2015 Annual Meeting for The Society for Mathematical Biology, Atlanta, GA
Across the estuaries of the east coast and wetlands of the Great Lakes, the invasive grass Phragmites australis outcompetes other vegetation and destroys local ecosystems. Because its roots are tolerant to salinity that other plants find hellish, Phragmites invasions begin with vegetative spread of genetic clones in brackish marshlands. This plant can grow over three meters tall at densities of 50 stems/m2, provides poor wildlife habitat, and is very difficult to eradicate.
A discrete life stage model on a yearly time step captures seed survivorship in a seed bank, sexual and asexual recruitment into a juvenile age class, and differential competition among all classes with adults. Small patches are often a single genetic individual, spreading asexually via stolons and rhizomes. When patches become genetically diverse, viable seeds are produced and invasion rates increase by an order of magnitude.
To aid in the management of Phragmites, we obtain invasion rates with and without genetic variation. These invasion speeds suggest prioritizing eradication of genetically diverse stands and simulations provide guidance on the scale of interventions.
Nydegger, Rachel; Duncan, Jacob P.; and Powell, James A., "Rooted in Hell: Predicting Invasion Rates of Phragmites Australis" (2015). 2015 Annual Meeting for The Society for Mathematical Biology, Atlanta, GA. Browse All Undergraduate research. Paper 42.