Species diversity and stability of natural secondary communities with different cutting intensities after ten years

Species diversity and stability of natural secondary communities in different layers with different cutting intensities 10 years later were investigated by calculating Marglef Richness index（R）,Shannon-Wiener diversity index（H）,Simpson diversity index（P）,and Pielou Evenness index（J）.Results show that the values of R,H and P among different layers are listed in a decreasing order：the shrub layer the arbor layer the herb layer,all the three indices values reach the maximum under medium selective cutting intensity after 10 years.The J value of the shrub layer shows a concave parabolic change with the increase in cutting intensity;it shows a linear increase for the arbor layer,whereas the J value of the herb layer shows an opposite change pattern.The values of R at different cutting intensities had high significant difference,but other indices had not significant difference.The stability of communities at different cutting intensities after 10 years is non-cutting low selective cutting intensity medium selective cutting intensity high selective cutting intensity extra-high intensity clear cutting.The stability of communities at different cutting intensities after 10 years shows that the greater cutting intensities,the worse the stability is.

Composition and Distribution of Soil Spider Assemblages in Three Natural Secondary Forests in Ziwuling, Gansu

Soil spiders were pitfall-trapped once every month in three forest vegetation types of Ziwuling natural secondary forest region, Gansu Province from April to October, 2004. A total of 2 164 spiders were collected, belonging to 43 species in 19 families, captured in 630 pitfall trap collections. Linyphiidae, Gnaphosidae and Lycosodae were found to be the dominant families in all habitat types, and the composition of soil spider assemblages was different between the three habitats. Ecological indices of diversity, richness and evenness were significantly different between the three habitats （ P 〈 0.05）. The relative abundance of guilds （based on numbers of individuals） varied greatly （P 〈 0.01）, which may releet resource availability within habitat types. The existence of different patterns within the assemblages reflects the importance of maintaining habitat heterogeneity and vegetation types in order to preserve soil spider biodiversity.

Composition and Characteristics of Natural Secondary Forests in Shenzhen,South China

The composition and structure of five natural secondary forests in Shenzhen were studied based on data of plots and were compared with Hong Kong zonal forest, so as to detect their succession stage and species diversity level. According to succession process of subtropical forest and ecological characteristics of dominant species, the authors speculate that five communities are at different stages. Sinosideroxylon community dominated by heliophilous evergreen broad-leaved tree (Sinosideroxylon wightianum) and conifer tree (Pinus massoniana) is at the third stage. Itea + Acronychia community dominated by two evergreen broad-leaved heliophytes (Itea chinensis and Acronychia pedunculata) is at the fourth stage. The others, i.e., Schefflera, Sterculia and Cleistocalyx + Sterculia community are at the fifth stage where some mesophytes are dominant but heliophytes have a weighed percentage of importance value. Due to succession stage and different forest management and conservation models, the species diversity of five communities is significantly lower than that of Endospermum community in Hong Kong. The values of Shannon-Wiener index and Pielous evenness index of five communities are 2.04–2.953 and 64.2%–74% respectively, but those of the Endospermum community are 4.74 and 79% respectively. The current situation of these communities suggests that the necessary measures should be taken to protect and restore the communities.

Positioning and function of secondary general hospital in community rehabilitation of disabled persons-a case study of a secondary general hospital in Changsha city

Objective:the positioning of secondary hospitals in the community rehabilitation work system and the status of community medical rehabilitation ser-vices for the disabled in Changsha were clarified through investigation and study of the 2019 income of a second-ary general hospital in Changsha.Suggestions from var-ious parties were integrated to provide feasible ideas for expanding the role of secondary hospitals in community rehabilitation.Methods:the 2019 income of a secondary general hospital in Changsha was statistically analyzed,a community rehabilitation questionnaire was designed,and a field survey was carried out focusing on 19 issues including rehabilitation service items,rehabilitation facil-ities and equipment,and the satisfaction of rehabilitation practitioners.Results:in the total hospitalization expenses of a secondary general hospital in Changsha city in 2019,rehabilitation physiotherapy expenses accounted for 7%,and drug treatment expenses accounted for 25%.In addi-tion,in the survey of community rehabilitation service sat-isfaction for the disabled,the difference between the very dissatisfied and very satisfied groups was statistically sig-nificant(P<0.05).Conclusion:taking a secondary gener-al hospital in Changsha city as an example,the treatment methods in secondary general hospitals are still dominated by traditional drug therapy,and the disabled are not sat-isfied with community rehabilitation services.Therefore,rehabilitation treatment projects to meet the rehabilitation needs of the disabled should be promoted in hospitals.

Leguminosae plants play a key role in affecting soil physical-chemical and biological properties during grassland succession after farmland abandonment in the Loess Plateau,China

Leguminosae are an important part of terrestrial ecosystems and play a key role in promoting soil nutrient cycling and improving soil properties.However,plant composition and species diversity change rapidly during the process of succession,the effect of leguminosae on soil physical-chemical and biological properties is still unclear.This study investigated the changes in the composition of plant community,vegetation characteristics,soil physical-chemical properties,and soil biological properties on five former farmlands in China,which had been abandoned for 0,5,10,18,and 30 a.Results showed that,with successional time,plant community developed from annual plants to perennial plants,the importance of Leguminosae and Asteraceae significantly increased and decreased,respectively,and the importance of grass increased and then decreased,having a maximum value after 5 a of abandonment.Plant diversity indices increased with successional time,and vegetation coverage and above-and below-ground biomass increased significantly with successional time after 5 a of abandonment.Compared with farmland,30 a of abandonment significantly increased soil nutrient content,but total and available phosphorus decreased with successional time.Changes in plant community composition and vegetation characteristics not only change soil properties and improve soil physical-chemical properties,but also regulate soil biological activity,thus affecting soil nutrient cycling.Among these,Leguminosae have the greatest influence on soil properties,and their importance values and community composition are significantly correlated with soil properties.Therefore,this research provides more scientific guidance for selecting plant species to stabilize soil ecosystem of farmland to grassland in the Loess Plateau,China.

Genotoxicity Assessment of Contaminated Drinking Water Sources in a Rural Community in Edo State of Nigeria

In most rural settlements in Nigeria, provision of potable water for drinking and domestic purposes is a big challenge;therefore analysis of drinking water is of great importance as contaminated water jeopardizes both the physical and social health of all people. Water samples were obtained during the dry and wet seasons from a borehole and a man-made lake constructed through self-help effort in Obazuwa community in Ovia North East Local Government Area of Edo State, Nigeria. They were analyzed for physicochemical parameters and subjected to cyto-genotoxic evaluation using the Allium cepa assay. Results of the physicochemical analysis showed that most of the parameters (pH, chromium, copper, chlorides, nickel, iron, zinc, cadmium, lead and manganese) of the lake water in both seasons exceeded World Health Organisation (WHO) permissible limits. Total heterotrophic bacteria and E. coli were present with dry season water samples having higher amounts. Compared to the control, the mitotic index decreased significantly (p < 0.05) in the water samples and were characterized by a number of chromosomal aberrations notably bridges, fragments, sticky chromosomes, disoriented chromosomes, and micronuclei in significant amounts and these were more pronounced in water samples obtained during the dry season. The findings in this study are of public health relevance as access to safe water is a fundamental human need and therefore, a basic human right.

Vegetation cover of the lahar valley on the Sarychev Peak volcano(Matua Isl.,Middle Kuril Islands) after the Eruption in 2009: current state and features of succession processes

The paper presents the study of the vegetation recovery after the descent of the lahar during the eruption of the Sarychev Peak volcano(Matua Isl.,Middle Kuriles) in 2009.The works were carried out in 2017.It was found that during the secondary succession,plant communities,typical of the altitudinal zonation of the volcanic structure vegetation,are formed on lahar sediments in the following manner: the upper sections of the slope are occupied by sparse meadow and shrub vegetation,the middle are presented by shrub belt with a developed canopy,and the lower are representative of shrub large-grass belt.At the same time,the ordination analysis of the vegetation cover of the lahar valley by the detrended correspondence analysis(DCA) revealed the dispersion of the counting areas along the altitudinal gradient.This is opposite to that characteristic for both,the background communities on the slopes of the studied volcanic structure,and for communities in dynamical equilibrium of a typical altitude profile.Besides,directly correlating indicators of α-diversity of communities indicate the presence of open young communities at the stage of a complex grouping.Since the species Duschekia fruticosa which is an identifier in buried sites,forms communities in a state of dynamic equilibrium,with individuals of 40–50 years old,and at the time of the work,formed a canopy with individuals of 7–8 years old,a complete recovery of the communities of the lahar valley is possible in no less than 40 years.The acquired data on the recovery of vegetation on lahar contribute to the study of succession processes in the sites located in the zone of active volcanism.In addition,in this work,for the first time,the rates of restoration of the vegetation cover following its destruction as a result of burial by lahar products,are estimated.The specific features of this process are also considered.Employing the broad range of mathematical methods for quantitative analysis of indicators of young communities inhabiting the substrate makes it possible to identify patterns of vegetation formed during succession processes.The specifics of this organization are taken into account in this analysis.

Single and combined effects of secondary polyethylene microplastic on the growth of Pak choi and the soil microbiome composition

It has been confirmed that microplastics(MPs)are present in the environment.This study simulated secondary PE-MPs via aging and mechanical processes to evaluate their effects on Pak choi(Brassica rapa L.)over 21 d.Two common pollutants,dichlorodiphenyltrichloroethane(DDT)and naphthalene,were used in the combined toxicity tests.The results indicated that the growth of Pak choi was significantly inhibited after exposure to secondary PE-MPs,and the combined effects were antagonistic,owing to the adsorption capacity of secondary PE-MPs to DDT and naphthalene.Oxidative stress in Pak choi can be markedly affected,leading to oxidative damage to plant cells.The moisture content,soil bulk density,soil density,cation exchange capacity(CEC),and FDA hydrolase in the planted soils increased in the treated groups,and the TOC content changed significantly.We also found that the microbial composition of the soil in the DDT and naphthalene groups showed more significant alterations than that in the other groups.Alpha diversity analysis showed that species diversity increased in the combined groups but indicated a clear downward trend in the single MPs groups.This study suggests that secondary PE-MPs harm the growth of Pak choi and can change soil properties,revealing the harm to the ecosystem of MPs in the soil.

Tap water microbiome shifts in secondary water supply for high-rise buildings

In high-rise buildings,secondary water supply systems(SWSSs)are pivotal yet provide a conducive milieu for microbial proliferation due to intermittent flow,low disinfectant residual,and high specific pipe-surface area,raising concerns about tap water quality deterioration.Despite their ubiquity,a comprehensive understanding of bacterial community dynamics within SWSSs remains elusive.Here we show how intrinsic SWSS variables critically shape the tap water microbiome at distal ends.In an office setting,distinct from residential complexes,the diversity in piping materials instigates a noticeable bacterial community shift,exemplified by a transition from a-Proteobacteria to g-Proteobacteria dominance,alongside an upsurge in bacterial diversity and microbial propagation potential.Extended water retention within SWSSs invariably escalates microbial regrowth propensities and modulates bacterial consortia,yet secondary disinfection emerges as a robust strategy for preserving water quality integrity.Additionally,the regularity of water usage modulates proximal flow dynamics,thereby influencing tap water's microbial landscape.Insights garnered from this investigation lay the groundwork for devising effective interventions aimed at safeguarding microbiological standards at the consumer's endpoint.

REGENERATIVE URBAN COMMUNITY DESIGN

INTRODUCTION Global sustainable development is inextricably tied to the development of cities,as accelerating growth in urban populations becomes a major driver of social,environmental and ecological change.Cities are major consumers of natural resources and producers of pollution and waste.Development solutions that can reduce urban environmental impacts,as well as increase urban quality of life,are urgently needed.How to ensure that rampant growth in urban communities follows a regenerative and sustainable path therefore becomes a critical and increasingly relevant question.

Role of magpie in bird community formation in secondary forest

We analyzed a bird community in a secondary forest and the results show that the magpie was one of the key groups in the secondary forest.The key group is identified based on the nests used by other birds at a rate of 25%-40.17%.The size of the community is different and the number of these key groups is not certain.

Bacterial-fungal interactions under agricultural settings:from physical to chemical interactions

Bacteria and fungi are dominant members of environmental microbiomes.Various bacterial-fungal interactions(BFIs)and their mutual regulation are important factors for ecosystem functioning and health.Such interactions can be highly dynamic,and often require spatiotemporally resolved assessments to understand the interplay which ranges from antagonism to mutualism.Many of these interactions are still poorly understood,especially in terms of the underlying chemical and molecular interplay,which is crucial for inter-kingdom communication and interference.BFIs are highly relevant under agricultural settings;they can be determinative for crop health.Advancing our knowledge related to mechanisms underpinning the interactions between bacteria and fungi will provide an extended basis for biological control of pests and pathogens in agriculture.Moreover,it will facilitate a better understanding of complex microbial community networks that commonly occur in nature.This will allow us to determine factors that are crucial for community assembly under different environmental conditions and pave the way for constructing synthetic communities for various biotechnological applications.Here,we summarize the current advances in the field of BFIs with an emphasis on agriculture.

Cradle for the newborn Monochamus saltuarius:Microbial associates to ward off entomopathogens and disarm plant defense

The Japanese pine sawyer,Monochamus saltuarius,as a beetle vector of Bur-saphelenchus xylophilus(pine wood nematode),is an economically important forest pest in Eurasia.To feed on the phloem and xylem of conifers,M.saltuarius needs to overcome various stress factors,including coping with entomopathogenic bacteria and also various plant secondary compounds(PSCs).As an important adaptation strategy to colonize host trees,M.saltuarius deposit eggs in oviposition pits to shield their progeny.These pits har-bor bacterial communities that are involved in the host adaptation of M.saltuarius to the conifers.However,the composition,origin,and functions of these oviposition pit bacteria are rarely understood.In this study,we investigated the bacterial community associated with M.saltuarius oviposition pits and their ability to degrade PSCs.Results showed that the bacterial community structure of M.saltuarius oviposition pits significantly differed from that of uninfected phloem.Also,the oviposition pit bacteria were predicted to be enriched in PSC degradation pathways.The microbial community also harbored a lethal strain of Serratia,which was significantly inhibited.Meanwhile,metatranscriptome anal-ysis indicated that genes involved in PSCs degradation were expressed complementarily among the microbial communities of oviposition pits and secretions.In vitro degrada-tion showed that bacteria cultured from oviposition pits degraded more monoterpenes and flavonoids than bacteria cultured from uninfected phloem isolates.Disinfection of ovipo-sition pits increased the mortality of newly hatched larvae and resulted in a significant decrease in body weight in the early stages.Overall,our results reveal that M.saltuarius construct oviposition pits that harbor a diverse microbial community,with stronger PSCs degradation abilities and a low abundance of entomopathogenic bacteria,resulting in the increased fitness of newly hatched larvae.