When mangrove planting goes wrong
MANILA, Philippines — Along a stretch of coastline, volunteers wade into shallow water, pressing mangrove seedlings into the mud — one by one, row after row.
It is a familiar scene across the Philippines, often repeated after storms, during company-led drives, and in community activities promoted as climate action.
The intention is clear: to protect coastlines and restore ecosystems. But many of these efforts proceed without a full understanding of the science behind where mangroves should be planted and the conditions they need to thrive.
Beneath the neat rows of newly planted seedlings lies a quieter reality: many will not survive, and some planting efforts may even damage the very ecosystems they are meant to protect.
“They’re always well-meaning, but how do we take that to a level where their good intentions are aligned with science-based protocols?” said Mariglo Rosaida Laririt, assistant director of the Department of Environment and Natural Resources’ Environmental Management Bureau.
At the heart of the issue is a principle known as species zonation — the natural arrangement of mangrove species along coastlines, shaped by salinity, tidal patterns, elevation, soil conditions, and wave energy.
Mangroves are not interchangeable. Each species occupies a specific ecological niche, formed through long-term adaptation to these conditions.
Along exposed, seaward zones, where wave action is stronger and salinity is higher, species such as Sonneratia (pagatpat) and Avicennia (bungalon) dominate. These species develop deeper, more extensive root systems that anchor them to unstable sediments and allow them to tolerate constant environmental stress.
Graphics by Ed Lustan/Inquirer.net
“For context, there are two genera, Sonneratia and Avicennia, that are more resilient in seaward areas,” said Leo Anthony Castro of the Global Mangrove Alliance Philippines.
Some of these species can shed bark to prevent barnacle buildup, while others grow specialized roots that allow them to “breathe” in waterlogged soils — adaptations critical for survival in harsh coastal environments.
Further inland, where waters are calmer and salinity is lower, species such as Rhizophora (bakhaw) thrive. Despite being the most commonly planted species, they are less suited to exposed coastlines.
“That’s the species that’s usually planted in many mangrove planting projects or initiatives because it’s easy to propagate,” Castro said.
That convenience, however, has led to a widespread mismatch.
“Many studies and post-typhoon assessments show that bakhaw has a higher mortality rate compared to Avicennia and Sonneratia,” he added.
Environmental cues, such as the presence of barnacles or existing mangrove species, often indicate which organisms can or cannot survive in a given site. But these signals are not always taken into account.
Proper restoration, experts said, begins long before planting. It requires baseline studies, site assessments, and an understanding of natural regeneration processes. In some cases, planting may not be needed at all.
If the science is well established, why do the same mistakes persist?
Part of the answer lies in the gap between knowledge and implementation.
“I wish I could say it’s templated, but some of us really just learn by experience,” Laririt said.
Mangrove restoration is inherently site-specific. Subtle differences in elevation, tidal flow, and sediment conditions can determine whether a species survives or fails — factors that are not always captured in generalized guidelines.
At the same time, key steps such as baseline studies, species identification, and ecosystem assessment are not always prioritized. In many cases, planting proceeds without a full understanding of what is already present on the ground.
This is particularly evident in cases where mangroves are planted over seagrass ecosystems.
“The thing is, when they plant mangroves in seagrass beds. The roots of mangroves are extensive; they could ultimately damage the seagrass beds. These are nursery grounds for commercially important fishes,” said Matthew Tabilog, founder of Mangrove Matters PH.
“They don’t understand that seagrasses are another ecosystem that also needs to be protected because they’re also vulnerable to climate change, coastal reclamation, and anthropogenic factors,” he added.
These missteps reflect a broader misunderstanding: that mangrove planting is always beneficial, regardless of context.
Graphics by Ed Lustan/Inquirer.net
Coordination gaps further complicate the issue.
“If groups or even local government units interact with DENR personnel in their vicinity, then the likelihood of them getting correct information is higher. But we also tell our field personnel — if you’re not sure, you can always ask the experts. And the experts don’t have to be us. We have a good relationship with non-government organizations who perhaps know better than we do,” Laririt said.
Yet, as some experts note, this coordination does not always happen.
“One of the problems is that they don’t consult experts. Some of these projects just come up suddenly. It can’t be one-sided, where NGOs are always the ones reaching out — they also need to take the initiative to engage and meet with us,” Castro said.
Without these linkages, projects are often implemented in isolation and detached from both scientific expertise and local knowledge.
Across the country, these gaps have produced a pattern of recurring mistakes.
In Catanduanes, a 2023 mangrove planting activity drew criticism after Rhizophora was planted in seaward zones already occupied by Sonneratia and Avicennia. These zones are defined by high salinity and wave exposure — conditions that favor species with stronger anchoring systems and higher tolerance to environmental stress.
Planting Rhizophora in these areas does not just lower survival rates. It can also disrupt existing ecosystems by introducing competition in zones where other species are already established.
READ: Mind your mangroves: Green groups cite wasteful project
Advocates also raised concerns about the lack of baseline studies and consultation prior to the activity — steps considered essential in determining whether planting was appropriate in the first place.
Similar issues have been documented in Bohol and Negros Occidental, where planting efforts were criticized as “unscientific,” with species selected based on availability rather than ecological suitability.
READ: DENR planted ‘wrong’ mangrove species, say advocates
In Cebu, a corporate-led mangrove planting initiative drew backlash after seedlings were placed directly on seagrass meadows. Seagrasses are not empty spaces. They are critical ecosystems that support marine biodiversity, serve as nursery grounds for fish and sustain coastal livelihoods.
Introducing mangroves into these areas, experts said, can alter sediment conditions, block sunlight and eventually displace seagrass communities — replacing one functioning ecosystem with another.
Large-scale planting efforts, particularly after disasters, have also revealed how urgency can override ecological considerations.
Following Typhoon Yolanda, mangrove rehabilitation programs were rapidly implemented across affected areas. In many cases, planting was carried out in mudflats, seagrass beds and exposed coastlines — sites where mangroves do not naturally thrive.
READ: Stop seafront planting of bakhaw propagules
These efforts were often driven by targets: the number of seedlings planted, the area covered, and the speed of implementation. However, without proper site matching, many of these plantations failed.
The emphasis on quantity over quality reflects a broader issue in restoration programs, where visible outputs are prioritized over long-term ecological outcomes.
The consequences of mangrove misplanting are often not immediate but cumulative, and in some cases, difficult to reverse.
At the most basic level, improperly planted mangroves fail to survive.
“Our No. 1 consequence is that we won’t be able to achieve our ultimate goal, which is to achieve a higher survival rate,” Tabilog said. “It will be ultimately wasteful to our resources, to our time.”
But the impact extends beyond failed seedlings. In some cases, planting is carried out in areas where mangroves would have recovered naturally, raising questions about whether intervention was needed at all.
“Planting is often done in situations where no planting is needed at all,” global organization Wetlands International noted, explaining that natural regeneration can occur when the right ecological conditions are present.
Even when mangroves do grow, their long-term ecological value may be limited if the wrong species are planted in unsuitable areas.
“Quality over quantity,” said mangrove botanist Genea Cortez, warning that planting thousands of the wrong species in the wrong places may do little to support long-term sustainability.
In some communities, these lessons have been learned through experience.
In Sorsogon, Benito Doma, a provincial board member, recalled how repeated planting of Rhizophora often failed during storms.
“When a storm hits, and it gets damaged, it dies. Even if just a branch breaks off, it won’t survive. You have to plant again,” he said.
Graphics by Ed Lustan/Inquirer.net
By contrast, Doma said Avicennia species proved more resilient — able to survive even when cut and continue growing over time, a reflection of its matatag (hardy) nature.
Over time, such observations shaped local approaches. Communities like those in Sorsogon recognized that different mangrove species support different forms of marine life, reinforcing the importance of maintaining ecological diversity rather than relying on a single species.
As awareness of mangrove misplanting grows, so too has public scrutiny, much of it unfolding online. But for Laririt, correcting the science should not come at the cost of discouraging participation.
“Let’s be kind,” she said. “There’s so much gatekeeping, and sometimes it’s because we want to sound like we know more than others. Maybe you do. But does it help?”
She warned that overly harsh criticism can alienate those trying to help.
“Do you think that those people who were shamed for planting the wrong species or planting in the wrong places would want to plant again? Maybe — or maybe not. Because they were already humiliated and embarrassed.”
At the same time, Laririt said many of these mistakes stem from a lack of accessible information.
“They thought about it. They thought it was a good idea to do something for nature. Unfortunately, no one explained to them how to do it correctly,” she said.
In recent years, the Philippines has seen measurable gains in mangrove cover, rising from about 240,824 hectares in 2010 to about 311,400 hectares in 2020. It is a sign that conservation and rehabilitation efforts are making an impact.
The challenge, then, is not just to call out what is wrong — but to make it easier for people to do it right.
Because while public participation remains critical, experts said it must be paired with clearer guidance, stronger coordination, and wider access to science-based knowledge.
“It’s not just about planting,” said Von Hernandez, vice president at Oceana. “It’s about doing it systematically.”
In the end, the measure of success is not how many seedlings are planted — but whether they grow into forests that can truly protect coastlines and sustain life. /dm