soil nitrogen

Woody native and exotic species respond differently to New Zealand dryland soil nutrient and moisture gradients

In many New Zealand dryland grass and shrubland areas, native and exotic woody species are invading, but it is unclear what environmental factors favour native dominance. One possibility is that differences in soil nutrients and moisture, or a combination of these factors, differentially affect the growth and hence invasive potential of native and exotic woody dryland species. We tested the prediction that native woody species outperform exotic woody species under low-nutrient and dry soil conditions.

Soil Changes under Mouse-Ear Hawkweed (Hieracium pilosella)

The rate of spread of mouse-ear hawkweed (Hieracium pilosella) patches, the effect of hawkweed on soil properties, and the nutrient content of hawkweed biomass was investigated on grazed unfertilised land on Glencairn Station (altitude 440 m, mean annual rainfall 500-600 mm) in the Mackenzie basin, southern South Island, New Zealand. Pallic soils (Typic Ustochrepts) under hawkweed patches and under surrounding herbfield were analysed for exchangeable cations, organic C and total N. Total nutrients in hawkweed and herbfield biomass were measured.