Mongabay · Natuur

Indigenous knowledge reveals reef-mangrove ecosystem links for fish

A collaboration between Australian scientists and Bardi Jawi rangers and elders has shown how fish species depend on the connection between reef and mangrove ecosystems. Culturally significant fish, vital to traditional fishing practices in northwestern Australia's Kimberley region, were found to migrate between these two environments more than other species.

This study integrated millennia of traditional ecological knowledge from the Bardi Jawi with Western scientific methods. While many findings confirmed existing traditional knowledge, rangers gained insights into how specific species might not survive if either reefs or mangroves are threatened by climate change or environmental impacts.

The research, published in Ocean & Coastal Management, involved Bardi Jawi and Oorany Rangers and Traditional Owners alongside scientists from the Australian Institute of Marine Science (AIMS). For a decade, this partnership has focused on studying and protecting the region's mangrove and reef ecosystems and traditional fishing grounds.

The Bardi Jawi, described as "Saltwater People" whose diet relies on healthy oceans, inhabit an area characterized by "red earth, blue ocean, and green mangroves." Their country is part of the Bardi Jawi Indigenous Protected Area and the Bardi Jawi Gaarra Marine Park.

A key finding was the interconnectedness of reef and mangrove ecosystems for fisheries sustainability, a concept long understood through Bardi Jawi traditional ecological knowledge. This understanding also informed the design of the protected areas.

While mangroves are known as fish nurseries, the study revealed a more extensive role. Despite reefs having greater biodiversity, ten culturally important fish species were found to be equally abundant in mangroves. These species, like the barramundi or bluebone, utilize tidal movements to migrate between ecosystems even after their nursery stage.

Lead author Katherine Cure noted that the study identified a distinct pattern for these culturally important species compared to the overall fish community. Some species used mangroves as refuges during reef vulnerability, with larger individuals of certain species, like the surgeonfish, found in mangroves.

The collaborative process, emphasizing Bardi Jawi traditional ecological knowledge, was highlighted as a significant aspect of the research. The relationship evolved over eight to ten years, with research questions increasingly guided by the needs of Traditional Owners and aligned with scientific interests.

Cure emphasized that First Nations peoples are the world's first scientists, with knowledge gained through millennia of observation and experimentation. This accumulated ecological knowledge provides valuable long-term data for Western science.

The Bardi Jawi's holistic approach, viewing the environment as an interconnected system including cultural elements, contrasts with the tendency of scientists to compartmentalize. This integrated perspective is crucial for understanding complex ecological cycles.

The exchange of knowledge is reciprocal. While reefs are vulnerable to rising global temperatures and marine heatwaves, mangroves offer landscape-level resilience. The study suggests that fish benefiting from mangroves contribute to overall ecosystem resilience.

Modern technology, such as drones and cameras, has aided the Bardi Jawi in monitoring rapid environmental changes like coral bleaching over large areas and understanding their impact on fish populations. Scientific data also helps them communicate with government policymakers, facilitating initiatives like the marine park's establishment.

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