The California Frog that was caught Red-legged. (Jeff Hadley)

(Picture: http://lpfw.org/our-region/wildlife/california-red-legged-frog/)

CALIFORNIA RED-LEGGED FROG

(Rana aurora draytonii)

Jeff Hadley

6/7/15

http://www.californiaherps.com/frogs/pages/r.draytonii.html

The California Red-legged Frog (Rana aurora draytonii) is a subspecies of the Red-legged frog that is endemic to California and Baja California.* It is the largest native frog in the Western United States and is currently found from Marin County, CA to some parts of northern Baja California, Mexico. It is listed as a threatened species under the Endangered Species Act with a recovery plan that was published in 2002.* The following page will introduce the California Red-legged Frog, describe its characteristics and habitat as well as summarize the Recovery Plan for this species.

                                    Description and Ecology                               

                  Coastal Drainage Habitat, SLO Connty          

(Pic: http://www.californiaherps.com)

The California Red-legged Frog (Rana aurora draytonii) is one of two subspecies of the Red-legged Frog, the other being the Northern Red-Legged frog which is similar to the California Red-legged Frog except they are smaller in size and have slightly different behavioral characteristics. The California Red-legged frog is the largest frog in the Western United States with a body size that can be up to 5.4 inches in females and 4.5 inches in males.* Other discernible characteristics of adults include red to salmon colored lower abdomen and hind legs, a back that has small dark spots and larger, more irregular dark blotches with blurry outlines. Two Dorsolateral folds (ridges of skin on the frog’s back) can be easily spotted on California Red-legged Frogs.*  Their main skin color varies greatly and can be brown, gray, olive or reddish-brown.* As shown in the two pictures at the top of the page, two California Red-legged Frogs may be colored very differently. These frogs breed between November to early-April and females lay their egg masses on emergent vegetation so that the egg masses will float on the water. The California Red-Legged Frog requires a Mediterranean Climate which provides temporal and spatial changes of habitat, and tends to use a mixture of aquatic, riparian and upland habitats.* These can include coastal drainages (found here in SLO County), ponds (natural & artificial), streams, aqueducts, marshes and other aquatic habitats. 

                Geographical Range: Current and Historical                

(Map: http://www.californiaherps.com/frogs/maps )

The current geographical range of the California Red-legged Frog is from as far north as Point Reyes National Seashore in Marin County, CA to as far south as some Northern areas of Baja California, Mexico. They also can be found in isolated drainages of the Sierra Nevada’s, Transverse Ranges and the Northern Coast.* Their elevation range is from near sea-level up to 5,000 ft. above sea-level, however almost all sightings have occurred below 3500 ft.* The California Red-legged Frog has been extirpated from an astonishing 70% of its former range.* It is now limited to almost exclusively Central California coastal drainages.

http://ecos.fws.gov/docs/recovery_plan/020528.pdf

Historically their range was much greater, covering most of California’s coast north to the Point Reyes area, inland to Redding, and all the way south to Northwestern Baja California. The map above represents the current range of California Red-legged Frog (Orange) as well as the Northern Red-legged Frog (Red) and the small area their two ranges overlap (purple). The Chart to the right shows the number of streams per county where the California Red-legged Frog is present as of 2001. 

                      ESA Listing Date and Type of Listing                    

(Pic: http://www.californiaherps.com/frogs )

In 1996 the California Red-legged Frog was listed as a threatened species under the ESA, with a recovery priority number of 6C, meaning it is a subspecies with high threats and low recovery potential.* The recovery plan for the California Red-legged frog was publish by Region 1 of The U.S Fish and Wildlife Service on May 28^th, 2002. 

Cause of Listing & Main Threats to Continued Existence

Although the main cause for the decline of the California Red-legged Frog varies from population to population given geographic location, the following factors have contributed to the listing of the California Red-legged Frog:*

• Degradation, fragmentation and loss of Habitat due to:
• Agriculture
• Urbanization
• Mining
• Overgrazing
• Recreation (Hiking, Biking, OHV, Fishing, etc)
• Timber Harvesting
• Non-native Plant Species (degrade habitat through infestation)
• Reduced Water Quality (Pesticides and other chemicals)
• Invasive Predator Species (Intentionally and Unintentionally Introduced)
• Drought – The recent drought has been detrimental to certain isolated communities where habitat has dried up and habitat fragmentation has resulted in no re-colonization from neighboring communities.  

Threats to California Red-legged Frogs and their recovery status per recovery unit.
Taken from the California Red-legged Frog Recovery Plan
http://ecos.fws.gov/docs/recovery_plan/020528.pdf

California Red-legged Frogs in San Luis Obispo County are most affected by activities such as agriculture, live-stock grazing, recreational activities, urbanization and water management. However, the Central Coast still has a High recovery status meaning there are “many existing populations and many areas of high habitat suitability.”*

                               Summary of Recovery Plan                              

The ultimate goal of this Recovery Plan is to de-list the California Red-legged frog which will occur when their is suitable habitat in all core areas, existing populations are stable and geographically spread throughout their range, the subspecies is successful at reestablishing currently uninhabited core areas, and further research to connect these core areas is done. Means and methods used to accomplish this will differ between geographic locations, so the geographical range of the California Red-legged Frog has been separated into 8 Recovery Units, which can be seen in the map below. From these units, 35 Core Areas were established where rehabilitation efforts will be focused. Preservation of suitable habitat will lead to a high chance of stable frog populations for future generations. 

Taken From the ESA Recovery Plan
http://ecos.fws.gov/docs/recovery_plan/020528.pdf

The most applicable Core Areas for us are 22 & 23, Estero Bay and Arroyo Grande Creek. Both of these Core Areas are located within SLO County, giving us legitimate reason to be aware of what we can do to help. The main strategies for recovery include reducing threats to protect current populations, restoring and creating suitable habitat, monitoring existing populations, and reestablish the subspecies to it's historic range.* Individually, we may not be able to complete all these activities, however we do have a moral responsibility to help protect and provide habitat for all endangered species to ensure that our children and children's children will be able to enjoy nature's wonders as we have. 

                                                                                                                                                                   

*References: 

U.S. Fish and Wildlife Service. 2002. Recovery Plan for the California Red-legged Frog (Rana aurora draytonii). U.S. Fish and Wildlife Service, Portland, Oregon. viii + 173 pp.

                                                                                                                                                                   

Thanks for Reading!