Since the mid-1990s, the coral of the Great Barrier Reef has declined by more than 50%, and this applies to virtually all species, at all depths and sizes, according to a new study.
The the investigation covered the 2,300 kilometers of the Great Barrier Reef and found worrying loss on almost every level.
“Our results show that the resilience of the Great Barrier Reef, its resilience, is compromised compared to the past, as there are fewer babies and fewer large breeding adults.
As in primary forests, these are corals the biggest ones that most concern marine scientists.
The loss of older corals like this could have a cascading effect on the entire system. reefsbecause larger colonies in a population disproportionately impact the genes and reproduction of the next generation, while providing more habitat and food for fish and other reefs.
“The global decline of large and old trees, for example, involves loss of critical habitat, food and carbon storage,” the authors. But while the size of terrestrial forests has been carefully monitored over the years, trends in coral size are rarely examined; it is traditionally a cover.
To fill this gap, researchers have documented the systematic decline in coral abundance in the Great Barrier Reef in size, habitats, sectors and taxa from 1995 to 2017. During this period, the reef experienced several local cyclones, four episodes of mass bleaching and two major outbreaks of thorn-crowned starfish (not to mention another severe bleaching event occurred earlier this year).
Explore the vast expanse of the Great Barrier Reef this is obviously quite a challenge, and to estimate the size of the colonies, the researchers used the intersection lengths of the lines as a proxy.
This means that a line has been placed on the barrier Reef to measure the total length of various bodies below.
The authors found that coral abundance declined dramatically in all colony sizes and all coral taxa. These changes were most pronounced in the northern and central regions of The great coral barrier, where most of the recent massive coral bleaching has occurred.
Of particular concern is the loss of medium and large colonies, as they could potentially delay reproduction and prevent older corals from rebuilding declining populations. At the same time, the disproportionate loss in small colonies suggests a reduction in the spread of small coral larvae.
“The systematic decline of small colonies in all regions, habitats and taxa suggests that a decline in recruitment has further eroded the recovery potential and resilience of coral populations.”
“But if we get to 3-4 ° C due to uncontrolled emissions, we will not have a recognizable Great Barrier Reef.
The study was published in the Proceedings of the Royal Society B.