Increasing reforestation efforts in coastal regions could significantly reduce the amount of sediment runoff reaching coral reefs and improve their resilience, according to a study by the University of Queensland.
The study analyzed more than 5,500 coastal areas around the world and found that nearly 85% of them leached sediment to coral reefs, the second most serious threat to the world’s reefs behind climate change. .
Dr Andrés Suárez-Castro of UQ’s Center for Biodiversity and Conservation Science said it was important to tackle the problem of sediment runoff if efforts to reduce human impact on reefs were to be successful. fruits.
“Increased sedimentation can make aquatic ecosystems more sensitive to heat stress, which decreases the resilience of corals to pressures caused by climate change,” said Dr Suárez-Castro.
“If the link between land and sea is not recognized and managed separately, any future efforts to conserve marine habitats and species are likely to be ineffective.”
Excess sediment runoff from land clearing and agrochemical pollution along coasts can increase sediment transport to coastal waters.
Dr Suárez-Castro said that one of the impacts of sediment runoff on coral reefs is a massive reduction in light levels that were essential for the growth and reproduction of corals and seagrass beds.
One solution proposed by Dr Suárez-Castro and his team is for countries to commit to restoring land and forests in coastal regions, which will help reduce the amount of sediment runoff.
“Reforestation is extremely important because it maintains the stability of soils which are essential to limit the risk of erosion – it also helps to trap more sediment and prevent it from reaching aquatic systems,” he said. .
“Building the resilience of corals by reducing sediment and pollution is also essential for improving the recovery potential of a coral reef.
“If land management to reduce sediment runoff does not become a global priority, it will become increasingly difficult, if not impossible, to protect marine ecosystems in the face of climate change.
The researchers said that while the benefits of land restoration activities were clear, it would be difficult to get countries and governments to engage in restoration activities.
“It is encouraging to see many countries with high coral diversity engaging large areas in land restoration, but the cost of reforestation, as well as political and social barriers can make it difficult to achieve these ambitious goals,” said the Dr Suárez-Castro.
“If an average of 1,000 hectares of forest were restored per coastal basin, land sediments reaching coral reefs could be reduced by 8.5% on average over 63,000 square kilometers of reef.
Dr Suárez-Castro and his team hope that local authorities can use their results to identify areas where reforestation can have the most benefit on coral reefs.
“Our approach can be adapted with local data to identify optimal actions for ‘win-win’ preservation for multiple ecosystems spanning land and sea,” said Dr Suárez-Castro.
“Several global initiatives such as the Paris Climate Agreement put forest restoration at the forefront of global conservation discussions and we hope our study can facilitate more informed and educated conversations about the importance of an approach. more integrated land-sea. “
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