DNA Study at Pioneer Mothers Memorial Forest
Professors and students from the University of Richmond, Wilkes University, Penn State University, and Purdue University collected DNA data from selected trees at Pioneer Mothers Memorial Forest in 2002. The study involved mature oaks and oak seedlings in the Pioneer Mothers Memorial Forest, a virgin tract of forest in southern Indiana which is now in a Research Natural Area.
The study was based on a premise that small mammals tend not to cache acorns from the several species of the white oak, instead they tend to eat these acorns immediately. These animals, however, do store acorns of the red oak species group.
The research sought to determine how this preference for caching acorns affects the distribution of seedlings. The expectation was that they would find white oak seedlings clustered around parent trees (where the acorn fell). In contrast, red oak seedlings should be widely scattered through the forest, perhaps even beyond the forest margin into adjacent open land (to the places animals like to store them). In previous years, the scientists had documented circumstantial evidence in support of this prediction.
The goal of this year's study was to test the prediction further. This was done by using the RECRUITS statistical model, which estimates seed shadows for each species, based on the mapped locations of each adult and seedling in the study plot. The other uses DNA fingerprinting to determine the parents of each seedling, and measure actual dispersal distances.
The Pioneer Mothers Research Natural Area was selected because the scientists wanted study plots from an undisturbed forest stand. The research methods had only minimal impact on the 17 acres studied. Each sample was flagged but the flags were removed after the samples were collected (over 4 days time). Tissue samples were taken from every seedling and adult oak tree within the study plots (e.g., leaf, twig, cambium, acorn). Using molecular genetic techniques (DNA fingerprinting), the researchers intend to determine which adult trees are the parents, and thereby measure dispersal distances directly.
The researchers hope to continue this study with subsequent visits in future years. In particular, they may wish to remap and sample seedlings on this plot (examining subsequent years of seedlings from these adult trees).
The DNA samples were taken back to the labs at Wilkes University and Penn State for analysis. It may take a year to process all the samples since more than 600 individual seedlings and mature tree samples were collected
These flags in the Pioneer Mothers Memorial Forest indicate the location of sampled seedlings.