The Oregon Coast landscape displays strong spatial patterns in air temperature, precipitation, and geology, which can confound our ability to detect relationships among land management, instream conditions, and fish at broad spatial scales. Despite this structure, we found that a suite of immutable or intrinsic attributes (e.g., reach gradient, drainage area, elevation, and percent weak rock geology of the catchments draining to each of our 423 study reaches) could explain much of the variation in pool surface area across the landscape and could contribute to an estimate of how many juvenile coho salmon (Oncorhynchus kisutch) one might expect to find in those pools. Further, we found evidence of differences in pool surface area across land ownership categories that reflect differing management histories. Our results also suggest that historical land and river management activities, in particular splash dams that occurred at least 50 years ago, continue to influence the distribution of juvenile coho salmon and their habitats today.
Aquatic monitoring programs vary widely in objectives and design. However, each program faces the unifying challenge of assessing conditions and quantifying reasonable expectations for measured indicators. A common approach for setting resource expectations is to define reference conditions that represent areas of least human disturbance or most natural state of a resource characterized by the range of natural variability across a region of interest. Identification of reference sites often relies heavily on professional judgment, resulting in varying and unrepeatable methods. Standardized methods for data collection, site characterization, and reference site selection facilitate greater cooperation among assessment programs and development of assessment tools that are readily shareable and comparable. We illustrate an example that can serve the broader global monitoring community on how to create a consistent and transparent reference network for multiple stream resource agencies. We provide a case study that offers a simple example of how reference sites can be used, at the landscape level, to link upslope management practices to a specific in-channel response. We found management practices, particularly areas with high road densities, have more fine sediments than areas with fewer roads. While this example uses data from only one of the partner agencies, if data were collected in a similar manner they can be combined and create a larger, more robust dataset. We hope that this starts a dialog regarding more standardized ways through inter-agency collaborations to evaluate data. Creating more consistency in physical and biological field protocols will increase the ability to share data.
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