AVALON, Calif. – Trekking through Catalina’s canyons, his eyes trained on the ground, Peter Dixon is on a quest. The Catalina Island Conservancy’s plant conservation manager is searching for one of 32 rare or endangered plants on Catalina, a tiny flowering annual known as the Thread-leaf rock cress (Sibara filifolia).
Once thought to be extinct on Catalina, Dixon and others have documented the presence of this elusive member of the mustard family on Catalina through forays into the far reaches of the Island. This boots-on-the-ground approach, aided by the latest technology in habitat modeling, illustrates the importance biologists place on protecting biodiversity on Catalina and on islands around the globe.
“Biodiversity is the richness and wonder of life, and the loss of any of the flora or fauna, particularly insular endemics, is a loss of the natural heritage of that place,” said Dixon. “Discovering and documenting rare and endangered species, like the Thread-leaf rock cress, help us understand the habitats they need so that we can protect those species and the biological diversity that is so critical to understanding the past and our future.”
Catalina and the other Channel Islands are often referred to as the “Galapagos of North America” because they harbor a tremendous diversity of plants and animals, including a disproportionately high number of species that are unique to the islands, called endemic species. Catalina alone has more than 60 endemic species identified so far, with surveys, like the one Dixon is conducting, seeking to document more.
Island species face greater risk of extinction because of the unique evolution of island ecosystems. The Global Island Partnership reports that about half of the 724 recorded animal extinctions in the last 400 years were island species, and at least 90% of the bird species that have become extinct in that period were island-dwellers.
The causes for the demise of these species are similar to those on the mainland: invasive plants and animals, human activities, climate change, pollution and other pressures. But islands are more vulnerable because species may be present in relatively small numbers, making extinction more likely. Island species also may have evolved free of predation and competition from other species, so they haven’t developed protective mechanisms.
The population of the Catalina Island fox, for instance, was about 1,300 before a stowaway raccoon brought canine distemper virus to the Island. The foxes had no natural immunity to the illness, and their numbers dropped to about 100 in 1999. The Conservancy, working in partnership with the Institute for Wildlife Studies, was able to bring the fox back from the brink of extinction.
On Catalina, many native plants haven’t developed the protective mechanisms of mainland plants because they evolved at a time when the Island’s largest grazer was the endemic Catalina California ground squirrel (Spermphilus beecheyi nesioticus), an animal with a head the size of a walnut. When tens of thousands of ranching and hunting-era herbivores were introduced in the 19th and 20th centuries to Catalina, the Island’s plants became severely overgrazed.
“Protecting biodiversity is essential to all our futures, and islands, like Catalina, pose a special challenge and significant opportunity to determine how to ensure the survival of native plants and animals so that these precious and fragile ecosystems can continue to thrive,” said Ann M. Muscat, PhD, Conservancy president emeritus. “Through the Conservancy’s work and its collaboration with many others who study life on Catalina, we can better determine what is needed to protect biodiversity on the Island and serve as a living laboratory for islands and mainland species around the world.”
About the Conservancy
Formed in 1972, the Catalina Island Conservancy is one of California's oldest land trusts. Its mission is to be a responsible steward of its lands through a balance of conservation, education and recreation. Through its ongoing efforts, the Conservancy protects the magnificent natural and cultural heritage of Santa Catalina Island, stewarding approximately 42,000 acres of land and more than 60 miles of rugged shoreline. It provides an airport and 50 miles of biking and nearly 150 miles of hiking opportunities within its road and trail system. The Conservancy conducts educational outreach through two nature centers, its Wrigley Memorial & Botanic Garden and guided experiences in the Island’s rugged interior. Twenty miles from the mainland, the Island is a treasure trove of historical and archaeological sites. It also contains numerous rare and endangered animals and plants. The Island is home to 60 species – and counting – that are found only on Catalina. For additional information, please visit www.catalinaconservancy.org.
The Catalina Island Conservancy was formed in 1972 and is one of California’s oldest land trusts. Its mission is to be a responsible steward of its lands through a balance of conservation, education and recreation. The Conservancy protects the magnificent natural and cultural heritage of Santa Catalina Island, stewarding approximately 42,000 acres of land, 62 miles of rugged shoreline and more than 80 miles of trails. It operates the Airport in the Sky, Wrigley Memorial & Botanic Garden and two nature centers. Twenty miles from the mainland, the Island is home to more than 60 plant and animal species found nowhere else in the world. - Watch Video
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