Disparities in tree mortality among plant functional types(PFTs)in a temperate forest:Insights into size-dependent and PFT-specific patterns

Tree mortality significantly influences forest structure and function,yet our understanding of its dynamic patterns among a range of tree sizes and among different plant functional types(PFTs)remains incomplete.This study analysed size-dependent tree mortality in a temperate forest,encompassing 46 tree species and 32,565 individuals across different PFTs(i.e.,evergreen conifer vs.deciduous broadleaf species,shade-tolerant vs.shade-intolerant species).By employing all-subset regression procedures and logistic generalized linear mixed-effects models,we identified distinct mortality patterns influenced by biotic and abiotic factors.Our results showed a stable mortality patte rn in eve rgreen conifer species,contrasted by a declining pattern in deciduous broadleaf and shadetolerant,as well as shade-intolerant species,across size classes.The contribution to tree mortality of evergreen conifer species shifted from abiotic to biotic factors with increasing size,while the mortality of deciduous broadleaf species was mainly influenced by biotic factors,such as initial diameter at breast height(DBH)and conspecific negative density.For shade-tolerant species,the mortality of small individuals was mainly determined by initial DBH and conspecific negative density dependence,whereas the mortality of large individuals was subjected to the combined effect of biotic(competition from neighbours)and abiotic factors(i.e.,convexity and pH).As for shade-intolerant species,competition from neighbours was found to be the main driver of tree mortality throughout their growth stages.Thus,these insights enhance our understanding of forest dynamics by revealing the size-dependent and PFT-specific tree mortality patterns,which may inform strategies for maintaining forest diversity and resilience in temperate forest ecosystems.

Beyond biogeographic patterns:Processes shaping the microbial landscape in soils and sediments along the Yangtze River

Deciphering biogeographic patterns of microorganisms is important for evaluating the maintenance of microbial diversity with respect to the ecosystem functions they drives.However,ecological processes shaping distribution patterns of microorganisms across large spatial‐scale watersheds remain largely unknown.Using Illumina sequencing and multiple statistical methods,we characterized distribution patterns and maintenance diversity of microorganisms(i.e.,archaea,bacteria,and fungi)in soils and sediments along the Yangtze River.Distinct microbial distribution patterns were found between soils and sediments,and microbial community similarity significantly decreased with increasing geographical distance.Physicochemical properties showed a larger effect on microbial community composition than geospatial and climatic factors.Archaea and fungi displayed stronger species replacements and weaker environmental constraints in soils than that in sediments,but opposite for bacteria.Archaea,bacteria,and fungi in soils showed broader environmental breadths and stronger phylogenetic signals compared to those in sediments,suggesting stronger environmental adaptation.Stochasticity dominated community assemblies of archaea and fungi in soils and sediments,whereas determinism dominated bacterial community assembly.Our results have therefore highlighted distinct microbial distribution patterns and diversity maintenance mechanisms between soils and sediments,and emphasized important roles of species replacement,environmental adaptability,and ecological assembly processes on microbial landscape.Our findings are helpful in predicting loss of microbial diversity in the Yangtze River Basin,and might assist the establishment of environmental policies for protecting fragile watersheds.

The power of green:Harnessing phytoremediation to combat micro/nanoplastics

Plastic pollution and its potential risks have been raising public concerns as a global environmental issue.Global plastic waste may double by 2030,posing a significant challenge to the remediation of environmental plastics.In addition to finding alternative products and managing plastic emission sources,effective removal technologies are crucial to mitigate the negative impact of plastic pollution.However,current remediation strategies,including physical,chemical,and biological measures,are unable to compete with the surging amounts of plastics entering the environment.This perspective lays out recent advances to propel both research and action.In this process,phytoaccumulation,phytostabilization,and phytofiltration can be applied to reduce the concentration of nanoplastics and submicron plastics in terrestrial,aquatic,and atmospheric environments,as well as to prevent the transport of microplastics from sources to sinks.Meanwhile,advocating for a more promising future still requires significant efforts in screening hyperaccumulators,coupling multiple measures,and recycling stabilized plastics from plants.Phytoremediation can be an excellent strategy to alleviate global micro/nanoplastic pollution because of the cost-effectiveness and environmental sustainability of green technologies.

Health risk ranking of antibiotic resistance genes in the Yangtze River

Antibiotic resistance is an escalating global health concern,exacerbated by the pervasive presence of antibiotic resistance genes(ARGs)in natural environments.The Yangtze River,the world's third-longest river,traversing areas with intense human activities,presents a unique ecosystem for studying the impact of these genes on human health.Here,we explored ARGs in the Yangtze River,examining 204 samples from six distinct habitats of approximately 6000 km of the river,including free-living and particle-associated settings,surface and bottom sediments,and surface and bottom bank soils.Employing shotgun sequencing,we generated an average of 13.69 Gb reads per sample.Our findings revealed a significantly higher abundance and diversity of ARGs in water-borne bacteria compared to other habitats.A notable pattern of resistome coalescence was observed within similar habitat types.In addition,we developed a framework for ranking the risk of ARG and a corresponding method for calculating the risk index.Applying them,we identified water-borne bacteria as the highest contributors to health risks,and noted an increase in ARG risks in particle-associated bacteria correlating with heightened anthropogenic activities.Further analysis using a weighted ARG risk index pinpointed the ChengdueChongqing and Yangtze River Delta urban agglomerations as regions of elevated health risk.These insights provide a critical new perspective on ARG health risk assessment,highlighting the urgent need for strategies to mitigate the impact of ARGs on human health and to preserve the ecological and economic sustainability of the Yangtze River for future human use.