India’s River Interlinking May Create Invasive Species “Highways”
CONTEXT
- The National River Linking Project (NRLP) proposes connecting major river basins to facilitate the transfer of water between different regions.
- Scientists have cautioned that such inter-basin water transfers could unintentionally create ecological pathways for the movement of invasive alien species and aquatic pathogens.
- The Lower Ganga basin already contains several invasive alien species and could potentially become a source of their spread towards the Mahanadi basin through new river connections.
KEY HIGHLIGHTS
- River interlinking aims to transfer water from surplus to deficit basins, but its environmental consequences may extend beyond hydrology to biodiversity, disease transmission and ecosystem stability.
- River basins function as relatively distinct ecological systems. Connecting them could enable invasive species, pathogens and competitors to cross natural biogeographical barriers that previously limited their spread.
- The Lower Ganga basin is reported to contain around 13 to 15 invasive alien species, many of which could potentially reach the Mahanadi basin through proposed water connections.
- Aquatic pathogens may also spread through inter-basin transfers, potentially affecting native fish populations and fisheries.
- Invasive species can compete with native and endemic species, disrupt food webs and alter the functioning of aquatic ecosystems.
- River-linking plans should therefore incorporate biodiversity impact assessments, ecological-flow requirements, biosecurity measures and invasive-species management, rather than focusing only on water availability and economic gains.
KEY CONCEPTS
- Invasive Alien Species (IAS): Non-native organisms that establish and spread in a new ecosystem and cause ecological, economic or social harm, including displacement of native species.
- Ecological Highways: Connections between previously isolated ecosystems that facilitate the movement and establishment of invasive species across natural ecological barriers.
- Biological Invasion: The process through which non-native organisms enter, establish and spread within a new ecosystem, potentially threatening native biodiversity.
WAY FORWARD
- River interlinking projects should undertake basin-level ecological impact assessments before creating new hydrological connections.
- Measures such as invasive-species surveillance, pathogen screening and robust biosecurity protocols should be incorporated into project planning.
- Ecological connectivity should be assessed carefully so that water-resource objectives do not unintentionally create pathways for biological invasions and disease transmission.