The integration of mineral element composition was compared in two tree species of contrasting ecology. The native Prosopis cineraria is slow growing and non-invasive, while the introduced P. juliflora is fast growing, highly aggressive and invasive, and causes substratum degradation in the semi-arid and arid areas of north and north-west India. The two species were sampled from 18 sites in this region. Their leaf samples were analysed for leaflet weight, area and leaflet specific weight, and ash, Ca, Mg, Na, K, Zn, Cu and P concentrations. The soil samples were analysed for pH, electrical conductivity, exchangeable Ca, Mg, Na, K, Zn, PO4, HCO3, and organic carbon contents. Analysis of the data showed that while P. cineraria exhibited numerous correlations amongst plant and soil characteristics, it was not so in P. juliflora. This lack of integration amongst plant and soil characteristics and the ability to meet its nutrient requirements in all situations could be the basis of the phenomenal spread of P. juliflora across varying environmental conditions, in contrast to P. cineraria. This study illustrates the use of such information in the assessment of the ecological success of plant species, especially its evaluation in alien environments.