Riparian Habitat Restoration Begins at Dos Rios Ranch
By Jeff Holt, Restoration Biologist and Julie Rentner, Central Valley Regional Director
On April 25, just one year since closing the acquisition of the 1600-acre Dos Rios Ranch in Stanislaus County, River Partners and the California Conservation Corps planted the first native trees and shrubs along the margins of an historic slough on the southern portion of the Ranch. The restoration of this large property, at the confluence of the Tuolumne and San Joaquin Rivers, will unfold in phases over the next eight years or so. In this first phase, restoration is focused on 198 acres including former agricultural fields, the site of an abandoned milking barn (the property was a dairy until the mid-1980’s), and the Steenstrup Slough – a 50-acre wetland that once connected directly to the San Joaquin River but now disconnected by a federal flood control levee.
In planning for this phase of the project, River Partners’ biologists have reached out to a variety of restoration experts including the USDA Natural Resource Conservation Service (NRCS), the Riparian Mammals Technical Group, the US Fish and Wildlife Service (FWS), the Tuolumne River Trust, Point Blue Conservation Science (formerly PRBO Conservation Science) and many others. A large number of state and federal agencies are funding the first and subsequent phases of the restoration. (See the accompanying box).
In the first phase of restoration at Dos Rios Ranch we will be constructing five acres of elevated refugia for terrestrial species and planting over 45,000 native trees and shrubs. The plantings will include fourteen different species of trees and shrubs and eight different species of herbs and grasses. The plantings and construction activity are designed, in large part, to benefit a number of threatened and endangered species.
For example, we are constructing high-elevation areas in the floodplain and restoring dense shrubby vegetation on existing high-elevation fields to provide flood refugia for the endangered riparian brush rabbit. High densities of valley oaks and other tree species will be planted to provide densely wooded areas for endangered forest-dwelling riparian woodrats. The planting of willow-dominated riparian forests with native herbaceous understories is to encourage the recovery of the endangered Least Bell’s vireo. And blue elderberry shrubs will be established across the site to provide habitat for the threatened valley elderberry longhorn beetle. Finally, in an article dated 1914, a local birder documented the largest breeding colony of tricolored blackbirds at Dos Rios Ranch. We are planning to treat invasive weeds in the Steenstrup Slough and restore hydrology to encourage recovery of this and other marsh-nesting birds.
The planting of the 198 acres is only the beginning of River Partner’s efforts in this first phase of restoration. Four years of irrigation and weed control will follow along with four years of performance monitoring, and two seasons of avian monitoring. All in all, it is estimated that work on the first phase of the restoration at Dos Rios will involve 30,000 worker-hours for laborers, college interns, managers and ecologists.
You can check out the project pages here.
The above article originally appeared in the June 2013 issue of the River Partners Journal.