Bioclimatic and physical characterization of the world's islands

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 island characterization for 17,883 of the world’s marine islands >1 km² (∼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 heterogene...