Imperial College London


Faculty of Natural SciencesDepartment of Life Sciences (Silwood Park)

Reader in Biodiversity Theory



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BibTex format

author = {Tao, R and Sack, L and Rosindell, J},
doi = {10.3389/fevo.2021.644328},
journal = {Frontiers in Ecology and Evolution},
pages = {1--14},
title = {Biogeographic drivers of evolutionary radiations},
url = {},
volume = {9},
year = {2021}

RIS format (EndNote, RefMan)

AB - Some lineages radiate spectacularly when colonising a region, but others do not. Large radiations are often attributed to species’adaptation into niches, but sometimes instead to other drivers, such as biogeography. Here we aim to disentangle the factorsdetermining radiation size, by modelling simplified scenarios without the complexity of explicit niches. We build a spatiallystructured neutral model free from niches and incorporating a form of protracted speciation that accounts for gene flow betweenpopulations. We characterise the behaviour of the model for a range of different networks of connectivity between patches. Wefind that a wide range of radiation sizes are possible depending on the combination of geographic isolation and species' dispersalability. For example, when considering isolated archipelagos, low rates of dispersal from the mainland result in decreasedcompetition and thus increased radiation size. Dispersal between habitat patches also has an important effect. At extremely lowdispersal rates, each habitat patch has its own endemic species, intermediate dispersal rates foster larger radiations. Asdispersal rates increase further, a critical point is reached at which identical lineages can vary greatly in radiation size due torare and stochastic dispersal events. At the critical point, some lineages remain a single species for a long time, whilst otherswith identical characteristics produce the largest radiations of all. The mechanism for this is a ‘radiation cascade’ in whichspeciation leads to reduced numbers of individuals per species, and thus reduced gene flow between conspecifics in isolatedpatches, leading to yet more speciation. Once a radiation cascade begins, it continues rapidly until it is arrested by a newequilibrium between speciation and extinction. We speculate that such cascades may occur more generally and are not onlypresent in neutral models. This may help to explain rapid radiation, and the extreme radiation si
AU - Tao,R
AU - Sack,L
AU - Rosindell,J
DO - 10.3389/fevo.2021.644328
EP - 14
PY - 2021///
SN - 2296-701X
SP - 1
TI - Biogeographic drivers of evolutionary radiations
T2 - Frontiers in Ecology and Evolution
UR -
UR -
UR -
VL - 9
ER -