At a Special Risk (IMAGE) University of Würzburg Caption A butterfly (pale clouded yellow, Colias hyale) on a chalk heath in Lower Franconia. This habitat with its species-rich insect communities is at a special risk in Bavaria because of the nitrogen input. Credit Ingolf Steffan-Dewenter Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.