Effects Of Human Activities On Terrestrial Vertebrates Diversity Patterns

Biodiversity refers to the diversification and variation of organisms and the complexity of habitat,including the diversity within species,between species,and ecosystems.Biodiversity is the foundation for the sustainable development of our civilization.However,since the Anthropocene,human activities have greatly altered the entire Earth and impacted the spatial pattern of biodiversity.The impact of human activities on biodiversity remains a complex and unresolved issue.Firstly,although humans have reshaped the global ecosystems,if the impacts of human activities have greater impacts on the spatial pattern of biodiversity than natural factors is uncertain.Secondly,which regions are more sensitive to anthropogenic factors? To better conserve biodiversity,it is urgent to know where human activities have the greatest impact on biodiversity.There are two hypotheses have been proposed: the threat hypothesis and the shelter hypothesis.The threat hypothesis posits that the biodiversity in regions with higher anthropogenic pressures is more sensitive to human activities.In contrast,the shelter hypothesis suggests that biodiversity in regions with lower anthropogenic pressures is easier to be influenced by human activities because of extinction filter effects.Such effects assume species that are sensitive to human activities have become local extinct in regions with higher anthropogenic pressures but still survive in regions with lower pressures.Therefore,the biodiversity in low-pressure regions is more sensitive to human activities.Thirdly,it is necessary to investigate whether there are regional differences in the mechanisms and intensity of human activities’ impacts on biodiversity.The impact of human activities is spatially heterogeneous,which means even the same factor can play different roles in different regions.Understanding such differences will be greatly helpful in biodiversity conservation.This study aimed to investigate the impact of anthropogenic and natural factors on biodiversity patterns of terrestrial vertebrates.We obtained information of functional traits from the different database and previous studies.Because of the knowledge gap of Amphibian functional traits,we constructed the world’s most comprehensive morphological database of Amphibian first.This database covered 4412 species,including 4038 species of Anura,259 species of Caudata,and 150 species of Gymnophiona.We collected 42,27,and 37 traits for the three orders respectively.Then,we collected the distribution and phylogenetic data of birds,mammals,Squamata,and amphibians and reconstructed the biodiversity patterns.We chose climate,altitude,net productivity,and climate fluctuations to represent natural factors.Meanwhile,land-use persist duration and the human footprint were used to represent historical and contemporary human activities,respectively.We quantified the impact of various factors on biodiversity using random forest analyses.We then identified regions where anthropogenic factors are primary factors,which means the most important factor in determining biodiversity patterns.Meanwhile,we identified hotspots that the effects of anthropogenic factors were significantly larger based on Local G statics.Furthermore,we examined the relationships between anthropogenic factors and biodiversity in each hotspot.The results of this study indicate that the spatial pattern of biodiversity is determined by natural factors in most regions.Topography and climatic velocity are the primary factors in middle and low latitudes.Climatic factors are the primary factor in high latitudes.In contrast,anthropogenic factors are primary factors just in a few regions.In addition,the areas where the land-use persist duration was the primary factor were larger than the human footprint.Our results support the shelter hypothesis.Biodiversity in regions that are greatly impacted by human activities rarely overlaps with regions that have the highest intensity of human activities or the longest land-use history.The biodiversity in regions with less intensity of human activities and a shorter land use history(200-300 years)was more vulnerable to human impact.At the same time,our study supported human activities impacted taxon groups and diversity metrics in different ways.Besides,there were more areas where land-use persist duration had a negative impact on biodiversity than human footprint index,especially in birds.In summary,natural factors are the primary driver of biodiversity patterns,but the impact of human factors cannot be ignored.The results support the shelter hypothesis,as biodiversity in regions with the highest human footprint index or longest land use history is not sensitive to anthropogenic factors.Furthermore,the effects of human activities on biodiversity vary across taxa,diversity parameters,and hotspot regions.To safeguard biodiversity effectively,conservation efforts should prioritize wilderness areas with minimal human disturbance.Additionally,our amphibian morphology database represents a significant contribution to the field,as it fills the gap in the absence of amphibian traits.When combined with other databases containing ecological,physiological,and behavioral data,it enhances our understanding of the functional structure of amphibian assemblages,and how environmental factors impact functional diversity on a global scale.