Effects of Global Environmental Changes on Ecological Systems

Human activities are the major forces underlying global environmental changes (e.g., nutrient enrichment, warming, shifts in precipitation levels, biological invasions). These environmental changes are negatively affecting the structure and functioning of Earth’s ecosystems. Their effects have been found to severely affect from organismal physiology to species interactions to ecosystem structure and function. In our research, we integrate large scale surveys, field and lab experiments, and data synthesis (e.g., meta-analysis) to test the effects of these changes in ecological systems. We are addressing the effects of nutrient enrichment and warming on ecological systems through the combination of large-scale surveys and field experimental manipulations. To do this, we are using natural (tank bromeliads and pitcher plants) and artificial microcosms. Tank-bromeliads and pitcher plants are model systems for studying the impacts of nutrient deposition on an entire ecosystem, because we can easily manipulate nutrient inputs in realistic field experiments, and measure nutrient pools and fluxes on time scales of days, weeks and months. In collaboration with Nick Gotelli (Vermont University) and Gustavo Romero (UNICAMP, Brazil). Synthesis work in the lab is focused on the effects of nutrient enrichment on aquatic and terrestrial ecosystems. We are also investigating how nutrient enrichment interacts with warming to affect key ecological processes such as, individual growth rates, biomass production, species interactions, and ecosystem functions. In addition, we are testing how shifts in precipitation affect plant functional traits, plant and animal community structure, and ecosystem functions. As part of the SESYNC working group on Disease, Ecosystem Processes, and Humans led by Elizabeth Borer & Eric Seabloom, we are also testing how multiple global changes affect plant-pathogen interactions and the extent of disease they cause. Other synthesis work we are currently working on is addressing the effects of invasive species (invertebrates and vertebrates) on nutrient dynamics at ecosystem level.