Professor of Biology Lee Kats has not only dedicated his time and work into halting amphibian decline; over the course of his 20 years at Pepperdine he has inspired his students and led them to publishing success.
He studied them as an undergraduate student and has been “hooked ever since.”
In Kats’ lecture on Thursday Oct. 22 he spoke on the growing problem of amphibian decline and how he and his students are making significant accomplishments in the field.
“This is a food chain story Kats said. A lot of things eat frogs.”
He explained that animals such as garter snakes only feed on tadpoles. As amphibian populations decline the number of snakes declines because they starve to death.
“Once amphibians decline the other species in the same environment tend to decline as well said senior Jae Chung, a student who has worked with Kats for two years.
Kats said that amphibian decline is mostly due to the introductions of new predators, wildfires and ultraviolet radiation.
New species such as the mosquito fish and crayfish often alter the natural population of frogs and other amphibians, such as the California Newt.
The mosquito fish is not a native of southern California streams, yet they were brought into these new environments to lessen the mosquito population. However, Kats noted that when they were dissected their stomachs were not full of mosquitoes; they were full of tadpoles.
The crayfish, which are also non-native to Southern California creeks and streams, are highly toxic. Because of this, they are unaffected by the toxic California Newts.
They [crayfish] can apparently eat these very toxic newts without a problem Kats said. Wherever these are present the newts are absent.”
Newts are not the only species at risk due to the invasive crayfish. “We’ve witnessed crayfish hunting adult frogs as well Chung said.
Kats mentioned that students have made traps to remove crayfish over the years from local streams such as Cold Creek.
We’re not going to get rid of them but we can get their numbers down he said.
Just as moving invasive species decreases the population of native amphibians, it can cause overpopulation of amphibians in other areas. Although some people complain of their overpopulation, amphibian decline is still a threat in other areas.
There aren’t many examples of overpopulation of frogs that are in their natural habitats Kats said.
Scientists suspect that the local wildfires are another threat to the amphibians, but had not been able to confirm this hypothesis.
There have never been any studies on how wildfires affect newts Kats said.
Some Pepperdine students who had worked with Kats decided to perform a study on this, discovering that there was a total habitat loss Kats said.
The fire not only affected the land around the creeks that these newts call home, it contaminated the water and made it almost impossible for the newts to survive past their tadpole stage or to lay their eggs there.
Ultraviolet radiation is yet another great risk to not only the California Newt, but many other amphibians as well.
This phenomenon threatens amphibians in their earliest stages. They are especially susceptible to damage when they are still eggs.
The eggs are cooked by the ultraviolet radiation Kats said.
Kats also mentioned the increasing effects of UV radiation in Central America. He and his students have gone to great lengths to study these effects.
I’ve been taking students to Costa Rica for 11 years Kats said. This is not for the faint of heart. This is off-trail in the rainforest.”
They have measured the levels of UV radiation at different locations in the rainforest and to what extent different levels of UV radiation affect the amphibians of Costa Rica.
Costa Rica is not the only place where students can help contribute to the cause.
“You could volunteer to be on the crayfish catching team Kats said. If it doesn’t bother you getting your feet wet and muddy we have a creek that we’ve been working at for a few years.”
Many of these students who have worked with Kats in these creeks and in Costa Rica went on to be published and make an impact in the field.
“Many of our students work on the topic of amphibian decline Kats said.
James P. Collins’ and Martha L. Crump’s newly published book, Extinction in Our Times: Global Amphibian Decline included the work of a few Pepperdine students.
Two or three of our students have papers that are cited in this Kats said.
Many of these students got started working with Kats in a Pepperdine laboratory. Kats works with a group of students on a weekly basis.
Every Wednesday morning before convocation this group gets together he said. We just get together and we talk about frogs.”
Chung added “One of the main components of his lab is trying to control the crayfish population so that the amphibian population has a chance to recover.”
This group meets at 9 a.m. every Wednesday morning in Keck Science Center room 360 in hopes of continuing Pepperdine students’ progress in this field for years to come.