First Invasion Hour: From Crop Fields to Food Webs and Ecological Theory

The first "Invasion Hour", organised by the Indian Forum for Invasion Biology (IFIB) on 20th September 2025, featured three presentations on invasive plant species research. The speakers shared their field observations, experimental approaches, and ecological frameworks for understanding and managing plant invasion in different ecosystems.

Our first speaker was Neha Yadav, an undergraduate Biology student from Azim Premji University. During the last semester break, Neha went to her village in Gorakhpur, Uttar Pradesh, and observed Lantana camara growing along the peripheries of the agricultural fields and Parthenium hysterophorus growing in the barren fields after crop harvesting. She noted a lack of awareness about these invasive plants and their negative impacts on soil fertility and crop yields among the farmers. She then undertook an awareness campaign among schoolchildren, educating them about the rapid action measures to manage these invasive plant species. Neha concluded her talk by emphasising the significant knowledge gap between researchers and farmers regarding invasive species and the need for conducting more studies on the effects of invasive species in agricultural ecosystems in India.

Neha engaged in educating school children in her village about invasive plants

The focus then shifted from farmlands to protected forests with Purnima Singh, a Senior Research Fellow from the University of Delhi. In the protected areas of Rajaji National Park, Ratapani Wildlife Sanctuary, and Satpura Tiger Reserve, she has been studying the ecological consequences of invasive plants on an insect, Oecanthus indicus, a species of tree cricket. Purnima documented cricket presence on various host plants, both invasive and native, in these protected areas, and observed that the insects use the invasive plants for various purposes, from resting to mating, but such dependencies on invasive plants may cause the insects to have reduced progeny in the long run. Purnima shared her plans for setting up preference assessments, planning volatile organic compound (VOC) profiling, and examining if host shifts are occurring.

Purnima in field recording calls of tree crickets

Dr. Kanhaiya Shah, a faculty member from the University of Delhi, concluded the invasion hour with a ‘driver-passenger’ model of biological invasion. He gave examples of two invasive plant species: Hyptis suaveolens, which acts as a driver of ecosystem change and dominates landscapes, and Ricinus communis, a passenger species that colonises areas already disturbed by human activities. Dr. Shah shared some valuable practical field research advice, starting from laminating the data sheets to documenting metadata, and emphasized connecting field data to ecological theories. He recommended different management strategies based on species type: manage the invasive population for driver species and manage anthropogenic disturbance for passenger species.

Dr. Kanhaiya Shah in a field invaded by Hyptis suaveolens

The session was attended by 33 participants, who engaged in a lively discussion after the presentations. The Q/A session highlighted the reduced fitness of the insects in the long run from over-reliance on the invasive species, the necessity of a robust network analysis to understand the complexity of plant-pollinator interactions, the development of herbicide resistance in invasive plants, the importance of common garden experiments to determine driver-passenger status for invasive species, and the challenges of conducting long-term ecological monitoring studies in India.

The first Invasion Hour showed promise for many similar sessions in the near future. We invite young people across India who are engaged in research or simply passionate about the biological invasion issue to participate in upcoming sessions. Drop an email here expressing your interest, and we will get back to you.

Finally, the IFIB team congratulates and thanks Riya and Aadrita for organizing the first Invasion Hour. IFIB will be back soon with the next session.