By Maddy Marsh, Arizona Game and Fish Department
During the monsoon season in the sky islands of southeastern Arizona, if you listen closely, you may hear the very distinctive “snore” of the Chiricahua leopard frog (Rana chiricahuensis). Endemic to mountainous regions of the Chihuahuan and Sonoran deserts in eastern Arizona, western New Mexico, and northern Mexico, and listed as threatened on the Endangered Species Act in 2002, conservation efforts are more important now than ever before to save this charismatic green frog from extinction.
Our conservation efforts are dependent on partnerships with other agencies, private landowners, and zoos. Through both education and outreach, like the El Paso Zoo has participated in for over ten years, as well as captive propagation, zoos have become a vital part of the recovery of this species. In fact, in conjunction with our conservation partners, there has been an increase in the number of populations since recovery of the Chiricahua leopard frog began.
The Chiricahua leopard frog is a highly aquatic member of the family of true frogs, Ranidae, and is typically green to brown in color with its namesake leopard-like spots on its back. They prefer riparian habitats in elevations between 3000-9000 feet and inhabit streams, wetlands, stock tanks, and many other bodies of water that have suitable food and cover. Breeding occurs throughout the year, though mostly from March to September. The snoring call of the male Chiricahua leopard frog in the breeding season may also be accompanied by croaks or grunts. During breeding, the females lay a large clump of eggs, called an egg mass, in shallow water attached to vegetation. Once the eggs hatch, they become tadpoles and will stay in the water for 3-6 months until they metamorphose into juvenile frogs. Juvenile and adult leopard frogs are less tied to water than tadpoles, and may be found in moist habitat at the water’s edge. Frogs are amphibians, a term that comes from the Greek for “dual life,” referring to their tie to land and water. As frogs, they have a hearty appetite and will eat whatever they can fit in their mouths, though their favorite food is usually insects. Other animals like to eat Chiricahua leopard frogs as well, which is one of the reasons frogs play such an important role in the balance of an ecosystem – they are predators and prey to both terrestrial and aquatic animals.
Nonnative, invasive species like American bullfrogs, crayfish, and exotic fishes, can throw off the balance in an ecosystem and pose a major threat to Chiricahua leopard. These “aliens” to the ecosystem are not only direct predators of all life stages of the Chiricahua leopard frog, but bullfrogs especially are able to spread amphibian diseases and outcompete native frogs for resources. Chytridiomycosis is an amphibian disease caused by the fungus Batrachochytrium dendrobatidis, or Bd, that causes amphibians to lose their ability to breathe through their skin. Bullfrogs can be carriers of this fungus, but are resistant to its effects, which can allow bullfrogs to infect Chiricahua leopard frogs when they share a habitat. Chiricahua leopard frogs are easily infected by Bd and it has been documented to cause die-offs across their range. Another threat to the Chiricahua leopard frog is habitat loss, such as diversion of water for human purposes and long-term drought. Due to their highly aquatic nature and need for permanent water to breed and survive, some Chiricahua leopard frog populations are struggling as water free of nonnative species becomes more scarce across the landscape.
So, what can we do to help? The Arizona Game and Fish Department and the US Fish and Wildlife Service have many conservation activities and partnerships that help protect this native species. One of them is called a Safe Harbor Agreement, which allows for private landowners to provide habitat for the frogs on their properties or ranches. Arizona Game and Fish and our many federal, state, and private partners survey Arizona populations multiple times a year to monitor population health and figure out which sites may need a little extra help with a supplement of the numbers of Chiricahua leopard frogs. We do this two ways: a wild-to-wild translocation or through a partnership with a captive breeding program. A wild-to-wild translocation is simply moving frogs or egg masses from a healthy population and moving them to a site with lower numbers. This has proven to be a very successful way to augment struggling populations. Some populations need more help through a captive breeding program, like the one at the Phoenix Zoo, which has raised over 26,000 frogs and tadpoles for release into the wild in Arizona since the program began 25 years ago. Another huge part of conserving this species is through education and outreach, which the El Paso Zoo participated in for over ten years. Simply by allowing the public to look, see, and read about these frogs in an exhibit, the word is getting out about how important this species is to their ecosystem and why we need to continue to protect them. It’s not all bad news for these frogs, though. Despite the threats and lack of water they continue to face, cooperation through partnerships and active management has led to an increase in populations since the species was listed. If you want to learn more about Chiricahua leopard frogs, please visit www.azgfd.gov or email me, Maddy Marsh, at firstname.lastname@example.org.