濒危喀斯特专性植物蚬木在中国的潜在适生区预测

Prediction of potential suitable areas for endangered karst obligate plant Excentrodendron tonkinense in China

关键词:  MaxEnt模型, 蚬木, 喀斯特专性植物, 气候变化, 适生区

Key words:  MaxEnt model, Excentrodendron tonkinense, karst obligate plants, climate change, suitable area

摘要:

蚬木(Excentrodendron tonkinense)是喀斯特季节性雨林建群种、喀斯特专性树种,属国家Ⅱ级重点保护野生植物、IUCN濒危植物,具有极高的生态经济价值。为了探究蚬木的潜在适生区在全球变化背景下的变动情况及其关键驱动因子,该研究利用最大熵(MaxEnt)模型分析未来气候变化情景(SSP1-2.6和SSP5-8.5)下蚬木在中国的潜在地理分布变化,并测试喀斯特地质背景分布对喀斯特专性植物适生区预测的影响。结果表明:(1)在加入喀斯特地质背景数据的情况下,适生区预测模型的AUC平均值为0.997,具有较好的预测效果,模型预测结果严格局限于喀斯特区域,与蚬木喀斯特专性植物的特性相符。(2)根据模型的拟合结果,喀斯特地质背景分布、最暖季降水量(800～950 mm)、最冷月最低温(7～11 ℃)为限制蚬木分布的关键因子。(3)未来随着温度升高,蚬木潜在适生区面积在喀斯特区域持续扩张,总体上呈现出向高纬度迁移的趋势,桂西南和滇东南的部分区域存在较大面积的稳定生境。综上认为,在预测蚬木等喀斯特专性植物的潜在地理分布时,必须考虑喀斯特地质背景的分布范围; 如果未来持续升温,其潜在适生区将向高纬度地区扩张,濒危程度可能受气候变化的影响不明显; 桂西南和滇东南部分区域是未来气候变化情景下蚬木保育和利用的适宜区。该研究结果为蚬木的引种栽培和可持续管理以及保护和利用提供了科学依据。

Abstract:

Excentrodendron tonkinense is a constructive species of karst seasonal rainforest and a karst obligate plant, which is also one of the national secondary key protected wild plant and an IUCN endangered plant, with high ecological economic value. In order to explore how the potential suitable areas of E. tonkinense change in the context of global change and its key driving factors, we used the maximum-entropy(MaxEnt)model to analyze the potential geographical distribution changes in China under future climate scenarios(SSP1-2.6 and SSP5-8.5), and tested the influence of the karst geological background distribution on predicting the suitable areas of karst obligate plants. The results were as follows:(1)In the case of adding karst geological background data, the average AUC value of the prediction model for the suitable area was 0.997, which had a good prediction effect. And the model prediction results were strictly limited to the karst region, consistent with the characteristics of karst obligate plant E. tonkinense.(2)According to the fitting results of the model, the karst geological background, the precipitation of the warmest quarter(800-950 mm), and the minimum temperature of the coldest month(7-11 ℃)were the key factors limiting the distribution of E. tonkinense.(3)With the increase of temperature in the future, the potential suitable areas for E. tonkinense would continue to expand in higher latitude karst areas; large areas of stable habitats existed in parts of southwestern Guangxi and southeastern Yunnan. In conclusion, the karst geological distribution is essential as predicting the potential geographic distribution of karst obligate plants such as E. tonkinense; if the temperature continues to rise in the future, its potential suitable areas will expand to high latitudes, and the degree of endangerment may be affected by climate, which means that it is not obvious under the influence of climate change; parts of Southwest Guangxi and Southeast Yunnan are suitable areas for the conservation and utilization of E. tonkinense under the climate change scenarios in the future. The results provide some scientific reference for the introduction, cultivation, sustainable management, protection and utilization of E. tonkinense.