Prior to European settlement, the U.S. coastal prairie ecosystem extended for more than 800 kilometers along the Gulf Coast plain from central Louisiana to southern Texas. Since the late 1800’s, habitat loss and fragmentation due to railway development and the conversion of land to agriculture has reduced coastal prairies to roughly one percent of their former range. Today, a serious threat to these remaining prairies is plant invasions, especially from Chinese tallow trees (Triadica sebifera (L.) Small). Much research has been devoted to discovering efficient control methods, which, in addition to mechanical removal and the application of herbicides, has included adjustment of grazing pressure by domestic livestock, water logging of soils, and prescribed burning. In this study, we used matrix population models to investigate how invasive populations would respond to different types of control measures. Using Chinese tallow response to prescribed burning as an example, we illustrated how matrix population models can be used to design and assess effectiveness of invasive plant control strategies on coastal prairie.
Results/Conclusions
Our preliminary projections of population trends of Chinese tallow without prescribed burning compared favorably with results reported in the literature, with an annual rate of population increase (λ ≈ 2). Sensitivity analysis revealed that population growth rate was most influenced by adult survival, and elasticity analysis indicated a strong influence of adult and large sapling survival. Among all prescribed fire frequencies (burning every two, three, or four years), the semi-annual treatment produced a significant decrease in population growth (λ < 1). The model indicated that sustained control efforts would be needed to efficiently control Chinese tallow population growth.