Unveiling the ecological alarm: People's perception towards exploring the impact of invasive plants on biodiversity and ecosystem services in the Western Himalaya

• The status and impact of the invasive plants Ageratina adenophora and Lantana camara on biodiversity and ecosystems were studied. • The mid-elevation Chir-pine forest is most vulnerable to invasions of alien plants. • Local communities recognize the negative impacts of invasive plants on human and animal health, biodiversity, and ecosystem services and processes. • Forest fires, climate change, transportation, and grazing contribute to the spread of Ageratina adenophora and Lantana camara in this region. This paper presents the insights from both an ecological and people's perception study, aimed at understanding the ecological status of selected two common Invasive Alien Plants species (IAPs), i.e., Ageratina adenophora (Sprengel) King & Robinson and Lantana camara L., and the perspectives of local communities towards their use, status, and influence on biodiversity and ecosystem services as well as controlling measures of these species. For the examination of the distribution and spread of these invasive species in the forests, a quadrat-based phytosociological assessment was conducted in the three dominant forest types [Sal ( Shorea robusta Gaertn f.), Chir-pine ( Pinus roxburghii Sarg . ), and Banj-oak ( Quercus leucotrichophora A. Camus)] of Uttarakhand State. However, to assess the perception and awareness of local communities towards these IAPs and their impacts on local biodiversity, ecosystem services, and processes, a questionnaire-based study was conducted in seven villages of the Nainital district, spanning three different vegetation zones: Sal, Chir-pine, and Banj-oak forests. Perception data were gathered from 112 households through questionnaire surveys and interviews with key informants such as teachers, elders, community leaders, and researchers. The results of the ecological assessment indicate that the mid-elevation zone, particularly the Chir-pine forest, is highly prone to species invasion. However, findings from the perception study reveal that the people are aware of these invasive species, and their negative impacts on human and animal health, native biodiversity, ecosystem services, and ecological processes. Interestingly, over the past decade, invasive alien plant species (IAPs) have interfered with forests in the study area, leading to a decline in native species. According to local perceptions, factors such as deforestation, forest fires, climate change, increased transportation, no use of species in daily life, and grazing have contributed significantly to the spread of these IAPs. However, some people use these species as fencing wood, firewood, and for composting, etc. The results of this study indicate that awareness and educational initiatives could play a crucial role in mitigating and managing invasion in the Himalayan region.