Amphibians are extremely vulnerable to environmental changes, and are now being used by researchers to give early warning of environmental threats. If frogs are showing population declines or other evidence of being stressed, it often indicates that there is present some toxic condition, generally air or water pollution.
These animals are endangered, and their numbers are declining. Consult the recommended books below for comprehensive information on amphibians in general, and the latest scientific efforts to ascertain what is causing their declining numbers.
Recommended Books and DVDs on Frogs - The Amphibians
Amphibians are often overlooked in the popular press when speaking about species threatened with extinction - perhaps because they do not excite the reader's sympathy in the way eagles or elephants do. Yet amphibians are fascinating and beautiful creatures; this book concisely and effectively discusses their biology and evolution. The book covers physiology, predator, protection, territorial behavior, migration, reproduction, parental care, contributions of amphibians to human welfare, and the general worldwide decline of amphibian populations. 1997, Princeton University Press
Frogs are cool. How else can we explain the human fascination with these tailless amphibians? Herpetologist Beltz presents an entertaining and comprehensive introduction to the order Anura (frogs and toads). Frogs are found on every continent except Antarctica and in virtually every habitat that has access to water. Beginning with a brief look at the natural history of frogs, the author then delivers a thorough look at all of the families of frogs. An extensive chapter on anatomy and physiology also covers the wonder of metamorphosis, and the discussion of adaptation and environment includes an extensive section on the current plight of amphibians, with many species vanishing. 2005, Firefly Books
Naturalists in every age have been intrigued by frogs, toads, and salamanders. Nature's Fading Chorus presents an anthology of writings on amphibians drawn from the entire Western natural history tradition, beginning with Aristotle's Inquiry Concerning Animals written in the fourth century B.C.E., and continuing through recent scientific accounts of the relatively sudden - and alarming - global declines and deformities in amphibian species. The offerings not only reveal much about amphibian life, but also provide fascinating insight into the worldviews of the many writers, scientists, and naturalists who have delved into the subject. 2000, Island Press
Frogs and toads have been around for 350 million years and are an integral part of many ecosystems. Amphibians are extremely vulnerable to environmental change, so vulnerable, in fact, that they are now considered to be "bioindicators," like canaries in a coal mine. And they're disappearing from wetlands and woods around the globe. Phillips accompanies a number of herpetologists in the field as they try to identify the causes of this alarming decline. All evidence points to human activity as the culprit, specifically water and air pollution, and the corresponding rapid changes in the world's weather patterns. 1995, Penguin