Ecosystem Restoration

Over the past decade, Earth’s environmental conditions have taken a significant turn for the worse, with its deteriorating ecosystems and declining biodiversity. This World Environment Day, the UN Environment Programme has announced the “UN Decade on Ecosystem Restoration” that will focus on ecosystem restoration in an attempt to bring back the ecologically diverse world we once had.

Ecosystem restoration means assisting in the recovery of ecosystems that have been degraded or destroyed, as well as conserving those which are still intact. Healthier ecosystems yield ecological benefits such as more fertile soils, larger stores of greenhouse gases, increased carbon sequestration, uninterrupted nutrient cycling, greater air purification, and a more stable climate that can ensure a sustainable future. The task of restoring ecosystems can be taken up by individuals, local communities, NGOs, and the government itself.

UN Decade on Ecosystem Restoration 2021–2030—what chance for success in restoring coastal ecosystems?

Let us explore a few examples of ecosystem restoration in India.

• Green bridge lake restoration: “Using nature to heal nature”

Green bridges are defined as an ecotechnological in-situ bioremediation system. They use biologically originated cellulosic/fibrous material with the root system of green plants as filters (lemon grass, barley grass, castor and varieties of bamboo). Fibrous material like coconut coir is used to form a porous wall-like structure strengthened by stones and sand. All the floatable and suspended solids are trapped in this bridge, lowering the turbidity of flowing water. Plants on the bridges increase the diffused oxygen level in water, which facilitate the growth of aerobic organisms, which in turn degrade organic pollutants, decreasing biological and chemical oxygen demand of the waterbody.

This method has been successfully implemented in the restoration of the Udaisagar lake in Udaipur, Rajasthan. The project was initiated in 2009 by Jheel Sanrakshan Samiti, working with the International Lake Environment Committee Foundation, Japan. The Green Bridge was installed at one end of Ahar river, where the river enters the Udaisagar Lake. Six bridges of varying length from 12 to 14 metres were installed. Once floating debris like plastic and water hyacinths were removed, sunlight and air could finally penetrate the water surface.

• Community-participative model of forest restoration: “Forest Guardians”

It involves the introduction of a restoration-based livelihood, where local communities are involved in active or passive restoration of ecosystems. Elders of such indigenous communities have invaluable traditional knowledge on endemic plants and their uses for wild fauna. If this know-how is used well, over half a million marginalised people can gain livelihoods. Restoration can also help buffer rural populations from the vagaries of agricultural incomes and reduce migration from villages.

This approach was initially adopted by an NGO called Junglescapes, which has been working since 2008 on the ecological restoration of degraded forests around Bandipur Tiger Reserve, Karnataka. They reclaimed over 2,500 acres of forests in the last 9-10 years, by restoring large areas invaded by Lantana and re-building the resilience of the ecosystem with the help of local communities.

• Floating treatment wetlands: “Using plants to reduce pollution”

Floating treatment wetlands (FTWs) are small artificial platforms that allow aquatic emergent plants to grow in water that is typically too deep for them. Their roots spread through the floating islands and down into the water, creating dense columns of roots with lots of surface area. Not only do the plants take up nutrients and heavy metals for their own growth, but they also act as a natural habitat for microbes to grow—forming a slimy layer of biofilm. A majority of nutrient uptake and degradation occurs here. The FTWs helped in the improvement of all recorded water quality indicators and a reduction of heavy metal concentrations.

This method was used in the restoration of Neknampur Lake, in Hyderabad. Plants such as vetivers, canna, bulrush, lemon grass, citronella, fountain grass, lilies, khus, were used. There was a great reduction in biological oxygen demand, and an increase in biodiversity. Conservationists have found bird nests and eggs belonging to whistling ducks, herons, and geese, as well as new turtles.

Floating treatment wetlands

• Fishbone model for mangrove restoration: “Striking down Salinity”

In this model, the water from a creek is diverted to the targeted site through feeder and field channels, converting the barren land with high saline content into fertile mangrove land. This was used to restore mangroves in Andhra Pradesh from 1997-2004, covering an area of 520 hectares in the Godavari and Krishna mangroves.

The process began with the digging of canals to reduce salinity, facilitate tidal flushing, and drain stagnant water. A fishbone design was utilized in order to facilitate easy flow of tidal water. The canals were dug in a trapezoidal shape in order to plant the saplings at the mid-level of the canal to ensure that they received tidal water, but at the same time were not submerged.

The biodiversity of the area has been positively impacted by the restoration, with the crab population going up significantly due to the increased water regime.

• Biorock coral restoration: “Calcification for Corals”

Biorock refers to the substance formed by electro-accumulation of minerals dissolved in seawater. It is a technique that applies low voltage electrical currents through seawater, causing dissolved minerals to crystallize on structures, growing into a white limestone (CaCO3) similar to that which naturally makes up coral reefs. Biorock technology can be powered by energy from the sun, winds, waves, and ocean currents, generated directly at the site. Coral larvae adhere to the CaCO3 and grow quickly. Fragments of broken corals are tied to the Biorock structure, where they are able to grow at least four to six times faster than normal, as they don’t spend their energy in building their own calcium carbonate skeletons.

The Zoological Survey of India, with help from Gujarat’s forest department, installed a Biorock structure one nautical mile off the Mithapur coast in the Gulf of Kachchh in January 2020.

With several such efforts being initiated throughout the country and the world, each individual’s contribution matters. With the combined actions of every citizen, the goal of complete restoration by 2030 does not seem quite an impossible task after all.

- written by Rachna V and Devansh Srivastava