ABSTRACT: Agriculture is greatly impacted by climate change, which can lead to situations of food security or insecurity at both regional and global levels. Pakistan is predicted to experience an area reduction and geographical shifting of major crops in the near future. In the present study, we assessed the potential future distribution of wheat and maize in Pakistan. Based on current locations of these crops, we ran a Maxent species distribution model to predict future changes in crop distributions. We used 58 presence records for wheat and 48 presence records for maize. The model simulated current and future climate change scenarios (RCP 4.5 and RCP 8.5) based on the CMIP5 model, MPI-ESM-LR. Results from our model showed a decline in production area, with a 30-35% reduction in wheat and a 23-36% reduction in maize in the year 2070, depending upon which climate change scenario was modelled (i.e. RCP 4.5 or RCP 8.5). The model predictions were highly accurate, with test AUC values of 0.88 for wheat and 0.89 for maize. A jackknife test for variable importance indicated that irrigation, precipitation seasonality and precipitation of the warmest quarter are the most important environmental variables determining the potential geographic distribution of the crops. Due to the varying severity and nature of climate impacts, adaptation strategies are needed. This study can aid policy makers in devising policies that can help reduce the threat of future food insecurity in the region.

中文翻译：

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预测巴基斯坦未来气候变化情景下适合小麦和玉米种植的地区

摘要：农业受到气候变化的极大影响，这可能导致区域和全球范围内的粮食安全或不安全状况。预计巴基斯坦将在不久的将来经历面积减少和主要农作物的地域转移。在本研究中，我们评估了巴基斯坦小麦和玉米的潜在未来分布。根据这些作物的当前位置，我们运行了M​​axent物种分布模型来预测作物分布的未来变化。我们使用了58条小麦的存在记录和48条玉米的存在记录。该模型基于CMIP5模型MPI-ESM-LR模拟了当前和未来的气候变化情景（RCP 4.5和RCP 8.5）。我们模型的结果显示，到2070年，生产面积将减少，小麦减少30-35％，玉米减少23-36％，取决于模拟的气候变化情景（即RCP 4.5或RCP 8.5）。模型预测非常准确，小麦的AUC检验值为0.88，玉米的AUC检验值为0.89。折刀重要性测试表明，灌溉，降水季节和最暖季的降水是决定作物潜在地理分布的最重要的环境变量。由于气候影响的严重性和性质各不相同，因此需要采取适应策略。这项研究可以帮助决策者制定有助于减少该地区未来粮食不安全威胁的政策。折刀重要性测试表明，灌溉，降水季节和最暖季的降水是决定作物潜在地理分布的最重要的环境变量。由于气候影响的严重性和性质各不相同，因此需要采取适应策略。这项研究可以帮助决策者制定有助于减少该地区未来粮食不安全威胁的政策。折刀重要性测试表明，灌溉，降水季节和最暖季的降水是决定作物潜在地理分布的最重要的环境变量。由于气候影响的严重性和性质各不相同，因此需要采取适应策略。这项研究可以帮助决策者制定有助于减少该地区未来粮食不安全威胁的政策。