Songbird responses to riparian restoration: A success story

Riparian habitats are among the most degraded in North America; in California’s Central Valley over 98% of the riparian habitat has been lost in the last century. Fortunately since the late 1980’s there have been unprecedented efforts to restore riparian habitats in the Central Valley. PRBO Conservation Science has been monitoring riparian bird populations at restored and intact remnant riparian sites to evaluate the success of riparian restoration projects throughout the Central Valley since 1993. Following restoration, vegetative structure and complexity increased. In many cases, restoration age (years since planting) was a strong predictor of songbird abundance. Restoration activities appear to be successfully providing habitat for a diverse community of songbirds. At many sites restored and remnant riparian had similar values for reproductive success, although there was also strong annual variation. Some of the annual variation in reproductive success we detected was associated with large scale weather patterns, including El Nino events. In 2005 we detected a breeding pair of Least Bell’s Vireos (a riparian obligate endangered species) in a horticultural restoration plot near the San Joaquin River National Wildlife Refuge; this species had not bred in the Central Valley since the mid 1900s. This nesting record, and the overall increase in riparian-associated bird abundance in restored habitat in the Central Valley, is further evidence that restoration conducted within an adaptive management framework can contribute to species and ecosystem recovery.