Expanding niche and degrading forests: Key to the successful global invasion of Lantana camara (sensu lato)

Estimating the distribution of invasive species and understanding the ecological reasons for their success is crucial for their management. Moreover, their ability to invade biogeographically distinct regions in short timespans poses interesting ecological questions. Lantana camara (sensu lato) is one such invasive species of global concern. In an unprecedented effort, we surveyed 207,100 km(2) of Indian forests by sampling 13715 grids of 5 x 5 km, each with 1-31 plots of 10 m diameter, to record the abundance of Lantana. For India, we modeled occupancy of Lantana in the sampled area by accounting for imperfect detection; and potential invasion outside the sampled area using MaxEnt with covariates of climate, soil, forest and human disturbance. Further, Lantana's response in comparable areas of its native and global invaded range was modeled using MaxEnt to provide a better understanding of its changing relationship with environmental factors. Lantana invaded 154,837 km2 of the surveyed area, and threatened 303,607 km2 of total Indian forests (44%); with preference to warm, humid, fertile areas, degraded by extractive human use. By combining our large-scale ground surveys with published data, we show that Lantana has expanded its climatic niche worldwide, with >11 million km2 suitable for its invasion. Niche comparison revealed that Lantana might have adaptive plasticity in its invaded range; where it was found to be more tolerant to higher temperatures, lower fertility and shade as compared to its native range. In light of Lantana's introduction history that suggest excessive hybridization between previously allopatric populations, and its known genetic diversity in the invaded range, the existing adaptive plasticity is suggestive of contemporary evolution. This adaptive nature can increase area under its invasion and pose an ecological conundrum of managing an evolving neophyte. (C) 2020 The Authors. Published by Elsevier B.V.