Invasion front dynamics of interactive populations in environments with barriers

Abstract

Invading populations normally comprise different subpopulations that interact while trying to overcome existing barriers against their way to occupy new areas. However, the majority of studies so far only consider single or multiple population invasion into areas where there is no resistance against the invasion. Here, we developed a model to study how cooperative/competitive populations invade in the presence of a physical barrier that should be degraded during the invasion. For one dimensional (1D) environment, we found that a Langevin equation as $$dX/dt=V_ft+\sqrt{D_f}\eta (t)$$ d X / d t = V f t + D f η ( t ) describing invasion front position. We then obtained how $$V_f$$ V f and $$D_f$$ D f depend on population interactions and environmental barrier intensity. In two dimensional (2D) environment, for the average interface position movements we found a Langevin equation as $$dH/dt=V_Ht+\sqrt{D_H}\eta (t)$$ d H / d t = V H t + D H η ( t ) . Similar to the 1D case, we calculate how $$V_H$$ V H and $$D_H$$ D H respond to population interaction and environmental barrier intensity. Finally, the study of invasion front morphology through dynamic scaling analysis showed that growth exponent, $$\beta$$ β , depends on both population interaction and environmental barrier intensity. Saturated interface width, $$W_{sat}$$ W sat , versus width of the 2D environment (L) also exhibits scaling behavior. Our findings show revealed that competition among subpopulations leads to more rough invasion fronts. Considering the wide range of shreds of evidence for clonal diversity in cancer cell populations, our findings suggest that interactions between such diverse populations can potentially participate in the irregularities of tumor border.

Barriers with Valve Mechanisms Are Predicted to Protect Crops from Slug Carriers of Rat Lungworm Disease

“…To explore how barriers with valve effects may reduce slug population densities in protected areas, we constructed a predictive model based on previous invasion models that mechanistically described organismal movement patterns in response to barriers [ 16 ]. We used findings from a previous field experiment to estimate the effect of a barrier apparatus with a valve mechanism on slug population densities [ 13 ], as well as laboratory experiments from the literature for slug speeds from which to estimate the velocity used in these models [ 12 ] (see Appendix A ).…”