Invasive species are recognized as potential threats to ecosystem. The threat of invasion is exacerbated as global commerce accelerates and anthropogenic disturbance increases. Lantana camara is one such noxious weed which is expanding and now established in many regions of the world, including India. Introduced in Indian subcontinent dating back to 1800s as an ornamental plant, it has resulted in serious ecological and economic repercussion. Some of these are altered native composition, ecological degradation, and fire facilitation to areas of invasion especially to ecologically rich regions such as protected areas. These nuisances caused by Lantana camara led us to investigate its invasion potential distribution in protected areas, namely Jim Corbett and Rajaji National Parks of Western Himalaya, to enable understanding of spread of invasion and its potential path of progression under wake of climate and anthropogenic changes.
Invasion potential distribution was modeled using three ecological niche modeling algorithms (i) Biomapper, (ii) GARP, and (iii) Maxent, as regards to their ability to predict the geographic distributions of species. The models used field locations of species, WorldClim current climate database, topographic, edaphic and ancillary environmental factors. The results mirror the known distribution fairly well with various degrees of predictions across models. Such predictions can guide conservation practices including decisions for early detection and timely mitigation to curb invasion.
To understand the dynamism and progression of the species in the wake of climate change and anthropogenic activities, investigation were carried out to develop future invasion potential distribution models of the species. Using three representative climate change models viz., CSIRO (Commonwealth Scientific and Industrial Research Organization), CCCMA (Canadian Centre for Climate Modeling and Analysis) and HadCM3 (Hadley Centre for Climate Prediction and Research’s General Circulation Model) across the time slices 2020 to 2080 under two regional climate change scenarios A2a and B2a, future potential distribution models were derived. The modeled results suggest that in the future, two National Parks may be infested heavily by the gregarious presence. The increase in invasion potential distribution is predicted slightly more pronounced under A2a scenarios than B2a scenarios indicating that the species may prefer warmer conditions than will be available in B2a scenario. Predictive models such as those developed in study can assist resource managers to circumvent negative ecological impacts in future resulting in substantial economic savings.
Lantana camara is hypothesized to alter fire regimes to greater extent causing damage to ecosystem properties. Thus, to elucidate its relationship with fire, if any, study on species presence and fire occurrences were carried out. Venn diagrams and distance matrix analysis were employed to discern relationship between the two. The empirical evidences obtained in research support the hypothesis that fire may be driven under presence of Lantana camara and vice versa may hold true. Information presented in research along with other studies on relationship dynamics will allow better management of Lantana camara.
Synergies are lacking across management, research, policies and decision making to manage invasion. Sustainable management of invasive species is challenging but inevitable given the increasing range of alteration caused by invasion. A Invasive Species Management Framework (ISMF) is proposed to combat and control invasive species across spatio-temporal scales. Information of this kind, as presented in this research, is critically needed to plan-out a befitting response to protect the ecosystems at a matching scale; else it may be impossible to make any headway towards meaningful control with small, scattered and sporadic attempts