Evolutionary Biogeography of Island Faunas

Island settings provide a natural laboratory for examining how dispersal, speciation and extinction interact against a backdrop of dynamic geology. The evolutionary biogeography of island faunas explores the processes by which species colonise, diversify and adapt in isolated environments, where limited area and barriers to gene flow foster distinct patterns of endemism and adaptive radiation. Variation in island age, size and connectivity—shaped by tectonic movements, volcanic activity and fluctuating sea levels—creates a complex landscape of opportunities and constraints that governs lineage accumulation. Insights from this field have elucidated mechanisms of founder‐event speciation, vicariance and ecological divergence, while informing conservation strategies for vulnerable insular taxa. Advances in molecular phylogenetics, palaeogeographic reconstruction and spatially explicit modelling now allow precise estimation of colonisation timing and diversification rates, deepening our understanding of how earth history and evolutionary processes co-operate to generate island biodiversity worldwide.

Research from Nature Portfolio

Recent studies have applied high‐resolution phylogenomic approaches to flightless beetles across the Sunda Arc, demonstrating that diversification closely tracks the chronology of island emergence and colonisation routes, with Sulawesi acting as a dispersal hub and classical barriers such as Wallace’s Line exerting less constraint than previously assumed. Foundational work on birdwing butterflies has further revealed that founder‐event speciation and density‐dependent diversification have driven multiple radiations across the Indomalayan‐Australasian archipelago, with extinction pulses correlated with palaeo‐sea‐level and climatic oscillations during the Miocene.

Evolutionary Biogeography of Island Faunas publication trend

The graph below shows the total number of articles in evolutionary biogeography of island faunas across all publications each year (not limited to Nature Index journals).

Technical terms

Endemism: The ecological state of a species being restricted to a defined geographic area, such as an island.

Vicariance: Species divergence resulting from the emergence of a physical barrier splitting a once continuous distribution.

Founder-event colonisation: Establishment of a new population by a small number of individuals dispersing to and reproducing in a previously unoccupied area.

Time-calibrated molecular phylogeny: A phylogenetic tree derived from genetic data that incorporates known divergence dates to estimate the timing of branching events.

Adaptive radiation: Rapid diversification of a lineage into multiple species occupying different ecological niches following colonisation of new environments.

References

1. Macroevolution of hyperdiverse flightless beetles reflects the complex geological history of the Sunda Arc. Scientific Reports (2016).
2. Deciphering the evolution of birdwing butterflies 150 years after Alfred Russel Wallace. Scientific Reports (2015).
3. Generalizing Bayesian phylogenetics to infer shared evolutionary events. Proceedings of the National Academy of Sciences of the United States of America (2022).