Endangered Species Day: May 21, 2021 - California Tiger Salamander

Celebrate the 16th Annual Endangered Species Day on May 21st, 2021. Every year on the third Friday in May, thousands of people around the world participate in Endangered Species Day by celebrating, learning about, and taking action to protect threatened and endangered species.

In honor of Endangered Species Day, we would like to introduce the adorable California Tiger Salamander! The California Tiger Salamander is a threatened and endangered amphibian species native to California. This spotted salamander enjoys munching on snails, insects, earthworms, and even small fish!

A female California tiger salamander with unfertilized eggs, observed near breeding ponds at Ellicott Slough NWR. Photo Credit: Ashley Spratt / USFWS

The California Tiger Salamander is found in many areas of California, including both Don Edwards San Francisco Bay National Wildlife Refuge and Ellicott Slough National Wildlife Refuge.

The California Tiger Salamander is federally listed as threatened throughout most of its range, including the two populations in the San Francisco Bay National Wildlife Refuge Complex. However, there are two distinct population segments in Sonoma and Santa Barbara Counties that are listed as endangered and at risk of extinction.

These stocky little salamanders are considered threatened due to habitat loss and fragmentation because of development, urban and agricultural runoff pollution, and most recently, California’s increasing drought years. In addition, non-native species such as bullfrogs, fish, crayfish, and non-native salamanders can extirpate the California Tiger Salamander from their breeding ponds through competition and predation.

Don Edwards SF Bay NWR’s Warm Springs Unit in South Fremont is comprised of grasslands and vernal pools, which are ephemeral (temporary) pools of water. The California Tiger Salamander is well-adapted to the vernal pool habitat as they are perfect for the water habitat that the salamander requires to have a successful breeding season.

A vernal pool at the Warm Springs Unit of the Don Edwards San Francisco Bay National Wildlife Refuge. Photo Credit: USFWS

As amphibians, The California Tiger Salamander’s life cycle includes an aquatic larval stage and a terrestrial adult stage. They spend most of the year in terrestrial habitat in underground burrows, such as those of California ground squirrels at Warm Springs. Adult California Tiger Salamanders migrate to breeding pools during the winter rainy season, where they breed, lay their eggs, and subsequently return to their upland habitat.

The recent drought over the last few years has a dual impact on the California Tiger Salamander population. The adult salamanders rely on large storm systems as the cue to leave their underground burrows and migrate to the vernal pools to initiate breeding. Without these large storms, fewer individuals, especially fewer females, will opt for self-preservation rather than make the breeding migration. In addition, the salamander larvae require at least 2.5-3 months in the water to fully develop. In drought years, the pools may not form or may dry up before the larvae can complete metamorphosis.

Droughts are common in California, and the California Tiger Salamander has evolved to meet these conditions by having a longer lifespan to survive multi-year drought periods. Despite their ability to survive this boom and bust dynamic, there is concern that climate change, decreasing precipitation, and more frequent drought years will have a growing impact on their already low population numbers.

Additionally, urban and agricultural runoff pollution also presents a threat to the California Tiger Salamander population. Vernal pools form from surface water runoff, and pollutants from pesticides and urban runoff also drain into these seasonal ponds. Amphibians are generally susceptible to contaminants introduced into their environment as their skin rapidly absorbs hazardous substances, which is also detrimental to the future of the California Tiger Salamander population.

FWS biologists partake in active monitoring of both the salamander populations and the water levels of the pools at Warm Springs and Ellicott Slough through a variety of survey methods.

Refuge biologists use a seine net in a vernal pool to catch samples of the California tiger salamander in order to conduct an aquatic survey of its population. Photo Credit: USFWS

You can make a difference by simply learning more about the California Tiger Salamander and spreading the word about this incredible creature!