Amphibian Conservation
Since the 1970s worldwide amphibian populations have been in decline. Habitat loss is the main cause of declines but pollution, degradation, invasive species, and a changing climate are also important factors.
Amphibians as Indicator Species
A spring peeper. © George Cevera
Amphibians serve important functions in the natural world. They have a huge role in the nutrient cycle; serving as both predator and prey, they help keep our waters clean, pests under control, and nutrients moving up the food chain. Most amphibians have distinct larval and adult stages which are split between terrestrial and aquatic habitats- making them uniquely vulnerable to loss and degradation.
Zoom+ This green frog's deformities are caused by parasites found in nitrogen and phosphorus rich waters due to fertilizer run-off. © Lee Ekstrom
Behavioral and physiological characteristics also make amphibians highly vulnerable to changes in their environment. Traits like their porous skin, crucial for respiration, preventing dehydration, and even drinking, is also incredibility sensitive to changes in temperature, the presence of contaminants, and even water chemistry like pH. Many amphibians are also philopatric, they return to the pond where they were born to breed, but if ponds are destroyed or can no longer be accessed due to roads or other barriers- they may not breed. Environmental stressors like habitat loss, pollution, climate change (increased UV radiation, fluctuations in rainfall and water temperature) can lead to deformities, delayed or premature metamorphosis, unsuccessful breeding, and even death.
Amphibians in decline
Since the 1970s worldwide amphibian populations have been in decline. Scientists estimate that over 150 species have gone extinct since 1980 and one-third of all amphibian species are threatened. Habitat loss is the main cause of declines but pollution, degradation, and invasive species are also important factors. The recent emergence of the amphibian fungal pathogen known as chytridiomycosis, together with climate change, may be the biggest threat to face amphibians yet.
Zoom+ Cope's gray treefrog © Dave Golden
Chytridiomycosis
Chytridiomycosis is the disease caused the chytrid fungus Bd (Batrachochytrium dendrobatidis). First identified in 1998 on dead frogs in South America, Bd feeds on the protein keratin which is found in the skin of adults and the mouths or jaw sheaths of tadpoles. As the fungi feed and reproduce it breaks down their skin, preventing proper water absorption and leading to desiccation, decreased respiration, damage to the nervous system, behavioral changes, and eventually death. Believed to be the main factor in the current wave of amphibian declines, Bd has been found on every continent except Antarctica. Although most mass mortalities attributed to chytridiomycosis have occurred in Central and South America, temperate zones like the western United States and northern Australia have also been devastated. Currently no Bd-related mortalities have been found in New Jersey's amphibians but preliminary data shows the fungus is present. With scientists knowing so little about the cause and spread of this disease, it is important to collect as much baseline data as possible to learn and hopefully prevent such an event from occurring in New Jersey.
In 2010, CWF teamed up with ENSP and Montclair State University to perform a state-wide survey to screen for chytridiomycosis. Through surveying a wide-variety of water bodies and a broad sampling of NJ's amphibians, including the state endangered eastern tiger salamander and state threatened Pine Barrens treefrog, we hope to learn what species and ecosystems are at highest risk in New Jersey and hopefully what can be done to prevent mortalities. This effort was recently documented in the Philadelphia Inquirer (2011).
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