Climate Change Impacts on the Future Distribution of Date Palms: A Modeling Exercise Using CLIMEX Farzin Shabani*, Lalit Kumar, Subhashni Taylor Ecosystem Management, School of Environmental and Rural Science, University of New England, Armidale, Australia Abstract Climate is changing and, as a consequence, some areas that are climatically suitable for date palm (Phoenix dactylifera L.) cultivation at the present time will become unsuitable in the future. In contrast, some areas that are unsuitable under the current climate will become suitable in the future. Consequently, countries that are dependent on date fruit export will experience economic decline, while other countries’ economies could improve. Knowledge of the likely potential distribution of this economically important crop under current and future climate scenarios will be useful in planning better strategies to manage such issues. This study used CLIMEX to estimate potential date palm distribution under current and future climate models by using one emission scenario (A2) with two different global climate models (GCMs), CSIRO-Mk3.0 (CS) and MIROC-H (MR). The results indicate that in North Africa, many areas with a suitable climate for this species are projected to become climatically unsuitable by 2100. In North and South America, locations such as south-eastern Bolivia and northern Venezuela will become climatically more suitable. By 2070, Saudi Arabia, Iraq and western Iran are projected to have a reduction in climate suitability. The results indicate that cold and dry stresses will play an important role in date palm distribution in the future. These results can inform strategic planning by government and agricultural organizations by identifying new areas in which to cultivate this economically important crop in the future and those areas that will need greater attention due to becoming marginal regions for continued date palm cultivation. Citation: Shabani F, Kumar L, Taylor S (2012) Climate Change Impacts on the Future Distribution of Date Palms: A Modeling Exercise Using CLIMEX. PLoS ONE 7(10): e48021. doi:10.1371/journal.pone.0048021 Editor: Vanesa Magar, Plymouth University, United Kingdom Received July 10, 2012; Accepted September 21, 2012; Published October 24, 2012 Copyright: 2012 Shabani et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: The university of New England have financially supported the Work. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: Fshabani@une.edu.au Introduction Climate is one of the principal aspects defining the potential range of plants and climate change directly affects the distribution of species [1]. Much evidence exists that the climate is changing globally, and land surface temperatures are expected to increase by 4uC between the present and 2100 [2]. Moreover, worldwide seasonal rainfall patterns are changing [2]. As a consequence, a number of serious issues arise. For example, the extent of pollution and aeroallergens will change [3]. Changes in the expansion and transmission of some infectious diseases, famine, crop failure, water shortages and population displacement are some of the other issues involved with climate change. Climate change clearly threatens different areas, such as biodiversity, agricultural production, and human health. For example, it is expected that by 2030, the risk of diarrhea will increase by 10% in some specific regions due to climate change [3]. Climate change can also have an impact on agricultural production by affecting the distribution of economically important crops due to changes in their physiology [4]. The annual income from date palms in the Middle Eastern countries decreased between 1990 and 2000 [5]. A number of factors could be involved in this reduction, and climate change could be one of them because significant losses in yield of some economically important crops have been attributed to plant diseases resulting from climate change [5]. It has been reported that climate change has caused a $438 million loss in wheat, $116 million in grapes and $67 million in sugar production in Australia and North America [6]. Date palm (Phoenix dactylifera L.) is a valuable plant that provides a significant source of income for both local farmers and governments in arid and semi-arid regions of the world [7]. A number of reports document the cultivation of date palms back to the 5th millennium BC. Since ancient times, the majority of date palms have continued to be grown in the hot deserts of North Africa and the Middle East, including Syria, the Persian Gulf region and north Yemen [8]. The native range of this species is from the south-eastern Azores to Pakistan, and its cultivation stems from the 4th millennium BC in Mesopotamia and Palestine [9]. The genus Phoenix includes up to 400 species [10–12] within the Arecaceae family. To mature, the fruit requires prolonged summer heat. Rain or high humidity during fruiting increases the risk of the fruit cracking and the onset of fungal diseases [13]. Long summers with high day and night temperatures, and mild, sunny, dry winters without prolonged frost are the ideal climatic conditions for this species [14]. Long-term management strategies to sustain economically important crops require information about the expected potential distribution and relative abundance of this plant under current and future climate scenarios. There are several distribution models that can provide information in this area, including species distribution models (SDMs), bioclimatic models and ecological niche models (ENMs). However, it has been reported that niche PLOS ONE | www.plosone.org 1 October 2012 | Volume 7 | Issue 10 | e48021