These correspond to floodplain and upland communities that are well known and recognized as occurring broadly along the western edge of eastern deciduous forests. Our focus for this lab will be within the oak-pine upland forest. Within this community there are many fine-scale patterns of vegetation that could be the effects of many different causes. We will look for these patterns and explore some of the potential causes. The general idea is that clumping indicates limited dispersal, or ability to colonize only in canopy gaps, or, perhaps, patchiness in the distribution of preferred microhabitats.
Regular distributions indicate strong competition.
The null hypothesis is a random distribution. In a past study completed by one of the upper-division field ecology labs, this study was completed on trees in order to test the hypothesis that mature trees will form a regular pattern of dispersion due to competition for light and nutrients. Nearly all dispersion analyses showed either clumping or a random distribution, with the larger trees tending to be randomly distributed. This year we will concentrate on the sub-canopy to discover what patterns exist in a selected set of understory shrubs. Two species at the Houston Arboretum American Beauty-berry, Callicarpa americana, and Arrow Wood, Viburnum dentatum , have berries that birds find irresistable.