Ancient geological dynamics impact neutral biodiversity accumulation and are detectable in phylogenetic reconstructions

Aim
Landmasses have been continuously modified by tectonic activity, the breakup and collision of landmasses is thought to have generated or suppressed ecological opportunities, altering the rates of speciation, dispersal and extinction. However, the extent to which the signatures of past geological events are retained in modern biodiversity patterns—or obliterated by recent ecological dynamics—remains unresolved. We aim to identify the fingerprint of different scenarios of geological activity on phylogenetic trees and geographic range size distributions.

Location
Global.

Time period
Geological time.

Major taxa studied
Theoretical predictions for any taxa.

Methods
We conducted spatially explicit simulations under a neutral model of range evolution, speciation and extinction for three different geological scenarios that differed in their geological histories. We set a limit on the number of populations that locally can coexist, which, along with the geographic boundaries of landmasses, influences the rate of range expansion.

Results
Our results demonstrate regions of similar size, age and ecological limits will differ in richness and macroevolutionary patterns based solely on the geological history of landmass breakup and collision even in the absence of species’ ecological differences, that is, neutrality. When landmasses collide, regional richness is higher, lineages exhibit more similar rates of speciation and phylogenetic trees are more balanced than in the geologically static scenario. Stringent local limits to coexistence yield lower regional diversity but in general do not affect our ability to distinguish geological scenarios.

Main conclusions
These findings provide an alternative explanation for existence of some hotspots of diversity in areas of high geological activity. Although a limit on the number of coexisting species largely influences regional diversity, its contribution to phylogenetic patterns is lower than variation in per-capita rates of speciation and extirpation. Importantly, these findings demonstrate the potential for inferring past geological history from distributions of phylogenies and range sizes.