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Conservation of saline patches in Central Otago needs better recognition of physical processes to secure future habitats

Rufaut, Catherine G., Craw, Dave, Druzbicka, Johanna, Law, Shanna
New Zealand journal of botany 2018 v.56 no.1 pp. 115-126
adaptive management, basins, flora, habitats, humans, indigenous species, land use, mining, rain, saline soils, salinity, surveys, viticulture, New Zealand
Saline soils are scattered within multiple inland basins in the semi-arid, rain shadow areas of the South Island, New Zealand. Competing land use activities in agriculture, mining, viticulture and human habitation have led to a strong decline in saline soils to an estimated < 1% of their original distribution. Small areas of ‘new’ (decades old) salinity have arisen at some highly modified sites but these are poorly understood in relation to older saline soils. Recent information from fine-scale geological surveys and geochemical analysis of substrates at two Department of Conservation scientific reserves in Central Otago, with specialist saline flora, is presented in a short synthesis. The goal is to amend existing viewpoints on plant–substrate interactions at what are abandoned gold mine sites. The current surface conditions at Springvale Reserve and Chapman Road Reserve, near Alexandra, which have developed acute salinity during the last 100 years since mining ceased, are outlined. The process of salt accumulation at each site is also clarified and seeks to rectify previous views on local salt source. The new geological data can inform conservation management of the sites, to better address the overall decline of saline habitat for indigenous plant species. A new adaptive management approach is proposed for each reserve that essentially harnesses effects of physical processes, to secure botanical values in the near future.