Effects of sheep grazing exclusion on alpine tall tussock grasslands

Substantial areas of alpine tall tussock grasslands are being retired from grazing as part of Crown pastoral lease tenure review because of the perceived negative impact of grazing livestock. However, relatively little is known about the effect of sheep exclusion on these grasslands. We analysed data from five grazing exclosure plots over a 6-year period to examine the effect merino sheep have relative to hares and rabbits in alpine tall tussock grasslands used for summer grazing.

Demographic drivers of biomass carbon recovery in degraded perennial tussock grassland, with and without domestic grazing

Many of New Zealand’s natural and induced tussock grasslands are in a degraded low-biomass state due to a combination of fire, overgrazing and weed invasion. The capacity of degraded grasslands to recover biomass is uncertain because legacies of degradation can strongly influence the demographic processes controlling ecosystem recovery. We develop a conceptual framework for understanding biomass carbon (C) flux in degraded perennial grassland based on demographic processes of growth, mortality and recruitment.