Sergei Petrovskii (Nara Women's University)
７月１１日 （火） 午後１：３０から
理学部3号館 ６階 数理生物学セミナー室
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The issue of pattern formation in biological communities
is one of the central problems in modern ecology. The spatial
distribution of species is usually highly inhomogeneous, both
in terms of total biomass and species composition. The
reasons of this heterogeneity, however, in many cases are still
understood rather poorly. In this talk, an account of recent
development in this field will be given. Most of attention will
be paid to the dynamics of relatively simple two-species prey-
predator model described by nonlinear partial differential
equations of "diffusion-reaction" type.
It will be shown that, under only a few weak restraints, the
"intrinsic" dynamics of this system leads to the formation of
realistic non-stationary irregular patterns. The formation of
the patterns is not induced by inhomogeneity of the system
parameters, external forcing or specific initial conditions. The
patterns arise due to rather an unusual spatio-temporal scenario
when regular spatial distribution of species is "displaced" by the
irregular one. Some ecological consequences of the pattern
formation will be considered, e.g. the change of the biodiversity
index. To assess the applicability of the results to the pattern
formation in ecological communities, I also discuss the robustness
of the main results to the choice of the type of inter-species
interactions.
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