[en] Full text: We present 2D numerical simulation studies investigating the impact of the electronic β- parameter and of curvature effects on the nonlinear evolution of drift tearing islands. We observe a bifurcation phenomenon that leads to an amplification of the pressure energy, the generation of ExB poloidal flow and a nonlinear diamagnetic drift that affects the rotation of the magnetic island. These dynamical modifications arise due to quasi linear effects that generate a zonal flow at the onset point of the bifurcation. Our simulations show that the transition point is influenced by the β-parameter such that the pressure gradient through a curvature effect strongly stabilizes the transition. Regarding the modified rotation of the island, a model for the frequency is derived in order to study its origin and the effect of the β-parameter. It appears that after the transition, an ExB poloidal flow as well as a nonlinear diamagnetic drift are generated thanks to an amplification of the stresses by pressure effects. (author)