Coral reefs are retreating from equatorial waters and establishing new reefs in more temperate regions, according to new research in the journal Marine Ecology Progress Series. The researchers found that the number of young corals on tropical reefs has declined by 85 percent – and doubled on subtropical reefs – during the last four decades.
"We are seeing ecosystems transition to new blends of species that have never coexisted, and it’s not yet clear how long it takes for these systems to reach equilibrium. The lines are really starting to blur about what a native species is, and when ecosystems are functioning or falling apart."
The researchers, an international group from 17 institutions in 6 countries, compiled a global database of studies dating back to 1974, when record-keeping began. They hope that other scientists will add to the database, making it increasingly comprehensive and useful to other research questions.