The Invasive Species Crisis: How Alien Plants Are Reshaping India’s Ecology and Economy

A groundbreaking study in Nature Sustainability reveals that invasive alien species (IAS) are transforming India’s natural landscapes at an alarming rate, with approximately 15,500 square kilometers of natural area invaded by new species annually. Key invaders like Lantana camara and Prosopis juliflora have already doubled their range in sensitive regions like the Western Ghats, now affecting two-thirds of the country’s ecosystems.

This expansion is accelerated by climate change, with wet- and dry-biome species shifting into new areas due to changing temperature and rainfall patterns. The consequences are severe: over 100,000 sq km of tiger habitat has been degraded, livelihoods of millions are threatened by blocked pastures and health issues, and cumulative economic losses since 1960 exceed $127 billion. The study urgently calls for a coordinated National Mission to address the crisis through stricter border checks, community-led management, and evidence-based restoration, highlighting that current fragmented efforts are insufficient against this escalating ecological and socio-economic threat.

The Invasive Species Crisis: How Alien Plants Are Reshaping India’s Ecology and Economy  

A groundbreaking study has revealed that invasive alien species are transforming India’s natural landscapes at a rate unprecedented globally, threatening biodiversity, human livelihoods, and economic stability on a massive scale. Published in Nature Sustainability, the research delivers a stark warning: with nearly 15,500 square kilometers of natural area being invaded annually, India faces a silent ecological crisis that could see entire ecosystems shift within a single generation. 

The Unseen Takeover: Scale and Speed of Invasion 

The study, analyzing over one million vegetation records collected between 2006 and 2022, paints a picture of rapid, widespread colonization. Almost two-thirds of India’s natural ecosystems now harbor at least 11 major invasive plant species. Among the most aggressive are Lantana camara, Chromolaena odorata, and Prosopis juliflora. 

Chromolaena odorata is expanding at an alarming pace of nearly 2,000 square kilometers per year, nearly doubling its range in biodiversity hotspots like the Western Ghats and Northeast India in less than two decades. Prosopis juliflora, originally introduced to curb desertification, now dominates vast landscapes in dry regions, outcompeting native flora essential for wildlife and pastoral communities. 

Table: Key Invasive Species and Their Impacts in India 

Climate Change: The Great Accelerator 

The research underscores that climate change is not a future threat but a current catalyst, actively reshaping invasion patterns. Species are no longer confined to their traditional climatic niches. 

• Wet-biome invaders like Ageratina adenophora and Mikania micrantha are expanding their reach with rising temperatures, declining soil moisture, and more frequent fires. 

• Conversely, dry-biome invaders like Prosopis juliflora and Xanthium strumarium are advancing with increasing rainfall and declining fire frequency. 

This biome-crossing ability means ecosystems everywhere are becoming vulnerable. Plants once thought limited to arid zones are now invading the Himalayan regions and wet evergreen forests. This creates novel and unpredictable threats, as these species encounter native plants and animals with no evolutionary history of coexistence. 

A Cascade of Socio-Ecological Consequences 

The impact of this green invasion extends far beyond botany, creating severe socio-ecological risks for millions. 

• Threat to Wildlife and Protected Areas: By 2022, invasions had impacted over 105,725 square kilometers of tiger habitat and 212,450 square kilometers of wild herbivore-occupied landscapes. Dense patches of Lantana and Chromolaena make forests impenetrable, reduce native food plants for herbivores, and disrupt the entire food chain, ultimately affecting predators like tigers. The study identified 167 protected areas as high-risk zones, indicating that even the core of India’s conservation network is under siege. 

• Impact on Livelihoods and Health: The crisis directly affects approximately 144 million people, 2.8 million livestock, and 200,000 square kilometers of smallholder farmland. Invasive species reduce the availability of fodder and fuelwood, lower soil fertility, and block access to essential resources. For instance, Prosopis juliflora not only chokes grazing lands but its pollen is also known to trigger respiratory ailments in local communities. The resulting resource scarcity can force marginalized households into longer, harder journeys for daily necessities and even trigger migration. 

• Staggering Economic Cost: The cumulative economic loss from invasive species in India between 1960 and 2020 is estimated at a staggering $127.3 billion (over ₹8.3 trillion). These losses stem from reduced agricultural productivity, the cost of management efforts, and the degradation of ecosystem services that economies depend on. 

The Path Forward: From Patchwork to Coherent Mission 

A critical finding of the study is the lack of a cohesive national strategy. Despite being a global invasion hotspot, India lacks a dedicated institutional mechanism or a national database for managing invasive species. Co-author Qamar Qureshi describes the current policy landscape as “a patchwork of intentions rather than a cohesive strategy”. 

The researchers propose a multi-pronged approach centered on a National Invasive Species Mission: 

• Prevention and Early Detection: The first line of defense is strengthening biosecurity at borders—through stricter checks on trade, travel, and shipping—to prevent new introductions. Expanding systematic monitoring, potentially using the National Tiger Conservation Authority’s framework, and promoting citizen-science initiatives can ensure early detection. 

• Prioritized and Evidence-Based Management: With limited resources, management must be strategic. Lessons can be drawn from the European Union, where scientists use species distribution modeling and climate scenarios to prioritize which invasive species to eradicate, control, or monitor. India can similarly identify high-risk clusters (like the Shivalik belt or the Nilgiris) and target the most damaging species first. 

• Community-Led Restoration and Sustainable Use: Empowering local communities is essential. Involving them in restoration projects provides livelihood support. Furthermore, exploring safe, sustainable uses for invasive biomass—such as for bioenergy, handicrafts, or composting—can help reduce existing stands without creating perverse incentives for their spread. Awareness campaigns are crucial, as studies in the Western Himalaya show communities are aware of the negative impacts but need support to act. 

The study in Nature Sustainability is more than an ecological alert; it is a call for a fundamental shift in how India perceives and manages its environment. Invasive species are not just weeds to be removed; they are symptoms of deeper systemic disruptions in land, water, and climate management. Addressing them effectively requires integrating invasion control into broader goals of climate adaptation, poverty alleviation, and ecological restoration. The choice is clear: act now with a unified, science-based, and inclusive mission, or risk losing the natural foundation upon which the nation’s biodiversity and millions of livelihoods depend.