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[ratio ]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.