  In the companion paper of this set (Capitan and Cuesta, 2010) we have
developed a full analytical treatment of the model of species assembly
introduced in Capitan et al. (2009). This model is based on the construction of
an assembly graph containing all viable configurations of the community, and
the definition of a Markov chain whose transitions are the transformations of
communities by new species invasions. In the present paper we provide an
exhaustive numerical analysis of the model, describing the average time to the
recurrent state, the statistics of avalanches, and the dependence of the
results on the amount of available resource. Our results are based on the fact
that the Markov chain provides an asymptotic probability distribution for the
recurrent states, which can be used to obtain averages of observables as well
as the time variation of these magnitudes during succession, in an exact
manner. Since the absorption times into the recurrent set are found to be
comparable to the size of the system, the end state is quickly reached (in
units of the invasion time). Thus, the final ecosystem can be regarded as a
fluctuating complex system where species are continually replaced by newcomers
without ever leaving the set of recurrent patterns. The assembly graph is
dominated by pathways in which most invasions are accepted, triggering small
extinction avalanches. Through the assembly process, communities become less
resilient (e.g., have a higher return time to equilibrium) but become more
robust in terms of resistance against new invasions.
