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Above and Below the Soil on Año Nuevo Island

Michelle Hester


Año Nuevo Island, part of Año Nuevo State Reserve in Central California, is a unique wildlife refuge. Though small in size compared to the Farallon or Channel Islands, it supports wildlife densities matching, and for some species exceeding, that of the larger islands. Valuable and irreplaceable habitat on Año Nuevo Island is in urgent need of restoration.

Past impacts on the island ecosystem have included heavy human exploitation of marine mammal and bird populations in the 18th century, followed by 75 years of further human disturbance after a Coast Guard lighthouse station was established in 1896. As a consequence, the island's plant community disappeared, natural erosion processes were accelerated, and some animal species were extirpated.

Since the State of California took ownership of the island in 1958, active protection practices and access restrictions have led to the recovery of some of this ecosystem, particularly seal and sea lion populations. Protection alone, however, cannot reverse the damage done to the plant community and to wildlife populations dependent on the vegetation and on soil stability.

At present, the species most affected by habitat degradation on the island is the Rhinoceros Auklet, a burrow-nesting seabird related to puffins. Auklets excavate nest burrows in soil, with tunnels about five feet long, where they rear their young in safety from predators. This species began colonizing Año Nuevo Island after an absence in California of over 100 years, in the 1980s, about the time when non-native rabbits were eradicated. Unfortunately, the loss of vegetation and subsequent accelerated erosion have led to an increase in the number of burrows that collapse, causing injury and death for adult and young birds.
Michelle Hester (left) and Julie Thayer plant saltgrass, revegetating Año Nuevo Island. PRBO Photo.
Since 1992, PRBO has cooperated in research and habitat restoration on Año Nuevo Island, primarily aimed at protecting marine bird populations (Summer 1996 and Winter 2001 Observers). The newest phase of this multi-faceted project, scheduled to begin in fall 2003, involves replanting denuded soil on the island's marine terrace with native vegetation. A native plant community here will help stabilize the soil, provide a source of nesting material, and increase visual cover and structural diversity, thus improving the ability of varied species to coexist above and below ground. Among the diverse wildlife that depend on this refuge are surface-nesting Western Gulls and Brandt's Cormorants, roosting Brown Pelicans, other underground nesters such as Cassin's Auklets and Pigeon Guillemots, and sea lions and northern elephant seals, which sporadically wander through seabird nesting areas.

Revegetating burrow-nesting habitats of Año Nuevo Island is a highly collaborative endeavor, led by Oikonos, a non-profit organization focusing on understanding ecosystem relationships, and PRBO. Año Nuevo State Reserve provides substantial support for this effort, as do the coastal and riparian habitat restoration specialists Go Native and the University of California at Santa Cruz, and the California Coastal Conservancy.


"We are excited to partner with Oikonos and PRBO in an endeavor to restore limited habitat for burrow-nesting seabirds on Año Nuevo Island. PRBO has contributed much in the past ten years to our understanding of bird populations. Its expertise and energy have greatly improved our ability to manage and protect this unique portion of Año Nuevo State Reserve."--Gary Strachan, Supervising Ranger, Año Nuevo State Reserve

Through these efforts we aim to reestablish a unique native plant community, conserve burrow-nesting seabird colonies, gain innovative knowledge-applicable elsewhere-of island restoration techniques, and contribute to the long-term conservation of biodiversity.