The world’s tropical coral reefs are under threat from overfishing, habitat modification, and global warming. One of the most visible signs of a decline in the condition of coral reefs is the widely documented shift from a healthy state in which corals dominate to a weedy state in which algae (so-called “macro algae") dominate. It has been repeatedly demonstrated that this phase shift can be triggered by a loss of algae-consuming herbivores, especially parrotfishes and surgeonfishes. However, the critical question has remained: How can this coral-algal phase shift be reversed"
By simulating overfishing in large experimental plots on the Great Barrier Reef, the researchers in the new study intentionally triggered a phase shift to algal dominance on a healthy reef. They then filmed the reef’s recovery with remote underwater digital videos cameras. Remarkably, only two of the 27 herbivorous fish species present on the reefs had any significant impact on its recovery from algal overgrowth. What was most surprising was that the dominant browser was a rare batfish, a species previously thought to be an invertebrate f eeder. Meanwhile, parrotfishes and surgeonfishes, which are the routine consumers of seaweed on coral reefs, were unable to reverse runaway algal blooms.
The study’s findings highlight the unexpected importance of a single rare species in the recovery of coral reefs, and potentially contribute to the identification and future protection of species groups that underlie the resilience and regenerative capacity of coral reef ecosystems.
Related biology news :
1. New species from old data
2. Same mutation aided evolution in many fish species, Stanford study finds
3. Fibril Shape Is The Basis Of Prion Strains And Cross-species Prion Infection
4. Reservoirs may accelerate the spread of invasive aquatic species, researchers say
5. Small species back-up giant marsupial climate change extinction claim
6. Aggressive aquatic species invading Great Lakes
7. Bush, Cheney and Rumsfeld are now species of slime-mold beetles -- but strictly in homage
8. Internet viruses help ecologists control invasive species
9. An (ecological) origin of species for tropical reef fish
10. Ancient DNA helps clarify the origins of two extinct New World horse species
11. Invasive parasite destroying fish species