Simulation Of Landscape Connectivity In Protected Area And Its Offsetting Effect

Habitat degradation and fragmentation caused by human disturbance is becoming one of the major drivers of biodiversity loss.The rapid growth of population and infrastructure has accelerated the loss of biodiversity,posing a serious threat to global biodiversity.Improving landscape connectivity of habitat is one of the effective measures to alleviate fragmentation and promote biodiversity.In this study,the spatial and temporal changes of population and land use in 12 coastal provinces in China were analyzed,and the spatial and temporal evolution of connectivity in protected area was evaluated based on the minimum cumulative resistance model.By comparing the improvement efficiency of landscape connectivity in different scenarios,an efficient method to optimize the spatial pattern of nature reserves was determined.The impacts of human activities on landscape connectivity of nature reserves were analyzed by simulating different population densities and land use scenarios.The negative effects of human activities on landscape connectivity were quantitatively offset by the method of adding protected area.The pericoupled corridors and spillover sites with priority are identified as the priority conservation area by using the "metacoupling framework" and"spillover effect theory".The results shows that:The spatial heterogeneity of human activities in coastal areas of China is obvious:the land use intensity is higher in the north and lower in the south,especially the farmland in the north.In terms of time,the intensity of human activities in this region has increased significantly since 2000,which is manifested by the rapid expansion of construction land.The direct source of the increase of construction land area is farmland(83.61%),while the indirect source is grassland and woodland(less than 10%).In the same year,the population density in this area increased significantly,and the population gravity moved to the southwest.The rapid urbanization process deepens the stress of human activities on the ecosystem,especially in the south.Increasing the number of protected areas can be an efficient way to improve the landscape connectivity,with the efficiency of 5.3 8～8.34.The addition of the ecological nodes makes up for the shortcoming of insufficient habitat distribution in some areas.Besides,more potential ecological corridors are established to integrate isolated protected area into the ecological network.Some of the new nodes also play a stepping stone role,providing more effective support for long-distance migration of species,which improves the mobility of species in these areas and the overall level of landscape connectivity in the region.The impact of population density on landscape connectivity exists a critical threshold characteristic.With the increase of population density,the average resistance of the corridor increases,while the average length of the corridor increases first and then decreases,especially when the population density is in the range of 70～80%,the length of the ecological corridor drops sharply.With the increase of land use intensity,the average resistance of the corridor shows a general increase trend,but the average length of the corridor shows a significant decrease trend.Different human activities have different impacts on the protected areas connectivity.Therefore,it is necessary to accurately identify the impacts of various types of human interference factors on the connectivity of the protected areas,and then put forward more targeted control measures to implement differentiated management.This study uses the method of adding nodes to realize the offset effect on human activities.In the ecological network,each additional 1.9 nodes and 1.2 nodes on average can offset 1%of the increase of population density and land use intensity,respectively.These nodes can come from local protected areas,biodiversity hotspots,key biodiversity areas,important plant areas,and important freshwater areas.This research guided by the "metacoupling framework" and "spillover effect"theory to identify the protection priority areas,which are named as pericoupled corridors and spillover sites,The overall resistance of the pericoupled corridor is low,and its mean resistance is only 0.6 times that of the long corridor,but the resistance variation of different areas in the corridor is great,its standard deviation is 4.3 times that of the long corridor.This requires reserve managers and conservation biologists to identify more accurate and species-specific important protected areas according to local specific environmental conditions and species habits when determining the priority areas for conservation.The spillover sites not only connect themselves to the ecological network,but also provide spillover effects for other reserves around them,that is,they provide stepping stone patches for species migration and support long-distance migration of species.These sites build more ecological corridors for the ecological network and provide more possibilities for the selection of migration paths.These conservation priority areas play an important role in improving overall landscape connectivity and providing more efficient ecological connectivity for protected areas.In conclusion,high intensity human activities in coastal areas have a significant impact on natural habitats.Through scenario analysis,it is the first time to answer that the key to improve the landscape connectivity of nature reserves is to increase the nodes of nature reserves rather than expand the area.This method can achieve quantitative offset of negative impacts on human activities,which provides a method support for improving regional biodiversity conservation practices.Combined with the"metacoupling framework" and the "spillover effect theory",this paper proposes a method to identify the priority areas for conservation.To accurately identify and strengthen the conservation management of these areas can effectively improve the landscape connectivity of protected areas.