Soil microbial communities, being at the interface of plant-soil feedback systems, can play a pivotal role in facilitating ecosystem response to the drivers of global environmental change, including invasive alien species (IAS). Studies evaluating the effect of plant invasion on soil microbial communities along altitudinal gradients can provide novel insights regarding the spread and impact of IAS and elevational range shifts in response to ongoing climate warming in mountains. In this study, we used metagenomic tools to investigate the impact of invasive Leucanthemum vulgare on taxonomic composition, relative abundance, alpha and beta diversity of soil microbial (bacterial and fungal) community, physicochemical properties and their interaction between invaded and uninvaded plots selected across multiple sites along an altitudinal gradient in Kashmir Himalaya. We found that the invasion by L. vulgare shifted composition, relative abundance, alpha and beta diversity of soil microbiome significantly in invaded plots. The relative abundance of soil microbial communities interestingly showed an increasing trend along the altitudinal gradient. The soil physicochemical properties were significantly correlated with microbial community abundance with temperature, K, pH, EC and Fe being the dominant determinants. Also, we found a significant effect of soil physicochemical properties on the microbial community abundance along the altitudinal gradient. Our findings unravel the plant invasion-induced shifts in the underground soil microbiome and physicochemical properties, which improve our understanding of plant invasion impacts on belowground biotic and abiotic components and can contribute in guiding integrated management of invaded mountain landscapes globally.

Climate change and other global change drivers threaten plant diversity in mountains worldwide. A widely documented response to such environmental modifications is for plant species to change their elevational ranges. Range shifts are often idiosyncratic and difficult to generalize, partly due to variation in sampling methods. There is thus a need for a standardized monitoring strategy that can be applied across mountain regions to assess distribution changes and community turnover of native and non-native plant species over space and time. Here, we present a conceptually intuitive and standardized protocol developed by the Mountain Invasion Research Network (MIREN) to systematically quantify global patterns of native and non-native species distributions along elevation gradients and shifts arising from interactive effects of climate change and human disturbance. Usually repeated every five years, surveys consist of 20 sample sites located at equal elevation increments along three replicate roads per sampling region. At each site, three plots extend from the side of a mountain road into surrounding natural vegetation. The protocol has been successfully used in 18 regions worldwide from 2007 to present. Analyses of one point in time already generated some salient results, and revealed region-specific elevational patterns of native plant species richness, but a globally consistent elevational decline in non-native species richness. Non-native plants were also more abundant directly adjacent to road edges, suggesting that disturbed roadsides serve as a vector for invasions into mountains. From the upcoming analyses of time series even more exciting results especially about range shifts can be expected. Implementing the protocol in more mountain regions globally would help to generate a more complete picture of how global change alters species distributions. This would inform conservation policy in mountain ecosystems, where some conservation policies remain poorly implemented.