The Deforestation of the Upper Awatere Catchment, Inland Kaikoura Range, Marlborough, South-Island, New Zealand
- Manaaki Whenua - Landcare Research, P.O. Box 69, Lincoln, New Zealand
Pollen analysis of a high altitude bog (Winterton Bog) and an alluvial soil sequence in the upper Awatere catchment on the western flanks of the Inland Kaikoura Range, and radiocarbon dates on wood and charcoal from the Marlborough region, have established a Holocene, (post 10 000 years B.P.) vegetation history for this area. The upper slopes of the catchment were almost entirely clad in Podocarpus and Phyllocladus dominant conifer/broad-leaved forest and the valley floor in Prumnopitys taxifolia for most of the Holocene, despite occasional forest fires in the region. Nothofagus forest spread into the wetter, mountainous region west of the Awatere valley at around c. 6000 years B.P., but failed to establish more than scattered stands on the drier Inland Kaikoura Ranges. Widespread fire broke out in the early Polynesian era and between 750 and 600 years B.P. the Awatere catchment lost most of its forest cover, which was replaced by bracken, grass and scrub. There was a slight recovery of forest and scrub after 600 years B.P. when burning frequency lessened. Increased burning, grazing, and introduction of exotic weeds accompanied the penetration of the region by European pastoralists in the 1860s. The post-1960 era is clearly indicated by the upsurge of Echium vulgare and Pinus spp. The Winterton bog has a finely balanced water budget, and it may have been initiated by changes in the seasonality of rainfall in the mid-Holocene.