Catalina's Reptiles and Amphibians are Small in Stature, Serious in Significance
Catalina Island Conservancy
Much attention is paid to Catalina Island's iconic critters - bison, fox and eagle. But the smaller, less conspicuous animals that dwell on the ground also deserve notice.
Reptiles and amphibians, collectively referred to as herpetofauna (herps) by scientists, play a crucial role in ecosystems worldwide, both as predators and prey. Herps consume invertebrates and small vertebrates, including insect and rodent pest species. They are themselves food for small mammals, birds and other herps.
Because of Catalina’s large size and proximity to the mainland, Allan A. Schoenherr, in his book, “Natural History of the Islands of California,” says the Island has a higher probability of species arriving and colonizing than the other Channel Islands.
With two native amphibian species (garden slender salamander and Pacific treefrog), three lizards (side-blotched lizard, Southern alligator lizard and Western skink) and five snakes (California kingsnake, Southern Pacific rattlesnake, gopher snake, western ringneck snake and two-striped gartersnake), Catalina Island beats out each of the Northern and Outer Channel Islands for herp diversity.
The natives have been joined by two more recent arrivals, the American bullfrog and the red-eared slider, a turtle (reptile). Bullfrogs are voracious predators of native wildlife and a problem west of the Rockies, where they have been introduced as a game species. Sliders tend to be released by well-meaning pet owners but originally only inhabited the Mississippi River system.
The gartersnake and amphibian species inhabit Catalina’s riparian or freshwater corridors. Although these streams and creeks are the scarcest habitat type on the Island, they contain the greatest diversity and abundance of species. During this intense drought year, it’s important to remember that saving water helps protect these ecological gemstones on Catalina.
Herps are valuable indicators of ecosystem health. These animals’ close contact with water, soil and air cause them to react quickly to changes in the environment. Environmental factors accelerating the decline of reptiles and amphibians worldwide include habitat destruction, disease, climate change and competition with, or predation by, invasive species.
According to the International Union for the Conservation of Nature, 31% of all reptile species and 32% of amphibians on our planet are either threatened or extinct. Amphibians are the most threatened class of animals with 42% of species declining worldwide. Their slimy, permeable skin readily absorbs fatal toxins and pollutants that are discharged into the environment.
There are ways to help these animals persist in their natural environment: Learn to identify them and observe their behavior; plant native plants in your garden that thrive in Catalina’s climate and need little chemical assistance, and avoid releasing non-native animals and plants.
Our native species have little defense against novel predators or competitors and little use for them as food and shelter. Lastly, please resist off-road vehicle use or off-trail hiking to help maintain healthy, intact habitats for all our Island wildlife.
By Alexa Johnson and Elizabeth Bailey
Alexa Johnson is the Catalina Island Conservancy’s Outreach and Naturalist Training Specialist. For more information, please visit our website.