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4 <br /> Status <br /> Fifteen distinct populations of L. bradshawii currently occur of the Willamette Valley <br /> (USFWS 1993) and southwest Washington. It is estimated that less than 0.1% of the <br /> historic populations of L. bradshawii remain (USFWS 1993). <br /> V. PROBLEMS FACING THE SPECIES <br /> Rangewide <br /> As described in the final rule to list L. bradshawii as endangered (53 FR 38451; <br /> September 30, 1988) and Recovery Plan (USFWS 1993), threats to the L. bradshawii <br /> include: (1) loss of habitat; (2) disease; and (3) reproductive strategy of the species <br /> combined with other stressors such as drought, land management practices, flood control, <br /> fire suppression. <br /> Habitat has been lost by succession, changes in hydrology, and urban or agricultural <br /> development. Willamette Valley wet prairies continue to undergo succession and <br /> invasion by trees and shrubs. This succession was once naturally controlled by <br /> widespread flooding, browsing animals, and fire. Flood control projects in the upper <br /> Willamette basin, urbanization, land use practices, and fire suppression have altered the <br /> historic processes that maintained native grasslands. <br /> Flood control and wetland fill and drainage have also affected L. bradshawii by reducing <br /> available habitat and, possibly, seed dispersal. Surface water reduction decreased the <br /> abundance and distribution of seasonally wet prairies throughout the Willamette Valley. <br /> Since L. bradshawii is dependent on wet areas, often within the floodplain of a creek or <br /> small river, hydrologic changes have drastically reduced habitat available to the plant. L. <br /> bradshawii seeds have also been found to have some buoyancy, and dispersal may be <br /> increased by flooding (USFWS 1993). If dispersal is enhanced by flooding, it is likely <br /> that the hydrologic changes have reduced dispersal quantity and distance. <br /> Most of the habitat for L. bradshawii occurs in and around Eugene and Corvallis, Oregon <br /> (USFWS 1993). Any undeveloped, flat grasslands which may contain L. bradshawii and <br /> other native wet prairie species are often primary targets for urban development. <br /> In addition to habitat alterations, disease may also be influencing L. bradshawii, <br /> particularly the smaller populations. A fungus that causes a brown spot disease occurs <br /> sporadically within a population, destroying the aboveground portions of the plants. <br /> Aphids and spittle bugs also parasitize L. bradshawii. These parasites were found <br /> exclusively on plants with seeds (Kagan 1980). The seed on fungus- infected plants <br /> seldom reached maturity before the plant died back. Parasitized plants had a significantly <br />