California Red-legged Frog
Rana aurora draytonii
Text by Mark Oatney

Status
Federally-listed Threatened Species

Habitat
Marshes, streams, ponds, wetlands and other usually permanent sources of water. When not breeding, may be found in damp woodland and meadows.

Range
This species once ranged from San Diego to the Oregon border along the coast mountains, across the central valley and into the foothills of the Sierra Nevada, where it was gained fame as the Celebrated Jumping Frog of Calaveras County. Today it is no longer found in the Sierra foothills or the central valley. It was formerly fairly common across the lower UCSC campus, especially in the area that renowned biologist Ken Norris named Frog Haven (or Heaven). Today it is much rarer locally.


Threats
• Mud
Red-legged Frog tadpoles cannot tolerate the high level of silt that washes into the remaining breeding pond from the growing cleared and developed land on the upper campus. This erosion is the single greatest threat to the frog’s survival.

• Waterflow
UCSC dumps storm polluted runoff water directly into cave systems. UCSC has no storm drains— all runoff from the ever-increasing cleared and developed land on campus runs either down or through the landscape on which it is built. The campus cave system also runs underneath (and now through) what were recently important breeding ponds for the Red-legged Frog. Increased water flow from the campus may have blown out the caves below these ponds, causing their ultimate collapse. Today, what was once old north pond is now a toilet-like torrent flushing into the cave that opened up beneath it.

• Habitat destruction
Continued campus growth is encroaching on remaining Red-legged Frog habitat. Proposals for faculty housing between the UCSC arboretum and the UCSC Farm and Garden Project would impact populations immediately.

• Traffic
Empire Grade cuts campus frog habitat in two. During breeding season, the frogs must cross Empire Grade Road to get to the remaining breeding pond. Traffic by the constantly-growing population of UCSC is a growing threat to these threatened frogs.

• Pesticides
Elsewhere in the Red-legged Frog’s range, there is increasing concern that the use of chemical pesticides is adversely affecting it and other declining amphibians.

Conservation
Campus growth needs to come to a halt until the effects of erosion, runoff, habitat destruction, and traffic on UCSC’s Red-legged Frog populations have been properly studied and addressed.