Deliberate or accidental invasions have
already constituted opportunities for eco
logical studiesls. However, all individuals
of a reintroduced population may be of
known origin. The size of the original population
is known exactly and this allows
predicted models of population dynamics
and genetics to be tested. Moreover, demographic
parameters can be estimated, at
least during the first years, for the overall
population and not only for an indeterminate
part of it.