气候变化情景下大花杓兰在中国的适生区预测

Prediction of potential distribution of Cypripedium macranthos under climate change scenarios in China

大花杓兰(Cypripedium macranthos)隶属兰科杓兰属,是国家二级重点保护野生植物,与大多数杓兰属植物分布在我国西南山区不同,主要分布于我国的华北、东北和台湾等地区。多年来,过渡采挖等导致了大花杓兰种群数量和个体数目急剧下降。鉴于大花杓兰特殊的分布格局和濒危现状,选择过去、当前和未来8个气候情景,利用MaxEnt物种分布模型结合38个环境变量及来源于数据库和最新实地调查的80个分布位点进行建模,分析了影响大花杓兰分布的关键环境变量,预测了其在当前、过去和未来气候情景下的适生区及其分布中心和迁移趋势。结果表明:当前情景下,大花杓兰适生区主要分布在我国东北和华北地区。影响其分布的5个关键环境变量分别是:UV-B最强月份均值(UV-B3,贡献率:54.0%)、森林覆盖率(FOR,贡献率:14.3%)、降水量季节性变化(BIO15,贡献率:7.4%)、温度季节性变动系数(BIO4,贡献率:6.8%)和草/灌木/林地(GRS,贡献率:4.6%)。其中,紫外辐射相关变量是首次被运用在杓兰属植物的适生区分布预测中,并被证实对大花杓兰的分布具有重要影响。过去3个气候情景下大花杓兰总适生区面积受冰期影响呈现先减少后增加的状态,未来4个气候情景与当前情景相比有增加的趋势。大花杓兰适生区分布中心除末次盛冰期位于河北省外,其余7个气候情景下均位于与辽宁省相近的内蒙古自治区东南部区域。气候变化背景下,采取对预测的适生区全面资源调查、生境和生长监测、科普宣教等策略对大花杓兰的保护至关重要。本研究的预测结果能够为大花杓兰甚至杓兰属植物的保育策略的制定提供理论性参考。

Cypripedium macranthos(Orchidaceae),the second-class protected plant in the National List of Key Protected Wild Plants,unlike most species in the genus Cypripedium,is mainly distributed in North China,Northeast China and Taiwan.In recent years,over-collection has led to a dramatic decline in both population size and the number of individuals.In view of the special distribution pattern and endangered situation of C.macranthos,we selected eight climate scenarios:historical,current,future(LIG,LGM,MH,Current,RCP2.6-2050,RCP2.6-2070,RCP8.5-2050,RCP8.5-2070),and then analyzed 38 environmental variables and 80 distribution points from the database and the latest field survey using maximum entropy(MaxEnt)model.The results showed that under the current scenarios,the suitable areas of C.macranthos were mainly distributed in Northeast China and North China,and five key environmental factors affecting its distribution were:mean UV-B of the highest month(UV-B3,contribution rate:54.0%),forest land(FOR,contribution rate:14.3%),precipitation seasonality(coefficient of variation)(BIO15,contribution rate:7.4%),temperature seasonality(standard deviation∗100)(BIO4,contribution rate:6.8%),and Grass/Scrub/Woodland(GRS,contribution rate:4.6%).For the first time,UV radiation variables were applied to predict the geographic distribution of suitable habitat for Cypripedium,which were identified to have a critical influence on the distribution of C.macranthos.In the historical three scenarios,the total suitable area of C.macranthos firstly decreased and then increased due to the glacial period.Meanwhile,compared with the suitable area in the current scenario,those in the future four climate scenarios had an upward trend.Except for the Last Glacial Maximum,the distribution centroid of the suitable area for C.macranthos was located in Hebei Province,while those of the other seven climate scenarios were located in the southeast of the Inner Mongolia Autonomous Region,close to Liaoning Province.In the context of climate change,the adoption of conservation strategies such as comprehensive surveys in suitable habitats,regular monitoring of habitat and plant growth,and science education was essentially important for C.macranthos.This study can provide theoretical references for the development of conservation strategies of C.macranthos and even the genus Cypripedium.