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How fast can conifers climb mountains? Investigating the effects of a changing climate on the viability of Juniperus seravschanica within the mountains of Oman, and developing a conservation strategy for this tree species

Al Farsi, Khalid A.A.Y., Lupton, Darach, Hitchmough, James D., Cameron, Ross W.F.
Journal of arid environments 2017 v.147 pp. 40-53
Juniperus polycarpos var. seravschanica, altitude, climate change, conifers, dieback, drought, dry environmental conditions, genotype, heat stress, heat tolerance, irrigation, keystone species, mountains, planting, seeds, sowing, trees, viability, Oman
The conifer, Juniperus seravschanica is a keystone species within Oman, yet its decline is typical of other arid-adapted, montane tree species. This research aimed to identify causes of decline and subsequent viable conservation strategies; strategies that may have wider application for tree conservation. Decline in J. seravschanica is typified by foliar dieback and little regeneration via seed; traits most apparent at lower altitudes. The research evaluated the viability of seeds collected at three different altitudes: 2100–2220 m (Low), 2300–2400 m (Mid) and 2500–2570 m above sea level (High). In addition, seeds and young trees were planted at these altitudes and maintained under differential irrigation. Results showed that trees grown at Low altitude produced fewer, less-viable seed. Transplanting young trees proved more successful than seed sowing in re-establishing plants in the wild. Age of transplant had an effect, however, with 5-year-old stock showing greater survival (>97%) than 2-year-old trees. The younger trees only established well when planted at High altitude, or provided with irrigation at Mid/Low altitudes. Water availability did not entirely explain survival, and in some locations direct heat stress too may be limiting viability. Practical conservation measures include identifying genotypes with greater drought/heat tolerances and planting only more mature nursery trees.