State or province

Hawaii, United States of America: 4 ecoregions. Each with its climate now and toward 2050, and its conservation tier.

Four ecoregions cover Hawaii and all four are tropical, which is true of no other state. The Hawai'i tropical moist forests hold the windward slopes, the Hawai'i tropical dry forests the leeward sides, and the Hawai'i tropical high shrublands and low shrublands the upper and drier ground. The low shrublands are in the Nature Imperiled tier. Rainfall does the sorting here, and it changes over remarkably short distances, so two gardens a few miles apart can be working in different ecoregions. The islands also carry one of the highest rates of plant species found nowhere else on earth, which makes the choice between a native and an introduced planting weigh more here than almost anywhere.