Assessing the effects of drought and temperature on the establishment of Juniperus seravschanica saplings in Northern Oman

Abstract

Climate change predictions pose a serious threat to the survival and distribution of Juniperus seravschanica in the northern mountains of Oman. A better understanding of this species responses to ecological changes is essential, if the potentially harmful effects of climate change are to be mitigated. One such step is to understand how changes in climate may influence the growth of juniper saplings. Two and five year old saplings were grown under different temperatures and watering regimes to determine effects on establishment and growth. Under an optimum growing temperature, reducing water to 50% and 25% of the optimal irrigation regime, significantly decreased the growth of juniper saplings. In field studies, saplings re-introduced to three different altitudinal locations showed varying rates in establishment success and growth. Both two year old and five year old saplings established better at higher altitude. Overall, survival rates were considerably better with transplanting five year old, rather than two year old saplings. Applying irrigation improved the survival of two-year old stock when grown at the lowest altitude, but rates were not always significantly different from other treatments. Apical extension growth was found to be reduced at higher altitude, indicating that temperature is influencing the growth of juniper saplings. However, it was the combination of drought and high temperatures that reduced the growth of non-irrigated saplings at lower altitudes. These preliminary results suggest there is a potential to re-introduce juniper saplings to their natural habitat as part of a conservation programme, but more time is required to judge the success of the transplanting initiative when dealing with slow growing trees like juniper