Response Of Ant Community To Urban Landscape

With the acceleration of global urbanization,the natural environment has become more and more fragmented,and the importance of urban green spaces to the protection of biodiversity and ecosystem functions has become increasingly prominent.Western China is undergoing rapid land cover change and urbanization,and urban biodiversity needs to be maintained by mitigating,reducing or eliminating the negative effects of man-made landscape modification.Ants are ideal for indicating land cover changes and contribute to ecosystem function on a scale.Therefore,this paper takes ants as the research object,and investigates ant communities in Nanchong City and eight cities(Pingwu,Jiuzhaigou,Kangding,Ganzi,Suijiang,Yuanmou,Yongren and Yulong)distributed in the West Sichuan Plateau and the Northwest Yunnan Plateau,so as to explore the response of ant communities to urban landscape was investigated under the background of different seasons and different altitudes.From September 2017 to August 2018,pitfall traps were used to investigate ant communities in 40 sample sites in Nanchong City,once a month for 12 months.A total of 21,707 ant samples were collected,which belonged to 4 subfamilies,12 genera and20 species,and were divided into 5 functional groups(Opportunists,Generalized Myrmicinae,Subordinate Camponotini,Cryptic Species,and Specialist Predators).We studied the effects of seasons and landscape differences caused by land cover change on ant species diversity and community composition,and focusing on major functional groups(Opportunists and Generalized Myrmicinae).First,Generalized Linear Mixed Models was constructed by combining 14 environmental factors and seasons to determine the factors affecting ant species richness.Bioenv analysis was then used to explore environmental factors influencing ant assemblage composition.The results showed that the number of species in different assemblages(Ant community,Opportunists and Generalized Myrmicinae)fluctuated seasonally and peaked in summer.Species richness in Opportunists was more sensitive to vegetation and fragmentation than in the Generalized Myrmicinae.The ensemble composition of the Opportunists was only sensitive to vegetation,whereas the Generalized Myrmicinae was sensitive to both vegetation and fragmentation,and the specific habitat indicators affecting the ant assemblage composition had seasonal variations.From June 2020 to August 2020 and from June 2021 to August 2021,pitfall traps were used to investigate ant communities in eight cities of the Western Sichuan Plateau and the Northwest Yunnan Plateau.A total of 55,993 ant samples were collected,belonging to 5 subfamilies,31 genera and 81 species,which were divided into 7functional groups(Opportunists,Generalized Myrmicinae,Subordinate Camponotini,Cryptic Species,Specialist Predators,Cold Climate Specialists and Tropical Climate Specialists).Combined with 14 environmental factors and altitude,Multiple Regression Analysis was conducted to explore the factors affecting the species richness of ant community.The results showed that the species richness of ant community was negatively correlated with altitude,herbaceous vegetation coverage,height of herbaceous vegetation and bare soil proportion,and positively correlated with the number of herbaceous vegetation species and litter thickness.Subsequently,Spearman correlation analysis was used to explore the factors affecting species richness in the subfamily of opportunists and generalized leafcutter ants.The results showed that: for opportunists,species richness was negatively correlated with herbaceous vegetation coverage and altitude.For Generalized Myrmicinae,species richness was negatively correlated with the number of herbaceous vegetation species and altitude,and positively correlated with litter thickness and height of herbaceous vegetation.Overall,our study shows that high-quality urban landscapes can support high ant species diversity.Furthermore,the species diversity of ant assemblages and the response of ant assemblages to urban landscapes varies seasonally.our results highlight the important roles played by vegetation complexity and habitat fragmentation in regulating the effects of land cover change on urban ant communities,contribute to a deeper understanding of the importance of urban landscapes,provide direction for urban landscape planning,and provide a theoretical basis for urban biodiversity conservation and ecological sustainable development.