Abdul Wahab Khan
Panaji
A study published in the Plant-Environment Interactions journal (2025) has called on the state’s River Rejuvenation Project to look beyond just beautification and instead address the need for deeper interventions, while flagging the decline in plant species diversity along Goa’s Sal and Zuari rivers due to increasing human activity and water pollution.
The authors of the study titled ‘Impact of Anthropogenic Pollution on the Plant Species Diversity and Composition Along the Riparian Ecotones of Goa’s Sal and Zuari Rivers’recommended that the River Rejuvenation Project address core issues such as waste management, unchecked construction and public awareness.
The study, conducted by Moses Musisi of the National Teachers’ College, Kaliro, Uganda, Dr Celly Quadros of the Government College of Arts and Sciences, Quepem, and Dr Krishnan Sellappan from the Goa University, found no sampling station along either river free from human disturbance, including activities such as urbanisation, sewage dumping, unregulated construction and agriculture. The study found these to be the key contributors to
ecological degradation.
These activities have altered water chemistry by increasing levels of nitrates, phosphates and turbidity, stated the study. The study found that water pollution mediates the link between human disturbance and species richness.
The Sal river, identified as the most polluted river in Goa by the Central Pollution Control Board, has a 22-km stretch unsuitable for bathing, fishing or recreation. Parts of the Zuari river showed relatively better species richness but are also seeing a rise in pollution indicators.
A total of 126 plant species from 45 families were recorded with the researchers finding a drop in plant species richness and an increase in dominance of a few hardy or invasive species such as Chromolaenaodorata and Sphagneticolatrilobata.
The Shannon-Wiener species diversity index ranged from 3.10 (very high) to 2.06 (moderately low), declining in areas with higher pollution. Seasonal variations also impacted diversity, with the pre-monsoon season showing lower species richness, especially in degraded zones.
The study concluded that changes in water salinity, soil texture and river channelisation accelerate biodiversity loss and disrupt natural plant regeneration in riparian zones.
