How Lantana Camara Is Quietly Destroying India's Tiger Reserves

Lantana camara produces a berry that looks edible, smells faintly sweet, and is mildly toxic to most mammals. That detail captures the plant's entire strategy: it offers just enough to get dispersed, and then it poisons the competition. Brought to India by the British as a hedge ornamental in the 1800s, it has since colonised an estimated five to seven million hectares of forest, with tiger reserves bearing a disproportionate share of that burden.

Lantana grows in dense, interlocking thickets that can reach three metres high within a few years of a forest disturbance, a fire, a logging gap, a road cut. Once established, it does three things simultaneously. Its leaf litter acidifies the soil and releases allelopathic compounds that suppress the germination of native seeds beneath it. Its canopy blocks enough light to prevent the grasses and forbs that chital, sambar, and gaur graze on from re-establishing. And its root system outcompetes native seedlings for moisture during the dry months when those seedlings are most vulnerable. The result is a monoculture where a mixed understorey once existed. Ecologists working in Mudumalai Tiger Reserve have documented that lantana-dominated patches support significantly lower densities of large herbivores than adjacent open understorey, the prey base that tigers depend on begins to thin before the tiger itself is ever threatened directly.

Lantana's dispersal agent is, ironically, the wildlife the reserves exist to protect. Frugivorous birds, particularly bulbuls, mynas, and barbets, consume the ripe berries and deposit viable seeds across the forest. Elephants occasionally move through lantana thickets and carry seeds on their feet and skin. The plant also resprouts aggressively after fire, which historically was the understorey's reset mechanism. Fire once cleared competing vegetation and allowed native grasses to reclaim disturbed ground; lantana has partially inverted that relationship, using post-fire gaps to establish faster than native species can recover. In Corbett Tiger Reserve, surveys have found lantana occupying substantial portions of the sal forest understorey, a habitat type that once supported dense grass cover for tigers to hunt in.

The connection between lantana cover and prey availability is not straightforward, but the evidence points in one direction. When the understorey closes over with lantana, the grasses that chital and sambar feed on disappear. The browse available to deer shifts to species they find less palatable or cannot reach. Herbivore density drops in heavily infested areas, which pushes tigers to range wider, increasing the probability of conflict at forest edges. Research in Rajaji National Park and parts of the Western Ghats reserves has linked high lantana density to reduced herbivore sightings in camera trap data. The plant does not threaten the tiger directly; it dismantles the food chain one trophic level below it.

Manual removal works, but at a scale that defeats most reserve budgets. Lantana must be uprooted, not cut, cut stems resprout within weeks. Burning is counterproductive in the ways described above. Biological control using the lantana lace bug, Teleonemia scrupulosa, has been trialled in parts of India with mixed results; it damages the plant but rarely kills established thickets. The most effective interventions documented so far combine mechanical clearing with immediate replanting of native grasses and shrubs to close the gap before lantana recolonises, a labour-intensive sequence that requires sustained funding over multiple seasons. The Wildlife Institute of India has been involved in mapping lantana spread across tiger reserves and piloting removal protocols, though scaling those pilots remains the unresolved challenge. What the evidence makes clear is that passive protection, simply fencing a reserve and stopping hunting, is not sufficient when an invasive plant is actively restructuring the habitat inside the fence.