Exploring the vital connection between biodiversity and global environmental changes in Brazil's coastal ecosystems
Explore the ResearchStretching over 7,500 kilometers along the eastern edge of South America, Brazil's coastline is a breathtaking tapestry of diverse ecosystems that form one of Earth's most dynamic interfaces between land and sea.
From the lush mangrove forests in the north to the spectacular rocky shores in the southeast, these habitats teem with life and provide essential services for both nature and humanity. Yet, this magnificent coastal zone faces an unprecedented threat from Global Environmental Changes (GECs)—a complex interplay of climate change, habitat destruction, pollution, and other human-driven disruptions 1 .
Brazil's coastal ecosystems serve as natural carbon sponges, absorbing atmospheric carbon dioxide at rates that dwarf those of terrestrial forests, while simultaneously protecting shorelines from erosion and storm surges 2 .
Global Environmental Changes (GECs) represent a suite of interconnected transformations to Earth's natural systems, primarily driven by human activities. These include: climate change, ocean acidification, biodiversity loss, land-use change, and alterations to nutrient cycles 1 .
Unlike natural environmental fluctuations that occur over geological timescales, GECs are occurring at an accelerated pace, pushing ecosystems beyond their capacity to adapt naturally. Along Brazil's coast, these changes manifest through rising sea temperatures, sea level rise, increasingly intense weather events, and changes in ocean chemistry—all of which create complex challenges for the preservation of biodiversity 5 .
Brazil's coastal habitats function as critical infrastructure in the planet's defense system against climate change. Mangroves, salt marshes, and seagrass beds—collectively known as "blue carbon" ecosystems—sequester and store massive amounts of carbon in their vegetation and especially in their waterlogged soils, where decomposition is slow and carbon can accumulate over millennia 2 .
Remarkably, although these ecosystems cover less than 2% of the ocean's surface, they're responsible for approximately half of the carbon buried in marine sediments annually 4 .
Despite being reduced to just 12% of its original extent due to centuries of deforestation, this biome still harbors an astonishing 5% of Earth's vertebrates and 8% of its plants, including species found nowhere else on the planet 3 .
The changing climate affects Brazilian coastal ecosystems through multiple pathways. Rising temperatures force species to shift their distributions toward cooler areas (poleward or to deeper waters), disrupting established ecological communities.
Sea level rise poses another critical threat, particularly to habitats that exist at the land-sea interface. Mangroves and salt marshes can potentially migrate inland as seas rise, but along much of Brazil's coast, this natural adaptation is blocked by human development—cities, farms, and infrastructure create what scientists call "coastal squeeze" 4 .
Meanwhile, ocean acidification resulting from increased CO₂ absorption threatens organisms with calcium carbonate shells or skeletons, including commercially important shellfish and the coralline algae that stabilize reef structures 5 .
While climate change presents formidable challenges, it operates in concert with more direct human impacts. The Atlantic Forest has endured the brunt of Brazil's population growth and development, with over 85% of its original vegetation cleared and what remains highly fragmented 3 .
This fragmentation is particularly damaging to biodiversity because it creates isolated "islands" of habitat too small to support viable populations of many species and prevents natural genetic exchange between populations 7 .
Additionally, pollution from agricultural runoff, urban wastewater, and industrial discharge degrades water quality, while overexploitation removes key species that perform important ecological functions. When combined with climate stressors, these local pressures create synergistic effects that are more damaging than any single threat alone 1 .
To understand how GECs are affecting Brazil's coastal biodiversity, scientists established the Rede de Monitoramento de Habitats Bentônicos Costeiros (ReBentos)—the Network for Monitoring Benthic Coastal Habitats. This ambitious initiative brings together 166 researchers from 57 institutions working along all 17 coastal states of Brazil 1 .
ReBentos represents a paradigm shift in Brazilian coastal science. Before its establishment, studies were fragmented and methodologically inconsistent, making it impossible to distinguish local phenomena from regional trends. By implementing uniform protocols across the entire coastline, researchers can now generate comparable data that reveal the true scale of environmental changes 1 .
Researchers
Institutions
Coastal States
Ecosystem Types
| Ecosystem Type | Observed Changes | Primary Drivers |
|---|---|---|
| Mangroves | Landward migration in some areas; mortality in sediment-poor areas | Sea level rise, coastal development |
| Sandy Beaches | Reduction in benthic diversity; changes in species composition | Warming, erosion, human trampling |
| Rocky Shores | Shift toward heat-tolerant species; decline in sensitive species | Temperature extremes, acidification |
| Coral Reefs | Increased bleaching events; decline in calcification rates | Warming, acidification, pollution |
Effective conservation of Brazil's coastal biodiversity requires thoughtful policy interventions. Currently, less than 2% of the Atlantic Forest biome is under protected status—far below the recommended minimum of 30% for adequate conservation 3 .
Expanding and connecting protected areas through forest corridors is essential to allowing species to move in response to changing conditions and maintaining genetic diversity 7 .
Top-down conservation measures alone are insufficient without engagement from local communities. The Atlantic Forest is home to 150 million people who depend on its resources for drinking water, livelihoods, and protection from storms 7 .
Blue carbon financing represents a promising approach that values the carbon sequestration services provided by coastal ecosystems. Through mechanisms like carbon credits, funds can be directed toward conservation and restoration projects that benefit both climate and biodiversity 2 .
Instead of fighting against natural processes with hard engineering structures, nature-based solutions work with ecosystems to enhance their natural protective functions.
Restoring mangrove buffers along vulnerable coastlines, for example, can provide protection from storm surge while simultaneously sequestering carbon and providing habitat for fisheries 4 .
The Netherlands has begun shoring up salt marshes in front of dykes to strengthen its coastal defense system 4 . Similar approaches could be adapted along Brazil's coastline.
The good news is that international agreements are increasingly recognizing the interconnection between climate change and biodiversity. The Kunming-Montreal Global Biodiversity Framework, adopted in 2022, works in synergy with the Paris Climate Agreement to address these linked challenges 2 .
Similarly, Brazil's commitment to the Paris Agreement could reduce climate impacts on biodiversity by 21% and cut extinction risk from climate change by half 6 .
The intricate relationship between biodiversity and Global Environmental Changes along Brazil's coast represents both one of our greatest challenges and most promising opportunities. The scientific evidence is clear: diverse, intact ecosystems offer powerful natural defenses against climate change, while simultaneously supporting livelihoods, protecting communities, and maintaining ecological processes we depend on.
The work of research networks like ReBentos provides the essential foundation for informed action—documenting changes, identifying vulnerabilities, and testing solutions. Their findings underscore the urgency of the situation: many changes are already underway, and some tipping points may already have been crossed. But they also offer hope, showing that with strategic intervention, ecosystems can retain remarkable resilience.
What happens along Brazil's coastline will have implications far beyond its borders. The carbon stored in its coastal vegetation and sediments, the species found nowhere else on Earth, and the scientific knowledge generated there are global assets. Protecting them requires immediate action, international cooperation, and a fundamental rethinking of our relationship with nature. The fate of Brazil's coastal biodiversity is not yet written—it will be determined by the choices we make today.