Wetlands perform a plethora of vital ecosystem functions and services, such as water storage, groundwater recharge, carbon sequestration, storm and flood protection, shoreline stabilization, erosion control, and storage of various organic and inorganic nutrients. Indeed, wetlands cover approximately 8-10% of the planet and hold 10-20% of terrestrial carbon stocks. They also provide valuable habitat for a diverse pool of aquatic and terrestrial species and are resting grounds for migratory species of birds. After the RAMSAR wetland convention of 1992, wetland conservation gained global importance. India is home to 37 RAMSAR-designated wetland sites (10 new sites added in 2020!), ranging from lakes and swamps to mangrove forests, coral reefs, and river systems. However, RAMSAR sites make up only 4.5% of India’s total wetland cover. Natural inland wetlands constitute 43% of this cover, followed by manmade inland wetlands (30%), natural coastal wetlands (24%), and manmade coastal wetlands (3%; Murthy et al. 2013).
This World Wetland Day, let us explore some of the ecosystem services and intrinsic values of wetlands and why India needs her wetlands more than ever in the face of climate change and development.
Coastal Wetlands Protect Shorelines from Storms:
Coastal wetland ecosystems such as mangrove forests provide valuable services to coastal communities, with one major service being protection against storm surge. India has a coastline of almost 7,500 km in length, and nearly 250 million people live within 50 km of the coast. Regions with the highest vulnerability to coastal damage are Mumbai, the Kutch region, southern Kerala and India’s Lakshadweep Islands, as well as the deltas of the Ganges, the Kaveri, the Godavari, and the Krishna Rivers. According to the Integrated Coastal Zone Management Project, initiated by the World Bank, the Indian coast experiences an average of 9 cyclones per year, and nearly 7 million coastal families are at direct risk from these storms. Mangroves constitute a total of 4,87,775 HA of land cover in India, with nearly 57% of these coastal forests occurring on India’s eastern coast.
Wetlands are Nature’s Wastewater Treatment Plants:
Wetlands serve as nature’s own wastewater treatment plants. Chemicals and nutrients enter wetlands both through surface water and groundwater inflows. Major inorganics entering wetlands are nitrogen and phosphorous from agricultural runoff. Wetland plants absorb nitrogen (often in the form of nitrate), and excess nitrogen is converted to nitrogen gas through the process of denitrification and lost to the atmosphere.
As wetlands retain water and allow particles to sink down into the sediment, they are particularly adapted to filtering out heavy metals, phosphorous, and organic nitrogen. Nutrients deemed useful are taken up by plant roots, while pesticides and metals remain attached to the sediment floor. When aquatic wetland flora dies, the nutrients that they absorbed return to the wetland floor, and often flow into downstream water bodies, making the wetland into a nutrient source instead of a nutrient sink during this period. But in general, wetlands act as water purifiers and storehouses of pollutants, allowing for improved outflow and downstream water quality.
Wetlands provide jobs and food resources for humans and wildlife alike:
India is the global leader in rice production, and paddy fields are the dominant man-made wetland found in the subcontinent. Paddy fields, which are low-lying and submerged year-round, are crucial to the economy as well as to groundwater recharge, purifying water, and providing habitat for various waterbirds. Another economic use of wetlands is the rise of shrimp farming (aquaculture farms) which are often situated in mangrove swamps and river deltas. Mangroves, which are estuarine trees or shrubs with dense roots built for respiration in a flooded land, are also the primary landcover converted for aquaculture farms globally. A study conducted by a team of scientists from Global Mangrove Watch (GMW) assessed the impacts of human activity on mangrove distribution and health globally and found that mangroves in Southeast Asia and India were home to 90 percent of the world’s aquaculture. India’s tryst with aquaculture began in the early 1990s, due to global demand for shrimp. However, these monocultures were susceptible to disease outbreaks and pollution, leading to a global aquaculture collapse in 1995. Restoration of the livelihoods lost due to the fall of shrimp farms occurred in the mid-2000s with shrimp ponds replacing the larger tracts of shrimp monoculture that were prevalent prior to the collapse. Sea level rise due to climate change is a major threat to the livelihoods depending on coastal wetlands such as aquaculture.
Wetlands support vast biodiversity:
High-altitude wetlands, such as Chandertal Wetland in the Chandra Valley located in the Himalayas of Himachal Pradesh, provide habitat to a unique set of wildlife. Here, one can find the snow leopard, golden eagle, Himalayan ibex, bharal or blue sheep, Himalayan marmot, and the Himalayan fox. Such globally-threatened ecological communities are sheltered by the wetland and the habitat it provides in an otherwise inhospitable climate.
The Bhitarkanika National Park, located in Orissa, hosts multiple patches of mangrove forest and has the world’s largest-known nesting beach for the endangered Olive Ridley sea turtle. Apart from turtles, the waters of Bhitarkanika are home to saltwater crocodiles, five species of marine dolphin (the most-common being the Indo-pacific humpbacked dolphin), the water monitor lizard, and the National Park has one of India’s largest heronries. Nearly 20,000 birds from 11 species nest in this heronry. Another mangrove wetland, the Sundarbans, is home to the Royal Bengal Tiger, India’s national animal, as well as the fishing cat, an apex predator of wetland ecosystems. This small cat is also the dominant predator in Coringa Wildlife Sanctuary, yet another mangrove forest in the South Indian state of Andhra Pradesh.
Loktak Lake, the largest natural lake in Northeast India, is an example of a naturally-occurring wetland and supports over 20,000 waterbirds of over 116 species, including globally-threatened species such as the Spot-billed pelican and the Greater Spotted Eagle . Additionally, the southeastern shores of this lake form a part of Keibul Lamjao National Park, the last natural refuge of the Manipur brow-antlered deer, or sangai. Lakes, too, can be valuable wetlands.
One of the only RAMSAR wetlands categorized as a river/stream in India is the stretch of the Ganges River falling between Brijghat and Narora. This stretch of the river is shallow, with intermittent deep pools, and serves as valuable habitat for the endangered gharial, Ganges river dolphin, mugger crocodile, Indian soft-shelled turtle, and common otter. Such rare and valuable species, and their wetland environment, must be preserved to retain India’s value as a global biodiversity hotspot.
As climate change continues to change environmental conditions present in and around wetland systems, we can expect to see a loss of biodiversity and available habitat in these important systems. As sea levels continue to rise, coastal wetlands are at risk of saltwater intrusion and physical damage due to increased storm frequency and intensity. These can lower the availability of high-quality habitat and resources that are crucial for maintaining wildlife populations, both residential and migratory (Bassi et al. 2014). Species such as the sangai, which are already facing eventual extinction in the wild, rely upon wetlands for their survival. And species of turtles, crocodilians, and dolphins (marine and river) are declining globally, with wetlands serving as important nesting and breeding sites for many endemic species.
Wetlands Under Threat:
Of India’s myriad ecosystems, wetlands and grasslands remain the least understood and the most misunderstood. Wetlands are dismissed as swampy wastelands and are often drained for development projects. A study by Bassi et al. (2014) found that the main causes of wetland loss worldwide include urbanization, land use changes, drainage for agricultural use, infrastructure development, and pollution from industrial and agricultural runoff, amongst others.
Conversion of wetlands for agricultural use is a key cause of wetland loss, one that is amplified as our nation’s population continues to grow. Between 1951 and 2009, cultivated land in India increased from 129 to 159 million hectares (Datasource: Indistat). As the population grows, so does the need for space and accelerated urbanization; between 1973 and 2007, the Greater Bengaluru Region lost 66 wetlands spreading over 1100 hectares to urban sprawl (Ramachandra & Kumar 2008).
Agricultural and industrial runoff contribute heavily to the contamination of wetlands in India. With the advent of the Green Revolution and the resultant intensification of agricultural activities, fertilizer usage in India increased from 2.8 million tonnes in 1973-1974 to 28.3 million tonnes in 2010-2011 (Datasource: Indistat). It is estimated that 10-15 percent of nutrients added to soil via fertilizers finds its way into surface water bodies (Indian Institute of Technology 2011). This leads to increased algal growth and depleted oxygen content in these water bodies. Untreated wastewater is another major source of water pollution that affects wetlands. Less than 31 percent of India’s wastewater generated from urban centres is treated, as compared to 80 percent in the western world (Central Pollution Control Board 2009).
Moving Forward: Conservation and Management of Wetlands:
The Thane wetlands of Mumbai welcome flocks of flamingos each year, but as development cuts into the area of these wetlands, will these rosy visitors deign to visit the city outskirts any longer? As our coastal mangroves vanish, can we ensure that our shorelines remain intact and stable against rising seas? And can we create a safe habitat for the last Manipuri brow-antlered deer on our planet if we drain the lake habitat in Manipur where they make their final stand?
There are steps that we can take to preserve our remaining wetlands and restore the degraded ones to functional health. For one, we can restore our lakes and rivers by dredging out garbage, preventing the addition of new wastes to the river, and demanding enforcement of sewage treatment plant outflow to divert them from these natural systems. We can also ensure the replanting of natural vegetation around lakes, rivers, and wetlands to restore habitat quality and allow for the wetlands’ natural biofilters to take on excessive water pollution. Yet another step is to recharge the groundwater by assessing the water table levels around wetlands and creating borewells downstream of wetland outflow in order to maximize the quality and quantity of water available to farmers.
Wetlands are crucial for the health of India’s forests, wildlife, and human population alike, offering a variety of services and resources. However, climate change and anthropogenic activities are causing a decline in the number of thriving wetlands in our country, and those that survive are facing severe drops in quality. Without wetlands, we will lose valuable services such as carbon sequestration, water filtration, sewage treatment, and coastline protection against storm surges. Wildlife habitat will be lost and India’s bird diversity will take a plunge as waterbirds no longer seek out our inland lakes on their migratory journeys.
This World Wetland Day, take a moment to spread the word about the conservation of our wetlands and remaining water resources.
- Follow this link to see a beautiful video on the Sundarbans mangrove swamps of West Bengal
- Here is a short video on the fishing cat, the only wild cat species truly adapted to life in wetlands
- Follow this link to see a short video by the Department of Environment and Forests, Kerala, on the rare Myristica swamps of the Western Ghats
- Here is a great educational video on the importance of wetlands by Texas Parks and Wildlife
- Watch this fascinating video on the mating dance of the Sarus crane, a rare waterbird endemic to wetlands of India