Salmon prefer to lay their eggs in areas where groundwater upwells into the streambed, which probably creates the constant flows and temperatures the eggs require as they develop. Unlike the detailed requirements for riparian buffers, regulations on activities that may alter the groundwater regime are absent. A key research question is how much human land use contributes to habitat degradation, and how well existing laws prevent future degradation. This question is one that geologists, as members of the scientific community, are uniquely qualified to address because they can identify watershed processes and evaluate impacts over short and long time scales. Current stream conditions reflect not just today's management practices but the legacy of past land use.
Geologists have a major role to play in understanding how aquatic ecosystems function.
Perhaps no other group of scientists has an equally intuitive understanding of the watershed concept, the idea that activities on land directly influence the health of water bodies. The increasing recognition that managing endangered species means managing habitats, coupled with a new understanding that a habitat includes physical components of the landscape, requires that geologists be actively involved in what we have often considered biological issues. The challenges for the geological community are to provide the scientific basis for ecosystem management, and to ensure that our voices are heard in the policy-making process. She joins about 30 other scientists this year who are working as staff members for committees, senators and representatives on Capitol Hill. McLellan is a professor of geology at the University of Maryland, where she has created and taught courses on environmental science and policy.