Forget the Hoe: Managing Invasive Plant Species with Dynamic Programming"

Abstract Bromus Tectorum is an invasive plant species known to reduce abundance of native perennial grasses, increase fire frequency and intensity, decrease animal performance, and alter microbial communities and ecosystem processes. Specifically, in the Intermountain West, Bromus has been associated with decreases in livestock performance. Land managers use several methods to control invasion, but no previous studies fully integrate the dynamic interaction between control methods and the biophysical behavior of Bromus invasion. This research uses dynamic programming in conjunction with a process based ecological model to solve for optimal management strategies of Bromus invasion. The model represents biological responses to different management strategies given exogenous land, animal, and weather characteristics. The model is solved for both finite and infinite time horizons. This research tests the hypotheses that it is not always optimal to manage Bromus invasions, but more realistically, invasions should only be managed in specific instances. Moreover, the control sets that constitute optimal responses to Bromus invasion depend entirely on the specifics of each instance.