Print PageAn important ecosystem property that is affected by environmental variability is net primary production, the amount of carbon removed from the atmosphere and stored in plants. Plant production can be divided into aboveground net primary production (ANPP) and belowground net primary production (BNPP). Previous research has provided us with good reason to expect that grasslands will be responsive to the changes in soil water predicted as a result of climate change. BNPP is known to make up half or more of total plant production in grasslands, and knowledge about it can provide important insight into changes in ecosystem processes. Yet there has been a paucity of studies examining the effect of altered soil water on BNPP. The objective of our research is to understand how changes in soil water will influence grassland ecosystem function in the driest portions of the central grassland region. We conducted a three year water manipulation experiment (2008 - 2010) at study sites on the shortgrass steppe and mixed grass prairie to examine the effects of altered soil water dynamics on total net primary production.
Results/Conclusions
We found that our water manipulation treatments were successful in changing the soil water content in the treatments- on average, the drought treatment decreased soil water by 20% and the water addition treatment increased soil water by 21%. These changes in soil water resulted in different, but significant responses in above and belowground production at our two grassland sites. There were few changes in ANPP at the shortgrass steppe, while there were significant changes to BNPP in 2009 and 2010 in response to our treatments. In contrast, there was a rapid increase in ANPP in response to water addition on the mixed grass prairie, while differences in BNPP were slow to emerge over the three year experiment.
