energetic cost of leaf construction in the invasive weed Mikania micrantha H.B.K. and its co-occurring species: implications for invasiveness

Construction cost (CC) is a quantifiable measure of energy demand for biomass production and is related to energy-use efficiency. Low construction cost was hypothesized to give invaders a growth advantage by utilizing energy efficiently. The present study examines the energetic cost of leaf construction in the invasive weed Mikania micrantha H.B.K. and its five common co-occurring species (Ageratum conyzoides L., Wedelia trilobata (L.) Hitchc, Lantana camara L., Urena lobata L. and Derris trifoliata Lour.), and provides insight into the success of this invasive weed. Mikania micrantha had the lowest leaf construction cost both on a mass basis (leaf CCmass, 1.32 g glucose g) and on an area basis (leaf CCarea, 28.80 g glucose m). Mikania micrantha dominated the studied community with 60% coverage. The low leaf CC associated with its great abundance indicated that low energetic cost might benefit its spread. Additionally, a higher specific leaf area (SLA) and lower C and N concentrations were found in M. micrantha, providing it with another competitive advantage. All the six studied species could be grouped into either an invasive or a native species category. Both the mean leaf CCarea and CCmass for the invasive were lower than those for the native species though the mean leaf CCmass was not significantly different. The result indicated that a low energetic cost of leaf construction might generally influence invasive potential. Using discriminant analysis, leaf CCarea was identified to be more powerful in distinguishing between invasive and native species. Therefore, leaf CCarea might be a valuable index to predict invasiveness and has a meaningful management implication.