Wednesday, August 8, 2007 - 10:50 AM

COS 65-9: Restoring habitat for the giant garter snake (Thamnophis gigas), a state- and federally listed threatened species

Debra Bishop, EDAW

Past maintenance activities at the Sacramento International Airport

(Airport) resulted in fill of wetlands at Prichard Lake and Jacob's Slough that was also potential giant garter snake habitat. Settlement agreements and negotiations with the U.S. Army Corps of Engineers and U.S. Fish and Wildlife Service resulted in mitigation land to be restored and developed both on-site and off-site. The Prichard Lake Restoration project, located on Airport property, would enhance the 13.5-acre mitigation site and would also convert an adjacent 33-acre rice field to giant garter snake habitat. The 217-acre Willey property in Sutter County would convert rice fields into giant garter snake habitat. Eric Hanson, a consulting herpetologist, assisted with design to ensure that habitat features were optimized for giant garter snake use. Both sites would incorporate channel, marsh, and upland habitat into the interior of the site to maximize edge for habitat interface.

Other habitat features include:

terraced transitions between habitat,

short distances between burrow and foraging areas, basking areas, vegetative cover from predators, habitat that supports giant garter snake foraging, direct connectivity to giant garter snake preserves, significant habitat edge length and varied topography, balanced cut and fill on-site, ease of controlling water within different areas, rapid flood-up to control undesired weeds, and a variety of elevations and side slopes to provide diversity.

The Willey property, which is surrounded on three sides by Natomas Basin Conservancy property, was designed in consultation with the conservancy to ensure compatibility with their adjacent preserves.

This

talk will focus on the current design considerations for habitat creation and restoration for GGS. Habitats types include channels, tule marsh, seasonal wetland and uplands. The talk will also focus on the construction of Prichard Lake and resultant habitat conditions.