Climate change due to increases in anthropogenic carbon is altering global patterns of temperature and rainfall. These environmental changes are transforming plant communities, which in turn may be causing local extinctions of many vertebrate species. For example, when faced with prolonged heat waves and droughts, trees may be unable to draw sufficient water from the soil and drop most of their leaves. Diminished leaf cover allows more sunlight to reach the ground, amplifying local warming trends and increasing heat and water stress for plants themselves and for many vertebrate species. The goal of this award is to evaluate how climate-driven changes to plant communities are increasing extinction rates for certain "cold-blooded" vertebrate species (i.e., lizards, frogs). This study hypothesizes that many such vertebrate species are going extinct in part because rising temperatures are directly stressful to them, and in part because rising temperatures also damage plant communities, upon which animals rely for food, water, and shelter. Intensive studies will be made at specific localities on five continents where targeted animal species have recently gone extinct. At these sites, researchers with expertise in plant and animal physiology and ecology will collaborate to quantify the extent to which recent droughts and warm-spells have altered plant communities, which in turn have increased heat and water stress on animals. These local studies will then be linked (via remote sensing methods and online databases), to create a worldwide data set that integrate information on temperature, rainfall, plant die-offs, and the physiological limits of targeted animals to heat and water stress. Such data will enable scientists to predict and test, with unprecedented accuracy across regions and continents, how extinction rates among targeted vertebrate species relate to current and expected changes in rainfall, temperature, and plant communities.
Previous models of climate-warming impacts have focused on plants or animals, but not both. For example, many climate change scientists study animal systems in isolation of plant systems, thus emphasizing only the role of changing climate per se on animal taxa (e.g., rising temperatures limit lizards from foraging in direct sunlight). This project differs by a) modeling how climate-driven changes to plant communities increase warm spells and drought conditions, and b) showing how changes to plant communities alters the environment available used by the targeted animals species and push their physiological limits, speeding their extinction rates. This model will be grounded by field studies that test for non-climate related causes of animal extinctions; this will enable scientists to determine the factors that explain the ever increasing extinction rates among targeted animals. New web-based products will be developed that use remote sensing technology to predict current and future degradations in ecosystems across the globe. A project of this scope requires collaboration among scientists with expertise in climatology, physiology, biodiversity, and remote sensing. An international team from 20 countries will work together on this project; a new generation of postdoctoral research fellows and hundreds of graduate students will be trained in the latest physiological and mathematical methods in climate change studies.
