基于Maxent模型的青藏高原优势种草分布格局模拟研究

Simulation of Distribution Pattern of Dominant Grass Species in Tibetan Plateau Based on the Maxent Model

以青藏高原嵩草、苔草、针茅3种优势种草为研究对象,通过植物标本库查询得到草地标本点位数据,选取气候、土壤质地、地形为环境因子,运用Maxent模型模拟出每种优势种草的分布格局,并运用刀切法筛选出主导环境因子,探讨主导环境因子对不同优势种草分布的影响与内在机制。结果表明,最冷季降水量、温度季节性变化标准差、年降水量、海拔是嵩草分布的主导环境因子(累计贡献率>80%);最冷季降水量、最暖季均温、年降水量、海拔对苔草分布贡献较大(累计贡献率82.55%);最暖季降水量、年均温、坡度、海拔对针茅分布影响较大(累计贡献率73.47%)。土壤质地对3种草分布影响很小(累计贡献率<5%)。总体上,生长季水热综合条件是制约青藏高原优势物种分布的最主要气候因子。

Taking Kobresia,Carex and Stipa as the research objects.The grassland specimen point data were obtained by querying the herbology database and the climate,soil texture and topography were selected as environmental factors to explore the influence and internal mechanism of the dominant environmental factors on the distribution of different grasslands,the Maxent model was used to simulate the distribution pattern of each dominant grass and the Jackknife method was used to screen out the dominant environmental factors.The results showed that the precipitation in the coldest season,the standard deviation of the seasonal variation of temperature,the average annual precipitation and the altitude were the dominant environmental factors for the distribution of Kobresia(accumulated contribution rate>80%);the precipitation in the coldest season,the average temperature in the warmest season,the average annual precipitation,and the altitude had a greater contribution to the distribution of Carex(accumulated contribution rate was 82.55%);the warmest season precipitation,the annual average temperature,the slope and altitude had the greatest influence on the geographical distribution of Stipa(accumulated contribution rate was 73.47%).Soil texture had little effect on this three grassland species(accumulated contribution rate<5%).In general,the hydrothermal conditions in the growing season were the most important climatic factors that restrict the distribution of dominant species on the Tibetan Plateau.