EFFECTS OF FUTURE LAND USE CHANGES ON TRICOLORED BLACKBIRD HABITAT IN THE FOOTHILL GRASSLAND REGION OF THE SIERRA NEVADA.
Daniel A. Airola; Northwest Hydraulic Consultants; 114 Merritt Way, Sacramento, CA, 95864; (916) 494-1283; d.airola@sbcglobal.net; Tara Collins, Chris McColl, Michael Lozano, Deren Ross

The California-threatened Tricolored Blackbird has declined due to loss of historic wetland habitats and recently from active colonies destruction during agricultural operations, conversion of open lands to perennial crops and development, and pesticide use. The grassland region of the eastern Central Valley and Sierra Nevada foothills between Placer and eastern Stanislaus counties (central foothills), annually supports about 50,000 breeding Tricolored Blackbirds, or ~30% of the statewide population. Colony sites in this area are subject to habitat loss, especially in Sacramento and Placer counties where >70% of the central foothill breeding population nests. We conducted a species conservation assessment in the central foothills region that considered several key factors. Lands were rated for habitat value based on the size and frequency of breeding populations over 2014-2018. Habitat conversion threats were determined from models that predict future regional build-out and from land use plans and project proposals. Existing and potential future conservation lands also were mapped. We then overlaid habitat value, threats, and conserved lands to identify the extent to which important habitats are conserved and threatened. Our results can contribute importantly to species conservation by directing development away from key habitats, establishing appropriate mitigation needs, and identifying priority areas for conservation.  

The Anthropocene: Decline & Extinction I