Field Notes
U.S. Fish & Wildlife Service
Field Notes Entry   
Collaboration continues for the Proposed Right-of-Way for Vegetation Treatment Program in the Limitrophe Division for Safety and Law Enforcement, Lower Colorado River, Yuma County, Arizona
Southwest Region, March 20, 2008
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The Arizona Ecological Services Office finalized a Biological Opinion on vegetation treatment in the Limitrophe Division along the Lower Colorado River on March 3, 2008.  The project, proposed by the Bureau of Land Management, grants a right-of-way to the Army Corps of Engineers, acting on behalf of the Border Patrol, for vegetation treatments to improve visibility and discourage crime in the Limitrophe area (that portion of the Colorado River from the Northerly International Boundary to the Southerly International Boundary) in Yuma County, Arizona, for 10 years.  We consulted on project effects to the southwestern willow flycatcher and Yuma clapper rail.  In general, adverse effects to southwestern willow flycatcher and Yuma clapper rails are from habitat loss caused by vegetation removal and pruning.  Approximately 560.8 acres would be treated in the project area.  However, 134 -144 acres of replacement habitat of higher quality would be provided to offset the loss.  Customs and Border Protection will implement a number of conservation measures including: a) athel tamarisk and native trees would be left onsite with no more than one-third of each individual tree being pruned from the ground up to a maximum of 8 feet; b) where practical, stands of arrowweed would be left onsite; c) a 10-foot wide no-treatment buffer would be implemented around wetland habitats (including marsh), areas within the high water line, and the edge of saturated soils; d) plants occuring in river channels would not be treated; and e) initial mechanical treatment and mechanical retreatment would occur between October 1 and March 31.  BLM and FWS developed mitigation criteria cooperatively.  Revegetated habitat will be managed and protected for 10 years.  Where site conditions are appropriate, replacement habitat will be designed with the appropriate patch size and width, density of cottonwood and willow, and other features to support willow flycatchers. 

We reached a non-jeopardy conclusion and no incidental take was anticipated.

Contact Info: Martin Valdez, 505-248-6599, martin_valdez@fws.gov
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