Assessments on Ecological Sensitivity and Ecosystem Service Value in Karst Area Based on GIS——Taking Bijie Prefecture in Guizhou for Example

Assessments on ecological sensitivity and ecosystem service value are two important basic works in eco-functional regionalization. According to the special ecological environment in Guizhou Province,GIS technology was used in the classification evaluations of soil erosion sensitivity,acid rain sensitivity and rocky desertification sensitivity in Bijie Prefecture,and then the comprehensive evaluation on eco-environmental sensitivity was carried out. Finally,the preliminary economic estimation of ecosystem service value in Bijie Prefecture was made by means of the appraisal approach for ecosystem service proposed by Costanza.

Using ecosystem service supply and ecosystem sensitivity to identify landscape ecology security patterns in the Lanzhou-Xining urban agglomeration, China

The construction of an ecological security pattern(ESP)is an important way to ensure regional ecological security and to achieve sustainable regional development.It is also one of the hotspot topics of landscape ecology research.This paper identifies the ecological source through the evaluation of the ecosystem service and ecosystem sensitivity of the Lanzhou-Xining(Lan-Xi)urban agglomeration.The minimum cumulative resistance(MCR)model modified by night light data NPP/VIIRS(National Polar-orbiting Operational Environmental Satellite System Preparatory Project/Visible Infrared Imaging Radiometer Suite)was used to measure the relative resistance of the materials and energy circulation between the source areas,and to establish the resistance surface of the ecological source area expansion.Then ecological corridors were identified based on ecological sources and resistance surface.The ecological strategic node is the ecological fragile point in the ecological corridors.The ecological strategic node is identified with hydrological module by superimposing the"ridge line"of cumulative ecological resistance with the ecological corridor.Combined with ecological sources,corridors and strategic nodes,the ESP of the Lan-Xi urban agglomeration can be constructed.The ecological source of the Lan-Xi urban agglomeration accounts for 28.42%of the total area,most of which is distributed within Qinghai Province.The nature reserves in the area are all located within the ecological source area.A total of 41 potential ecological corridors have been identified in the study area.The total length of the potential corridors is 1201.03 km,comprising 23 source corridors and 18 radiation corridors.There are 30 strategic nodes identified in the Lan-Xi urban agglomeration.These locations are the most vulnerable areas of the ecological corridors.Ecological engineering should be applied in the construction of corridors.Affected by the ecological source,the potential ecological corridor extends from the northwest to the southeast,which is basically consistent with the direction trend of the mountains in the region.