{"id":345491,"date":"2025-08-15T03:07:10","date_gmt":"2025-08-15T03:07:10","guid":{"rendered":"https:\/\/www.europesays.com\/uk\/345491\/"},"modified":"2025-08-15T03:07:10","modified_gmt":"2025-08-15T03:07:10","slug":"the-heart-shaped-mangrove-formation-fading-due-to-rising-seas-pacific-islands","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/uk\/345491\/","title":{"rendered":"The heart-shaped mangrove formation fading due to rising seas | Pacific islands"},"content":{"rendered":"

On the west coast of New Caledonia<\/a>, Isobelle Goa searches the thick, tangled mangrove roots for mudcrabs. Goa lives on the outskirts of the archipelago\u2019s most famous mangrove formation: a light-green, heart-shaped patch of forest known as the Heart of Voh.<\/p>\n

\u201cIt is grandiose. It\u2019s what God has put on the land for us,\u201d Goa says.<\/p>\n

\u201cIt has a presence about it. My heart carries this heart with it. It is important to protect it and be kind to the mangroves inside.\u201d<\/p>\n

Its iconic outline brought the Heart of Voh international recognition and is plastered across billboards on New Caledonia, a symbol of the Pacific territory\u2019s pristine natural environment.<\/p>\n

But the heart is now under assault from the climate crisis, as rising seas change the salinity of the water and alter the kind of vegetation that can survive there. Its distinctive shape and the ecosystem within it are also changing.<\/p>\n

Oundjo resident Isobelle Goa lives near the Heart of Voh. Photograph: Cooper Williams<\/p>\n

In the late 1990s the pale, barren surface of the heart contrasted sharply with the green mangrove forest around it, creating its iconic silhouette when viewed from above. Sitting slightly above the surrounding mudflats, the heart\u2019s soil was dry and salty \u2013 too extreme for vegetation to grow.<\/p>\n

\u201cIt was just a yellowish salt flat,\u201d says Dr Cyril Marchand, a mangrove expert at the University of New Caledonia. \u201cNo mangroves could survive there.\u201d<\/p>\n

Over the past 20 years, the conditions in the water began to change. A species of salt-tolerant mangrove called Avicennia started to grow there and has now fully colonised the heart.<\/p>\n

The change is linked to rising sea levels: data shows waters along New Caledonia\u2019s west coast have risen about 2mm a year for several decades. As tidal waters flow into the heart more frequently, the salty soil becomes diluted \u2013 the ideal conditions for Avicennia to grow. As the species spreads, the heart\u2019s distinctive shape is changing.<\/p>\n

Marchand says if sea levels continue to rise, the salinity will reduce further. That will again change the conditions to allow another species of mangrove \u2013 Rhizophora \u2013 to spread across the heart.<\/p>\n

\u201cIt\u2019s possible that in 30, 40 or 50 years, only Rhizophora will grow there,\u201d Marchand says. \u201cThe heart may vanish entirely.\u201d<\/p>\n

The Heart of Voh in 1992, taken by photographer Yann Arthus-Bertrand. When Arthus-Bertrand photographed the heart in 1999, the mud bank was bare and the yellow contrasted starkly against the lush green mangroves that surrounded it. Photograph: Yann Arthus-Bertrand<\/p>\n

While increased mangrove cover seems positive, sea level rise is also inundating and removing mangrove habitat closer to sea. The changing ecosystem means sea levels and mangroves are pushing closer to coastal communities, reducing land availability and marine habitats.<\/p>\n

Tracking changes in the heart<\/p>\n

Mangroves have always shifted and changed over time, but Marchand says it is now happening at an unprecedented speed. By drilling deep into the mud and assessing sediment patterns, Marchand and his team were able to determine how mangroves have moved over time.<\/p>\n

\u201cIn the past, it would take 500 years [for mangroves to migrate this far], now it\u2019s happening in decades, driven by climate change,\u201d he says.<\/p>\n

Changes to mangroves \u2013 and the ecosystems they support \u2013 are significant for coastal communities relying on them for livelihoods. Globally, it is estimated<\/a> that more than half of mangrove systems are at risk of collapse by 2050, and between 1994 and 2020 coverage of mangroves decreased by 3.4% around the world.<\/p>\n

\u201cIt\u2019s important for the whole world to protect mangroves because our biodiversity is just so unique,\u201d Marchand says.<\/p>\n

\u201cFor the local people, the fishermen, the Kanak, mangroves are important. The Heart of Voh is symbolic of that.\u201d<\/p>\n

In recent years, satellite technology has been used to track real-time changes in the Heart of Voh and surrounding mangroves.<\/p>\n

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\u201cWe can go up to 15 centimetres of resolution using satellite imagery and collect data during the night and bad weather like cyclones,\u201d says R\u00e9mi Andreoli, deputy director at Bluecham, a company specialising in satellite imagery and data collection. \u201cIt\u2019s a lot easier to observe from space than walking through mud up to your knees.\u201d<\/p>\n

Andreoli has been tracking the Heart of Voh mangrove system for the past 12 years. The satellite data can detect biochemical changes otherwise invisible to the eye. The information is used by researchers monitoring changes to the Heart of Voh, as well as to assess the impact of mining activities on the environment.<\/p>\n

\u201cIt\u2019s really powerful to monitor variation between species and changes in tree cover and to see how mangroves are evolving over time in the face of climate change,\u201d Andreoli says.<\/p>\n

\u201cWe use this information to help businesses, decision makers and scientists to assess mangroves status and protect their environment.\u201d<\/p>\n

\u2018We can\u2019t let it slip away\u2019<\/p>\n

Protecting the heart is a priority for the local community and tourism operators.<\/p>\n

For over 15 years G\u00fcnter Gerant, a pilot at tourism flight company Haut Vol, has shown tourists the Heart of Voh by air. He says it is one of the most famous things to see in New Caledonia.<\/p>\n

\u201cWe [Haut Vol] started the discovery flights because everyone wanted to see the Heart,\u201d Gerant says.<\/p>\n

The veteran pilot plays an important role in the local economy. \u201cPeople come to see the Heart, our mangroves and our coral reefs so it\u2019s really important to maintain these ecosystems for our livelihoods,\u201d he says.<\/p>\n

G\u00fcnter Gerant flys tourist over the Heart of Voh. The heart is now filled with Avicennia mangroves due to rising sea levels. Photograph: Cooper Williams<\/p>\n

Back in Voh, locals stress the importance of protecting their mangroves.<\/p>\n

Goa and a team of women from the nearby village plant mangrove propagules in a nearby nursery. She knows the mangroves are critical to her community\u2019s survival.<\/p>\n

\u201cIt\u2019s an ecosystem that protects us from erosion and big waves. It protects us and the country,\u201d she says. \u201cGeneration after generation teaches our children to hunt in the mangroves. We can\u2019t let it slip away.\u201d<\/p>\n

Goa adds: \u201cWe have to protect it for the future of our culture.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"On the west coast of New Caledonia, Isobelle Goa searches the thick, tangled mangrove roots for mudcrabs. Goa…\n","protected":false},"author":2,"featured_media":345492,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3843],"tags":[728,70,16,15],"class_list":{"0":"post-345491","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-environment","8":"tag-environment","9":"tag-science","10":"tag-uk","11":"tag-united-kingdom"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@uk\/115030579196640640","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts\/345491","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/comments?post=345491"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts\/345491\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/media\/345492"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/media?parent=345491"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/categories?post=345491"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/tags?post=345491"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}