Monday, May 16, 2011

About poison frogs

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Ranitomeya uakarii, a newly-described poison frog species (photo: Jason Brown)

About poison frogs

The poison frogs (families Aromobatidae and Dendrobatidae) are a diverse group of small, diurnal frogs known for their bright coloration, toxicity, and complex parental behaviors. The group contains roughly 250 species occurring from Nicaragua to Bolivia and throughout the Amazon basin as far east as the Atlantic coast of Brazil. Within this range, poison frogs inhabit a wide variety of ecological niches: high-elevation cloud forests (Oophaga arborea), Amazonian lowlands (Ranitomeya ventrimaculata), and dry Andean scrub forest (D. mysteriosus), to name a few. Approximately 1/3 of poison frog species possess potent toxins which they use for defense against predators. Three of these species are known to be fatal to humans. One, Phyllobates terribilis, is used by the Emberá tribe of Colombia for the arming of poison darts used in hunting. This species is so toxic that darts remain lethal for up to three years without losing their ability to kill medium-sized game. Other species exhibit complex parental care. In Oophaga pumilio, females guard eggs until they hatch. Upon hatching, the mother transports each tadpole on her back to a suitable water body such as a bromeliad axil. Though a female may have a half-dozen tadpoles distributed throughout several bromeliads, she will visit each one every few days to deposit an unfertilized egg for her young, which is the only food these tadpoles will eat.

Global Amphibian Extinctions

Amphibians worldwide are going extinct. Multiple factors, such as global climate change, habitat loss, and infectious diseases, are causing an unprecedented loss of diversity. In 1987, the golden toad (Bufo periglenes) was a common sight in the isolated cloud forests of Monteverde, Costa Rica. In 1988, the frogs began to disappear. By 1989, they were gone, and none have been seen since May 15th of that year. Similar extinctions are occurring throughout the genus Atelopus, a widespread group of riparian toads found throughout the highlands of the neotropics. Of the 77 known species of Atelopus, at least 3 are extinct, and 70 are listed as endangered or critically endangered. Despite these declines, new species continue to be found, underscoring the diversity of this genus. Undoubtedly, many species of Atelopus have gone extinct before they were ever discovered. The insidious chytrid fungus (Batrachochytrium dendrobatidis), is a novel pathogen responsible for many of these declines and is quickly spreading throughout most of the world. Habitat loss also threatens many tropical amphibians. Amazonian deforestation is reducing the amount of habitable rainforest by roughly 3.7-4.9 million acres per year (Kricher, A Neotropical Companion).

Poison frog habitat in central Peru (photo: Evan Twomey).

Deforestation not only destroys habitat directly but modifies adjacent habitat by creating hotter, drier conditions than normal. Many poison frogs, which often have small distributions near human settlements, are experiencing drastic reductions in habitat size and quality. Due to their bright colors and interesting behaviors, poison frogs are in high demand in the pet trade. Against CITES regulations, these frogs are frequently smuggled out of their native habitat by the hundreds to be sold in Europe or the US. These practices result in extremely high mortality in smuggled frogs, and in some cases, can substantially degrade natural populations.

Our Goal

This website exists for two primary reasons. The first is to promote the study and conservation of poison frogs by gathering and condensing new and old information and making it available to the general public. Unlike many other poison frog websites, we provide original field accounts, with original photography of wild frogs in hopes to increase awareness and interest of these incredible animals. All our accounts are written by people that have seen and photographed the species in its natural environment. As many of these frogs are at risk due to habitat loss and smuggling, we attempt to provide a summary of the current conservation issues regarding each species. We also summarize the phylogenetic status for each species to emphasize the importance of conserving unique evolutionary lineages.

The second purpose of this website is to provide a platform us to announce recent happenings in the poison frog field. We are a small group of field biologists dedicated to the investigation of poison frog diversity and conservation. Our work focuses on traveling to remote or unknown areas to document poison frog diversity and distribution patterns. On these expeditions, we have expanded the knowledge base of many poorly understood species, rediscovered lost species, and on occasion, we have discovered species previously unknown to science.

Comments or questions regarding this site or our current activities can be directed to Evan Twomey (evan.twomey@gmail.com).



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