资源简介:
Droughts are forecast to become increasingly frequent and intense in many regions worldwide, likely impacting community structure, ecosystem functioning, and ecosystem services. The International Drought Experiment (IDE) is a coordinated, multi-site drought experiment requiring only a moderate investment of time and resources by investigators. This coordinated, distributed experiment will quantify the impacts of extreme drought across a wide range of terrestrial ecosystems based on a common experimental design and a comparable suite of measurements. We aim to establish two stand-alone experiments following the IDE design at Cedar Creek. Precipitation reduction shelters will be established during spring 2017 to simulate a 1 in 100 year dry event, which at our site corresponds to removing 43% of annual precipitation. The tIDE (trait IDE) study will be established in e248 plots in the Big Biodiversity experiment field. The three precipitation treatments described above will be applied at the subplot level and fully crossed with the two current irrigation treatments (ambient or ambient plus ~2 cm per week of irrigation) and with two of the current fertilization treatments (unamended or 14 g N m-2), with six true replicate plots for each of the 12 treatment combinations, for a total of 72 subplots. Standard measurements across these two experiments and all other DroughtNet sites will include peak aboveground biomass clipping, soil carbon and nitrogen content, plant community composition from % cover, plant traits, and meteorological measurements (daily precipitation, air temperature). Many sites will also measure light availability, root biomass, soil moisture, and decomposition rates of tea bags and tongue depressors. Pre-treatment data will be collected during 2016. The experiment is expected to have minimal impacts on Cedar Creek and on other projects.