Sharon E. Clarke

DISTRIBUTION OF SALMON-HABITAT POTENTIAL RELATIVE TO LANDSCAPE CHARACTERISTICS AND IMPLICATIONS FOR CONSERVATION

The geographic distribution of stream reaches with potential to support high-quality habitat for salmonids has bearing on the actual status of habitats and populations over broad spatial extents. As part of the Coastal Landscape Analysis and Modeling Study (CLAMS), we examined how salmon-habitat potential was distributed relative to current and future (+100 years) landscape characteristics in the Coastal Province of Oregon, USA. The intrinsic potential to provide high-quality rearing habitat was modeled for juvenile coho salmon (Oncorhynchus kisutch) and juvenile steelhead (O. mykiss) based on stream flow, valley constraint, and stream gradient. Land ownership, use, and cover were summarized for 100-m analysis buffers on either side of stream reaches with high intrinsic potential and in the overall area encompassing the buffers. Past management seems to have concentrated nonindustrial private ownership, agriculture, and developed uses adjacent to reaches with high intrinsic potential for coho salmon. Thus, of the area in coho salmon buffers, 45% is either nonforested or recently logged, but only 10% is in larger-diameter forests. For the area in steelhead buffers, 21% is either non-forested or recently logged while 20% is in larger-diameter forests. Older forests are most extensive on federal lands but are rare on private lands, highlighting the critical role for public lands in near-term salmon conservation. Agriculture and development are projected to remain focused near high-intrinsic-potential reaches for coho salmon, increasing the importance of effectively addressing nonpoint source pollution from these uses. Percentages of larger-diameter forests are expected to increase throughout the province, but the increase will be only half as much in coho salmon buffers as in steelhead buffers. Most of the increase is projected for public lands, where policies emphasize biodiversity protection. Results suggest that widespread recovery of coho salmon is unlikely unless habitat can be improved in high-intrinsic-potential reaches on private lands. Knowing where high-intrinsic-potential stream reaches occur relative to landscape characteristics can help in evaluating the current and future condition of freshwater habitat, explaining differences between species in population status and risk, and assessing the need for and feasibility of restoration.

HISTORICAL CHANGES IN POOL HABITATS IN THE COLUMBIA RIVER BASIN

An historical stream survey (1934-1945) was compared with current surveys (1987-1997) to assess changes in pool frequencies in the Columbia River Basin. We sur- veyed 2267 km of 122 streams across the basin, representing a wide range of lithologies, stream sizes, land use histories, ownerships, and ecoregions. Based on pool classes inherited from the historical surveys, the frequencies of large (

Oregon, USA, ecological regions and subregions for water quality management

20 m 2 and

Comparison of Digital Elevation Models for Aquatic Data Development

0.9 m depth) and deep (

Landscape-level ecological regions: Linking state-level ecoregion frameworks with stream habitat classifications

20 m 2 and

Summer total phosphorus in lakes: A map of Minnesota, Wisconsin, and Michigan, USA

1.8 m depth) pools have decreased significantly (P , 0.01) since the 1930s. We classified streams as natural or commodity based on their watershed management and land use histories. Natural streams were in watersheds minimally affected by human ac- tivities (e.g., wilderness or roadless designation, limited entry), with only 12% having roads in riparian areas. Commodity streams were defined as having watersheds managed pre- dominantly for extraction of resources via timber harvest, livestock grazing, and other human activities. Ninety percent of these streams had roads in the riparian areas. In natural streams, large-pool frequencies increased or remained the same in 96% of the streams (88% for deep pools). In commodity streams, large- and deep-pool frequencies decreased in 52% and 54% of the streams, respectively. Despite differences in stream size and the level of human activities, the magnitude and direction of these changes were consistent. Land ownership did not influence trends; pools decreased significantly on both private and public lands. Only where entire watersheds or headwaters were designated as wilderness or roadless areas did pools consistently remain unchanged or increase. Pool frequencies decreased in all ecoregions except the North Cascades ecoregion. We developed regional histories of human activities for the Columbia River Basin. Human activity histories were typically of low spatial resolution and available for broad geographic areas only; we rarely were able to obtain information at the scale of individual watersheds. Consequently, we were unable to test the relationship between temporal and spatial patterns in human activities and their influence on site-specific trends in pools. Despite our inability to isolate causal mechanisms, management emphasis and human activities clearly influenced trends in pools. We conclude that the persistent effects of human activities have simplified stream channels and reduced large- and deep-pool frequencies in watersheds outside of designated wilderness and road- less areas in the Columbia River Basin.

MODELING STREAMS AND HYDROGEOMORPHIC ATTRIBUTES IN OREGON FROM DIGITAL AND FIELD DATA 1

To aid in producing a protection and management strategy for the freshwater resources of Oregon, USA, we have defined an initial set of ecological regions and subregions of the state that organize the spatial similarities and differences in water quality. We have delineated and mapped these subregions using existing maps of ecological regions, maps of selected environmental characteristics, remote sensing imagery, and descriptive literature. To help in interpreting the resulting map, a unique approach to mapping regions is used. We have described the relative widths of regional boundaries, and we ranked the characteristics used in determining them. Water quality managers in Oregon intend to apply these subregions as an organizational framework for data display and reporting, prioritizing monitoring and pollution control strategies, developing biological criteria for water quality standards, and developing other regional water quality management approaches.

Historical Changes in Fish Habitat for Select River Basins of Eastern Oregon and Washington

Thirty-meter digital elevation models (DEMs) produced by the U.S. Geological Survey (USGS) are widely available and commonly used in analyzing aquatic systems. However, these DEMs are of relatively coarse resolution, were inconsistently produced (i.e., Level 1 versus Level 2 DEMs), and lack drainage enforcement. Such issues may hamper efforts to accurately model streams, delineate hydrologic units (HUs), and classify slope. Thus, the Coastal Landscape Analysis and Modeling Study (CLAMS) compared streams, HUs, and slope classes generated from sample 10-meter drainage-enforced (DE) DEMs and 30-meter DEMs. We found that (1) drainage enforcement improved the spatial accuracy of streams and HU boundaries more than did increasing resolution from 30 meters to 10 meters, particularly in flatter terrain; (2) streams and HU boundaries were generally more accurate when delineated with Level 2 than with Level 1 30-meter DEMs; and (3) the 10-meter DE-DEMs better represented both higher and lower slope classes. These findings prompted us to have 10-meter DE-DEMs produced for the Coast Range Province of Oregon, increased confidence in CLAMS outputs from the 10-meter DE-DEMs, and should benefit others interested in using DEMs for aquatic analyses.

Comparing Riparian and Catchment Influences on Stream Habitat in a Forested, Montane Landscape

Regionalization is a form of spatial classification, where boundaries are drawn around areas that are relatively homogeneous in landscape characteristics. The process of delineating ecological regions, or ecoregions, includes the analysis of ecosystem structure. To date, ecoregions have been developed at national and state scales for research and resource management. Stream classification is another method to order the variability of aquatic habitats that spans spatial scales from microhabitat to valley segment. In this study, landscape-level ecoregions are developed for the upper Grande Ronde River basin in northeastern Oregon, 3000 sq km in area. The ecoregion framework presented here is proposed to bridge the gap between stream habitat and state-level ecoregion classifications. Classification at this scale is meant to address issues of management at local scales: to aid in sampling design, in extrapolation of the results of site-specific studies, and in the development of best management practices that are more predictive of ecosystem response than current methods.

Influence of mapping resolution on assessments of stream and streamside conditions : lessons from coastal Oregon, USA

A map of summer total phosphorus in lakes has been compiled for Minnesota, Wisconsin, and Michigan to clarify regional patterns in attainable lake trophic state. Total phosphorus was used as a measure of lake trophic state because: (1) phosphorus plays a central role in controlling the overall fertility of most lakes, (2) total phosphorus values are available for a great number of lakes, and (3) phosphorus is measured in a consistent manner. The maps were compiled using patterns of total phosphorus data and observed associations between these data and geographic characteristics including physiography, land use, geology, and soils. Regions depicted on the map represent areas of similarity in phosphorus concentrations in lakes, or similarity in the mosaic of values, as compared to adjacent areas. Within each region, differences in total phosphorus can be compared to natural and anthropogenic factors to determine the types of lakes representative of each region, the factors associated with differences in quality, and the realistically attainable phosphorus levels for each type of lake.