Rising Seas Threaten 42% of Land Species
Climate change driven sea level rise could inundate habitats for more than 42% of terrestrial vertebrates by the end of the century, Mongabay reported.
A global study published in Science overlaid habitat suitability maps for 34,120 land species with Intergovernmental Panel on Climate Change emissions projections. Researchers examined roughly 90% of known amphibians, reptiles, birds, and mammals to measure future coastal exposure.
Global Inundation Risks by 2100
The study found that between 14,325 and 15,324 species will face habitat loss from coastal flooding by 2100, depending on future emissions scenarios. Only 5.9% of these exposed species are currently classified as at risk from climate change on the IUCN Red List.
Up to 63% of birds, 52% of mammals, 36% of reptiles, and 24% of amphibians will likely experience habitat loss. “Conservation planning needs to consider not only where species occur today, but also which parts of their habitat are projected to remain above water in the future,” co-author Zhong-Wen Jiang told Mongabay in an email.
Reptiles face nearly double the habitat loss of birds or mammals overall. Under high emissions scenarios, three species—the Catalina chuckwalla, the Restinga toadlet, and a Brazilian worm lizard—are projected to lose more than half of their global available habitat.
Amazon and Southeast Asia Impacts
The Amazon River delta will suffer the greatest extent of terrestrial vertebrate habitat loss due to its high biological diversity. More than 100,000 hectares of riparian forests and coastal wetlands in the low-lying Amazon delta could be inundated by 2050.
Southeast Asia presents severe biodiversity risks because many range-restricted and threatened species live near coasts. Nearly triple the number of threatened species found elsewhere in the world are sustained by flooded ecosystems across Sumatra, Borneo, and Peninsular Malaysia.
The researchers identified Myanmar, Vietnam, and Indonesia as critical regions for expanding protected areas. However, 96% of identified refugia habitats that could help species adapt currently lie outside existing protected areas.
Already an Existential Threat
Coastal species already face immediate pressures from rising waters and severe weather. Shorebirds in Europe encounter nest flooding, while the Bengal tiger in the Bangladesh Sundarbans is expected to lose most of its mangrove habitat to the ocean by 2070.
In 2016, scientists declared the Bramble Cay melomys the first mammal to go extinct due to habitat loss from human-caused sea level rise. University of British Columbia conservation scientist Jennifer Magel, who did not participate in the research, pointed out that rigid man-made structures block coastal wetlands and hinder their natural inland migration.
“Decision-makers need to factor the impacts of future sea level rise into land use and conservation decisions that are being made now, so that key areas can be protected while there is still time to act,” Magel told Mongabay.
Species Habitat Protection Questions
How many species will lose habitat to rising seas?
The global study projects that more than 42% of terrestrial vertebrates will see a portion of their habitats inundated by 2100. This exposure affects up to 63% of birds and 52% of mammals across various emissions scenarios.
Which regions face the highest risk of habitat loss?
The Amazon River delta will suffer the greatest physical extent of habitat loss due to high biodiversity and low-lying coastal terrain. Meanwhile, Southeast Asia harbors range-restricted species in Peninsular Malaysia, Borneo, and Sumatra that face severe extinction risks.
Why are refugia habitats difficult to protect?
Researchers found that 96% of identified refugia areas that could help land vertebrates escape future flooding lie outside existing protected areas. Many host regions in Myanmar, Indonesia, and Vietnam also suffer from a lack of conservation funding and limited technical capacity.
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