Amphibians, like frogs and salamanders, don't live in the ocean or skies like fish and birds, but lots of places on land. In the last few decades, their numbers have gone down and some species are at risk of disappearing forever. This is called a decline in amphibian populations.
The main reason for this decline is that their habitats are being destroyed by humans who are cutting down trees and destroying their wetland homes. Pesticides and other chemicals are also polluting their habitats, which makes it harder for amphibians to survive. Finally, a disease has also been spreading among amphibian populations, which makes them even more likely to die. All of these things, together, are adding up to fewer and fewer amphibians living on land.