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In the fight to protect the planet's wildlife, scientists are calling for a greater focus on our oceans. While much of the world’s attention is on saving forests and other land habitats, experts believe the oceans are being left out of the conversation.
"Although the ocean contains more than 95 per cent of the habitable volume of our planet, all indicators of connectivity included in the GBF have either been proposed or implemented on land or in rivers but not in the sea," read a perspective published in Nature's npj series journal Ocean Sustainability on September 4, 2024.
The authors called for the inclusion of existing, widely used approaches that quantify coastal / marine and migratory connectivity to address the gap in the Kunming-Montreal Global Biodiversity Framework (GBF).
The article was authored by Anna Metaxas, professor at departments of oceanography and biology, Dalhousie University, Halifax, NS, Canada, with her team Autumn-Lynn Harrison, research ecologist at the Migratory Bird Centre, Smithsonian's National Zoo and Conservation Biology Institute, and Daniel C Dunn, associate professor at Centre for Biodiversity & Conservation Science, School of the Environment, University of Queensland.
They believe that GBF, the global plan to protect nature, doesn't focus enough on the oceans. The GBF aims to stop the loss of various plants and animals by setting goals for how to protect different environments. One important idea in this plan is "ecological connectivity” which ensures that different places where animals live should be connected so they can move around and survive.
However, the ways we currently measure this connection are mostly meant for land, not for oceans. Connectivity in the ocean is more complex due to its three-dimensional nature. Unlike on land, where animals move horizontally and face barriers like mountains, ocean animals can move up and down, and ocean currents play a big role. Features like islands or deep-sea canyons can create barriers in the ocean too.
Marine animals move differently at different stages of their lives. For instance, some small fish swim far with ocean currents, while birds that migrate like seabirds have different needs as they grow.
The scientists assessed seven connectivity-specific indicators listed in GBF to check how connected marine environments are. Seven indicators are Bioclimatic Ecosystem Resilience Index – BERI; Dendritic Connectivity Index – DCI; Parc connectedness – Parc; Protected Area Isolation Index – PAI; Protected Areas Network metric – ProNet; Protected Connected Index - ProtConn and ConnIntact).
These methods were mostly made for land, and only one of them, DCI, has been used for rivers. The current methods for connectivity, like BERI, work well on land but not in oceans.
These indicators work for specific species or regions but aren’t effective for the entire ocean. Scientists are still learning about the ocean especially the deep parts with ongoing mapping efforts.
Anna and her team are pushing for these indicators to be re-evaluated and adapt to suit the marine environment and recommend actions to improve protection for marine animals.
The authors recommended the following actions:
Creating new ways to measure how marine and coastal areas are connected
Modify land use methods for use in marine environment
Understand how species move and migrate across the oceans
Find better ways to measure how connected marine protected areas are
Ensure the global ocean is fully integrated into the GBF’s targets and measures