Research On The Prediction Of The Potential Distribution Of Mountain Vegetation Based On The Climate-Vegetation Model Under The Background Of Global Climate Change ——Taking Northwest Yunnan As An Example

The assessment of vegetation response to climate change is the key and basis for understanding the ecological effects of climate change.Mountains covering an area of about 1/4 of the world's land constitute a unique mountain ecosystem,and mountain vegetation is an important guarantee for more than 70% of the land's freshwater resources and ecosystem services.mountains are second only to the polar regions,which are very sensitive to global ecological changes.The study of vegetation-climate model is an important aspect of understanding vegetation distribution pattern and dynamic change,and can provide an important scientific basis for mountain biodiversity protection,vegetation restoration and reconstruction and prediction of vegetation change.In this paper,Holdridge and CSCS models are used to study the distribution pattern of potential vegetation in mountainous areas,and the applicability of the model is verified by the current natural vegetation.Based on the historical and future climatic data,the evolution of the historical pattern of vegetation is analyzed,and the potential vegetation change in the future is predicted,with emphasis on the historical process and future trend of the change of alpine ecosystem and alpine tree line.The results show that:(1)There are differences in the type resolution of potential vegetation predicted by the two models in northwest Yunnan.The overall accuracy of the CSCS model is higher(65.1%),the altitude distribution of the simulated alpine tree line and the current high tree line have the same trend,and the accuracy of simulating alpine ecosystem is 70%.(2)The largest area of potential vegetation in northwest Yunnan is 21197.8km ~2,and the smallest is monsoon evergreen broad-leaved forest,accounting for 1.04%.The vertical change of vegetation type is significant.(3)The replacement dynamics of vegetation types have appeared since the last interglacial period.the distribution area of cold and mild temperature vegetation is the largest in the last glacial maximum,and the distribution area of warm,warm and subthermal vegetation is the largest in the middle of Holocene.dry vegetation types did not appear until modern times,and the tree line rose the highest in this period.(4)Under the three Rcp scenarios,the higher the radiation intensity is,the faster the vegetation area of cold-temperature type and mild-temperature type decreases,while the vegetation area of warm-heat type and sub-heat type increases and spreads to high latitudes and high elevations.(5)By 2070 s,the alpine tree line climbed the highest under Rcp8.5,and the alpine ecosystem may show a retreating trend in the future.