DEVELOPING AN EVOLUTIONARY NICHE MODEL FOR TROPICAL SOUTH AMERICA

The Amazon rainforest and adjacent Andes mountains represent one of the world’s greatest biodiversity hotspots – if not the most biodiverse region on Earth. The origin of this great biodiversity has been a topic of debate for more than one hundred years (discussed by Darwin, among others) – and despite this long history of investigation, remains a core problem in modern science

Within the Andes/Amazon system, the geophysical environment encountered by organisms is governed by the rise of the Andes mountains affecting topography, precipitation patterns and soil nutrient input; changes in global and local climate conditions affecting temperature, precipitation and seasonality, the development of the various Amazon foreland basins affecting lowland drainage patterns and the hydrology of the rivers and lakes within that drainage system affecting local topography and soil chemistry. The complex interplay of these geophysical factors presents an ever-changing environment in which biota must compete and adapt, necessarily driving genetic change over time. Likewise, changes in the biota will affect the geophysical environment, for instance by affecting soil chemistry, erosion and rainfall. High biodiversity, however, requires not just geophysical conditions which can support many species, but also a history which fuels speciation – biodiversity can only increase when speciation outpaces extinction.

Here we present an evolutionary niche model, currently in development, which combines (a) conventional ecological niche modelling (using MaxEnt) applied over changing climatic conditions with (b) a model of the biological processes that affect how a species’ distribution and genetics might change over time, potentially leading to an allopatric speciation event.