Keystone species are animal species that are critical for keeping ecosystems healthy and balanced. Complex relationships and ...

Some animals matter so much to their ecosystems that losing them is like removing the keystone from an arch—the entire structure begins to collapse. These keystone species shape food webs, carve out ...

University of Delaware entomologist Doug Tallamy’s research has identified “keystone” plant species that make up the foundation of many U.S. ecosystems by producing food for native insects, thus ...

The Roman arch was held together and anchored by a wedge-shaped stone in the center of it. This stone added stability to ...