Conservation Watershed Network - History and Purpose

Under the 2012 Planning Rule (FSH 1909.12 CH 23.13) a framework is laid out for plan components of the Revised Land Management Plan (RLMP) “… to provide for ecological conditions necessary to maintain the persistence or contribute to the recovery of native species within the plan area, including at-risk species identified in assessment.” If the Responsible Official determines that additional species specific plan components are needed to maintain the persistence or contribute to the recovery of at risk species, these specific plan components will be included in the RLMP.

The Grand Mesa, Uncompahgre and Gunnison National Forest has therefore designated Conservation Watershed Networks (CWN). Conservation Watershed Networks are a specific subset of sub-watersheds (12-14 digit Hydrologic Unit Codes) where prioritization for long-term conservation and preservation of At Risk aquatic species occurs. These sub-watersheds were selected based upon the presence, conservation status or viability, and likely continued persistence for either native green lineage Colorado River cutthroat trout (green lineage CRCT) or boreal toad (BOR).

In the absence of hybridization and competition with non-native fishes, habitat quality and connectivity is the most important factor for the persistence of native cutthroat trout. Consequently, during the selection of CWN for cutthroat trout, sub-watersheds were designated based on two criteria:

1. Conservation status designated by the CRCT Conservation Team (2006).

   Cutthroat trout populations which have greater than 90% genetic integrity are termed Conservation Populations.

   AND

2. The inhabited stream length is at least 8km (~5 miles, Hilderbrand and Kershner 2000) OR the supporting watershed is at least 14.7 km2 (~3,600 ac, Harig and Fausch 2002).

Selection of boreal toad Conservation Watershed Networks is based on the BOR Recovery Teams criteria for population viability (Loeffler 2001). In order for the population to be considered viable:

1. There must be documented breeding activity andrecruitment to the population in at least four (4) out of the past ten (10) years.

   OR

2. There has been an average observed total of at least, twenty (20) breeding adults at the breeding locality, producing an average of at least four (4) viable egg masses per year, with a stable number of breeding adults

   AND

3. The population faces no known, significant and imminent threat to its habitat, health, and environmental conditions.

Although there are many documented observations of boreal toad across the GMUG NF, in the face of Chytridiomycosis, the amphibian fungal disease caused by Batrachochytrium dendrobatidis(Bd), the species has suffered severe declines in Colorado. Disease vectors are not well understood and many once robust populations have become extirpated after the detection of Bd.

Of the documented observances of boreal toad across the GMUG, only three currently support successful breeding. Two of these populations (Texas Creek and Upper East River sub-watersheds) are at high altitude sites within wilderness. It is thought that the remoteness of these sites has helped to prevent the intrusion of the invasive chytrid fungus. Unfortunately in the past two years Texas Creek has become positive for Bd. Currently it is unknown if the Texas Creek population has lost its viability due to Bd. To-date the other site, located in the Maroon Bells-Snowmass Wilderness, remains free of Bd. Every effort should be made to not only protect and conserve the Upper East River population but also keep it free of chytrid.

Similarly the final sub-watershed, Headwaters Buzzard Creek, is unique because even with the presence of chytrid, boreal toads are undergoing successful reproduction. Although the factors effecting this occurrence are not fully understood, it is possible that these toads have an innate resilience to chytrid. It remains, that management approaches and allowable activities within this sub-watershed should make every effect to maintain and protect the essential habitat supporting this unique population.

References

CRCT Conservation Team. 2006. Conservation agreement for Colorado River cutthroat trout (Oncorhynchus clarkii pleuriticus) in the States of Colorado, Utah, and Wyoming. Colorado Division of Wildlife, Fort Collins. 10p.

Harig, A. L., & Fausch, K. D. (2002). Minimum habitat requirements for establishing translocated cutthroat trout populations. Ecological Applications, 12(2), 535-551.

Hilderbrand, R. H., & Kershner, J. L. (2000). Movement patterns of stream-resident cutthroat trout in Beaver Creek, Idaho–Utah. Transactions of the american Fisheries Society, 129(5), 1160-1170.

Forest Service Handbook 1909.12 Land Management Handbook. https://www.fs.usda.gov/detail/planningrule/home/?cid=stelprd3828310

Loeffler, C. (ed.), 2001. Conservation plan and agreement for the management and recovery of the Southern Rocky Mountain population of the boreal toad (Bufo boreas boreas), Boreal Toad Recovery Team. 76 pp. + appendices.

Watershed and Subwatershed Description:

This data set is a complete digital hydrologic unit boundary layer to the Subwatershed (12-digit) 6th level for the entire United States. This data set consists of geo-referenced digital data and associated attributes created in accordance with the "Federal Guidelines, Requirements, and Procedures for the National Watershed Boundary Dataset; Chapter 3 of Section A, Federal Standards, Book 11, Collection and Delineation of Spatial Data; Techniques and Methods 11-A3" (04/01/2009). http://www.ncgc.nrcs.usda.gov/products/datasets/watershed/index.html . Polygons are attributed with hydrologic unit codes for 1st(Region), 2nd(Sub-Region), 3rd(Basin), and 4th(Sub-Basin) Hydrologic Unit Level codes, names, Sub-Basin acres and square miles. This data set was obtained from the source in July 2010.