high country

We sampled soils and vegetation within and outside two sheep and rabbit exclosures, fenced in 1979, on steep sunny and shady slopes at 770 m altitude on seasonally-dry pastoral steeplands. The vegetation of sunny aspects was characterised by higher floristic diversity, annual species, and low plant cover. Here the exotic grass Anthoxanthum odoratum dominated on grazed treatments, and the exotic forb Hieracium pilosella on ungrazed. Shady aspects supported fewer, and almost entirely perennial, species.

Soil characteristics were examined within and adjacent to two vegetation exclosures near Porters Pass, Canterbury retired from grazing 45 years ago. Soils were analysed for a range of simple physical (topsoil depth, bulk density), chemical (pH, exchangeable cations, P, S, total C and N) and biochemical (microbial carbon) properties to determine whether the vegetation recovery inside the exclosures was reflected in soil differences.

Hieracium, or hawkweed species, serious weeds in South Island high country, may be controlled by appropriate pastoral management. Experimental trials at Lake Tekapo, related to S and P fertiliser rates of 0-100 kg ha-1 yr-1, 27 different combinations of over-drilled and resident species and different seasons or intensities of grazing treatments on Hieracium dominated fescue tussock were conducted. These were monitored for 9 years in terms of fertiliser inputs used, sheep stocking rates, and vegetation changes.