Ecological Barrier Deterioration Driven by Human Activities Poses Fatal Threats to Public Health due to Emerging Infectious Diseases

The coronavirus disease 2019(COVID-19)and concerns about several other pandemics in the 21st century have attracted extensive global attention.These emerging infectious diseases threaten global public health and raise urgent studies on unraveling the underlying mechanisms of their transmission from animals to humans.Although numerous works have intensively discussed the cross-species and endemic barriers to the occurrence and spread of emerging infectious diseases,both types of barriers play synergistic roles in wildlife habitats.Thus far,there is still a lack of a complete understanding of viral diffusion,migration,and transmission in ecosystems from a macro perspective.In this review,we conceptualize the ecological barrier that represents the combined effects of cross-species and endemic barriers for either the natural or intermediate hosts of viruses.We comprehensively discuss the key influential factors affecting the ecological barrier against viral transmission from virus hosts in their natural habitats into human society,including transmission routes,contact probability,contact frequency,and viral characteristics.Considering the significant impacts of human activities and global industrialization on the strength of the ecological barrier,ecological barrier deterioration driven by human activities is critically analyzed for potential mechanisms.Global climate change can trigger and expand the range of emerging infectious diseases,and human disturbances promote higher contact frequency and greater transmission possibility.In addition,globalization drives more transmission routes and produces new high-risk regions in city areas.This review aims to provide a new concept for and comprehensive evidence of the ecological barrier blocking the transmission and spread of emerging infectious diseases.It also offers new insights into potential strategies to protect the ecological barrier and reduce the wide-ranging risks of emerging infectious diseases to public health.

Research strategy for constructing a green infrastructure network based on spatial prioritization

The destruction of the ecological system caused by urban expansion has led to the environmental deterioration,cities have become increasingly vulnerable.In this study,six districts and counties along the Yellow River in Zhengzhou were selected as the study area.First,green infrastructure elements were extracted by morphological spatial pattern analysis.Then,outside the urban areas,we used connectivity analysis to evaluate the importance of core areas,adopted minimum cumulative resistance model to extract potential corridors,and identified the important corridors by using the gravity model.Finally,in the urban areas,we set up an evaluation system to assess the demands for ecosystem services.The results showed that:(1)Seven landscape types of green infrastructure be identified in study area.(2)There are 17 vital cores,136 potential corridors,and 24 vital corridors outside the urban areas.(3)The blocks with high demand for ecosystem services are mostly concentrated in the old blocks with dense populations and poor infrastructure,and there are 5 blocks with comprehensive high-demand.Based on identified importance for green infrastructure land space,and high-demand level for ecosystem services areas in this study,a green infrastructure net plan was proposed based on spatial conservation prioritisation.