In 2013 the U.S. Geological Survey-Biological Resources Division published a study that examined the U.S.-specific trends of a worldwide phenomenon known as amphibian species decline. It found significant declines in the populations of frogs, toads, and salamanders throughout their habitats nationwide, including of course Florida. Surprisingly, these declines were evident even in ecosystems protected within national parks and wildlife refuges. The study found that, on average, populations of all amphibians examined vanished from habitats at a rate of 3.7% each year. This rate is alarming and estimated at more than 200 times the average “background” extinction rate. But what could be causing this precipitous drop in the numbers of our native amphibians?
Several things, it turns out: The most obvious cause is habitat destruction. Worldwide population is over 7.2 billion and rapidly rising. Here at home nearly 1,000 people move to Florida each and every day. With more people comes more development and conversion of natural habitats. Pesticides and other toxins in the environment have been shown to have a detrimental impact to normal development in amphibians. Altered precipitation patterns due to global climate change, and increased ultraviolet radiation resulting from ozone depletion, might already be having negative consequences. And there has been a dramatic increase in the incidence of infectious diseases, particularly a pathogenic fungus known as chytridiomycosis, amongst amphibians since the 1990s. While no one of these factors may be enough to cause widespread and severe populations declines, it is theorized that taken together these factors and possibly others are having a devastating effect on the world’s amphibians. But why amphibians in particular?
Amphibians possess a permeable skin through which they breathe, making them very susceptible to contaminants in the environment and harmful solar radiation. They also live in both aquatic and terrestrial settings, which increases their exposure and risk. They have often been called nature’s “canaries in the coalmine” because of their pronounced vulnerabilities, which makes their current disappearance so worrying. As a group, amphibians have been in existence for 400 million years and have survived through four previous global mass extinction events. The fact that amphibian species are now in worldwide decline is one of the factors leading scientists to theorize that we are now in the midst of a sixth mass extinction, this one being entirely human-caused.
Fort Matanzas currently has nine documented amphibian species, all either frogs or toads.
1. Southern Toad
2. Eastern Narrowmouth Toad
3. Green Tree Frog
4. Barking Tree Frog
5. Squirrel Tree Frog
6. Southern Leopard Frog
7. Spadefoot Toad
8. Greenhouse Frog (Exotic)
9. Cuban Tree Frog (Exotic)
Remember that all plants and animals in the park are protected by state and federal laws. Please do not try to catch the creatures--just observe them from a distance.
