Restoring the Dunes
Inglenook Fen-Ten Mile Dunes Natural Preserve

by Renée Pasquinelli, Sr. State Park Resource Ecologist

The Inglenook Fen-Ten Mile Dunes Natural Preserve encompasses nearly 1,300 acres of coastal dunes within MacKerricher State Park that extend from Ward Avenue north to the Ten Mile River. As defined in the Public Resources Code, "Natural preserves consist of distinct areas of outstanding natural or scientific significance established within the boundaries of other state park system units. The purpose of natural preserves shall be to preserve such features as rare or endangered plant and animal species and their supporting ecosystem,...".

The Ten Mile Dunes complex, which includes Inglenook Fen, is a natural heritage treasure of statewide significance. It is comprised of a unique, relatively pristine native dune and wetland ecosystem that supports three federally and state listed species (Western Snowy Plover, Charadrius alexandrinus nivosus, Menzies' wallflower, Erysimum menziesii spp. menziesii, and Howell's spineflower, Chorizanthe howellii), and numerous other special status plants. Chorizanthe howellii is found no where else in the world but in the dune systems in and around MacKerricher State Park. The Inglenook Fen, an ecological intermediate between a bog and a marsh, is the only known remaining coastal fen in California.

One of the major threats to the Ten Mile Dunes ecosystem is the highly invasive European beachgrass, Ammophila arenaria. European beachgrass first became established in the dunes near the mouth of the Ten Mile River sometime in the 1960's and 1970's. Since then, it has spread southward throughout the foredunes, and in places, eastward into the hinddune. The establishment of European beachgrass in the dunes alters the naturally dynamic processes of sand movement and displaces habitat of the native species. The dense grass creates a nearly impenetrable barrier, which traps sand that is blown inward from the beach. As the sand covers the clumps of beachgrass, shoot elongation is stimulated, thus building the height of the foredune and further blocking the natural movement of sand. A recently published book, titled Ecology and Restoration of Northern California Coastal Dunes (Pickart, Andrea and John Sawyer 1998), states: "One of the highest conservation priorities that emerges from this review of northern California dunes is the control or eradication of European beachgrass at Ten Mile dunes. These dunes, already under conservation ownership, are in a relatively early stage of invasion by European beachgrass. In particular, the portion of MacKerricher State Park south of Inglenook Fen would be relatively inexpensive to restore, if restoration were to begin immediately. Considering the history of spread of European beachgrass on the North Spit of Humboldt Bay (Buell et. al. 1995), we believe that there is a narrow window of opportunity at MacKerricher before this management challenge becomes extremely difficult and costly".

The native dune species have evolved over time and are adapted to a relatively open, dynamic sandy environment. The western snowy plover is particularly dependent upon the open sand for nesting habitat. Snowy plovers build their simple nests in depressions in the sand and require unobstructed views so that they can watch for predators. Where European beachgrass covers the foredune, there is relatively little area remaining between the wave washed beach and suitable drier sand in which plovers can nest. Even if suitable habitat exists inland from the European beachgrass covered foredunes, survival for the flightless fledglings is still a problem. For the first few months of life, the young must walk to feeding areas along the beach. For a small plover, passing through a foredune of dense, tall grass can be an impossible feat. A plover report that was produced for State Parks reads: "Suitable habitat south of the mouth of the Ten Mile River and marginally suitable habitat west of Inglenook Fen is threatened by further encroachment of European beachgrass and the resulting stabilization and heightening of the foredunes. The presence of the haul road could also promote dune stabilization in these areas by altering the natural dune processes. Beachgrass has already reduced the amount of suitable habitat in both areas and the habitat adjacent to Inglenook Fen is currently isolated from the beach by the beachgrass barrier. Removal of the beachgrass from these areas would increase the size and quality of potential nesting habitat. Removal of the haul road or realigning the haul road further inland could potentially improve the quality of habitat in these areas as well." (Edson, Leo J. 1998).

Until recently, very little funding had been available to remove these weedy plants and restore the dunes. Gratefully, State Parks received donations a few years ago through the State Park Ethical Strategies program for dune restoration in the southern half of the park, and some very generous local volunteers have helped to maintain these areas.

Enthusiastic volunteers from Americorps, and a distinguished member of the California Native Plant Society, have helped to remove European beachgrass plants at the northern end of the dunes.
In 1999, the European beachgrass removal program finally began to receive substantial funding. Through the efforts of State Park Ecologists, a Department of Fish and Game Plant Ecologist, US Fish and Wildlife Service Biologists, and many others who wrote letters of support, large sums of money were identified and approved for the program. The funding sources were: Section 6 of the Federal Endangered Species Act, the Environmental Enhancement and Mitigation Program of CalTrans, and the Park Department's Deferred Maintenance Program. A massive effort to restore the dunes began in the winter of 1999-2000.

To date, European beachgrass has been removed from approximately one mile of foredune habitat, but there is still a long ways to go. Resource Management Division has clearly recognized the importance of completing the dune restoration and has supported a proposed Major Capitol Outlay project to accomplish this goal. However, the proposal was not included in the 03/04 budget, and given the current fiscal crisis, it is uncertain when such a project will be approved. With the proposed reorganization, it is also doubtful that there will be adequate staff to manage the program.
Restoration of the Inglenook Fen-Ten Mile Dunes Natural Preserve is a critical program in need of funding, with several endangered species at stake. We are quickly losing populations of the western snowy plover throughout the State, and habitat loss has been identified as one of the main contributing factors. Along the Ten Mile Beach, we observed first-hand how crucial it is for the plovers to have open areas, not just for nesting, but also for areas to retreat to when the winter storms bring crashing waves over the beach. While conducting the winter surveys, an Environmental Services Intern was dismayed to report that she no longer saw the plovers after major storms. Upon closer examination, we were delighted to find that about 15 plovers had taken refuge farther up in the foredune where we had recently removed the beachgrass. Not only is restoration and protection of the Natural Preserve mandated by government regulations, but the Ten Mile Dunes and the Inglenook Fen are highly worthy of preservation...for their precious natural values, like the snowy plovers, and their distinction as a unique part of our state's natural heritage.

REFERENCES CITED:
Buell, A.C., A.J. Pickart, and J.D. Stuart. 1995. Introduction history and invasion patterns of Ammophila arenaria on the north coast of California. Conservation Biology 9:1587-93.

Edson, Leo J., Wildlife Biologist, EDAW, Inc. 1998. Western Snowy Plover Surveys and Habitat Assessment for the MacKerricher Coastal Trail Project (unpublished report written under Contract PCU 0909 for the California Department of General Services).