Long-term Interactions Among Bodiversity, CO2, and N in a Perennial Grassland Ecosystem

Rapid human-caused increases in atmospheric carbon dioxide (CO2) levels during the next 50 years are almost certain to lead to global warming, influencing the growth and performance of vegetation worldwide. Plants and their ecosystems absorb roughly one-third of the CO2 emitted from fossil fuel combustion each year, and it is critical to understand whether plants can continue this important function as CO2 levels continue to rise. Realistic field experiments that test whether vegetation will continue to absorb extra C, and whether such C capture may be constrained by infertile soils or loss of diversity, number fewer than five in the world. The BioCON (Biodiversity, CO2, and Nitrogen) experiment is one of these, and is unique in testing interactions among atmospheric CO2, soil N supply, and plant species richness and composition, all of which have been simultaneously manipulated since 1998 in a temperate perennial grassland in Minnesota. This project will expose plants to CO2 levels expected to occur late in the 21st century; LTREB funds will help to maintain this experiment from 2007-2011 and to support a large number of measures of plants and soils relevant to both ecosystem science and atmospheric change.

This research will address issues of major importance to society regarding the potential impacts of human activities on environmental processes at local to global scales. It will determine whether lack of soil nitrogen constrains the long-term ability of ecosystems to capture and sequester carbon. Additionally, BioCON broadly enhances research and education, as a unique facility open to and encouraging new initiatives from interested scientists and students, and promoting teaching, training, and learning for students, teachers, journalists and others.