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National Center for Ecological Analysis and Synthesis

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3701-3710 of 6248
  1. Publication

    Effects of land cover on stream ecosystems: Roles of empirical models and scaling issues

    We built empirical models to estimate the effects of land cover on stream ecosystems in the mid-Atlantic region (USA) and to evaluate the spatial scales over which such models are most effective. Predictive variables included land cover in the watershed, in the streamside corridor, and near the study site, and the number and location of dams and point sources in the watershed. Response variables were annual nitrate flux; species richness of fish, benthic macroinvertebrates, and aquatic plants; and cover of aquatic plants and riparian vegetation.

  2. Publication

    Ecological forecasting and the urbanization of stream ecosystems: Challenges for economists, hydrologists, geomorphologists, and ecologists

  3. Publication

    Frequency analysis under nonstationary land use conditions

  4. Publication

    Trend assessment in rainfall-runoff behavior in urbanizing watersheds

    A typical flood frequency analysis is based on gauged annual maximum discharges. One assumption behind the analysis is that the measured discharge signal is stationary. The validity of this assumption can be difficult to establish, particularly where urbanization has occurred within the gauged watershed, altering the response of the affected watershed to precipitation. This alteration can produce a nonstationary streamflow signal that can be significant, depending on the percentage of the watershed altered.

  5. Publication

    Bias in species range estimates from minimum convex polygons: Implications for conservation and options for improved planning

  6. Publication

    Reconstructing ecosystem dynamics in the central Pacific Ocean, 1952-1998. I. Estimating population biomass and recruitment of tunas and billfishes

  7. Publication

    Reconstructing ecosystem dynamics in the central Pacific Ocean, 1952-1998. II. A preliminary assessment of the trophic impacts of fishing and effects on tuna dynamics