PhD thesis,
Espaço e diversificação: uma perspectiva teórica
University of São Paulo, São Paulo : Instituto de Biociências, Master's Dissertation in Ecologia: Ecossistemas Terrestres e Aquáticos, (2014)
DOI: 10.11606/D.41.2014.tde-22092014-112838
Abstract
Some of the most consistent ecological patterns encountered in nature, such as
species-area relationships and rank-abundance distributions, can be predicted from a class
of neutral models. In this context, neutrality means demographic equivalence between
individuals of all species. Within this class of neutral models, species extinction by
demographic fluctuations is counterbalanced by some speciation mechanism. Each
particular speciation mode leaves an imprint in the resulting patterns. A model with a
mechanistic speciation implementation was shown to generate patterns dependent on
geographic constraints. I used individual based simulations with a mechanistic speciation
implementation to investigate whether the intrinsic spatial patterning of organisms could
transform biodiversity patterns. I found out that there is a phase transition on speciation
modes that is dependent on the spatial structure of the community. An extended range of
the biodiversity patterns found in nature can be unified into a single model because of
this phase transition. Clade richness and age relationships may be understood by the
predicted critical slowdowns in diversification. A new interpretation is given to the post
mass extinction "Dead Clade Walking" effect. An objective and biologically reasonable
redefinition of allopatric speciation is explored by exploiting the phase transition. I
propose the "speciation credit" effect, and its potential implications for long term
biodiversity conservation.
