Bioclimatic and physical characterization of the world’s islands

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 110; no. 38; pp. 15307 - 15312
• Main Authors: Weigelt, Patrick, Jetz, Walter, Kreft, Holger
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences 17.09.2013; National Acad Sciences
• Subjects: Altitude; Animal and plant ecology; Animal, plant and microbial ecology; Arid climates; Bioclimatology; Biodiversity; Biogeography; Biological and medical sciences; Biological Sciences; Climate; Climate change; Cluster Analysis; data collection; ecoregions; ecosystems; Environment; evolution; Flowers & plants; Fundamental and applied biological sciences. Psychology; Geological Phenomena; Harbors; Heterogeneity; Islands; Models, Biological; multicultural diversity; Oceans and Seas; Ordination; Physical Sciences; Plant species; Plants; Principal Component Analysis; Rain; Seasonal variations; Seasons; species diversity; Species richness; Species Specificity; Synecology; temperate zones; Temperature; Terrestrial ecosystems; Wet climates; World; Species diversity; Geographic distribution; vascular plant diversity; Vegetation; environmental regionalization; Biogeography; island biogeography; Island; Species richness
• ISSN: 0027-8424; 1091-6490; 1091-6490
• DOI: 10.1073/pnas.1306309110

The Earth’s islands harbor a distinct, yet highly threatened, biological and cultural diversity that has been shaped by geographic isolation and unique environments. Island systems are key natural laboratories for testing theory in ecology and evolution. However, despite their potential usefulness for research, a quantitative description of island environments and an environmental classification are still lacking. Here, we prepare a standardized dataset and perform a comprehensive global environmental characterization for 17,883 of the world’s marine islands >1 km ² (∼98% of total island area). We consider area, temperature, precipitation, seasonality in temperature and precipitation, past climate change velocity, elevation, isolation, and past connectivity—key island characteristics and drivers of ecosystem processes. We find that islands are significantly cooler, wetter, and less seasonal than mainlands. Constrained by their limited area, they show less elevational heterogeneity. Wet temperate climates are more prevalent on islands, whereas desert climates are comparatively rare. We use ordination and clustering to characterize islands in multidimensional environmental space and to delimit island ecoregions, which provides unique insights into the environmental configuration and diversity of the world’s islands. Combining ordination and classification together with global environmental data in a common framework opens up avenues for a more integrative use of islands in biogeography, macroecology, and conservation. To showcase possible applications of the presented data, we predict vascular plant species richness for all 17,883 islands based on statistically derived environment–richness relationships.