Restoration Initiatives
Restoring Riparian Habitats
Riparian habitats are the most productive, biologically diverse, and valuable habitats in the Southwest. Riparian areas here account for less than 2 percent of the land, yet over 65 percent of the Southwest's wildlife depends on these areas. Riparian habitats are also one of the most threatened habitats in the Southwest, primarily due to ever-increasing demands for water for agriculture and municipal uses. The disruption and extraction of surface and groundwater flows underlies a myriad of other factors that have led to the degradation of aquatic and riparian areas, including loss of fish habitat, loss of native plant species, loss of terrestrial wildlife habitat and species, and invasion of non-native species.
Tamarisk invasion along stream corridors poses a significant threat to riparian systems, altering soil nutrient and water availability, outcompeting and reducing the diversity of other plants, increasing fire hazard, and altering stream hydrology. As a result, restoration efforts are increasingly focused on controlling these species. Unfortunately, the scarcity, high demand for, and extensive modifications of rivers and groundwater flows makes restoration of riparian habitats in the arid Southwest particularly challenging because water extraction and manipulation activities tend to facilitate tamarisk invasion. Moreover, there is increasing evidence to suggest that restoration treatments involving tamarisk removal are unlikely to succeed where ecological processes associated with natural flow patterns are not intact. Even in systems where streamflows are relatively intact, there is a great deal of uncertainty related to the potential for natural recovery of native vegetation following invasive species removals.
Given the challenges and uncertainties associated with restoration of riparian areas in the Southwest, land managers must undertake a close examination of watershed conditions prior to proceeding with landscape-scale restoration work. Managers must also carefully consider the social, political, and ecological viability of restoration treatments before proceeding. We are currently working in partnership with the BLM to begin to address the viability of large-scale tamarisk removal on a naturally-flowing stream, the Paria River, by implementing a tamarisk removal project over a mild to moderately infested section of stream. We will be continually monitoring the success of removal treatments and recovery of native vegetation in relation to a number of environmental factors. Monitoring data will be used to inform removal efforts in the lower canyon, where infestation by these species is significantly greater. We are also working in partnership with the BLM and the Forest Service to assess conditions in other streams and desert washes located within the ranch boundaries by mapping tamarisk invasion across these areas and synthesizing this information to determine the most appropriate next steps toward controlling this species across the ranches.
Finally, we are in the process of assessing spring conditions and identifying opportunities to decrease the impacts of livestock on springs and in riparian areas. The status of spring, seep, hanging garden and stream ecosystems will continue to be a focal point for monitoring, as these systems are highly important for wildlife, subject to additional stress as a function of upstream water diversion and climate change, and ecologically rare and diverse in this region.
