Decisionmaking model helps control invasive species within limited budgets
Fast growing aquatic and riparian invasive weeds plague many western river systems. These weeds clog water ways and can also consume large amounts of water. Salt cedar is one of these menacing weeds and consumes an estimated 2.5 million acre-feet of water per year across the west which is enough water for about 10 million people. This loss is responsible for about $288 million in agriculture production each year and causes an estimated $43 million annual loss of hydroelectric power production along the Colorado River alone.
Local land managers can use a new decisionmaking model to establish priorities for treating noxious weeds. Stewardship Consulting, Inc., of Boulder, Colorado, in cooperation with Reclamation's Science and Technology Program and other partners, has developed this model, which considers seven factors to prioritize noxious weed occurrences for control.
Invasive weeds (weeds that are not native and thus have no natural enemiess) can cause many problems. In the US, noxious weeds take over about 4,600 acres a day —ruining an area the size of Delaware every nine months. Invasive weeds cost hundreds of millions of dollars each year. Weeds can alter ecosystem processes, degrade wildlife habitat, reduce biological diversity, reduce the quality of recreational sties, and reduce crops and rangeland, and even poison livestock. Riparian weeds (weeds that live along waterways) consume water and block canals, which harms Reclamation's ability to deliver water. Salt cedar alone consumes 2.5 million acre-feet a year in the western US, enough water for 10 million people. Purple loosestrife clogs waterways and wetlands, causing $46 million in damages a year.
Everyone's resources are limited, and deciding where to start combatting these menaces can be overwhelming. Now on Reclamation lands, local managers can use this model set to identify the priorities for problem areas. The model provides information about the size and location of weed patches, along with information about weed species biology. Further, the model determines control priorities based on the locations of the weed occurrences, the level of threat to resources posed by a weed species, how rare the weed is locally, how feasible it is to control, and how close it is to canals and other paths that can spread the seeds. This information is usually obtained from a noxious weed inventory of local Reclamation lands, although some land managers may already have the needed information. Weed experts stress focusing initial weed control efforts on small, isolated patches of the worst weed species before the weeds become well established.