Population Dynamics P systems refer to a formal framework for ecological
modelling. The semantics of the model associates probabilities to rules, but at the
same time, the model is based on P systems, so the rules are applied in a maximally
parallel way. Since the success of the rst model using this framework [5], initially
called multienvironment probabilistic P systems, several simulation algorithms have been
de ned in order to better reproduce the behaviour of the ecosystems with the models.
BBB and DNDP are previous attempts, which de ne blocks of rules having the
same left-hand side, but do not de ne a deterministic behaviour when di erent rules are
competing for the same resources. That is, di erent blocks of rules present in their lefthand
side common objects, being applicable at the same time. In this paper, we introduce
a new simulation algorithm, called DCBA, which performs a proportional distribution of
resources.Junta de Andalucía P08-TIC04200Ministerio de Educación y Ciencia TIN2009-1319
