Human activity altering floristic diversity along Sal, Zuari: Study

Panaji: A new study on the ‘Floristic Diversity of Goa along Zuari and Sal rivers’ by three local researchers shows that plant diversity along the riverbanks reflects long-term human pressures that have reduced vegetation richness. The researchers found increased turbidity and nutrient loads due to unchecked sewage discharge, construction, and aquaculture, resulting in a shift away from natural river conditions.

The study notes that these changes have led to the dominance of disturbance-tolerant species. Findings by principal investigator Celly Quadros, researcher Venecha Carvalho, and co-authors’ guide Krishnan Sellappan state that the absence of certain plant species points to deteriorating soil and water conditions in both rivers.


“Construction along the riverbanks, plastic waste choking water channels, and indiscriminate dumping of solid waste and untreated effluents directly into the river contributed to the deterioration of water quality and the surrounding environment. The spread of invasive or pollution-tolerant plants reveals how disturbed environments reshape biological communities,” said Quadros.

The study highlights that mangroves along the Sal and Zuari rivers provide critical protection to coastal villages from tidal surges and help maintain fish populations that local communities depend on. It notes that mangrove species from the genera Avicennia, Rhizophora, and Acanthus grow luxuriantly in these areas, stabilising shorelines and providing breeding grounds and habitats for fish, crabs, and birds.

“However, the proximity of the Sal river to tourist-heavy areas like Cavelossim and Benaulim has increased pressure on these mangroves, making them more vulnerable to human interference and degradation,” the study states. The Zuari estuary supports dense mangrove forests, particularly around Cortalim, Borim, and Panchwadi, which play a vital role in controlling coastal erosion during the monsoon, said further Quadros.

She added that the study found anthropogenic activities such as construction, agriculture, and mining near the rivers pose a threat to the ecological balance of both systems.

“Rapid urbanisation in cities like Margao along the Sal, and shipbuilding and maintenance activities along the Zuari, have led to heavy pollution from untreated sewage, household waste, and industrial effluents entering these rivers. By showing what currently exists and what is at risk, our study advocates stricter regulation of construction along riverbanks, proper waste management systems, and community-based conservation measures. Ultimately, the vision behind this work is that it should benefit not only the scientific community but also the rivers themselves,” Quadros said.

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