200713600 - Beavers as stream restorationists? Determining systemwide status and trends in beaver impoundments in tributary streams, and the relationships between beaver impoundment and salmonids
Sponsor: University of Idaho
Budgets: FY07: $106,695 | FY08: $105,890 | FY09: $85,889
Short description: Beaver dams have strong effects on stream processes, fish, and wildlife. The project sponsors will use GIS to estimate status and trends in beaver ponds, and GIS and existing fisheries data to test hypotheses about how ponds affect salmonids at watershed scales.
Final Council recommendation (Nov 2006)
Funding category: Expense
Recommended budgets: FY07: $0 | FY08: $0 | FY09: $0
ISRP final recommendation: Fundable in part
The proposed work addresses an important problem and could lead to significant benefits for focal and non-focal species. Only Objective 1 is fundable. The results from this work could serve as a basis for designing large-scale empirical studies on the influence of beaver dams on salmonid abundance. Objective 2 is not fundable. For numerous reasons detailed below, research on objective 2 is not likely to be meaningful. The sponsors need to identify related projects within the basin and search for possible collaborative relationships. Technical and scientific background: Overall, the background section is fairly complete. The problem is well defined and relevant to fish and wildlife. The sponsors point out that beaver ponds could be preferred habitat for introduced brook trout, but are they also used by other non-native aquatic species? And do they promote the establishment of non-native aquatic and riparian plants? The sponsors also did not discuss potential negative effects of beaver dams such as elevated water temperature. Nor did they discuss how human activities have affected beavers historically, the extent to which these impacts persist today, and the realistic possibility for beaver restoration. A number of the references (particularly the Naiman and Pollock refs) were based on data from the coastal rainforest ecoregion, suggesting that relatively little is known about fish ecology in beaver ponds in the northern Rocky Mountains. Aren't there more appropriate references for the interior Columbia, e.g., with respect to fish use as wintering habitats? There appears to be an assumption that beaver had access to all potentially impoundable reaches and, if so, the assumption should be justified or at least acknowledged? Rationale and significance to subbasin plans and regional programs: The proposal addresses specific biological objectives in the Fish and Wildlife program and information needs identified by the ISAB and ISRP. Little is said about the proposal’s significance to subbasin and regional plans. Surely this project can be related to specific action items in, say, the Clearwater subbasin plan (where part of this study is likely to occur). Relationships to other projects: The sponsors do not identify any relationships with ongoing projects or collaborative efforts. There surely are other projects that are related to the proposed project such as wildlife mitigation, wetland restoration, projects directed at restoring stream function and salmonid habitat, and so forth. There is no mention of the habitat assessment projects that are currently ongoing, or the road decommissioning projects, which may affect beaver distribution. There are so many habitat improvement projects related to the proposed work that it is important to know how they might affect the results of this GIS-based analysis of current vs. historical beaver ponds. The sponsors need to identify related projects and search for possible collaborative relationships (these could take a variety of forms including information exchange) with, for example, sponsors of other projects, state agencies and tribes. As currently envisioned, the project gives the appearance of standing alone and apart for other efforts within the basin. Objectives: Objective 1 is accomplishable, given certain clarifications as described below. First, have the investigators considered the possibility that some beaver impoundments in small headwater streams might be obscured by the forest canopy and might not be easily seen in air photos? Second, is it possible that other flow obstructions (e.g., landslide and debris flow deposits, push-up dams) might create impoundment shapes that can be mistaken for beaver ponds? Third, given the available GIS coverages, how confident can we be that data layers for beaver ponds are up to date and have been ground-truthed? Finally, comparison of current beaver ponds with data from 1927-1939 (example given for Clearwater/Nez Perce) will contrast existing conditions with an area that had already been impacted by trapping, grazing, mining, and other anthropogenic disturbances. How will this be taken into account? Objective 2 is not likely to yield meaningful results on the influence of beaver dams on salmonid abundance because a number other important variables influencing abundance apparently will not be taken into account in the analysis. 1. There are many other projects (e.g., supplementation) that might affect the number of smolts produced by different watersheds. It will be difficult to attribute differences in smolt yield to beaver ponds without explicitly considering the effects of these projects. 2. Variables that are important in determining productivity of streams for salmonids, such as pool frequency and depth, large wood abundance and amount of spawning gravel apparently will not be taken into account at the watershed scale in the analysis. 3. The proposed work does not consider temporal variability in pond complexes resulting from disturbances such as flood and fires. A dynamics view of beaver pond complexes is needed. 4. Beaver ponds could benefit juvenile rearing (especially for coho), but the effects may be masked by post-juvenile mortality resulting in low outmigrant or adult abundance. To be meaningful the benefits of beaver should be assessed by life stage and species. To demonstrate possible effects would require demonstrating that fish use the ponds in preference to the upstream and downstream flowing water section of the stream. Tasks (work elements) and methods: The procedures for conducting the GIS analyses are adequately described. However, there was no mention of field verifying the results of GIS analysis in a subset of the selected watersheds. For example, there didn't seem to be any way of determining with certainty that an impoundment was created by beaver activity or some other process. Field validation of a sample of the territory seems essential. The sponsors need to carefully consider the following: Task 1.1: What is the resolution of the aerial photos for detecting ponds? How small of a pond can be detected? From which subbasin will the HUCs be selected, and why were they chosen? Why does the selection of HUC’s need to be stratified? Why not just random selection? If there are only five HUC’s per subbasin why bother to stratify? Task 1.3: Will the HUC’s used in task 1.1 also be used for this work? If not, why not? Task 1.4: The sponsors refer to land use and ownership categories. What are the categories? The sponsors propose to estimate future impoundable reaches under policies encouraging landowners to permit beaver use. What are the policies? Will there be different scenarios reflecting different kinds and extents of land use change? What would be some examples of “active or passive” management actions? Monitoring and evaluation: There did not seem to be any discussion of monitoring or evaluation. In fairness to the proposal, there was no easy way to do this, but the study appeared to lack any provisions for ground-truthing the results of what was essentially a desktop analysis. A field verification component was needed. Facilities, equipment, and personnel: The facilities, equipment, and personnel appear well qualified to carry out the stated objectives. Information transfer: The proposal mentions building a standalone website to display and disseminate results but does not mention peer-reviewed publications. An analysis of current vs. historical beaver pond distribution and abundance would make an interesting paper. Information will be made available to managers to aid in making habitat restoration decisions. Benefits to focal and non-focal species: A project that leads to increasing the abundance of beaver ponds will likely benefit a variety of focal fish and wildlife species. The proposal could have done a better job of describing how the GIS-based beaver impoundment analysis will be compared to known migration blockages so that a better understanding of potential vs. realized benefits can be estimated (e.g., what fraction of the historical distribution of beaver ponds are currently upstream from impassable barriers?). Objective 2 likely is not accomplishable and therefore would yield no benefit. Since beavers are not a focal species, it is assumed this project will ultimately benefit them directly. The task that examines the influence of beaver ponds on non-native brook trout abundance is worthwhile, although teasing out the specific effects of beaver ponds on brook trout (as opposed to, say, water temperature) will be difficult.
State/province recommendation: MS: Recommended Action
Review group: MSRT
Recommended budgets: FY07: (n/a) | FY08: (n/a) | FY09: (n/a)
Comment: BPA would like to see more cost share for this type of activity.