IAPS Targeted: Eichornia crassipes and Salvinia molesta
The Wasgamuwa National Park (WNP) is an important conservation area in Sri Lanka because of its high biodiversity, and remains a sanctuary for threatened species like the Sri Lankan elephant, sloth bear, water buffalo, leopard. WNP is also home to multiple tanks, natural water holes, villus, and ebeys. It is in these water bodies that the aquatic IAPS Eichornia crassipes (water hyacinth) and Salvinia molesta (giant salvinia) have overrun the native aquatic flora:
- Eichornia and Salvinia are aquatic IAPS that can grow rapidly, have long roots, and can form dense mats on the surface of freshwater bodies. This can lead to larger animals mistaking the water body for grassland, and causing them to be trapped under water.
- These species can also disrupt the aquatic ecosystems they infect because they can increase evaporative loss of the water bodies they invade, they can block water flow and sunlight, suppress the growth of native aquatic plants that provide shelter and breeding areas for fish, and they can encourage the growth of disease vectors such as the Dengue virus.
These aquatic IAPS can result in the decline of the park’s aquatic biodiversity, and affect the water quality of fresh water accessible to the other land animals in the park. The plants have also disrupted human interests, such as irrigation and navigation.
In March of 2023, the FEO conducted a pilot study before committing to removing these IAPS from most of the tanks in WNP. We are removing these plant species manually and letting them compost in situ. Currently, we have cleared three ebeys in the park (about 50% of the anticipated work). We will also be continuing our monitoring of the cleared tanks over the next 1.5 years, to maintain the water bodies we have cleared of Eichornia and Salvinia, ensuring that they stay clear of these aquatic invasive species.