The National Academy Press (of the National Academies) has posted this Open Book (for browsing only), from the Committee to Evaluate Indicators for Monitoring Aquatic and Terrestrial Environments (National Research Council). The text provides criteria and methodologies for selecting and developing ecological indicators; proposes several ecological indicators and relevant data sources; and suggests...

Lichens and the tiny animals called tardigrades ("water bears") that live in them are sensitive to certain air pollutants such as sulfur dioxide. Accordingly, they can be useful bioindicators of air quality. Designed to engage students in the scientific process, this Web site, produced by PathFinder Science, offers a learning program based on lichen cover and tardigrade density and diversity on...