Habitat loss is the greatest threat to amphibians wherever they live. Whether they swim, jump, climb, or crawl, amphibians cannot pick up and move when their homes are destroyed or seriously altered.
The most vivid example is the destruction of the Amazon rainforest over the last four decades. Towering forests, where amphibians (and other animals) made homes in every niche from puddles and buttress roots to the canopy, were logged or burned and bulldozed for large-scale cattle ranching and agriculture. While deforestation slowed significantly about 10 years ago, it is on the upswing in many Amazon basin countries again.
Freshwater wetlands—marshes, swamps, bogs, fens and vernal pools—are critical habitats for thousands of amphibian species. Scientists estimate that more than three-quarters of the world’s wetlands have been lost, most of them in the last century. Within the continental United States, more than 116 million acres, or 53 percent, of presettlement wetlands have been destroyed. Illinois ranks sixth among the states in overall percentage of wetlands lost. A report by the Illinois Department of Natural Resources notes that 37 of the state’s 41 amphibian species use wetlands at least part of the year, including eight endangered or threatened frogs and salamanders.
A habitat divided
Habitat fragmentation can be as devastating to a species as total loss. For example, when chunks of grassland are destroyed, populations of American toads that interact with each other across a larger region are suddenly isolated from one another. Over time, this can lead to less genetic diversity, leaving these populations less adaptable to changes in the environment, which could eventually lead to extinction.
Another form of fragmentation occurs when roads divide a habitat. Many amphibian species return to specific sites each year to mate and breed—migrations that can involve hundreds of thousands of animals converging on a breeding pond at the same time. And worldwide, they are increasingly forced to cross busy roads to get there. Road mortality is a significant threat to spotted salamanders in many parts of their range, which includes the Chicago area. Researchers found that annual road kills involving more than 10 percent of adult spotted salamanders in a given area could wipe out that local population.
Conservation-minded communities from New Jersey to the Netherlands have responded to the plight of migrating amphibians by closing roads, recruiting volunteers to carry the animals across roads, or building permanent tunnels under the thoroughfares.
Make a change to help
Get your hands dirty for amphibians! Take part in one of Shedd’s Great Lakes Action Days (GLADs). You’ll not only discover where amphibians live in the Chicago area, you’ll also help improve their habitat through restoration activities.
FrogWatch USA is a citizen science program coordinated by the Association of Zoos and Aquariums. It gives people the opportunity to get out and appreciate their local wetlands as they record data on calling frogs and toads. The information will be used by researchers to help conserve these amphibians and their habitats.