Snake Declines Linked to Frog Fungus
The decline of amphibian species due to a fungal disease called chytridiomycosis (or chytrid for short) has been well documented. Many tropical amphibian communities have experienced dramatic declines in numbers, and several species have become extinct as a consequence of chytrid. While this is obviously a serious problem for amphibian conservation, the loss of these communities has consequences for the ecology of many other species that interact with amphibians in some way.
Amphibians often find themselves in a pivotal position in the community of the habitats that they live in. This is especially the case in the tropics, where frogs in particular are very numerous. They are not only major predators of insects, but are also hunted by many other species. As such, frogs represent a key component of tropical forest communities.
It has long been feared that the decline of frogs from tropical forests would have cascading consequences for their prey and predators alike. In a recent scientific paper published in in the renowned journal Science, Elise Zipkin and her collaborators have documented, for the first time, the cascading effect of the decline in frogs due to chytrid on a snake community in Panama.
Frogs are eaten by most snake species at some point during their lives, and this groundbreaking survey was able to show that the snake community suffered from a decline is species diversity as a result of the decline of frogs. Not only that, the study also showed that the body condition of the snakes that were found after the decline, had a lower body condition than those prior to the decline in frogs. This suggests that those snake species that remain are finding it harder to find food and survive.
Our work in the cloud forests of Alta Verapaz is helping us to not only understand what is happening to the frog community, but it will also help us to better understand the relationship between frogs and frog feeding snakes, such as the Rax Bolay, in the region.
Yellow blotched palm pitviper
Hartwegs Spikethumb Frog
Biodiversity is declining at unprecedented rates worldwide. Yet cascading effects of biodiversity loss on other taxa are largely unknown because baseline data are often unavailable. We document the collapse of a Neotropical snake community after the invasive fungal pathogen Batrachochytrium dendrobatidis caused a chytridiomycosis epizootic leading to the catastrophic loss of amphibians, a food source for snakes. After mass mortality of amphibians, the snake community contained fewer species and was more homogeneous across the study site, with several species in poorer body condition, despite no other systematic changes in the environment. The demise of the snake community after amphibian loss demonstrates the repercussive and often unnoticed consequences of the biodiversity crisis and calls attention to the invisible declines of rare and data-deficient species.