified as areas that are likely to contain high relative abundances of invasive riparian species With help from our volunteers, we have mapped tamarisk throughout the House Rock Valley, and in the sections of Kanab Creek and the Paria River that flow through the Kane Ranch allotments. We are using this information to work with the Forest Service and BLM to prioritize and develop strategies for tamarisk control work in these areas.
Future Work
Our results to date indicate that severity of tamarisk infestation and the potential for removing these species and restoring native vegetation varies across these different areas of the ranches, as described below.
Kanab Creek
In Kanab Creek, the infestation is substantial enough that removals will require significant resources to remove and revegetate the area that would be beyond the capacity of a volunteer-driven effort. Moreover, streamflow in Kanab Creek is significantly altered, leading to reduced potential for restoration success. Thus, before any future tamarisk control work occurs in Kanab Creek, a number of complicating factors must first be considered, including the effects this may have on the endangered Southwestern Willow Flycatcher, which is likely to nest in the dense, monotypic stands of tamarisk in Kanab Creek. Moreover, natural processes associated with the natural flood regime have been disrupted by upstream water use, and this may be the fundamental process that regulates the persistence of native and invasive riparian species. Without restoring natural flow patterns to the Kanab Creek drainage, restoration efforts have a reduced likelihood of success. We will continue to work with the North Kaibab Ranger District to determine the best alternatives for moving forward with restoration activities.
Paria River
In contrast to Kanab Creek, the Paria River is only moderately infested throughout much of the Kane Ranch allotments, and natural flow patterns remain in place. Restoration activities are more likely to be successful in this area of the ranch and we have already initiated a project to remove tamarisk and Russian olive (another invasive non-native species) from an 18-mile section of the canyon. We are monitoring the success of our restoration efforts and will use this information to adaptively move forward in controlling these species throughout the Paria River drainage.
House Rock Valley
In House Rock Valley, tamarisk primarily exist in isolated dry washes and surrounding water sources and at this time, are not able to spread as quickly and are a lower priority for initiating restoration work relative to Kanab Creek and the Paria River. We will work with the BLM to decide the appropriate next step for the control of tamarisk across this area.
