Presentation Type

Poster

Keywords

freshwater ecosystems, conservation, disease, amphibian health, environmental stress

Department

Biology

Major

Biology

Abstract

Many local streams of the Santa Monica Mountains are populated by the native California Newt, Taricha torosa, a species of special concern. Arroyo Sequit is one of these streams, the upper and lower portions of which are split by a culvert and the Mulholland Highway. This stream and the surrounding areas burned during the Woolsey fire of 2018. Since the fire, construction has been ongoing in and around the stream. Two years post-fire (during the summer of 2020) significantly more newts were found in the stream than years prior. A large proportion of these newts were unhealthy in appearance, presenting with symptoms including emaciation, cloudy eyes, infected vents, and necrotic and bleeding tails. A higher incidence of infection was noted at Lower Arroyo (below the culvert, where construction activity is concentrated) than at Upper Arroyo. Pathology studies by the National Wildlife Health Center found that these newts tested negative for ranavirus and B. salamandivorans but positive for B. dendrobatidis, a chytrid fungus to which newts are not typically susceptible. Although the final pathology report came back inconclusive, it is clear that the newt population of Arroyo Sequit is exhibiting concerning health abnormalities. We suggest that a combination of environmental stressors, including wildfires and construction, may have an immunocompromising effect. We speculate that this may be a factor in the health decline of this newt population.

Faculty Mentor

Dr. Lee Kats

Funding Source or Research Program

Summer Undergraduate Research Program

Presentation Session

Session E

Start Date

23-4-2021 3:15 PM

End Date

23-4-2021 3:30 PM

Share

COinS
 
Apr 23rd, 3:15 PM Apr 23rd, 3:30 PM

Decline in Amphibian Health in Local Stream

Many local streams of the Santa Monica Mountains are populated by the native California Newt, Taricha torosa, a species of special concern. Arroyo Sequit is one of these streams, the upper and lower portions of which are split by a culvert and the Mulholland Highway. This stream and the surrounding areas burned during the Woolsey fire of 2018. Since the fire, construction has been ongoing in and around the stream. Two years post-fire (during the summer of 2020) significantly more newts were found in the stream than years prior. A large proportion of these newts were unhealthy in appearance, presenting with symptoms including emaciation, cloudy eyes, infected vents, and necrotic and bleeding tails. A higher incidence of infection was noted at Lower Arroyo (below the culvert, where construction activity is concentrated) than at Upper Arroyo. Pathology studies by the National Wildlife Health Center found that these newts tested negative for ranavirus and B. salamandivorans but positive for B. dendrobatidis, a chytrid fungus to which newts are not typically susceptible. Although the final pathology report came back inconclusive, it is clear that the newt population of Arroyo Sequit is exhibiting concerning health abnormalities. We suggest that a combination of environmental stressors, including wildfires and construction, may have an immunocompromising effect. We speculate that this may be a factor in the health decline of this newt population.