Wetlands can be tough places for people to spend time in.
Treacherous to traverse and dangerous to build on, some assault our ears and skin with the buzz and bristle of mosquitoes, and our noses with the scent of mud and decay.
Low-lying by nature, we can sludge through them for hours and never get to a good view.
But the world is not (yet) fully oriented around human pleasure, and the very features that make wetlands distasteful and/or uninteresting to us make them crucially valuable for scores of other species – and many key ecological processes, too.
Scroll down to learn more about the different types of wetland, why they’re important, the challenges they face and ways to protect them: soggy socks and mosquito bites optional.
There’s no universal system for classifying wetlands, which is perhaps unsurprising as they are inherently frontier ecosystems – the myriad places on our planet where water and land meet.
Different countries and regions also tend to have different categorization systems, depending on how wetlands manifest in their particular geographies and biomes.
You might be surprised at just how many ecosystems come under the ‘wetlands’ banner. Some common types include:
Wetlands are quietly doing more than most of us realize. That includes acting as the “kidneys” of our landscapes: filtering our freshwater and removing all kinds of contaminants through complex physical, biological and chemical processes.
They also sequester and store large amounts of carbon dioxide and other greenhouse gases, making them particularly important to preserve in the face of the climate crisis.
Inland wetlands alone store about 30 percent of global soil organic carbon, despite covering just 6 percent of the Earth’s land surface area.
Wetlands are also home to a wide range of plant and animal species.
Many are critical nurseries for fish and other aquatic animals because they’re nutrient-rich and relatively protected from large predators and wild waters. This makes them particularly important for coastal livelihoods and the seafood sector.
And they protect us from extreme weather events – an increasingly important task in the era of climate change.
Mangroves shield coastal communities against storm surges and sea level rise, while inland wetlands reduce the impacts of flooding by storing and slowly releasing surface water, rain and floodwaters.
Beyond all of these practical reasons, wetlands matter in and of themselves. What’s more, they are culturally important to many societies around the world, frequently as sites of pilgrimage and ritual – revered for both their fertility and their mystery.
With so much still to learn about what goes on in these diverse and dynamic ecosystems, the prerogative is clear to keep our remaining wetlands safe from destruction – and to continue visiting, investigating and appreciating them, too.
Unfortunately, much of humanity’s ambivalence to – and misunderstanding of – wetlands is evident in the ways we treat them.
Wetlands are disappearing three times faster than forests, earning them the dubious honor of being the Earth’s most threatened ecosystem.
From draining for pasture to flooding for shrimp farms, to dumping sand and cement on top of them for coastal tourism and development, a full 35 percent of the world’s wetland area disappeared between 1970 and 2015.
Many of our wetlands are also contaminated from agricultural and industrial runoff, as well as human wastewater.
To an extent, they can absorb and store these contaminants and keep them away from other aquatic ecosystems and the human food chain for hundreds or even thousands of years.
But when dried out, these “swampy vaults” become vulnerable to wildfires, which can unleash those toxins – plus large amounts of greenhouse gases – into the wider world.
That dangerous drying can happen as a result of deliberate human activity (chiefly draining for other land uses, and extracting water to use elsewhere), or due to the climate crisis, which is altering precipitation patterns, evapotranspiration rates, snowmelt, the infiltration of water into the soil, and more.
It’s predicted, for instance, that global heating will reduce some North American inland wetlands by up to 50 percent over the next half century.
Invasive species pose another ongoing threat to wetland ecosystems.
For example, water hyacinth (Pontederia crassipes), which is native to South America, has been introduced across the globe for its pretty purple flowers. It’s now considered the most invasive aquatic plant in the world.
It forms dense mats that can cover entire lakes and rivers, crowding out local plant and animal life, decreasing water quality, and preventing people from boating and swimming – an especially big deal in more remote places where boats are the main form of transport.
As usual, the cheapest and most effective approach to maintaining important ecosystems is to protect those that are still intact.
International agreements are one way to boost awareness and commitment to protecting existing wetlands at national and global levels.
These include the Ramsar Convention on Wetlands – which will host its Conference of Parties (COP15) later this month with the famed freshwater backdrop of Victoria Falls, Zimbabwe.
Signed in 1971, the Ramsar Convention was the first major global environmental agreement and remains the only one focused solely on a specific ecosystem.
While it has no enforcement mechanism, it has led to the designation of over 2,500 Wetlands of International Importance across more than 2.5 million square kilometers worldwide.
Signatory countries have committed to maintaining these sites’ ecological character while ensuring ‘wise use’ by local and regional communities.
As science reveals the incredible power of wetlands to store carbon, they’re also increasingly in the eyes of policymakers looking to reduce emissions to achieve their Paris Agreement targets.
For instance, mentions of wetlands in nationally determined contributions (NDCs) doubled between 2020 and 2022. Yet there’s still a long way to go.
Peatlands, for instance, remained largely unrepresented – of all the parties known to have peatlands, only 13 percent included them in their NDCs that year.
As countries prepare to submit their next round of NDCs at the end of this year, wetland advocates are lobbying to get these ecosystems included in ways more commensurate to their worth.
Any international agreement, however, is only as good as the action it inspires on, and reflects from, the ground.
Another critical step is thus facilitating community stewardship of wetland areas. This requires collaboration, clear land tenure, accessible monitoring practices, recognition of Indigenous knowledge, and the inclusion of marginalized groups that are often most reliant on these ecosystems.
Given how many of our wetlands have already been destroyed, restoration is also key.
This can take many forms: rewetting drained peatlands, rewilding rivers by giving them space to flow and flood, eliminating invasive species, and reforesting degraded mangrove swamps – or creating the right hydrological, sediment and soil conditions for them to grow back naturally.
In many parts of the world, people are also creating wetlands that didn’t exist before – for instance, leveraging their water-filtering capacity to reduce nitrate runoff from dairy farms, or sucking up stormwater in urban areas to avoid flood damage.
If you’ve read this far, you hopefully now understand more about the value of wetlands at a planetary level. But what might that mean for your everyday life?
A great first step is to work out which watershed you live in (we all live in one) and where your nearest wetlands might have been, if they’re not there now. (If you’re in the USA, the National Wetlands Inventory might be helpful.)
Look carefully: these low-profile landscapes are notoriously easy to miss – even, I’m embarrassed to admit, for professional nature enthusiasts like myself.
I wrote about peatlands (a type of wetland) for years before realizing I’d been regularly driving past some of the biggest and most carbon-rich peatlands in Aotearoa New Zealand without even noticing them.
Once you’ve located your wetlands, you might be able to find ways of helping to protect and restore them – such as picking up litter, clearing invasive species, and planting natives.
For me personally, it means pulling out invasive blackberry canes and planting a native flax called harakeke (Phormium tenax) on my lunch break.
Sometimes my gumboots get stuck in the mud; often I get scratched by twigs and bitten by mosquitoes. Always, I emerge feeling clearer and more connected.
After all, as nature writer Robert Macfarlane notes in a conversation about his new book on rivers: “we are never dry-footed on the bank. We’re never standing there watching the current move past us, even with notebook in hand.”
Our own bodies are mostly liquid and always flowing; certainly more a marsh than a dry forest. To rediscover the movements and relationships of the water and land around us is perhaps to find something forgotten about ourselves, too.
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