Assessing the influence of invasion of Lantana camara on vegetation attributes and soil properties across varied disturbance gradients in semi-arid forests of Aravali hills, Delhi

This study highlights the coupling effect of disturbance and Lantana camara invasion on vegetation and soil properties in the least disturbed (LD), moderately disturbed (MD) and highly disturbed (HD) sites in the semi-arid region of Aravalli Mountain, South Delhi. A total of 60 quadrats of 10 m × 10 m were laid for tree species and 5 m × 5 m for shrub species in the LD, MD and HD sites for phytosociological study. Soil samples were collected at three places: areas occupied by Lantana camara (LC) and Adhatoda vasica (AV), as well as areas of bare soil (no vegetation) at two different depths: the upper layer (0–10 cm) and the lower layer (10–20 cm). Results showed higher tree diversity in the LD site, whereas shrub diversity was high in HD site. The relative density (RD) of invasive L. camara and soil properties was maximum in MD (61.5%) and minimum (55.5%) in HD site, however low soil nutrients in HD site may be due to the lower RD of LC. Statistical analysis showed significant (p < 0.05) high soil moisture, soil organic carbon (SOC), microbial biomass carbon (MBC) and nitrogen (MBN) in MD site. SOC, TN, MBC and MBN were higher under LC-occupied regions compared to AV in LD and MD sites. In HD site, nutrient content was higher under AV region, reflecting that in nutrient-deficit soil, native species adapt and resist the invasion of LC. However, among the different biotic and abiotic factors, disturbance is one of the major drivers that promotes plant invasion.