未来气候变化对重庆榨菜种植适宜区的影响

榨菜为十字花科植物,是我国特有的经济作物,气候因子是影响榨菜种植分布的重要因素.通过收集榨菜分布的279个坐标点和22个高分辨率环境因子图层,利用MaxEnt模型进行重庆榨菜种植区预测,并基于该模型预测政府间气候变化专门委员会(IPCC)发布的RCP 2.6、RCP 4.5、RCP 6.0和RCP 8.5气候情景下21世纪50和70年代榨菜种植区分布范围.结果表明: MaxEnt模型的预测效果为优秀,其中,最湿月份降水量(贡献率为30.2%).年均温变化范围(17.2%)、最冷月份最低温(9.6%)、等温性(9.1%)、昼夜温差月均值(8.1%)和平均最高温度(7.5%)6个因子为主导因子,累积贡献率高达81.7％,且其各主导因子阈值分别为173～183 mm、27.2～28.3 ℃、1.8～3.8 ℃、22.5～24 ℃、6.2～6.8 ℃和14.8～18.0 ℃.在当前气候条件下,榨菜的适宜种植区比例为4.2%,主要集中在重庆涪陵的东北、西部和东部、长寿的东部和南部、垫江的南部和东南部、丰都的西北部和北部、忠县的东南部区域,以及武隆和南川的少部分区域等,中度适宜种植区面积比例为6.3%.在RCP 2.6、RCP 4.5、RCP 6.0和RCP 8.5气候情景下,预测21世纪50年代榨菜适宜生境的比例下降,分别为2.7%、3.8％、3.1％和3.2％;21世纪70年代比例也下降,分别为3.1%、3.7％、3.5％和2.9％,而中度适宜种植区的比例有所上升.

Influence of climate change on the suitable ranges for planting pickled mustard tuber in Chongqing.

Pickled mustard tuber (Brassica juncea var. tumida) belonging to Cruciferae, is a unique economic crop in China. Climate is an important factor affecting the distribution of pickled mustard tuber. Based on species presence data at 279 locations and 22 high-resolution environmental factor layers, we analyzed the potential planting area of pickled mustard tuber in Chongqing by MaxEnt model under the current conditions and the future distributions for the periods 2050s and 2070s under the climate change scenarios of RCP 2.6, RCP 4.5, RCP 6.0 and RCP 8.5 described in the Special Report on Emissions Scenarios (SRES) of IPCC (Intergovernmental Panel on Climate Change). The results showed that MaxEnt model was excellent in predicting its potential plan-ting area. The cumulative contributions of dominant factors reached as high as 81.7%, including precipitation of wettest month, temperature annual range, minimum temperature of coldest month, isothermality, mean diurnal range and average maximum temperature. The threshold of those factors was 173-183 mm, 27.2-28.3 ℃, 1.8-3.8 ℃, 22.5-24 ℃, 6.2-6.8 ℃ and 14.8-18.0 ℃, respectively. Under current condition, the optimum suitable areas of pickled mustard tuber, which amounted to 4.2%, were in the northeast, west and east of Fuling, the east and south of Changshou, the south and southeast of Dianjiang, the northwest and north of Fengdu, the southeast of Zhongxian, and a small part of Wulong and Nanchuan, while the proportion of moderately suitable areas was 6.3%. Under four climate change scenarios, the optimum suitable areas would drop to 2.7%, 3.8％, 3.1％, 3.2％ and 3.1%, 3.7％, 3.5％, 2.9％ for the periods 2050s and 2070s, respectively, while moderately suitable areas would rise gradually.