Grasslands in California are among the most unique, biologically diverse, and endangered ecosystems in the United States and the world. Ninety percent of all endangered and threatened species in California inhabit grassland ecosystems. Much of their loss has resulted from agricultural conversion, population growth, conversion to non-native and invasive plant species, and encroachment of native vegetation due to suppression of fire on the landscape.
In the Mattole and the neighboring King Range National Conservation Area (KRNCA), roughly 40-50% of grasslands have been lost to encroachment of native and non-native vegetation, especially Douglas-fir (Pseudotsuga menziesii). Of the grasslands that remain, most have been converted to non-native annual grasses (NNAG). The conversion of native perennial grasslands to NNAG has a tremendous impact on grassland ecosystems and the watershed.
Unlike NNAG, native perennial grasses are deep-rooted and long-lived. Some species of native grass in the Mattole, such as purple needlegrass (Stipa pulchra), are bunchgrasses that typically can live for 200 years—and maybe many hundreds more. The root systems of these long-lived grasses range in depth from 6 to 12 feet—some growing as deep as 20 feet—compared to 6 to 12 inches of shallow-rooted NNAG. The deep roots of native perennial bunch grasses stabilize steep hill slopes and create subsurface soil ecosystems where a diversity of soil microbes, insects, and mycorrhizae flourish. Alternatively, NNAG encourage desert-like subsurface conditions, decreasing soil carbon and fertility and increasing runoff.
Large amounts of root biomass found in native perennial grasslands generally increase water infiltration which helps sustain soil moisture. This allows plants to stay greener longer, providing long term forage for wildlife throughout the hot dry Mattole summer. Native grasslands are not just grass, but within them exists an abundant diversity of native forbs and shrubs that offer similar ecological benefits.
Individual bunchgrasses also act as structures that provide shade and micro-climates for grassland fauna. Because native grasslands have evolved with fire, and hold water in the soil and plants longer, native grasslands are fire adapted and resistant. Intact native grasslands reduce the intensity and risk of wildfire to human and wildlife communities.
Over the past decade, the MRC’s Native Grasslands Enhancement Program has focused on gaining a better understanding of Mattole and KRNCA grasslands, and planning and implementing high priority restoration projects. We are utilizing many techniques to restore grasslands and understand that a successful grasslands restoration project is one that not only restores structure, but also the associated ecological processes and functions. To increase the likelihood of success, we utilize a variety of treatments and approaches, some of which are described below.
As part of the Mattole Estuary Enhancement project that is being implemented by the Mattole Salmon Group and MRC, in partnership with BLM, encroaching large Douglas-fir trees were removed from a historic grassland and relocated and placed by a helicopter as in-stream salmonid habitat in the Mattole Estuary. Over three acres of Douglas-fir removal sites were seeded with native grasses and mulched with native grass straw. This project demonstrates how byproducts of prairie reclamation projects can be utilized in salmonid habitat
Recently, in partnership with the BLM, we have started mechanical removal of coyote brush and Douglas-fir on approximately 120 acres as part of an 800 acre Prosper Ridge Prairie Restoration Project. This project includes mechanical removal of vegetation with chainsaw, excavator and masticator, broadcast burning, as well as native grass revegetation through seeding and plug planting.
High quality native plant materials are the most important component of successful native plant restoration projects. The MRC’s native plant nursery grows 13 native grass species for our riparian and grasslands restoration projects and produces 30,000 native grass plugs per year. We have done extensive broadcast seeding and have installed over 175,000 native grass plugs on our revegetation sites. The MRC also manages a 1.75 acre native grass farm, planted from locally sourced Mattole seed. This farm provides an abundant source of seed for large scale projects, and decreases the amount of seed taken from wild populations. The farm also produces native grass straw for mulching on restoration sites.
Grasslands are part of the mosaic of ecosystems that make up the Mattole watershed and are an essential piece of the puzzle that is necessary for the whole system to function properly. As we move forward, it is important that we take a deep look at the ecological problems and develop solutions inclusive of all the parts that benefit the system as a whole. When we tinker with nature, we must do our best to save all of the parts.
For more information about our native grassland program or native plant materials, please feel free to contact us at 707-629-3514 or visit our website at www.mattole.org/programs/restoration.