秦岭山地生态分界线的论证

Discussion and analysis on the geo-ecological boundary in Qinling Range

山地自然生态分界线,实际为一条生态过渡带。分界线位置的准确划分,有助于把握现代气候-植被-土壤的敏感变化特征,也是指导当地大农业生产的基础依据。秦岭山地长期以来被认为是中国东部重要的南北生态分界线,即亚热带和暖温带的分界线。但对该界线的具体位置,历来存在着北坡、分水岭和南坡3种争议。根据作者多年的工作积累和对相关问题的思考,以文献评析为基础,以气候-植被参数计算结果为依据,并通过对秦岭山地不同区域植物区系和植被垂直带谱已有研究结果的比较分析,从中得出如下主要结论:(1)根据秦岭地区气候-植被参数等值线的分布,整个秦岭山地都应属于暖温带,这一结论可与国际有关研究相互接轨。(2)根据对秦岭不同区域植物区系调查结果的比较分析,秦岭南坡大部分区域都应属于暖温带,而南麓海拔1000m等高线附近很可能是暖温带的南缘。(3)根据对秦岭南北坡植被垂直带谱的比较分析,南麓海拔1000m等高线应该是一条重要的生态分界线。综合来看,将秦岭山地的南北分界线放在南坡海拔1000m附近比较适宜。上述归纳研究所获结论,将通过在秦岭山地深入开展现代"3S"技术支撑下的植被、土壤、气候等生态与地理方面的综合研究,最终得到完全验证。

The geo-ecological boundary is a transitional ecotone that differentiates two or more ecozones. Accurate determination of the boundary is crucial for distinguishing and examining the sensitive responses of vegetation and soil to regional climate change and help set guidelines for developing local agriculture-forestry-husbandry production. Qinling Range has been recognized as the geo-ecological boundary between Subtropical and Warm-temperate zones in eastern China, but the precise boundary has been argued for decades with three different viewpoints： in northern piedmont, along the ridge, or in southern piedmont. We conducted comparative analyses using Kira＇s Warmth index （WI） and Holdridge＇s Potential Evapotranspiration Rate （PER）, local vertical vegetation spectrums, ratio of temperate to subtropical floristic composition, and indicator species of agricultural and forestry produces across the whole Qinling Range. Our resultsindicated ： （ 1 ）, the distribution pattern of WI and PER isograms suggested the whole Qinling Range was within the Warm-temperate zone, （2） floristic compositional analysis showed most of the ten regions investigated in the range were within the Warm-temperate zone with the altitude 1000 m of southern piedmont being the southern edge of Warm-temperate zone, and （3） vertical vegetation spectrums （five on north side and eight on south side, respectively） confirmed that the majority of the range was within the Warm-temperate zone and the contour 1000 m in southern piedmont is the ecological boundary line.