Climate change threatens Lakshadweep’s coral reefs: Study
A mention of Lakshadweep islands conjures up images of pristine beaches, clear blue seas and coral reefs that are home to a diversity of plant and animal life. Researchers, however, are asking how long the islands will remain in their idyllic state.
A nearly two-decade-long study by the Oceans and Coasts Program of the Nature Conservation Foundation (NCF) has found that the absolute coral cover in these islands has diminished from 51.6% in 1998 to 11% in 2017, a staggering decline.
The study has found that the alarming rate of coral mortality and their shifting species compositions, combined with a slow rate of recovery, could severely limit their ability to resist future disturbances resulting from climate change.
“The enormous drop in coral cover is a result of repeated and increasingly severe climate change-related disturbance,” says Shreya Yadav, who along with Teresa Alcoverro and Rohan Arthur, published the findings in the journal Coral Reefs earlier this month. She adds, “By monitoring the same reefs since 1998 through a series of El Niño disturbance events, we found that the way a single reef responds to and recovers from a stressor can change drastically through time. Reefs are infamously complex and dynamic systems, but our study shows that in the Lakshadweep, a changing community of corals in a warming environment has led to a four-fold drop in recovery rates since 1998.”
El Nino is a periodic weather phenomenon associated with the warming of surface temperatures in the Pacific Ocean thought to be responsible for drought in India and other parts of South Asia.
DEATH BY EL NIÑO
The Lakshadweep islands are an archipelago of 36 atolls in the eastern Indian Ocean, off the south-west coast of India. An atoll is a ring-shaped reef, island, or a chain of islands formed of coral.
Over their research period, the team monitored six reefs across three islands to find out answers to two questions. How resistant are the reefs to climatic anomalies?
And, how well do they recover? They found that El Niño events — which kill large tracts of coral -- are occurring more regularly than ever before. Three mass bleaching of corals have been experienced here in the last 20 years -- in 1998, 2010 and 2016.
“Each of this was linked to an El Niño current, and each was of a higher intensity than the previous one,” says Arthur, the senior author of the research paper.
He adds, “The good news is that with every subsequent El Niño event, less coral is dying — the reefs are becoming more resistant. The bad news is that their ability to recover from each event has declined dramatically. The even worse news is that the frequency of these disturbance events is increasing all the time — killing the reef before it is able to limp back to health again.”
BENGALURU:
A SLIVER OF HOPE
While the overall findings indicate that the Lakshadweep islands are facing a full frontal assault from climate change, there are small slivers of hope to hang on to.
Yadav says, “We also found that the amount of coral death following each disturbance event has been declining since 1998. This is because a more resistant community of corals now dominates these reefs.”