General objectives for this project:

Our goals for this project are: (1) Increase our ability to predict the environmental drivers of the subdominant community (2) Increase our understanding of how these communities vary on site, and how they may change in a drier future climate, and (3) begin to correlate the drivers of coexistence (whether biotic or abiotic) across the scale of inquiry: from plant to community to population. 

To understand and predict the role of environmental variability on the subdominant plant community depends on our ability to link responses across scales (individual-community-population) and to reliably measure temporal differences in microclimate variability, which varies withinin the tallgrass prairie according to landscape structure. To increase our ‘ecosystem-level' understanding, we have begun a replicated study that spans the varying site drivers and environmental variability present at the Konza Prairie. We have continuous microclimate monitoring (temp., PAR, soil water & N availabiltiy), within a replicated experimental framework that spans both landscape (watersheds), and biological drivers (dominant C₄ grasses) of community structure. At each research location, there is a paired plot in which one plot (5*5m) contains the representative native plant community and the adjacent plot contains just the subdominant species (dominant C₄ grasses removed). Because previous work on site has shown the greatest predictor of sub-dominant productivity and occurrence is an inverse relationship with grass productivity and occurrence (Briggs and Knapp 2001), such an approach should hopefully provide greater insight for the both the role of biotic and abiotic drivers of the sub-dominant plant community.

Using this framework we hope to answer several questions, including:

•  what is the specific mechanism by which grasses are affecting on the subdominant community to regulate their occurrence/productivity?

•  how do environmental factors interact to promote or mitigate this response?

Also, because these relationships will likely vary based on site-specific resource limitations, replicating this protocol across the drivers of community structure (fire/grazing/topography) will hopefully provide insight into the role of shifting resource limitations (or co-limitations) on species co-existence. Using this experimental framework, we will hopefully be able to address the similarity/differences of mechanisms operating across specific scales of reference (individual physiology – community – population).