Using Human Pressure Index And Vegetation Index To Explore The Conservation Effectiveness Of Nature Reserves In Yunnan Province,China

The assessment of the conservation effectiveness of protected areas(PAs)is an advanced research field of conservation biology and the theory of nature reserves(NRs).and it is also an important basis for the management and optimization of PAs.It is difficult to carry out the assessment of the conservation effectiveness of the PAs according to the detailed investigation of the protection objects of each PA in the regional scale.At present,there is still a lack of mature evaluation methods and index systems,which needs urgently to explore.Because human pressures(human disturbances)are the main driving forces for the loss of biodiversity,and vegetation ecosystem is the main conservation objective in most PAs,or provides habitat for the main protected object,human pressure index and vegetation index that indirectly reflect the conservation effectiveness of PAs are often used to assess the protection status of the network of regional PAs.The mature network of PAs taking NRs as the core has been established in Yunnan province,and achieved good effectiveness of biodiversity conservation since 1980s.However,since there have been no systematic and clear studies and cognitions for the whole PAs' conservation effectiveness in Yunnan province,it is difficult to provide scientific supports for the urgent need to carry out the optimization of the protected area network in Yunnan province.This study has taken Yunnan province as the study area and targeted 20 national and 38 provincial NRs in Yunnan province.This study has collected population density and GDP density data with 1 km×1 km spatial resolution grid files,and land use data with 30 m×30 m spatial resolution grid files in different years(1995,2000,2005,2010 and 2015),and gotten the SPOT_Vegetation-NDVI(Normalized Difference Vegetation Index)data with 1 km×1 km spatial resolution grid files and each year from 1998 to 2015.This research has used three types of human activity factors,such as population density,economic density and human land use rate were adopted to construct and calculate the internal and external(2 km annular areas outside the boundary of NRs)human pressure indices(HPI)of NRs in Yunnan province in different years(1995,2000,2005,2010 and 2015)and SPOT_Vegetation-NDVI data were obtained to calculate the internal and external vegetation indices of NRs in Yunnan province from 1998 to 2015.Using the comparative analysis of time series and spatial variation(between the internal and external areas of NRs),this study has constructed a method for assessing the conservation effectiveness of the network of regional PAs based on the single indicator and the combination of two indicators.This research has revealed the conservation effectiveness of national and provincial NRs,identified the priority NRs,and explored optimization strategies from regional and local(NRs)scales in Yunnan province.The main conclusions are as follows:(1)Present situations of human pressures in 2015.The human pressures of national and provincial NRs were generally in a low and lower level in Yunnan province.Provincial NRs(PNRs)were facing higher or relatively high internal and external human land use pressure than national NRs(NNRs)in Yunnan province.As far as the type of NRs was concerned,geological relict NRs were facing the highest human pressures,follwed by wetland ecosystem NRs,forest ecosystem NRs,wild animal NRs and wild plant NRs.The human pressures of NRs in Yunnan province mainly came from land use and population,and land use and population pressures coexisted each other.(2)Conservation effectiveness of NRs based on the change of comprehensive HPI(CHPI).The trend of the change of CHPI has showed that the protection effectiveness of most NNRs and PNRs in Yunnan province was good from 1995 to 2005,loderate from 2005 to 2010 and became worse from 2010 to 2015.The difference of the growth of the internal and external human pressure of NRs has revealed that the conservation effectiveness of most NRs was good from 1995 to 2010,while the conservation effectiveness of most NRs became worse from 2010 to 2015.From the grade of NRs,NNRs is better than PNRs,but the conservation effectiveness of NNRs relatively declined from 2010 to 2015.From the type of NRs,the protection effectiveness of forest ecosystem NRs was the best,followed by wildlife NRs,wild plant NRs,wetland ecosystem NRs and geological relict NRs,but the conservation effectiveness of forest ecosysteru NRs relatively declined from 2010 to 2015.(3)Conservation effectiveness of NRs based on the change of NDVI.The whole conservation effectiveness of NNRs and PNRs in Yunnan province was good from 1998 to 2015.The protection effectiveness of NNRs was generally better than PNRs.In terms of the type of NRs,the protection effectiveness of forest ecosystem NRs was good,wild plant NRs and wild animal NRs had moderate conservation effectiveness,and the conservation effectiveness of wetland ecosystem NRs and geological relict NRs became worse.(4)Comprehensive conservation effectiveness of NRs.The number of good,moderate and bad comprehensive conservation effectiveness among 58 NRs in Yunnan province were 14,28 and 16 respectively.Compared with PNRs,the comprehensive conservation effectiveness of NNRs was better.In terms of the type of NRs,the comprehensive protection effectiveness of forest ecosystem NRs and wild animal NRs was good,and others were moderate or even bad(wetland ecosystem NRs).From the spatial distribution,the comprehensive conservation effectiveness of NRs in the central part of Yunnan province was poor.The comprehensive protection effectiveness of NRs toward the eastern(Qujing)and Western(Dali)areas centered in the central part of Yunnan province was bad,and they will be the important areas for regulation and optimization of NRs in the future.(5)Priority NRs.There were 17 NNRs and PNRs in Yunnan province that focused on priority attention,among which NNRs including Cangshan Erhai,Dashanbao and Wenshan,and PNRs including Jian Lake,Pearl River's Source and Zhanyi Haifeng should be put the highest emphasis on.Th:is study has indicated that the human pressure index,vegetation index and their combination could indirectly assess the conservation effectiveness of the network of regional PAs to a certain extent.The former could better reveal the characteristics of the current situation of human pressures faced by NRs in Yunnan province,while the latter could better indicate the effectiveness of vegetation's ecological protection.The combination of the two indicators could reflect the comprehensive conservation effectiveness of NRs in Yunnan province.This research could provide a reference for exploring the assessment methods of conservation effectiveness of the network of PAs at the regional scale.