Ecological causal explanation differs from mechanism explanation in that the former emphasizes "dependent relation" and the latter emphasizes "produce process". Raerlinne argues that ecological causal explanation is fallible and inadequate, which needs to be advanced to ecological mechanism explanation; Darden insists that causal explanation must be replaced by mechanism one. P?laru responds by arguing that ecological mechanism explanation, while is able to answer how mechanism occur, cannot explain overall causality, and that ecological causal explanation can be adequate and irreplaceable. In fact, for ecological cognition, both different explanations possessing their own merits can complement and optimize each other. To explaining ecological phenomena a mutual integrated approach is expected to apply.