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;~ ,-"", Recoverv rate: The recovery rate of breeding populations will be a function of local population dynamics (i.e. total population size, annual reproductive success and mortality rates, rates of dispersal from other breeding locations) and habitat suitability. Because local populations are widely separated and small in size (Muiznielcs et at. 1994, Sferra et at. 1995), recovery rates are anticipated to, be slow. Proposed Critical Habitat The Service proposed a total of approximately 1038 !em of riparian areas along streams and rivers as critical habitat for the southwestern willow flycatcher (U.S. Fish and Wildlife Service 1993) in Arizona, California, New Mexico, and Utah. Critical habitat areas provide, or with rehabilitation will provide, the following physical and biological features and primary constituent elements: Space for individual and population growth; food, water (seasonal wetland), air, light, minerals, and other nutritional or physiological requirements; cover, shelter, and roost sites, sites for breeding, reproduction, and rearing of offspring: habitats (vegetation type, feeding sites and nesting grounds) that are protected from disturbance or are representative of the historic geographic and ecological distributions of the species. Constituent elements include the riparian ecosystem system above the water's surface or within 100 meters (m) of the water's edge. This includes riparian thickets of shrubs or small trees or areas where such vegetation may become' established. . ENVIRONMENTAL BASEUNE The environmental baseline includes past and present impacts of all Federal, State, or private actions in the action area, the anticipated impacts of all proposed Federal actions in the action area that have undergone formal or early section 7 consultation, and the impact of State and private actions which are contemporaneous with the consultation process. The environmental baseline defmes the current status of the species and its habitat in the action area to provide a platform to assess the effects of the action now under consultation. Humpback Chub The 1995 biological opinion includes an environmental baseline focused primarilY on the aquatic environment, and that section is incorporated by reference to this document. Recent final reports from three of the studies of endangered and native fishes for the GeES also provide detailed accounts of humpback chub ecology and habitat use in the Little Colorado River, the Colorado River from Lees Ferry to Lake Mead, and tributaries to the river (U.S. Fish and Wildlife Service 1994b, Valdez et al. 1995, Valdez and RyeI1995). Valdez and Ryel (1995) recounted that 535 km of potential historic habitat that was available to a population of humpback chub centered in the Grand Canyon in the late 1800s and identified factors reducing that range: Lake Mead inundation of lower Grand Canyon, 13 percent; Lake Powell inundation, 10 percent; and Glen Canyon Dam operations. 14 percent. Thus, 37 percent or 199 km of potential habitat was lost. Biological and Conference Opinions Glen Caoyon BcachlHabitat-Bullding Flows 2116196 I:!