Technology aids conservation: Observing frog behavior in frozen lakes using ROVs.

“What do frogs do in winter?” That is a question we hear frequently. Meters-thick ice covers high elevation Sierra Nevada lakes for about nine months of the year. For an animal that spends summer days lounging on rocks in the sun, winter imposes a radical shift in lifestyle. But historically, we could not document frog winter behavior through direct observation. Although scuba diving allows observation of some taxa, winter ice, elevation, and remoteness prevent us from diving in Sierra lakes.

Enter David Lang and his team, who developed the Trident underwater drone at OpenROV and Sofar Ocean Technologies. Over the past few years, our team used a Trident to search for frogs in a frozen lake. This technology allowed us to find frogs and tadpoles, and to capture video to document their overwintering behavior. David and some of his colleagues joined us at our study lake on two late winter expeditions and experienced our “eureka” moments in which we saw frogs and tadpoles as never before. Through the lens of the Trident and the VR goggles, we finally saw the frog’s eye view of life under the ice.

In his recent OneZero article, David describes how the Trident makes this project possible. More generally, he explores the potential for tech to enhance conservation projects. We are happy to see David’s story published, and honored that he focused on our project. Read his story here.

New article on ranavirus in Sierran frogs

“Ranaviruses infect mountain yellow-legged frogs (Rana muscosa and Rana sierrae) threatened by Batrachochytrium dendrobatidis” by Tom, Roland, and Angela Picco (United States Fish and Wildlife Service) appears in Herpetological Conservation and Biology. The paper (available here) documents the presence of a ranavirus in a small number of mountain yellow-legged frog populations. Despite causing occasional tadpole mortality events, ranaviruses play a small role in large scale mountain yellow-legged frog declines, especially when compared to the fungal pathogen Batrachochytrium dendrobatidis.

Ecological consequences of frog declines

Read the new paper here. Published today in the journal Ecosphere, Tom, Roland, and Cherie Briggs (UC Santa Barbara) describe some of the ways in which mountain yellow-legged frog declines impact alpine lake communities. Contrary to expectations, the large scale loss of these frogs is not associated with secondary extinctions or changes in structure and composition of the benthic macroinvertebrate community, which contains most of the prey and competitor species for frogs and tadpoles. Notably, these results differ from 1) the consequences of frog declines in other ecosystems, and 2) the consequences of fish introductions in the Sierra. Although impacts of frog declines on the taxa examined in this study were small, mountain yellow-legged frog declines are associated with secondary declines in other species, like gartersnakes.