Wetland authority to assess invasion of alien species in TN's water bodies

CHENNAI: As a first step to remove alien invasive species from wetlands across the state, Tamil Nadu State Wetland Authority (TNSWA) has proposed a state-wide assessment of such species that are damaging the ecological balance of the water bodies.

Under the assessment, the Authority, with the help of experts or institutions, will identify and document existing aquatic invasive alien species surveys and literature review. A comprehensive list and documentation of aquatic invasive alien species in the local aquaculture trade that may have the potential to become invasive alien species if they enter the natural ecosystems will be prepared.

Apart from conducting the assessment, standard operating procedures (SOPs) will be devised for the safe recovery, handling, and management of aquatic invasive alien species that may be banned from import, breeding, and sale in Tamil Nadu.

Further, the Authority will prioritize wetlands that are highly vulnerable to invasive species colonization to undertake targeted intervention and conservation efforts.

"As part of the efforts to address the growing threat of aquatic invasive alien species in wetlands, a comprehensive programme needs to be initiated in alignment with the objectives of wetland conservation and wise use," an Authority document said.

In another development, the Authority has already invited competent agencies and institutions to create drone-based mapping and conduct GIS analysis of Ramsar recognized wetlands.

The drone, LiDAR (Light Detection and Ranging) and bathymetric surveys in 15 Ramsar sites including Vedanthangal bird sanctuary, Pichavaram mangrove, Longwood Shola Reserve Forest in The Nilgiris, Nanjarayan bird sanctuary, Kazhuveli bird sanctuary and Karaivetti bird sanctuary.

Under the initiative, land use and land cover classification maps of wetland and its surrounding buffer within a minimum of 300m will be prepared. Sedimentation analysis will be performed to identify areas that have high silt or sludge deposits, through a bathymetric survey performed at post and pre-monsoon.

Moreover, hydrological and water flow analysis will be studied to understand evapotranspiration rates, sedimentation rate, groundwater interaction, flood mapping, and risk assessment. Detection and monitoring of invasive species within the surveyed wetlands through machine learning and classification techniques, and biodiversity assessments, including flora and fauna surveys, vegetation health analysis, and biomass estimation are also part of the exercise.