Restoring SunderbansDate: 29 September 2019 Tags: National Park and Wildlife Sanctuary
Increasing anthropogenic activities along with natural stresses have led to massive degradation of one of India’s World Heritage Site , the Sunderbans.
A group of researchers performed a task of identifying the major reasons for the decline and also devising new restoration strategies. They surveyed 19 shoreline mangrove patches, collected soil and water samples and studied them and highlighted that lack of essential nutrients and increasing salinity were the main problems in Sunderbans declining.
Nutrient depletion especially phosphorus and nitrogen was found to be directly connected with the decline in forest cover.
The researchers also saw a change in the species distribution like salt-sensitive ones such as Heriteira fomes, Xylocarpus species and Phoenix paludosa were not able to cope up with the increase in the salinity and declined while the tolerant varieties thrived.
The researchers stabilised the site of restoration by planting four native salt-tolerant varieties of grass. These grasses proved to exhibit the highest survival in the lower and middle intertidal zone.
During the last five years (2014–2019) almost about one-hectare area of the degraded patch has been restored by the growth of these grasses.
The grass rhizosphere also provided a nutritive atmosphere to the colonizing mangroves because this root zone decomposes microbes and helps release more nutrients in the mudflat soil.
These grasses also provided protection from high energy waves and subsequent erosion of soil. The team also used native plant growth-promoting bacteria to enrich the degraded land.
High salt-tolerant varieties were planted near the shoreline and the moderate ones farther.
Biorestoration is a process by which a piece of land is returned to its normal state by making use of plants, microbes and other natural methods to increse its fertility.