The Functioning Coho Summer Habitat ranks 6th fields on the basis of the following factors (as requested by the MidCoast Watersheds Council): length of potential habitat (low-gradient unconfined stream reaches as defined by the DEM analysis), large woody debris frequency, percent pools, channel widths per pool, length of riffle habitat with gravel substrate, length of riffle habitat with bedrock substrate, percent shade, and Rapid Bioassessment juvenile coho per sq m (link to analysis). All factors were combined to form a final ranking for each 6th field. All factors were weighted equally. A high value for each factor increased the ranking, except for length of bedrock-dominated riffles and channel widths per pool, where high values reduced the ranking. We used a ranking method that prevented bias due to protocol differences between different data sources. Sixth fields missing one or more of the factors were also ranked; ranks were normalized to prevent lack of data from lowering a 6th field's rank relative to other 6th fields. For details on the methods used to develop the 6th field rankings, see the full methods document (coho_summer_ methods. doc). The highest possible ranking is 1 (best- functioning habitat by these criteria); the lowest possible ranking is 100 (lowest-functioning habitat by these criteria). This analysis incorporates data from AHI surveys, from Rapid Bioassessment snorkel surveys, and from DEM analysis.

The rankings can help prioritize 6th fields for actions designed to improve coho summer habitat, such as riparian plantings for shade and bank stabilization, riparian fencing, and placement of large woody debris. The rankings should not be used alone for this purpose, but should be used in conjunction with other data, particularly field verification of suitable conditions.

All 6th fields with AHI data available were ranked in this analysis, even those which may be inaccessible to coho. Some 6th fields may not currently be populated with coho, but may offer good opportunities for restoration actions such as barrier removal that could re-introduce coho into those areas. Before using the rankings, we recommend careful review of the detailed methods for each individual analysis that entered into the multi-factor analysis (Full Report).

Spreadsheet Data: aqhab_sum_final.xls

Shapefile: aqhab_sum final.zip

Metadata: MD_aqhab_sum_final.doc

More Information

Please address questions or comments to:

Dr. Ralph Garono
Principal Investigator
Earth Design Consultants, Inc.
rgarono@earthdesign.com

Laura Brophy
Principal Investigator
Green Point Consulting
brophyl@peak.org | homepage