Ecological processes, remediation and regulation of contaminated soils

Land is used for agricultural production, industrial development, urban construction, and environmental beautification, thus soil environment is an important component of living ecosystems for human survival.……

Integrating landscape ecological principles and land evaluation for sustainable land use

Many existing methods for appraisal of agricultural areas and farming systems are short of dynamics and spatial analysis. The main objective of this paper is to merge approaches in classical land evaluation, largely based on soil science, and newer approaches in landscape ecology, which are rather based on the relationships between spatial patterns (physiography, land use and farming system design, vegetation etc.) and processes (farming activities, scale changes, geomorphological processes, bio ecological processes). Rapid changes in rural areas have an impact on both processes and patterns. Planning for sustainable use of these areas should include the assessment of the interrelations between these patterns and processes.

Ecological predictors of extinction risks of endemic mammals of China

In this brief report, we analyzed ecological correlates of risk of extinction for mammals endemic to China using phylogenetic eigenvector methods to control for the effect of phylogenetic inertia. Extinction risks were based on the International Union for Conservation of Nature （IUCN） Red List and ecological explanatory attributes that include range size and climatic variables. When the effect of phylogenetic inertia were controlled, climate became the best predictor for quantifying and evaluating extinction risks of endemic mammals in China, accounting for 13% of the total variation. Range size seems to play a trivial role, explaining -1% of total variation; however, when non-phylogenetic variation partitioning analysis was done, the role of range size then explained 7.4% of total variation. Consequently, phylogenetic inertia plays a substantial role in increasing the explanatory power of range size on the extinction risks of mammals endemic to China. Limitations of the present study are discussed, with a focus on under-represented sampling of endemic mammalian species.

Source-sink landscape theory and its ecological significance

Exploring the relationships between landscape pattern and ecological processes is the key topic of landscape ecology,for which,a large number of indices as well as landscape pattern analysis model were developed.However,one problem faced by landscape ecologists is that it is hard to link the landscape indices with a specific ecological process.Linking landscape pattern and ecological processes has become a challenge for landscape ecologists.“Source”and“sink”are common concepts used in air pollution research,by which the movement direction and pattern of different pollutants in air can be clearly identified.In fact,for any ecological process,the research can be considered as a balance between the source and the sink in space.Thus,the concepts of“source”and“sink”could be implemented to the research of landscape pattern and ecological processes.In this paper,a theory of sourcesink landscape was proposed,which include:(1)In the research of landscape pattern and ecological process,all landscape types can be divided into two groups,“source”landscape and“sink”landscape.“Source”landscape contributes positively to the ecological process,while“sink”landscape is unhelpful to the ecological process.(2)Both landscapes are recognized with regard to the specific ecological process.“Source”landscape in a target ecological process may change into a“sink”landscape as in another ecological process.Therefore,the ecological process should be determined before“source”or“sink”landscape were defined.(3)The key point to distinguish“source”landscape from“sink”landscape is to quantify the effect of landscape on ecological process.The positive effect is made by“source”landscape,and the negative effect by“sink”landscape.(4)For the same ecological process,the contribution of“source”landscapes may vary,and it is the same to the“sink”landscapes.It is required to determine the weight of each landscape type on ecological processes.(5)The sourcesink principle can be applied to non-point source pollution control,biologic diversity protection,urban heat island effect mitigation,etc.However,the landscape evaluation models need to be calibrated respectively,because different ecological processes correspond with different source-sink landscapes and evaluation models for the different study areas.This theory is helpful to further study landscape pattern and ecological process,and offers a basis for new landscape index design.

Biogeography and diversity patterns of antibiotic resistome in the sediments of global lakes

Lakes act as one of the reservoirs and dispersal routes of antibiotic resistance genes(ARGs)and pathogenic resistant bacteria in aquatic environments.Previous studies reported the occurrence and distribution of ARGs in lakes worldwide;however,few investigated the biogeography and diversity patterns of antibiotic resistome in the environment.To fill this gap,a large-scale data set of sediment metagenomes was collected from globally distributed lakes and characterized comprehensively using metagenomic assembly-based analysis,aiming to shed light on the biogeography and diversity patterns of ARGs in lake ecosystems from a global perspective.Our analyses showed that abundant and diverse ARGs were found in the global lake sediments,including a set of emerging ARGs such as mcr-type and carbapenem-resistant Enterobacteriaceae related genes.Most of the identified ARGs were generally associated with the commonly used antibiotics,suggesting the role of increasing antibiotic consumptions on the resistome prevalence.Spatially,the composition and diversity of ARGs varied across geographical distances and exhibited a scale-dependent distancedecay relationship.Notably,the composition of ARGs was largely shaped by bacterial community structure,and their diversities were co-governed by stochastic process(∼48%)and deterministic process(∼52%).Findings provide a valuable insight to better understand ecological mechanisms of ARGs in lake ecosystems and have important implication for the prevention and control of resistome risk.