By: Audrey Rader, Watershed & Habitat Restoration Program Manager
Due to drought conditions, habitat fragmentation, historic unsustainable grazing and timber harvests, and flooding events, watersheds within the Madrean Archipelago have been severely degraded. Smith Canyon is one such degraded site, located in the Sonoita Creek Watershed and part of the Nogales Ranger District of the Coronado National Forest.
In collaboration with entities such as the Arizona Department of Environmental Quality, Arizona Game and Fish Department, United States Fish and Wildlife Service, United States Forest Service, United States Geological Survey, and the University of Arizona Cooperative Extension, Borderlands Restoration Network staff has implemented various watershed restoration techniques across Smith Canyon in an effort to address the aforementioned habitat degradation concerns. Restoration treatments within Smith Canyon were designed to reduce erosion impacts and nonpoint source pollution downstream, with the overarching goal of improving the overall ecological function of the watershed.
Smith Canyon consists of mixed mesquite shrubland and oak grassland across roughly 90 structurally similar sub-basins. The unique, repeated pattern of these ~90 sub-basins presents an exciting opportunity for rigorous, large-scale experimentation when considering each sub-basin as a replicate unit.
In 2018, Roy Petrakis (USGS) developed a model to cluster sub-sets of these sub-basins based on their structural and biophysical traits. BRN staff then assessed each of these clustered sub-basins by level of restoration need (high/medium/low), allowing BRN staff to standardize best management practices across the adjacent Stevens and Little Casa Blanca Canyons for future projects.
Between June 2019 and November 2019, BRN staff installed erosion control structures per the restoration prescription in all of the clustered sub-basins. As an effective and low-cost technique employed around the world for thousands of years, erosion control structures are potent restoration tools in arid regions suffering from ecosystem degradation and the destructive effects of drought, fire and flooding. These structures consist of several parallel rows of self-reinforcing rocks or wood incorporated into the bed of the eroding channel. Often only one-rock high in profile but several rows wide, these structures rest at right angles to the direction of flow but remain passive to overtop flows. This arrangement allows these structures to trap organic-rich sediment upstream, while slowing flows and increasing water infiltration into the channel bottom and banks.
Erosion control structures temporarily detaining water in Smith Canyon after a rain event.
These structures extend the hydro-period for plant establishment without retaining water long term. When placed in a coordinated series according to landforms and observed water flows, each individual erosion control structure is part of a system that decreases erosive forces, increases surface water availability, and aids ecological recovery. Each of the 90 sub-basins received at least five erosion control structures constructed of rock and five erosion control structures constructed of dead and down woody material, depending on local resource ability. After installing the erosion control structures, BRN staff monitored each erosion control structure within the sub-basins for theoretical sediment yield by measuring their basin length, width, and height.
Finally, in collaboration with the Gornish Lab of the University of Arizona Cooperative Extension, BRN tested the effectiveness of various planting methods on reducing erosion in Smith Canyon. Planting methods included seedling out-planting (plugs), pelletized seed addition, and bare seed addition. The target species used for this study included Giant Sacaton (Sporobolus wrightii), Blue Grama (Bouteloua gracilis), Parry’s Penstemon (Penstemon parryi), and Soaptree Yucca (Yucca elata), chosen in order to tease out details on the influence life-form may have on treatment success and habitat value.
Planting treatments included forb seeds, forb pelletized seed, forb plugs, forb and grass seeds, forb and grass pelletized seed, and forb and grass plugs. These treatments were randomly assigned across six plots, with each treatment type replicated ten times. Five of the planting treatment replicates were installed in control sub-basins with no erosion control structures and five of the planting treatment replicates were installed in sub-basins with erosion control structures. Plots were 2m x 2m in size to cover the width of the sub-basin flow-lines. BRN and University of Arizona staff will monitor survival and recruitment of each planting method in addition to the relative cost of each. We hope this data will help improve the efficacy and cost effectiveness of planting efforts for practitioners across the borderlands region.
In the face of ever-increasing anthropogenic and natural stressors, it is critical to restore our degraded watersheds. Restoring watershed conditions to a trajectory of recovery improves water quality and quantity with additional benefits to surrounding habitats and downstream populations. We hope these projects will validate the effectiveness of various watershed restoration techniques and inform future management of the Madrean Sky Islands.
Special thanks to the Frances V. Seebe Charitable Trust for support of this project.
Contact Audrey Rader with any questions.
By: Cholla Nicoll, Borderlands Wildlife Preserve Lead Technician
The next time you're out at the Borderlands Wildlife Preserve, swing by the newly updated welcome kiosk! After many zoom meetings and wordsmithing marathons, Borderlands Restoration Network and Wildlife Corridors, LLC are proud to have some exceptional new informational signage at the Preserve's welcome kiosk, including trail maps and brochures,
Like most good things, these signs were a group effort. They could not have been completed without generous donations, hours of volunteer time, and the help and guidance of motivated staff. We hope visitors to the preserve will enjoy the new signs, have lunch or a post hike break at the picnic table, and refill a water bottle from the beautiful mosaic drinking fountain created by the Patagonia Creative Arts Association.
The kiosk signage provide insights into the creation of the preserve, our partners, trail maps, wildlife information, and usage guidelines. The welcome area will continue to grow into a shared space for humans, plants, and wildlife alike. Future plans include additional signage on the back of the kiosk, along with a gentle interpretive nature trail and demonstration garden. As those plans develop, we are hard at work designing new interpretive trail signs for the preserves much loved Smith Canyon Loop Trail.
One of the new interpretive signs will introduce all of the local wild cats known to this region. Wild animals, especially cats, can hide in plain sight giving many of us humans the misconception that they might not be there at all. If we look closely as we hike though, there are signs of these animals just under our feet waiting to be discovered. Learning how to identify wildlife tracks and sign can open the door to a much more interactive experience in nature.
We hope visitors will enjoy the new kiosk and the peace and tranquility of the Borderlands Wildlife Preserve. In the meantime, here is some sign we found including a mountain lion track and a humorous image of a gray fox leaving behind some scat.
If you are interested in learning more about wildlife tracking, my recommended favorite book is Mammal Tracks and Sign: A Guide to North American Species Second Edition authored by Mark Elbroch.
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