On a weekday morning in June, the ponds in the Connected Lakes section of the James M. Robb Colorado River State Park are as smooth as glass. Waterfowl float on the surface, while anglers sit on shady banks. Dog walkers stroll the paths, and cyclists cruise by. This quiet refuge, right on the edge of town, is much used and appreciated by Grand Junctionites, myself included.
The reason I can see the ducks and the anglers can reach the banks is because of an intensive effort to remove the impenetrable thickets of invasive tamarisk and Russian olive that previously choked the banks of the ponds and the nearby river. This effort has been overseen by Park Manager Pete Firmin and supported by grants from the Colorado Water Conservation Board and other sources. The Tamarisk Coalition, recently re-named RiversEdge West, has been a key partner in obtaining funding and planning and implementing projects.
When Firmin took over as manager in 2010, most of the opportunities to purchase land to expand the park system had already been taken. Instead of working to make the park system bigger, Firmin has focused on making it better — better for wildlife, and better for recreation.
Removing tamarisk and Russian olive improves public access, habitat and safety. Tamarisk is particularly bad at crowding out other species. It also increases the danger of wildfire. Its fine leaves, twiggy branches and thick trunks have the perfect combination of kindling and fuel to catch fire and sustain hot, damaging blazes, like the one that broke out in DeBeque Canyon and seared a portion of the Island Acres section of the park. One of the fire’s casualties was a cottonwood with a bald eagle nest in it. Firmin said that a combination of tamarisk and cheat grass made the fire more intense and harder to manage than it would have been if those invasive species were less prevalent.
It’s not enough to just remove invasive species, of course. Two of the things that make weeds so successful at taking over in the first place are their hardiness and rapid growth rates. Genuine restoration requires multiple years, starting with removal, then application of herbicides to control regrowth and secondary weeds like kochia, and then establishing more desirable plants, like native cottonwoods, willows, buffalo berry, sumac and bunch grasses. New Mexico privet has recently been added to the list, since it thrives just south of here and is likely to withstand the warmer temperatures we are beginning to see. Firmin notes that one of his most successful restoration efforts has been at the ponds near 29 Road. The ponds previously provided no recreation at all, because thick stands of tamarisk and Russian olive prevented access. Now, though, the area hosts higher waterfowl numbers and a very popular hunting blind. People also enjoy fishing there. Desirable species are taking hold, with conditions improved by a donation of sediment from the Grand Valley Drainage District, which had been cleaning out its ditches.
Learning what strategies work best to establish healthy stands of desirable native species requires experimentation, and there are trade-offs. Allowing native plants to re-seed naturally once the invasives are removed can be slower than planting seedlings or pole cuttings, but it also requires less cost and labor. Irrigating new seedlings helps them survive, but it isn’t always feasible.
Regardless of the revegetation strategy, new plants are always vulnerable to being overwhelmed by weeds if a maintenance program isn’t kept up long after the final grant reports are turned in. Impressive results are not achieved overnight. A stand of lush, mature sumac across the path from a newly planted area likely took decades to achieve its current form.
Firmin is currently shifting his focus to upkeep on areas that have already been cleared of invasives, rather than clearing new areas. His goal is to nurture the new plantings to the point where they are healthy enough to thrive and hold off the weeds regardless of what changes in park budgets and management priorities may come in the future.
This kind of patient, careful work is a major contributor to making our parks and other public lands the valuable public resources that they are. If you would like to contribute, check for volunteer opportunities on the websites for RiversEdge West (riversedgewest. org) or the James M. Robb Colorado River State Park (cpw.state.co.us/placestogo/ parks/JamesMRobbColoradoRiver).
Hannah Holm coordinates the Hutchins Water Center at Colorado Mesa University, which promotes research, education and dialogue to address the water issues facing the Upper Colorado River Basin. Support for Hutchins Water Center articles is provided by a grant from the Walton Family Foundation. You can learn more about the center at // www.coloradomesa.edu/water-center.