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对自然保护区的定期评估有助于提升其管理和保护水平。本研究以苍山自然保护区所在的大理市、洱源县、漾濞县3个市/县作为子研究区域,构建了基于倾向评分配比(propensity score matching)和配对t检验(paired-samples t-test)的保护成效评估技术方案。选取海拔、坡度、与最近居民点的距离、与最近道路的距离4个因子作为环境变量,通过对每个县单独进行分析,分别对比了自然保护区晋升国家级时(1995年)与20年后(2015年)其森林覆盖面积的变化,以此来评估苍山自然保护区的森林保护成效,并对各环境变量与森林覆盖变化值的关系进行了偏相关分析(partial correlation analysis)。结果表明:大理市境内苍山自然保护区内的森林覆盖变化值显著高于保护区外部,且该区段的森林覆盖率最高。洱源县境内苍山自然保护区内、外的森林覆盖变化率均高于其他2个市/县,且保护区内、外森林覆盖变化值差异不显著。漾濞县境内苍山自然保护区内、外森林覆盖变化率最低,但其保护区外0–10km区域的森林覆盖变化值显著高于10 km以外区域,保护区的存在对其周边0–10 km区域产生了正面的溢出效应(neighborhood leakage)。海拔、坡度、与最近居民点的距离、与最近道路的距离4个协变量在3个市/县的不同研究区段内均与森林覆盖变化值呈现出了不同程度的相关性。本研究所采用的倾向评分配比法和按照行政区划对自然保护区分区进行评估的方法,为自然保护区整体保护成效的评价提供了新的技术思路。
Regular assessment of nature reserves helps to improve their management and protection. In this study, three cities / counties in Dali, Eryuan and Yangbi counties, where Cangshan Nature Reserve is located, were selected as sub-research areas. Based on propensity score matching and paired-samples t- test) protection effectiveness evaluation of technical programs. Taking four factors as elevation, slope, distance to the nearest residential area and the distance to the nearest road as the environmental variables, by analyzing each county separately, the author compares the natural reserve in promotion of national level (1995) and 20 years (2015) to assess the effectiveness of forest conservation in Cangshan Nature Reserve, and to conduct a partial correlation analysis of the relationship between environmental variables and changes in forest cover. The results showed that the change of forest cover in Cangshan Nature Reserve in Dali City was significantly higher than that in the outside of the nature reserve, and the forest coverage rate in this area was the highest. The change rate of forest cover inside and outside Cangshan Nature Reserve in Eryuan County is higher than that in the other 2 cities / counties, and there is no significant difference in the change of forest cover within and outside the reserve. In Yangbian County, the change rate of forest cover in the Cangshan Nature Reserve is the lowest, but the change of the forest cover in the 0-10km area outside the protected area is significantly higher than that in the area 10km away. The existence of the protected area affects the area around 0-10 km Has a positive neighborhood leakage. The four covariates of elevation, slope, distance from the nearest residential area and the distance to the nearest road show different degrees of change with the changes of forest cover in different study sections in three cities / counties. The propensity score distribution method and the method of evaluating the nature reserves in accordance with the administrative divisions provide a new technical idea for the evaluation of the overall protection effectiveness of nature reserves.