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Helping Local Organizations Enhance Spadefoot Toad Terrain in Orange County, California

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Local organizations have joined forces to restore and enhance wildlife communities in open-space park reserves on and near the coast in Orange County, CA. Among the beneficiaries of their efforts is the Western spadefoot toad (Spea hammondii), a locally rare species in Orange County, where its natural habitat, which includes coastal plains, grasslands, and coastal sage scrub, has become threatened.

tadpole held in palm of hand tadpole held between fingers
Metamorphosis: This tadpole has nearly completed the transformation (metamorphosis) to its terrestrial life stage. The development from egg to metamorphosis can take place over a 28- to 32-day period!

Life in a rut—a rain-filled rut, that is—can be highly productive for breeding Western spadefoot toads, and the efforts of members of several organizations, plus local volunteers, docents, naturalists, park rangers, and school children, are helping ensure that at least some Western spadefoot toads have plenty of suitable locations in which to breed. Restoring habitat for these toads can be as simple as using a global-positioning-system (GPS) unit and putting a spade to the earth.

Breeding pools: Road ruts filled with rain runoff are breeding pools for Western spadefoot toads at Laguna Coast Wilderness Park. Shallow depressions that are located near the road edge can be deepened for toad habitat in a way that still allows vehicle passage. All the vernal pools shown here have been enhanced.

Road rut filled with rain runoff

Road rut filled with rain runoff

Road rut filled with rain runoff

As an ecologist for the U.S. Geological Survey (USGS), I have worked since 2001 in a pilot program at Laguna Coast Wilderness Park at Laguna Beach designed to educate, provide guidance, and demonstrate inexpensive ways to prevent continued loss of breeding populations and habitats of the Western spadefoot toad. The groups involved in this effort are the Laguna Canyon Foundation; Laguna Greenbelt, Inc.; the Nature Conservancy of Orange County; and Harbors, Beaches, and Parks, a division of Orange County's Public Facilities and Resources Department.

Now, just 2 years after the start of the pilot program, participants are creating small breeding pools for the toads throughout Laguna Coast Wilderness Park. Meeting volunteers 1 day each month at the park during the toad's breeding season, I help the group identify spadefoot-toad breeding sites and record their locations on a GPS unit. Then I demonstrate how to use a spade to modify the sites to restore natural habitat features conducive to the toad's reproductive success.

Digging occurs in areas where road depressions already exist. The depth and length of the pools vary, depending on the roadside location. In most instances, the dugout depression is approximately 25 to 30 cm deep. Because of its roadside location, the depression has a narrow shape, approximately 0.5 to 1.0 m wide and 1.5 to 4.5 m long. Regular participants at these meetings include Barbara Norton, park ranger at Laguna Coast Wilderness Park; Scott Thomas, landscape architect for Orange County; and Harry Huggins, of Laguna Greenbelt, Inc.

Spadefoot toads are known for the wedge-shaped spade on their hind feet used to dig small burrows to escape heat and arid conditions. Western spadefoot toads breed early, during winter and spring (January through May). Brief episodes of rainfall set in motion their rapid reproductive cycle in shallow depressions that are temporarily filled with rainwater, which are referred to as vernal pools. A choice breeding pool may even be a rain-filled road rut.

Before working in the Pacific Southwest, I conducted inventory and monitoring surveys of amphibian communities on U.S. Department of Defense installations in Fort Belvoir, VA. During those surveys, I saw that some of the best temporary pools for breeding amphibians occurred in road ruts formed by military vehicles traveling over the terrain. When I began conducting monitoring surveys on amphibians and reptiles in southern California as part of the multiagency Natural Communities Conservation Plan/Habitat Conservation Plan (NCCP/HCP), I took GPS coordinates of road-rut locations. Later, during rainy periods, I returned to the road ruts to survey for amphibian activity. The rain-filled road ruts contained Western spadefoot toad tadpoles, which were in most of the road ruts in Laguna Coast Wilderness Park, as well as in road ruts at the adjacent Crystal Cove State Park.

To my surprise, upon my second return to these locations to monitor the tadpoles, I discovered that these vernal pools had been drained. The inadvertent drainage of these temporary breeding sites alerted me to the need to educate reserve managers on the life cycle of this and other amphibians and led to the pilot education program at Laguna Coast Wilderness Park.

On Nov. 12, 2003, from 7:00 to 8:30 p.m., T'Shaka Touré will give a public lecture at the Natural History Museum of Orange County, on "Amphibians and Vernal Pools in the County of Orange."

Education efforts at Laguna Coast Wilderness Park gave rise to the Spadefoot Toad Enhancement Project sponsored by the Irvine Ranch Land Reserve.

The enhancement project now includes the Laguna Coast Wilderness Park, Crystal Cove State Park, Irvine Regional Park, Fremont Canyon Wilderness Area, Limestone Canyon Wilderness Area, Peters Canyon Regional Park, Weir Canyon Wilderness Area, and additional lands managed by the Irvine Ranch Land Reserve.

These ongoing efforts have begun to aid in increasing the breeding populations of the Western spadefoot toad in the region.

Related Web Sites
A Field Guide to the Reptiles and Amphibians of Coastal Southern California
U.S. Geological Survey (USGS)
Laguna Coast Wilderness Park
Orange County Public Facilities & Resources Department / Harbors, Beaches and Parks Division
Laguna Canyon Foundation
non-profit organization
Laguna Greenbelt, Inc.
advocacy group

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in this issue: Fieldwork cover story:
Ancient Landscapes Beneath South Carolina Beaches

Tracking Hawaiian Coral Larvae

Suspended Sediment in Hawaiian Waters

Sediment Movement Near the Sea Floor

Outreach Gulf of Mexico Fishery Management Council

Helping Spadefoot Toads in California

Meetings ESRI User Conference

Diving Into Coral Disease

Publications September Publications List

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