基于MaxEnt分析我国羊草分布区的生物气候特征

羊草（Leymus chinensis）是欧亚大陆草原区东部草甸草原及干旱草原上的重要建群种之一。利用生物气候数据分析我国羊草的适生气候特征，客观反映我国羊草的地理分布范围及主导其分布的生物气候因子，能为我国羊草的分布潜力提供科学依据。本研究从我国数字植物标本馆获取204个羊草标本记录数据，并从WorldClim获取生物气候数据（1950-2000年），用最大熵模型（MaxEnt）模拟羊草的地理分布，检测其生物气候主导因子及其适宜值。结果表明，冷季降雨量（bio19）对羊草分布的增益最大，干季降雨量（bio17）和最干月降水量（bio14）依次次之。同时羊草分布概率分别与冷季降雨量（bio19），干季降雨量（bio17）和最干月降水量（bio14）为单峰响应关系。较纬度和海拔因子，经度是影响我国羊草分布格局的主要因子。

Analysis of Suitable Bioclimatic Characteristics of Leymus chinensis Using MaxEnt Model

Leymus chinensis is one of the most important species in the meadow grassland and the steppe Grassland in the eastern part of Eurasian grassland. The climatic characteristics of Leymus chinensis region in China were analyzed by bioclimatic data,which objectively reflected the geographical distribution of Leymus chinensis and the main bioclimatic factors leading to its distribution,and provided scientific basis for the distribution potential of Leymus chinensis in China. This study obtained 204 specimens of Leymus chinensis record data from China's digital herbarium Herbarium and bioclimatic data from WorldClim (1950-2000 years),and the maximum entropy model (MaxEnt) was used to simulate the geographical distribution of Leymus chinensis and investigate its biological climate factor and appropriate value. The results showed that the cold season precipitation (bio19) had the maximum gain for the distribution of Leymus chinensis,dry season rainfall(bio17) followed and then dry precipitation (bio14). At the same time,the probability distribution of Leymus chinensis was the single peak response relationship with rainfall in cold season (bio19),dry season,(bio17) and the driest season (bio14). As for latitude and altitude,longitude was the main factor affecting the distribution pattern of Leymus chinensis. At the same time,the reliability of MaxEnt simulation was high,and the geographical distribution of Leymus chinensis could be accurately reflected. 3 bioclimatic quantitative conditions leading to the geographical distribution of Leymus chinensis were preliminarily revealed.