|
| Aim Island biogeography focuses on understanding the processes that underlie a
set of well-described patterns on islands, but it lacks a unified theoretical framework
for integrating these processes. The recently proposed general dynamic
model (GDM) of oceanic island biogeography offers a step towards this goal.
Here, we present an analysis of causality within the GDM and investigate its
potential for the further development of island biogeographical theory. Further,
we extend the GDM to include subduction-based island arcs and continental
fragment islands.
Location A conceptual analysis and a simulation of oceanic islands.
Methods We describe the causal relationships between evolutionary and ecological
processes implied by the GDM, implement them as a computer simulation and
use this to simulate two alternative geological scenarios.
Results The dynamics of species richness and rates of evolutionary processes in
simulations derived from the mechanistic assumptions of the GDM corresponded
broadly to those initially suggested, with the exception of trends in extinction rates.
Expanding the model to incorporate different scenarios of island ontogeny and
isolation revealed a sensitivity of evolutionary dynamics to attributes of island
geology.
Main conclusions We argue that the GDM of oceanic island biogeography has
the potential to provide a unified framework for island biogeography, integrating
geological, ecological and evolutionary processes. Our simulations highlight how
the geological dynamics of distinct island types are predicted to lead to markedly
different evolutionary dynamics. This sets the stage for a more predictive theory
incorporating the processes governing temporal dynamics of species diversity on
islands. | |
|