In this paper pattern formation and interactions in a spatially extended Belousov-Zhabotinsky reaction medium are investigated numerically. Backfiring, nonannihilation collisions and reflections at nonflux boundaries have been observed in the vicinity of three types of bifurcations including supercritical and subcritical Hopf-bifurcations and the Canard bifurcation. In the vicinity of a supercritical Hopf-bifurcation, backfiring and collision-stable behavior do not appear until the system exhibits small amplitude oscillations. In complement to earlier investigations, this study illustrates that the collision-stable behavior also exists under the dynamics where the system has only one stable attractor. The influence of relative molecular diffusivities on the backfiring and nonannihilation collisions has been characterized over a broad range of bifurcation conditions, which shows that increasing the relative diffusivity of the activator favors the appearance of the above complex behavior. The transition from a supercritical Hopf-bifurcation to a Canard bifurcation has also been investigated. (C) 2003 American Institute of Physics.