Explaining extreme differences in species richness among co-occurring palm clades in Madagascar.
Resource type
Journal article
Date published
October 9, 2024
Abstract
Imbalance in species richness among related clades is a pervasive, yet incompletely understood feature of biodiversity. Comparison of species-poor and species-rich clades that have evolved within the same region can shed light on the mechanisms underlying this phenomenon. The long-isolated island of Madagascar is an ideal place for doing this. Madagascar harbours at least ten clades of palms (Arecaceae) that have colonised the island independently and diversified to widely differing degrees, ranging from one to 180 known species. We estimated colonisation times and diversification rates for these clades based on an extensive phylogenomic dataset and tested the degree to which clades that arrived in Madagascar earlier have more species (time-for-speciation effect), finding a moderate effect. For context, we tested for time-for-speciation effects in other plant and animal lineages, finding variable but qualitatively similar results. These findings suggest that variation in diversification rate (i.e. speciation and/or extinction rate) is a major driver of species richness imbalance among Malagasy clades, both in palms and elsewhere. We demonstrate that in palms, differences in diversification rates originated long before colonisation of the island, suggesting a minor role of classical “island radiation” and a stronger role of heritable traits driving diversification rate. Ability to colonise new climates also appears to play a role. Future work should address the interplay between the dynamic environment of Madagascar and the inherited traits of colonising lineages to fully explain the island’s intriguing mix of species-poor and species-rich clades.
Funder
| Funder name | Awards |
FP7 People: Marie-Curie Actions< European Union | Grant 327259 |
Villum Fonden, Denmark | Grant 0025354 |
Calleva Foundation, United Kingdom | |
Garfield Weston Foundation, United Kingdom | |
Journal title
Evolutionary Journal of the Linnean Society
Article number
kzae026
Publisher
Oxford University Press (OUP)
Place of publication
Oxford, UK
eISSN
2752-938X
Official URL
Rights statement
In Copyright
Additional information
IF = none
Collection