Comparative response of seedlings of selected native dry tropical and alien invasive species to CO2 enrichment

Abstract

Aims Global climate change and ongoing plant invasion are the two prominent ecological issues threatening biodiversity world wide. Among invasive species, Lantana camara and Hyptis suaveolens are the two most important invaders in the dry deciduous forest in India. We monitored the growth of these two invasive species and seedlings of four native dry deciduous species (Acacia catechu, Bauhinia variegata, Dalbergia latifolia and Tectona grandis) under ambient (375-395 μ mol mol-1) and elevated CO2 (700-750 μ mol mol-1) to study the differential growth response of invasive and native seedlings. Methods Seedlings of all the species were exposed to ambient and elevated CO2. After 60 days of exposure, seedlings were harvested and all the growth-related parameters like plant height; biomass of root, stem and leaves; total seedling biomass; R/S ratio; allocation parameters; net assimilation rate (NAR) and relative growth rate (RGR) were determined. Important Findings Biomass, RGR and NAR of all the species increased under elevated CO2 but the increase was higher in invasive species and they formed larger seedlings than natives. Therefore under the CO 2-enriched future atmosphere, competitive hierarchies could change and may interfere with the species composition of the invaded area.