that, by virtue of their attachment to the substrate, are also associated with location. Areas of 
aquatic vegetation represent the smallest, discrete scale that research described in this plan will 
concentrate upon and will be studied at the greatest level of detail. Project 2 (Shoreline-, Lake- 
and Estuary-Scale Research) extends to larger scales, but at lesser detail, and will consider how 
vegetated habitat interacts with other habitat types to determine biotic structure at the ecosystem 
scale. 
The emphasis on aquatic vegetation in this project is appropriate for several reasons. First, 
aquatic vegetation is one of the most widespread and important types of aquatic habitat, in part 
because of the exceptional productivity of the plants. Recreationally and commercially important 
fish, shellfish, and wildlife, as well as rare and endangered species that are especially valued by 
human society, frequently exploit this productivity, either using the vegetation as a direct food 
resource, or indirectly, by feeding on smaller forage organisms that rely directly on the 
vegetation. Aquatic vegetation also strongly influences local physical and chemical habitat 
conditions of significance to fish and shellfish, including substrate type and stability, wave and 
current energy, and water quality. The structural complexity of aquatic vegetation provides 
shelter and nursery areas for its inhabitants. Overall, research will focus on evaluating the 
importance of habitat attributes of vegetated aquatic systems to the assessment endpoints of 
interest to society (see Figure 4). Aquatic vegetation is itself a key endpoint of research plans 
being formulated under the other aquatic stressors implementation plans, including Nutrients 
(Section 5) and Diagnostics (Section 8), and research outlined in this plan will be closely 
integrated with those efforts. 
Identification and Prioritization of Assessment Endpoints 
The assessment endpoints are organisms believed to be dependent on aquatic vegetation and 
identified as of societal value, and hence of regulatory and policy importance. Societal 
relevance will be the dominant criterion for assessment endpoint selection, but societal relevance 
needs to be intersected with ecological relevance and EPA research capabilities and regulatory 
mandates. Endpoints most likely will be chosen from the above listing of candidate species. 
However, other, intermediate endpoints such as forage fish species may also be required because 
the link between societally relevant species and aquatic vegetation may be mediated through 
secondary production, water quality, or other functional aspects of aquatic vegetation. During 
the development of specific research plans, the researchers participating in this effort will 
evaluate critically the suitability and appropriateness of proposed assessment endpoints with 
regard to regional EPA concerns, the laboratory capabilities, and the research activities of other 
agencies. Additionally, a concerted effort will be made to coordinate this research with that of 
other offices within ORD such as NERL and Federal and State resource management agencies. 
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