NHEERL is studying the potential effects of global change on vulnerable ecosystems. Species or ecosystems whose natural habitat is within an ecotone are expected to exhibit the first signals of global change. Latitudinal migration of high altitude wild flowers, for example, may be such a signal. Identification of changes within these sentinel species would significantly decrease the uncertainty as to whether climate change is indeed occurring and provide information on the vulnerability of these sensitive ecosystems to climate change. Our research also focuses on coastal areas which are extremely vulnerable to sea-level rise and therefore considered high risk. The high population density, loss of coastal wetlands, the costs of defending sheltered shorelines and property, the loss of beaches and recreational facilities, as well as the impact on the infrastructure of coastal cities(i.e., sewers, drinking water supplies, etc.) establish the coastal regions as the most vulnerable region to climate change. The last component of our research focuses on the impacts of atmospheric stressors -- such as UV-B -- on ecosystem health, including potential linkages to amphibian decline.