Research - Management Practices:
Colorado Wetlands Monitoring and Evaluation Project
Wetlands support a disproportionate segment of our wildlife, including birds; one estimate is that 75 percent of the wildlife of Colorado use wetlands, yet these wetlands account for less than 2 percent of the state’s area. Despite the importance of wetlands, the US Fish and Wildlife Service estimates that approximately half of our nation’s wetlands have been lost. Threats to wetlands and rivers persist today – including development pressure, pollution, sedimentation, agricultural and municipal water needs, and invasive species of plants and animals.
To protect and restore Colorado’s wetlands, the Colorado Division of Wildlife created the Colorado Wetlands Partnership (CWP), a voluntary, incentive-based program for restoring, enhancing, creating, managing, and protecting biologically significant wetlands and associated uplands in the state. Since the inception of the CDOW Wetlands Program in 1997 and with the cooperation of several major partners, including Ducks Unlimited, The Nature Conservancy and USFWS Partners for Fish and Wildlife, Intermountain West Joint Venture, and Playa Lakes Joint Venture, over $20 million has been spent on wetlands protection projects (acquisition, restoration, enhancement) within the state. However, conservation project sites had not been evaluated systematically for biological contributions; in other words, the accomplishments of these projects in protecting wildlife habitat and populations have not yet been documented. To address these information needs, RMBO created the Wetlands Monitoring and Evaluation Project (WMEP) to assess ecological outcomes from wetland conservation projects in the CWP.
We were particularly interested in knowing the types of wetlands protected, the types of restoration, enhancement, or protection practices applied, how birds used restored wetlands, and the success of various conservation projects in providing critical bird habitat.
RMBO began implementing the WMEP in 2002. Initial years of the project involved protocol development, establishment of four intensive monitoring efforts to document avian and plant community response to wetland conservation projects, and completion of 165 site assessments in 11 Wetlands Focus Areas (see map).
We also developed a database, Evaluwet, which contains five database modules with 47,627 data records. Through different phases of the project we focused on projects providing waterfowl nesting habitat in the San Luis Valley and songbird responses to riparian habitat restoration statewide (please see 2006 report for detailed results). Most recently we investigated how restored shallow wetlands are providing migratory shorebird and waterfowl habitat along the South Platte River (2007 report). We conducted 257 surveys of 16 wetlands at 11 sites. We observed 16,527 birds representing 60 species, including 33 species of conservation priority under one of the North American bird conservation iniatives. We also conducted 210 weekly surveys of water depths and extent of surface area flooding on 26 wetlands at 18 sites. At the conclusion of the migration season, we sampled wetland vegetation, documenting 132 species of plants.
The abundance of wetland-dependent birds as well as species richness varied greatly among sites. Sites that hosted high numbers of birds also hosted high numbers of species. Hydrologic conditions also varied greatly among sites, with some sites never providing wetland conditions throughout the study season and others being wet the entire season. Dry sites rarely hosted wetland-dependent birds. We found strong temporal trends in the abundance of waterfowl and shorebirds through the study season, in part driven by the migration chronologies of various species. Waterfowl and shorebird densities were most highly related to wetland size and percent of unvegetated area flooded in shallow water depth classes. We found no relationships between bird use and specific vegetation characteristics or percent of wetlands in the area surrounding wetland sites.
We calculated avian use-days for the study area and estimated over 75,000 use days on these study areas alone. Because our sites were selected randomly, they should be representative of all restoration sites within the South Platte River WFA. Thus, we can project that restoration projects within this Focus Area collectively support a minimal estimate of 410,760 avian use days per spring migration season.
A number of management implications may be drawn from this work. First, management of surface water levels drives the use of sites by both waterfowl and shorebirds. Sites that hosted high numbers of waterfowl also were used by high numbers of migrating shorebirds, demonstrating the compatibility of managing for both bird groups on the same sites. In March and April when waterfowl are most abundant, flooding of depths less than 40 cm is related to high waterfowl use, while during late April and May flooding of less than 20 cm and especially less than 4 cm will most benefit shorebirds. For both groups, the maintenance of open areas free of vegetation is also related to high bird use. Finally, we found that some sites with augmentation water rights provided high quality habitat, indicating a compatibility of use between augmentation water rights and wildlife habitat conservation.
The Wetlands Monitoring and Evaluation Project is a model program for evaluating the outcomes of wetland conservation projects and has been instrumental in supporting the wetlands protection efforts ongoing in Colorado and the Rocky Mountain region.
The project provides land and project managers feedback on the efficacy of their restoration practices and helps them to design adaptive management practices. Program administrators are provided information about the breadth and successes of their program. In addition, because wetland ecosystems continue to undergo threats and available funds cannot meet all conservation opportunities, WMEP information can help determine the most effective strategies for preserving Colorado’s wetlands. Finally, evaluation and monitoring are extremely important for documenting the success of programs to their funding sources and supporters, including Congress. This project was active from 2002-2007; is it no longer funded.