Development of an Aquatic Habitat Geographical Information System for Pacific Lamprey Habitat in Rock Creek (Siletz), Oregon
Bridging Traditional Ecological Knowledge and Ecosystem Science
Flagstaff, AZ, August 13-15, 1998
The Siletz tribe has an interest in the population levels of the Pacific lamprey because tribal members have previously used the lamprey for subsistence, medicine and ceremonies. The most predominate role of the lamprey is its use as a food source. The lamprey is a high-energy food, packed with vitamins and minerals. Rock and Little Rock Creeks in the Siletz River basin have historically had the most productive lamprey hooking sites, but now tribal members rarely see lamprey there. The Pacific lamprey, just as any other native animal species, plays an important part of the ecosystem ecology and their decline could be an indicator of greater ecological problems in the region. Because of the apparent decline in the Pacific lamprey population, the Siletz tribe is focusing the habitat characterization study on the Rock Creek watershed.
The Pacific lamprey study addresses the following issues: causal factors of the population decline, healthy ecosystem requirements for the lamprey, design of sustainable ecosystem management strategies, and cultural and environmental education for tribal members. The Pacific lamprey project began by conducting interviews with knowledgeable Siletz Elders. The interviews with the Elders gave us insights to aquatic habitat parameters, local lamprey ecology and the population decline as it relates specifically to the Pacific lamprey in Rock and Little Rock Creeks. Additionally, the interviews substantiated the local concern about the Pacific lamprey and served as a guide for further research. The objectives for my portion of this study were to assess the physical habitat available to spawning and juvenile lamprey and to create geographic information system (GIS) data layers. For the aquatic habitat inventory, stream surveys completed with methods and protocols created by the Oregon Department of Fish and Wildlife (ODFW) were used. These data were compiled using dynamic segmentation, an Arc/INFO network analysis method, and linked to 1:24000 stream coverages. ODFW currently uses dynamic segmentation to associate their aquatic survey data to 1:100,000 stream coverages. However, this scale does not provide an adequate resolution or accuracy for analysis on a small watershed like Rock Creek. By using stream coverages of 1:24,000, we improved the usefulness of the data for restoration site selection because individual sites can be analyzed for restoration potential. Dynamic segmentation allows the user to query the data based on location or habitat criteria. A GIS is a valuable tool that can be used to assist the natural resource decision making process. The most powerful aspect of the GIS is the ability to georeference data to specific on the ground locations. Background information on the aquatic habitat requirements of Pacific lamprey, combined with the GIS coverages, can show the available and suitable habitat areas for lamprey spawning and rearing. By using the database queries to understand relationships between land use and habitat or ecological parameters, resource managers can focus their restoration techniques in the most cost-effective manner. The GIS, in addition to existing traditional ecological knowledge, will assist the Siletz Indians in making effective land use management decisions and establishing restoration potential for the Rock Creek watershed.