The research program of Inderjit Singh is an interdisciplinary and multifaceted attempt with a global coverage to understand ecological-evolutionary processes of non-native invasive plants achieving success and influencing native communities. He has contributed to the better understanding of allelopathic interactions in natural ecosystems and why some non-native species become so successful in ranges far from their native range and impact biodiversity and ecosystem metrics.
Inderjit's work showed that invasive species exert neutral to facilitative effects on their native neighbors but exert neutral to negative impacts on the non-native communities (Inderjit et al. 2011, Ecology; Becerra et al. 2018, Global Ecology & Biogeography; Kaur et al. 2012, PLoS One). Inderjit and his group have studied the role plant chemicals in providing competitive advantage to species in their native versus non-native ranges. His studies on the patterns of production of terpenes by A. adenophora, an aggressive invasive species in Asia, showed contrasting levels of chemical production in native range and non-native ranges (Inderjit et al. 2011, Ecology), which may provide competitive advantages to the invader (e.g., Inderjit et al. 2021, New Phytologist; Inderjit et al. 2011, Trends in Ecology & Evolution; Inderjit et al. 2006, Trends in Plant Science; Kaur et al. 2014, Soil Biology & Biochemistry). Through collaborative studies, Inderjit and his collaborators showed that the invasive species allocated more nitrogen for cell wall proteins, which are associated with defense against enemies, while in the non-native ranges it allocated more nitrogen resources for photosynthesis compared to defense (e.g., Feng et al. 2009, PNAS; Feng et al. 2011, Journal of Ecology).
Using Chromolaena odorata, an aggressive invader in the Western Ghats of Kerala, as a model invader, Inderjit and his student demonstrated that the species influences the establishment and growth of native species through accumulating soil pathogens that suppress the seedling establishment of native species (Mangla et al. 2008, Journal of Ecology). They showed that soil microbial communities associated with invasive species facilitate its growth and fitness (Inderjit and van der Putten, 2010, Trends in Ecology & Evolution). Inderjit contributed to developing conceptual frameworks. For example, (i) conceptual framework for biological invasion (Gurevitch et al. 2011 Ecology Letters), (ii) exchange and naturalization of non-native species (van Kleunen et al. 2015, Nature; Cai et al. 2022, New Phytologist, in press), (iii) human-assisted vegetation changes (Inderjit et al. 2017. Oikos) (iv) intensification of invasion risks following the introduction of new pasture plants (Driscoll et al. 2014. PNAS), and (v) belowground feedbacks mediate spatial self-organization and community assembly (Inderjit et al. 2021, Physics of Life Reviews).
Inderjit is a full Professor in the Department of Environmental Studies, University of Delhi, India and Director of the Centre for Environmental Management of Degraded Ecosystems. IHe addresses fundamental and applied questions relevant to plant ecology at regional and continental scales. One of his current goals to unravel the complexity of invasion impacts, understand the linkages between drivers of invasion impacts. Tackling these goals involve studying belowground feedbacks (plant-soil feedbacks, allelopathy) that drive vegetation patterns and community assembly. With colleagues, he has generated evidence that plant chemical traits form the basis of much of the ecological functions of non-native species at various levels of ecological organization. In turn, these functions interact with various biotic factors, such as soil biota, to mediate the role of plant chemicals in the environment. Inderjit is studying in what ways plant chemistry influence population, community and chemical ecology, for example, routes through which canopy chemistry mediate plant-soil feedbacks.
Inderjit has led or facilitated broad and successful research collaborations in North America, South America, Europe, Middle-East and Asia. He has performed research in diverse ecosystems including deserts, grasslands, agroecosystems, boreal Canadian forests, tropical and temperate forests. He has several short-termed appointments throughout the world including, Gerrit Parmile Wilder Chair Professor at the University of Hawaii at Manoa during 2011-2012, visiting professor positions in USA, Canada and Europe. Inderjit's leadership experience includes serving as Associate Editor for several journals including Scientific Reports (UK), Journal of Applied Ecology (UK), Biological Invasions (USA), AoB Plants (USA) and NeoBiota (Europe). Some of major administrative positions Inderjit hold in the past were: Dean, Faculty of Science, University of Delhi, Head, Department of Environmental Studies, University of Delhi and the Director, Centre for Environmental Management of Degraded Ecosystems, University of Delhi. He has published >100 research papers, and edited seven books. The leadership and influence of Inderjit are reflected in many plenary or keynote talks and lectures he has been invited to give at pre-eminent international conferences and meetings. Inderjit is an elected Fellow of Indian National Science Academy (FNA, INSA), New Delhi India. He received Distinguished Visitor Award from the University of Alberta, Canada in 2018. Inderjit was awarded the Robert H. Whittaker Distinguished Ecologist Award from the Ecological Society of America (ESA) in 2015; and also Outstanding Young Weed Scientist Award, Weed Science Society of America in 2001. Inderjit is elected for the Humboldt Research Award in 2022 and currently working at the Department of Biochemistry, Max Planck Institute for Chemical Ecology, Jena.