基于MaxEnt模型的四川省红豆杉潜在分布区分析及适宜性评价

摘要

A total of 31 environmental variables that affected the distribution of Taxus chinensis were selected based on the data source from the 201 localities of Taxus chinensis found in the second national survey of key wild plant resources in Sichuan to designate and evaluate the potential distribution areas of Taxus chinensis in Sichuan by using the maximum entropy model (MaxEnt) and the ArcGIS geographic information system. The results indicated that for the growth of Taxus chinensis, the most suitable area was 11508.75089 km2,accounting for 2.37% of the total area of Sichuan,the suitable area was 13340. 48764 km2,accounting for 2.75%,the relatively suitable area was 12099.52738 km2,accounting for 2. 49%,the unsuitable area was 448368.7435 km2,accounting for 92.39%. and the most suitable,suit-able and relatively suitable areas were mainly distributed at the edge of the mountain regions around Si-chuan Basin,such as Chaping Mountains, Longmen Mountains, Daba Mountains, Huaying Mountains, Dalou Mountains,Daxiangling Mountains and Qionglai Mountains. 12 environment variables had the ma-jor impact on the distribution of Taxus chinensis,including the altitude,the annual temperature,the pre-cipitation in July,the mean diurnal temperature range,the average temperature in the coldest season,the precipitation variation coefficient,the lowest temperature in coldest season,the slope,the solar radiation in March,the average temperature in July,the average temperature in the driest season and the average temperature in November. The most suitable environment for Taxus chinensis was mountains or ravines with high plant coverage rate in subtropical region where required the comparatively warm climate with 7. 5~15 ℃ in annual mean temperature and 7~10℃ in the mean diurnal temperature range,1000~2400 meters above sea level,the abundant precipitation,50 ~ 160 mm precipitation in July,50~75 precipi-tation variation coefficient,the adequate light,and 11 000~12 200 KJ/m2·d solar radiation in March.%以全国第二次重点保护野生植物资源调查中201个红豆杉分布点为基础数据源,筛选31个影响红豆杉分布的环境变量,应用MaxEnt最大熵模型,结合ArcGIS地理信息系统,划定四川省红豆杉潜在分布区并进行适宜性评价.结果表明,红豆杉在四川省的最适生区域面积为11508.75 km2,占全省面积的2.37%;适生区域面积为13340.49 km2,占全省面积的2.75%;较适生区域面积为12099.53 km2,占全省面积的2.49%;不适生区域面积为448368.74 km2,占全省面积的92.39%;最适生、适生及较适生区域主要位于茶坪山、龙门山、大巴山、华蓥山、大娄山、大相岭及邛崃山等盆周山地边缘.31个影响红豆杉分布的环境变量中,海拔、年均温、7月降水量、昼夜温差月均值、最冷季均温、降水量变异系数、最冷月最低温、坡度、3月光照强度、7月均温、最干季均温及11月均温是对红豆杉分布有主要影响的12个环境变量.红豆杉最适生环境为气候较为温暖,年均温7.5~15℃,昼夜温差月均值为7~10℃,海拔1000~2400 m,降水量充沛,7月降水量50~160 mm,降水量变异系数为50~75,光照充足,3月光照强度为11000~12200 KJ/m2·d的亚热带地区且植被覆盖率较高的山沟或山林中.