Mangroves serve as a bridge between land, freshwater, and the sea; they sustain rich and diverse ecosystems, and are crucial for shoreline protection and carbon storage. The Mangrove Alliance’s 2024 report states that India’s mangroves are home to 5,746 species, with 84% being animals, spanning 21 major taxonomic groups.

Across the country, several community-based mangrove restoration projects have been initiated over the past few years. According to the Forest Survey of India, the country’s mangrove cover expanded by more than 336 square kilometres between 2011 and 2021. In contrast, during nearly the same period (2010-2020), the global mangrove area has been declining at an average annual rate of 0.07%.

However, studies show that on the ground, many restoration efforts rely on large-scale plantation drives, often planting a single fast-growing mangrove species such as Rhizophora, Sonneratia, or Avicennia. These activities, carried out under popular models like Ecological Mangrove Rehabilitation (EMR) and Community-Based Ecological Mangrove Rehabilitation (CBEMR), focus more on silviculture than on true ecological restoration.

Experts caution that large-scale plantations alone are unlikely to deliver meaningful ecological outcomes. “Success should not be measured in how many hectares are being planted, but rather in survival rates, long-term establishment, and the recovery of ecosystem functions. What truly counts is the return of critical services such as coastal protection, carbon sequestration, the restoration of native biodiversity, and livelihood support like fisheries,” says K. Kathiresan, a scientist who has spent decades of his career studying mangroves.

Plantation-heavy approaches, he cautions, could risk eroding the natural biodiversity of mangrove plant communities. “India’s increase in mangrove cover has not come from plantations alone, but consideration of the existing mangrove forest, where natural regeneration and colonisation occur. Any obstacle that prevents this natural regeneration must be avoided,” he says.

Baseline data matters

India hosts a wide diversity of mangrove types across its coastline. Moreover, the country’s mangrove ecosystems are highly heterogeneous. On the east coast, they are shaped largely by freshwater influence, while the west coast mangroves are dominated by saline conditions. This means restoration approaches cannot follow a uniform model; each landscape requires site-specific strategies rooted in local ecology.

For comprehensive ecological mangrove restoration, two elements are indispensable, say mangrove scientists — robust baseline data to design site-specific restoration plans, and sustainable long-term monitoring to evaluate implementation and outcomes. In India, however, both remain limited or inconsistent, creating critical gaps in the restoration process.

“Key insights highlight that baseline data is non-negotiable for designing context-specific interventions, and scientific monitoring ensures credibility through adaptive management. But standardised protocols remain a gap in many Indian projects, limiting scalability and policy integration,” says Sumantha Narayana, Coastal and Ocean Ecosystem Manager with The Nature Conservancy (TNC) in India.

TNC runs a mangrove restoration initiative in the non-protected areas of the Sundarbans, integrating ecological science with social considerations. “Our project began with detailed baseline studies, including biophysical assessments of soil salinity, hydrology, and species diversity, alongside socio-economic profiling across project villages. The work is carried out with IISER Kolkata and the Nature Environment and Wildlife Society (NEWS) as implementing partners,” Narayana says.

Maintaining a robust repository of baseline data requires rigorous pre-project research and sustained monitoring during and after the rehabilitation process.

According to Kathiresan, the first step in any restoration project should be to identify why a site has degraded by comparing it with a nearby healthy mangrove patch, assessing factors ranging from vegetation and hydrology to human pressures. “Conservation and creating the right ecological conditions — which requires understanding baseline ecology, local hydrology, species interactions, and restoring the ecosystem’s original structure and functions — should always come first. Secondly, reducing livelihood pressures like cattle grazing can allow mangroves to regenerate on their own,” Kathiresan says. He stresses that planting should only be the third priority.

Field examples from the past support this approach. A 2002 study analysing physico-chemical parameters of Tamil Nadu’s Pichavaram mangrove forest showed that rising soil salinity had reduced nutrient levels, sharply lowering microbial activity which is essential for mangrove root development. In contrast, the healthier mangrove patches benefited from higher rainfall and surface water runoff from the surrounding watershed. To flush out the salinity, a network of canals was created based on a fishbone model, which proved highly effective; after the salinity was flushed out, the mangrove forest was successfully rehabilitated. Monitoring later showed these canals also became productive fish habitats, boosting local fisheries.

Another rapidly growing threat to mangrove ecosystems is anthropogenic pollution. In the Sundarbans, for instance, the Ganges-Brahmaputra-Meghna Delta delivers high concentrations of riverborne pollutants along with freshwater. With expanding agriculture and aquaculture around mangrove regions and along upstream riverbanks, nitrogen-rich runoff increasingly flows directly into mangrove patches, creating polluted pockets and causing eutrophication that disrupts ecosystem balance.

Under such conditions, plantation alone cannot achieve ecological restoration; unless the underlying issues are addressed, said Kathiresan.

Missing outcome tracking

Despite expanding investments in restoration worldwide, researchers have repeatedly highlighted the absence of a global database that tracks restored sites and their outcomes. Published literature tends to emphasise successful projects while failures are rarely documented, leaving critical knowledge gaps about which approaches are truly working.

“Continuous monitoring of restored mangroves follows MRV (Measurement, Reporting, Verification) protocols, tracking indicators such as carbon sequestration potential, biodiversity recovery, and socio-economic benefits,” Narayana says.

An evaluation study of a decade of mangrove restoration in Mumbai (2012–2022) found that 13 of the 25 sample sites saw no growth throughout the period, while the remaining sites together added 30.44 hectares of mangrove cover. From 2012–2022, over USD 5 million was invested in the projects.

The study aimed to highlight the importance of monitoring restoration outcomes and the gap in public outcomes evaluation for Mumbai’s coastal restoration projects. It was observed that, de jure, Mumbai’s mangroves are legally protected under the Coastal Regulation Zone; de facto, large-scale exemptions for nationally significant infrastructure frequently permit the clearance of thousands of mangrove trees. It also found that while most mangrove clearances occur in the city’s urban core, restoration efforts were largely concentrated in suburban and peri-urban areas.

Additionally, though GIS-based satellite monitoring allows government agencies and researchers to regularly assess Mumbai’s total mangrove extent, there was no public monitoring of the city’s 1,500 hectares of restored areas. Existing academic and government datasets did not distinguish natural expansion from areas regenerated through restoration.

Utchimahali Mariappan, a mangrove ecologist at the M.S. Swaminathan Research Foundation (MSSRF), notes that the lack of accessible papers, reports, or columns presenting baseline assessments of mangrove restoration projects remains a major gap. He stresses that post-plantation monitoring remains weak.

“Building on the successful Joint Forest Management models demonstrated by MSSRF, restoration efforts should move beyond one-time planting drives toward sustained ecosystem recovery. Agencies are encouraged to develop clear exit strategies that ensure long-term care either by continuing post-plantation support or by formally empowering local communities to monitor and maintain restored sites,” Mariappan says.

He emphasises developing frameworks that bring together government bodies, corporate partners, scientists, and community groups to strengthen accountability and promote ecological best practices. He further suggests that restoration projects benefit from rigorous evaluation processes undertaken jointly by the implementing agency, the forest department, and independent research institutions to ensure transparent and credible outcomes.

A monitoring framework

The Society for Ecological Restoration (SER) has developed international standards for ecosystem restoration, including a monitoring framework. This framework outlines six key ecosystem attributes to gauge restoration progress: structural diversity, ecosystem function, species composition, physical conditions, absence of threats, and external exchanges.

Globally, however, structural diversity is the frequently assessed attribute in restoration projects, followed by ecosystem functions, physical conditions, and species composition. Far fewer projects examine external exchanges or the absence of threats. Crucially, most projects tracked outcomes for fewer than ten years, far too short to meaningfully evaluate the recovery of ecosystem functions.

“One important component for monitoring is blue-carbon sequestration. Blue-carbon drives much of today’s restoration funding, yet it remains a largely overlooked component in monitoring restored sites. Most projects monitor outcomes for only three years, but blue-carbon sequestration requires a larger window,” Kathiresan says.

Approximately 78% of mangrove carbon is stored in the top one metre of soil. Leaf litter production typically stabilises after three to five years, which decomposes and gets incorporated into the soil, thus contributing to carbon storage. Meaningful soil-carbon monitoring, thus requires at least five years to detect early trends, and around 10-15 years before robust comparisons against mature reference sites become possible.

“India needs clear guidelines for more research, monitoring, and trading capacity building,” Kathiresan adds.

Drafting India’s restoration standards

Compiling syntheses of mangrove restoration work demands extensive time and resources, largely because project data is scattered across diverse sources. With hundreds of different success metrics used worldwide, producing systematic, data-driven assessments remains a major challenge.

To address this, the Mangrove Restoration Tracker Tool (MRTT) was launched in 2023. By standardising how projects record data, including partially successful or failed efforts, the tool aims to build a shared evidence base that enables independent evaluation, helps practitioners learn from one another, and strengthens the financial, ecological, and social returns of restoration investments.

The open-access platform provides a structured framework covering the full lifecycle of a restoration project. Its data-entry system is organised into three main sections — registration, intervention, and monitoring, further divided into ten sub-sections.

However, given that such tools and guidelines are voluntary rather than legally mandated, their widespread uptake among practitioners in India remains uncertain. The Central government’s ambitious Mangrove Initiative for Shoreline Habitats and Tangible Incomes (MISHTI) scheme has formally identified “Monitoring and Evaluation” as a key component, though it is still too early to determine the extent of its implementation.

Presently, the Bureau of Indian Standards (BIS) is working with leading mangrove scientists to develop a Working Draft on Mangrove Restoration in India. Nehru Prabakaran, scientist at the Wildlife Institute of India and a member of the Working Group, told Mongabay-India that BIS follows a biodiversity sector standardisation protocol, and a dedicated committee formed in 2023 is working to create a unified standard operating procedure for mangrove restoration in the Indian context.

“The standards are yet to receive BIS approval, but once approved, I hope they are made mandatory,” Prabakaran says.

Read more: Study maps microplastics in Mumbai’s mangroves

Banner image: Mangrove saplings being planted at a nursery in Kochi, Kerala. (AP Photo/Shawn Sebastian).

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Aditi Tandon Senior Production Editor

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BiodiversityCoastCoastal erosionEcologyEcosystem servicesEnvironmentFishMangrovesPlantationsPlantsReforestationWetlandsIndia

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