Island Biogeography and Species Diversity

Island biogeography examines how the size and isolation of landmasses surrounded by water shape the richness and composition of their biota. Classic theory posits that larger islands host more species due to greater habitat heterogeneity and lower extinction rates, while more isolated islands receive fewer colonists. This framework has expanded to include functional diversity (traits that influence ecosystem processes) and phylogenetic diversity (evolutionary distinctiveness), revealing that area and distance affect not only species counts but also the range of ecological roles and evolutionary lineages. Insular systems serve as natural laboratories for studying community assembly, evolutionary radiation and extinction dynamics. Contemporary research integrates geometric, demographic and climatic factors to predict how habitat loss, invasive species and changing environments will re‐shape diversity on islands, with implications for global conservation planning and the management of biodiversity hotspots.

Research from Nature Portfolio

Recent theoretical advances have applied extreme value theory to the species–area relationship, showing that the classic triphasic curve emerges from the spatial distribution of individual species ranges relative to a sampling focal point. This approach yields analytic expressions for the transitions between rapid, intermediate and accelerated phases of species accumulation and can be fitted to empirical data across continents and taxa. Complementary work on habitat loss demonstrates that the geometry of area reduction – whether from edges inward, from the centre outward or at random – critically influences the proportional loss of species as well as phylogenetic and functional diversity. Finally, global mapping of island vulnerability to climate change highlights that islands at all latitudes differ in exposure to sea‐level rise, temperature and rainfall shifts. Analyses of plant lineages reveal that projected losses of deeply divergent clades may exceed random expectations, underscoring the urgency of targeted risk assessments.

Island Biogeography and Species Diversity publication trend

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

Technical terms

Species–area relationship: An empirical power‐law or triphasic pattern describing how the number of species increases with the area sampled.

Endemism: The state of being restricted to a particular geographic location, often a single island or archipelago.

Functional diversity: The range and distribution of ecological traits within a community that influence ecosystem functioning.

Phylogenetic diversity: A measure of biodiversity that accounts for the evolutionary distances among species in a community.

Small‐island effect: A phenomenon in which species richness on very small islands shows little or no relationship with island area, often due to stochastic and edge influences.

References

1. Modelling the species-area relationship using extreme value theory. Nature Communications (2025).
2. On the decline of biodiversity due to area loss. Nature Communications (2015).
3. Vulnerability to climate change of islands worldwide and its impact on the tree of life. Scientific Reports (2019).
4. A global analysis of avian island diversity–area relationships in the Anthropocene. Ecology Letters (2023).
5. Scientists’ warning – The outstanding biodiversity of islands is in peril. Global Ecology and Conservation (2021).
6. Species–area relationships on small islands differ among plant growth forms. Global Ecology and Biogeography (2020).