Nature seems to be well equipped to maintain and keep its ecosystem clean. It is only man, who tends to interfere with it, demanding credit in the job, but landing up only disrupting the pristine earth’s eco-balance.
This is well manifested by a new benefit of sharks to the ecosystems. A recent study has discovered that the Australian tiger sharks are able to control where local herbivores can nibble, by literally maintaining a ‘tidy lawn’ for their neighbors in the marine environment.
Particularly in the seagrass communities, a countless other creatures are found to depend on the presence of sharks. Lead author of the study, Aaron Wirsing told Discovery News,
Seagrasses form the foundation for many near-shore marine ecosystems. (In Western Australia’s Shark Bay seagrass is) nourishing and sheltering a host of invertebrates and fishes that, in turn, support top predators like sharks.
It is interesting to find how the tiger sharks’ presence can specifically affect the feedings of dugongs, the large aquatic mammals resembling their manatee relatives. Dugongs precisely spend much of their day chewing on seagrass.
It is the dugong grazing that can hold the growth of seagrass in check, which otherwise if left unchecked; the herbivores would simply wipe out all of the seagrass. Thanks to the tiger sharks here.
But, unfortunately, human influence as usual has kept both the tiger shark and dugong populations dangerously low. Fishing net entanglement as well as habitat destruction has lead to the dugongs’ boom in certain regions, like the Tanzanian waters.
This study is published in the current issue of Animal Behavior.