Land Bird Conservation Plan Colorado  

Executive Summary
Overview of Colorado
Physiographic Region 36
Physiographic Region 62

  • Alpine Tundra
  • Aspen
  • Cliff/Rock
  • High Elevation Riparian
  • Lowland Riparian
  • Mixed Conifer
  • Mountain Shrubland
  • Ponderosa Pine
  • Sagebrush Shrubland
  • Spruce-Fir
  • Wetlands
  • Physiographic Region 87
    Implementation Strategies
    Literature Cited
    Appendices

    Physiographic Region 62: Southern Rocky Mountains

    Wetlands

    Description and Ecology: The habitat category of wetlands encompasses a large variety of ecosystems of large and small proportions. The state of Colorado has numerous representatives of this variety: marshes, wet meadows, seeps, springs, rivers, lakes, ponds, swamps, fens, bogs, hanging gardens, and playas (Windell et al.1986, Benedict 1991). Many of Colorado's wetlands, including some that support priority species, are artificial. Such wetlands include irrigated meadows and man-made reservoirs, lakes and ponds with their associated marshes. Less than 3% of the surface area of Colorado originally occurred as wetlands (Dahl 1990). Approximately 40% to 60% (0.4-1.2 ha; 1-3 million ac) of the original wetlands area have been lost (Dahl 1990, Wilen 1995). Losses are greater proportionately in wetlands than in other habitat types in Colorado.

    Wetlands in Colorado range in size from a few square meters (e.g., springs and splash pools) to large areas of wet meadows and riparian wet forests. They include wetlands along riparian corridors that may continue for many kilometers yet are quite narrow (discussion of riparian habitats will be found in the appropriate sections: lowland riparian or high elevation riparian habitats). What all wetlands have in common is water. The water occurs in sufficient quantities and in such patterns that the soils, geomorphology, and vegetation respond characteristically, forming repeated patterns on the landscape. The repeated patterns are categorized as types of wetlands.

    All wetlands likely play a role in the lives of birds, at least as sources of water. But many wetland types are very small and unlikely to make a large contribution to Colorado's avifauna (although any wetlands may be important to local conservation). Wetlands that support high priority bird species include lakes, ponds, reservoirs, wet meadows, playas, and marshes. The remaining, smaller wetlands are perhaps best considered as patch types and important habitat components within a larger habitat matrix.

    Importance and Conservation Status: Thirty-seven of Colorado's breeding bird species are dependent on wetlands. That means that 14% of the breeding species depend on less than 3% of the state's area. Many of the species are common and are presently of little current conservation concern (e.g., Red-winged Blackbird). However two species are in need of special conservation attention in Colorado: Willet and Short-eared Owl.

    In the water-restricted western United States, water resources are necessary for life, and control of water can become a most lucrative asset. Water law in Colorado, as in most western states, recognizes water as one of a bundle of property rights. As such, water is owned, bought and sold, as property. For mining operations, agricultural irrigation, and drinking water for a growing population, water has been harnessed, moved, stored, slowed, and spread. Wetlands have often been considered impediments to efficient water use, slowing its downstream progress to areas of human use. Many wetlands have been drained and others heavily altered. Dahl (1990) estimated wetland losses in Colorado to be approximately 50%. More specific estimates for wetland losses in the Southern Rocky Mountains are not available, and interpretations are very complicated because of the large number of created wetlands.

    Wetland manipulations have resulted in the addition of many acres of wetlands in Colorado (Kingery 1998). For example, large irrigation canals have moved water from mountain rivers or streams into the prairie. Some of the water has escaped the confines of ditches and leaks into the surrounding landscape, creating artificial springs. Such seepages have created wet prairie, wet meadows, small standing waters, shrub thickets, and woody groves. Such areas are often rich with birds, and where trees and shrubs occur, the associated birds represent those found in riparian habitats. The largest changes in the wetlands of Colorado's prairies have come from the creation of water storage facilities, reservoirs and ponds (Kingery 1998). These reservoirs are often placed on top of existing wetlands and greatly expand the total wetlands acreage. (This does not imply good or bad since there may be a significant change in wetlands or habitat type with the creation of these wetlands. It is important to remember that different wetland types are not equivalent in biodiversity terms.)

    The wetlands that support high priority bird species in Colorado have experienced many changes over the past 150 years. Shallow lakes and ponds that supported large populations of breeding waterfowl have declined in many areas and have been replaced by reservoirs with little vegetation. A common goal of water users--to provide the smallest surface area of water to limit evaporation losses--often creates wetlands habitats that are relatively sterile.

    Since agricultural practices have created numerous marshes, the comparative extent of marshland habitat is difficult to assess. However, it is clear that native graminoid-dominated marshes have suffered extensive losses, especially when the condition of the landscape in which they occur is considered (J. Sanderson, personal communication). For example, a marsh which has adequate breeding habitat for Northern Harriers may lie in a landscape that is inadequate or ecologically dysfunctional.

    The concept of no net loss of wetlands appears adequate for protecting wetlands associated birds in Colorado. However, the existing guidelines for wetland mitigation and their focus on jurisdictional wetlands rarely give adequate attention to bird communities or to high priority species without legal status. Cumulative changes of wetland types and loss of ecosystem-level biological attributes continue to reduce the amounts of wetlands habitats suitable for the more sensitive wetlands species. Recommendations for making wetlands mitigation more suitable for birds often do not adequately address concerns for the most sensitive species.

    The wetland types that support most wetlands bird species in the Southern Rocky Mountains are playas, marshes, wet meadows, lakes, and ponds. The status of these wetlands communities is checkered: lakes, ponds, and seeps have increased, but springs, wet meadows, and playas have suffered notable losses. Marshes have probably declined somewhat, but mostly have shifted from native condition to altered and scattered patches.

    Priority Species: Two species are identified as high priority species for wetland habitats in Physiographic Area 62: Willet and Short-eared Owl


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