A comparative study of leaf nutrient concentrations in a regional herbaceous flora.

Mineral nutrient concentrations were determined in leaves of 83 mostly herbaceous species collected from central England. Most samples were analysed for N, P, K, Ca, Mg, Na, Fe, Al, Mn, Cu and Zn. Concentrations of K, N and P showed similar levels of interspecific variability, with the highest concentrations being 6-9 times the lowest. Mg and (especially) Ca were much more variable, with the highest concentrations being 24 and 49 times the lowest respectively. Only in the case of P concentration was the majority of the variance in the data found at or below the species level. Most of the variance in Ca and Mg concentrations was between monocots and dicots. Concentrations of N and P were strongly positively correlated with each other. Only Ca and Mn were consistently associated with soil pH, positively and negatively respectively. Dicots tended to accumulate more Ca and Mn from high soil concentrations than did monocots. Concentration of P was significantly positively correlated with maximum potential relative growth rate. Plants of woodland and arable habitats contained high concentrations of P, and those of pasture and skeletal habitats contained low concentrations of P. The P: N ratio was higher in plants of arable habitats. Species with P-rich leaves tended to be currently increasing in abundance. The results suggest that plants with nutrient-rich foliage grow quickly, dominate nutrient-rich ecosystems and are generally increasing as a result of the eutrophication and disturbance arising from human exploitation.