10 Years at Beehive Bend
Beehive Bend, Sacramento River Wildlife Area, in 1999. See See next photo for how it looked in 2008. Photo by River Partners staff.
Beehive Bend is one of River Partners’ first projects. Thanks to continual monitoring, we have documented an increasing trend in bird species at this site.
By Michael Rogner, River Partners
In 1991 the California Department of Fish and Game (DFG) acquired a 269 acre parcel in rural Glenn County. The site was named the Beehive Bend Unit after the name of a sweeping curve along the Sacramento River. A new channel was blasted in the early 1900’s to shorten the distance river boats needed to take, leaving the remnant channel as an oxbow lake. Lining the old channel was classic Sacramento River riparian forest – a towering canopy of valley oak, Fremont cottonwood, Gooding’s willow and western sycamore, all draped in a veil of wild grape. Oregon ash and box elder, festooned with Dutchman’s pipevine and poison oak, dominated the mid-story. The understory, like most places on the river, was a mix of native and non-native species.
However, in the midst of this lush habitat was approximately 60 acres that had been farmed for at least 40 years. When farming ceased this area lay fallow for a decade and vegetation quickly colonized the rich soils, though few of the plants were native. Instead, a tangle of yellow star thistle, Johnson grass, and black mustard dominated the site, providing poor habitat and little opportunity for forest regeneration.
The lesser goldfinch is one of the species found at Beehive. Photo by Frank Leung.
In 1999, DFG contracted with River Partners to restore the Beehive Bend Unit. This project came during a critical period in the evolution of restoration design, and was one of the first to incorporate a sophisticated plant design based on a mosaic of vegetative structure designed specifically to maximize the niches exploitable by native birds. To help evaluate the restoration, River Partners worked with PRBO Conservation Science to monitor breeding songbirds in both the remnant riparian and restoration area, and the project design was developed in part with PRBO recommendations. What began as a threeyear study has now extended into ten years of monitoring through subsequent funding efforts. Longer term views are critical to understanding the efficacy of restoration, as Dr. Nat Seavy of PRBO points out, because “some species do not use restored sites until about 10 years after restoration. Monitoring beyond the typical three-year period is critical for understanding whether or not restoration has been successful in creating bird habitat.”
Riparian habitats are dynamic, yet predictable patterns occur and wildlife responds accordingly. Early-successional habitat includes such pioneering plant species as willows and blackberry that colonize new sandbars after flood events, and this vegetative structure is mimicked by young restoration. Some of the first avian species to respond to this habitat include black-headed grosbeak, lesser goldfinch and spotted sandpiper. Because early-successional habitat is in short supply, these birds flock to restoration sites, and have been documented abandoning long held territories in old riparian in favor of restorations as young as two years old.
Dams, diversions, and levees have greatly altered floods and seasonal flows, and as a result, earlysuccessional habitat is now rarely created by the Sacramento River. Most of the remnant habitat along the river is comparable to the existing riparian at Beehive Bend, or is in agricultural production. While this can provide important habitat for some birds, many sensitive bird species need a different type of forest, the lush quick growth of shrubby willows, California blackberry and other rapidly growing native plants. In the absence of more dynamic rivers, restoration plantings provide important habitat. The trick is how to best manage these areas for the long term, and this question can only be answered with long-term monitoring on existing projects so we can accurately evaluate their impacts.
So how has Beehive Bend performed over its first decade? Trends from the 1999-2007 point-count data suggest some interesting results. In the existing riparian forest, avian species richness has averaged 9.8 (species per point, over two visits per breeding season) of funding, the study resumed in 2006 (current funding will take us through the 2008 field season) and PRBO found that the restored forest now harbored a bird community that was nearly as species rich as the existing riparian (richness = 9.0 in the restoration, 9.22 in the existing riparian over the next two years). Looking at Beehive in the context of a larger study, 20 bird species were examined over a similar time period across a hundred mile segment of the lower Sacramento River and twelve were found to be increasing, while only one was decreasing. While this is great news in an era when so many studies are documenting negative trends, we must continue to work closely with our partners to further refine and improve our restoration designs, working toward a common goal of ensuring the long term vitality of California’s wildlife.