Assessment of Aquatic Habitat Monitoring Data in the Rogue River Basin and Southern Oregon Coastal Streams

Executive Summary

In 2001, a first iteration of a Rogue Basin Aquatic Integrity Assessment was completed. The objective of that project was to analyze the Rogue River Basin at the sixth field hydrologic unit level to determine a relative watershed integrity score. The analysis was based on surrogate data such as road density, road/stream intersections, fish movement barriers, and recent logging history to predict water quality and salmon habitat suitability.

The first objective of this study was to evaluate the previous modeling using field-derived data instead of surrogate data. Field data examined included stream temperature, aquatic invertebrates, and stream surveys along with a revisiting of the fish barrier data. The second objective was to build the necessary databases required to construct a cumulative effects model for aquatic integrity for a portion of the Rogue Basin. Considerable energy was placed on constructing ancillary datasets and laying the analytical groundwork. Key findings of this project are presented below.

Next steps in the development of the cumulative effects model are to include the impacts of the 2002 Biscuit fire and its post-fire management in the modeling and build a link between past and current land management (e.g., mining, roads, logging, agriculture, etc.

Key Findings

Salmonid Habitat

• Most of the highest quality, low gradient salmon habitat in the Rogue Basin has been heavily degraded by human activity.
• In large part, suboptimal salmon habitat now forms the conservation core for salmonids in the Rogue Basin, and many of these remaining areas (e.g., serpentine sites) are often more sensitive to human activities (e.g., mining).
• Non-inventoried roadless areas are important conservation elements in protecting and restoring aquatic habitat integrity, especially for those sites on the valley floor. Sites in the Lower Rogue and Applegate subbasins are particularly important.
• Areas least protected in the current reserve network, many of which were historically the best salmon habitat, are the areas most in need of restoration.
• Salmon recovery in the Rogue Basin will depend upon actions implemented on private lands. Public lands can supply important components (e.g., cold water recharge, coarse woody debris, spawning habitat, some limited rearing habitat), but the long-term recovery of the salmonids in the basin will hinge on the actions taken on private lands.
• Fish barriers and water use diversions trump all other impacts on aquatic systems at certain times of the year in the Rogue Basin and are critical issues for restoring aquatic integrity.

Aquatic Integrity Modeling & Conservation Planning

• Natural variability in geomorphology, landscape position, and climate results in aquatic systems that differ in composition, structure, and function. Aquatic integrity modeling is often confounded when these landscape variations are not accounted for in the model.
• Surrogate data as presently used in producing aquatic integrity models are likely to be underestimating impacts on aquatic systems.
• Unfortunately, lack of data continues to be a serious issue for the Rogue Basin for conservation planning purposes, especially on the critically important private lands portion of the basin and mainstem reaches.
• While progress is being made, more work is needed to produce models that have high predictive power and that can lead to detailed, site specific management prescriptions.

For more information, please contact Jim Strittholt.