The growing number of malformed frogs has been making global headlines. Amphibian populations in general have dropped worldwide during the past 20 years, often because of habitat loss and alteration. Amphibians are excellent environmental quality indicators because contaminants readily enter their bodies through the skin and accumulate more quickly than in other animals.
Scientists need to know why amphibian populations are declining and what is causing the increased rate of malformation in frogs. The U.S. Geological Survey (USGS) developed the Amphibian Research and Monitoring Initiative (ARMI) in 2000 to monitor amphibian population trends on U.S Department of the Interior (USDI) lands, and to study the causes of declines. By working with other federal agencies, researchers hope to mitigate or correct problems, stabilizing amphibian populations.
The ARMI offers a better way to describe, model, and monitor interactions between the environment and amphibians. It overcomes the inherent difﬁculty of reliably estimating populations in species that easily elude detection by swimming away or blending in with their environment. This new predictive model and web-based tool will help ﬁeld biologists locate potential amphibian habitats, and help land managers make decisions about conserving critical habitat.
A new broad-scale technique called Proportion Area Occupied (PAO) measures the presence or absence of amphibian species at speciﬁc sites over time. By collecting and analyzing whether amphibians are present or absent, ARMI describes population trends across large areas. While PAO is not unique to ARMI, this program is among the ﬁrst to employ it on such a large geographic scale. The ARMI also has encouraged further development of existing PAO methods.