Prairies in the loess hills are dominated by little
bluestem (Schizachyrium scoparium) and side-oats grama (Bouteloua
curtipendula) on south- and west-facing slopes. Tall
grasses like big bluestem (Andropogon gerardii), switchgrass (Panicum
virgatum), and indian grass (Sorghastrum nutans) are dominant on
north- and
east-facing slopes and in lowlands. Cool season grasses such as junegrass
(Koeleria macrantha), porcupine grass (Stipa spartea), Canada
wildrye (Elymus canadensis) and Dichanthelium spp. are important
as well. Many interesting forbs are also found,
including many species
that are at their eastern-most range limit, such as yucca (Yucca glauca)
and
skeleton rush (Lygodesmia juncea).
Dozens
of forb species are found even in small remnants (Wilsey et al. 2005
Conservation Biology), and forbs make up a large portion of the species
diversity of a given site.
We are beginning to construct studies on what determines species diversity in loess hills prairies. Studies are planned to look at how grass species identity might impact prairie forb recruitment from over-seeding experimental plots (see picture below). It is poorly known how species identity influences diversity, and which species traits are associated with species diversity suppression. Measurements of species growth rates, height, and lateral spread will be measured to develop a mechanistic understanding of how species impact the diversity of developing prairie communities, and in turn, how differences in diversity will impact ecosystem processes.
