Introduction
India harbours nearly 8% of the world's recorded biodiversity across four global biodiversity hotspots. However, this mega-diverse status is under severe pressure due to biological invasions, habitat thinning, and multifaceted anthropogenic activities that disrupt fragile ecological equilibria.
Impact of Biological Invasion and Habitat Thinning
- Invasive Alien Species: Exotic flora such as Lantana camara (which occupies over 40% of India's tiger landscapes) and Senna spectabilis (proliferating across the Nilgiri Biosphere Reserve) alter soil chemistry and suppress native flora. This depletes the forage base of native herbivores, indirectly exacerbating human-wildlife conflict.
- Habitat Thinning and Canopy Degradation: Unlike outright deforestation, habitat thinning involves the reduction of canopy cover and forest density. As highlighted by the India State of Forest Report (ISFR), degradation of moderately dense forests into open forests induces pronounced 'edge effects,' alters microclimates, increases forest fire vulnerability, and facilitates the inward spread of invasive plants.
Other Major Drivers of Biodiversity Loss
- Linear Infrastructure and Fragmentation: Highways, railways, and power transmission corridors (such as National Highway 44 cutting through Pench Tiger Reserve) bisect contiguous habitats, leading to frequent roadkill, fragmented breeding populations, and genetic isolation.
- Anthropogenic Climate Change: Rising sea surface temperatures trigger recurrent coral bleaching in marine hotspots like the Gulf of Mannar and Lakshadweep. In terrestrial zones, rapid alpine warming forces high-altitude Himalayan flora and fauna to shift upward into contracting climatic envelopes.
- Pollution and Eutrophication: Agricultural runoff carrying chemical fertilisers and untreated industrial effluents enter critical Ramsar wetlands (such as Vembanad Lake), inducing severe eutrophication, hypoxia, and mass die-offs of aquatic organisms.
- Overexploitation and Illegal Wildlife Trade: Unregulated poaching and trafficking threaten vulnerable fauna such as the Indian Pangolin, while unsustainable extraction of non-timber forest produce compromises natural forest regeneration.
Conclusion
Preserving India's biological heritage necessitates multi-stakeholder ecological restoration initiatives, exemplified by state-level drives to eradicate invasive alien species, alongside mainstreaming wildlife crossings in infrastructure design. These measures are vital to fulfil Target 6 of the Kunming-Montreal Global Biodiversity Framework.