Effects of Forest Restoration Techniques on Community Diversity and Aboveground Biomass on Area Affected by Mining Tailings in Mariana,Southeastern Brazil

Currently there is an urgent and special attention in actions to restore tropical forests.In this study,we evaluated the effect of different restoration methods on aboveground biomass(AGB)stock,tree community diversity and structure,in areas affected by the Fundão tailings dam collapse in Mariana,Minas Gerais state,Brazil.We measured and compiled data of the AGB,community diversity and structure attributes in 36 plots distributed in six restoration treatments and six replicas:planting of native tree seedlings with fertilization and pH correction(PSf)and without fertilization and pH correction(PS);seeding of native trees with fertilization and pH correction(SDf)and without fertilization and pH correction(SD);natural regeneration with fertilization and pH correction(NRf)and without fertilization and pH correction(NR).No significant differences in substrate properties and AGB between treatments.Although biomass storage between treatments was not statistically different,there is a clear pattern showing higher values active restoration method.The Pielou index ranged from 0.520(SDf)to 0.943(NR),except for SDf all the others treatments had values higher than 0.76.This result suggests floristic heterogeneity,without ecological dominance in the plant community.Overall,active restoration had important implications for the forest restoration where natural regeneration is limited.

Influence of Environmental Variables on the Natural Regeneration of a Forest under Restoration after Bauxite Mining and in a Reference Ecosystem in Southeastern Brazil

The shrub-tree floristic composition of the natural regeneration stratum of a bauxite mine in the process of restoration and in a reference ecosystem(remnant of a preserved secondary Seasonal Semi-Deciduous Forest)were analysed to evaluate forest restoration conditions after five years of planting.The influence of canopy openness,accumulated leaf litter and soil attributes in the regeneration stratum were also investigated in both the forests.The floristic composition of the regeneration stratum in the forest under restoration(16 species and 5,083 individuals ha-1)and in the reference ecosystem(58 species and 26,250 individuals ha-1)are distinct due to the difference in the environmental variables.Results showed that the reference ecosystem favours the presence of species that tolerate environments with greater shading and higher aluminium and organic matter content in the soil like Psychotria carthagenensis Jacq.,while the forest under restoration favours the presence of species adapted to fertile soils and those that tolerate greater luminosity like Vernonanthura phosphorica(Vell.)H.Rob.

Study on Site Preparation and Restoration Techniques for Forest Restoration in Mining Tailings of Mariana,Brazil

Ecological restoration in forest ecosystem is a priority in Mariana,Brazil.Thus,we evaluated the effects of passive and active restoration methods through different site preparation techniques by manipulating physical-chemical properties of substrates on tree community coverage in Mariana,Brazil.A total of 48 plots(12×12 m each)were established in two areas along the flood plains with accumulation of tailings.The following treatments were established:(1)planting of native tree seedlings with fertilization(PSf)and(2)without fertilization(PS);(3)direct seeding of native trees with fertilization(SDf)and(4)without fertilization(SD);(5)natural regeneration with fertilization(NRf)and(6)without fertilization(NR).Differences in substrate properties and tree community coverage were evaluated between treatments,the substrate properties and tree community coverage relationship,and main effects of substrate fertility and texture on tree community coverage.There were marked differences in substrate and plant coverage between treatments.On average,the highest plant coverage was found in treatment with fertilization,such as NRf(59,5%)and SDf(48%).However,the treatment with seedling planting(PSf and PS)and NR did not show differences(~37%),while the lowest values were observed in SD(23%).There is a strong relationship between substrate fertility and plant community coverage,with significant positive effects.We observed that the passive and active restoration methods can be complementary in the soil and plant community coverage recovery.

Soil Seed Banks in Two Environments of Forest Restoration Post Bauxite Mining:Native Tree Plantation and Natural Regeneration

The objective of this study was to compare the soil seed bank in an area under natural regeneration(F1)and another reforested through seedling planting(F2),seven years after bauxite mining,in Southeast,Brazil.In each area,10 sampling points were randomly distributed,using three samples of topsoil to represent each point.The samples were transported to a shade house and evaluated for six months,where emerging individuals were identified every two weeks.Floristic similarity was evaluated with cluster analysis based on the Jaccard index(SJ).Species richness and abundance of individuals were compared using Student's t test.In F1,2,114.94 propagules m-2 were registered,belonging to 51 species and 24 botanical families,Shannon-Wiener diversity index H’=2.770 and Pielou evenness index J’=0.705.In F2,1,168.62 propagules m-2 were registered,belonging to 42 species and 22 families,H’=2.618 and J’=0.700.The(SJ)between F1 and F2 was 0.61,indicating a high similarity.The results showed high density of propagules,good diversity and absence of ecological dominance.The high number of individuals and diversity of tree species with zoochoric dispersion found in the areas indicates that both natural regeneration and reforestation were efficient in the ecological restoration of bauxite mined areas.

Methylene blue enhances polyethylene glycol-fusion repair of completely severed rat sciatic nerves

Complete transection of peripheral mixed nerves immediately produces loss of sensory perception,muscle contractions and voluntary behavior mediated by the severed distal axons.In contrast to natural regeneration(~1 mm/d)of proximal axons that may eventually reinnervate denervated targets,re-innervation is restored within minutes by PEG-fusion that consists of neurorrhaphy and a sequence of well specified hypo-and isotonic calcium-free or calcium-containing solutions,the anti-oxidant methylene blue(MB)and the membrane fusogen polyethylene glycol(PEG).In this study,we examined the relative efficacy of PEG-fusion with no MB(0%),0.5%MB,or 1%MB on the recovery of voluntary behaviors by female Sprague-Dawley rats with a complete mid-thigh severance of their sciatic nerve bathed in extracellular fluid or calcium-containing isotonic saline.The recovery of voluntary behaviors is the most relevant measure of success of any technique to repair peripheral nerve injuries.We assessed recovery by the sciatic functional index,a commonly used measure of voluntary hindlimb behaviors following complete sciatic transections.We reported that both 1%MB and 0.5%MB in sterile distilled water in our PEG-fusion protocol with neurorrhaphy significantly increased the rate and extent of behavioral recovery compared to PEG plus neurorrhaphy alone.Furthermore,0.5%MB was as effective as 1%MB in voluntary behavioral recovery as assessed by the sciatic functional index.Since sterile 1%MB is no longer clinically available,we therefore recommend that 0.5%MB be included in upcoming human clinical trials to evaluate the safety and efficacy of PEG-fusion.All animal procedures were approved by the University of Texas Institutional Animal Care and Use Committee(AUP-2019-00225)on September 9,2020.

Estimation of carbon sequestration in reclaimed coalmine degraded land dominated by Albizia lebbeck, Dalbergia sissoo and Bambusa arundinacea plantation： a case study from Jharia Coalfields, India

Reclaimed mined lands provide an excellent opportunity to sequester carbon and combat global warming. Carbon sequestration on reclaimed sites depend on age of reclamation, composition of species, geomining conditions （soil characteristics） and prevailing climate. The aims of the present study were to calculate carbon （C）--stock of biomass of 4 years old plantation （dominated by Albizia lebbeck, Dalbergia sissoo and Bambusa arundinacea）, understorey vegetation and litter, soil organic carbon in reclaimed minesoil （RMS） and compare with reference forest site. Allometric equation was used for the estimation of biomass C stock and found 13.0 Mg C ha i （A lebbeck 7.8 Mg C ha-I, D sissoo 3.5 Mg C ha-l and B. arundincea 1.2 Mg C ha-l）, while stock of understorey vegetation was 0.98 Mg C ha-~. In RMS, C stock was 16.3 Mg C ha-1, out of which inorganic C contributed 1.7 g kg-l （8 % of total soil C）, Coal C 8.7 g kg^-1 （43 % of total soil C） and biogenic C 9.8 g kg^-1 （49 % of total soil C）. Total C stock in reclaimed site was calculated as 30.3 Mg C ha^-1（equivalent to 111 Mg CO2 ha-b. The study concluded that （i） coal C is responsible for overestimation of C stock in RMS （ii） Maximun C stock stored in aboveground biomass component and （iii） reclaimed mined lands will take approximately 17 years to reach the level of C stock of reference forest site in dry tropical climate.

Attributes of stand-age-dependent forest determine technosol fertility of Atlantic forest re-growing on mining tailings in Mariana,Brazil

Understanding how soil fertility changes due to environmental conditions and stand-age-dependent forest attributes is important for local-scale forest restoration.We evaluated the effects of stand-age-dependent forest attributes(plant community composition and litter stock)on soil and technosol fertility across two second-growth Atlantic forests(SGF)after the deposition of mining tailings in Mariana,southeastern Brazil.We hypothesized that technosol fertility in the SGF tailings is positively affected by plant community composition variability,stand age,and litter stock.We used total exchangeable bases and organic matter as fertility indicators for technosol and soil,and species composition and litter stock as stand-age-dependent forest attributes.Our results showed significant differences in the stand-age-dependent forest attributes and soil chemical properties between the two forest patches(SGF tailing and SGF non-tailing)evaluated.Thus,there was a marked gradient of litter storage and fertility between soil and technosol that can be important forest recovery indicators for the affected plant communities.Furthermore,according to the tested models,we corroborated the hypothesis that technosol fertility is positively affected by stand age,plant community composition variability,and litter stock,which may contribute considerably to forest recovery on tailings.Our results demonstrate that the fertility predictors analyzed to explain the forest recovery on tailings can also be considered as ecological indicators for assessing forest restoration in areas impacted by mining tailings in Mariana.

Effects of climate variability and land use/land cover change on the Daihai wetland of central Inner Mongolia over the past decades

The wetland ecosystem and its driving mechanism are significance impact on the ecological environment and the sustainable development of semi-arid regional economy.Agricultural and industrial land use/land cover change(LUCC) is also important for wetland system.The Daihai wetland(DW)in Inner Mongolia has been suffering from severe environmental problems such as water resource shortages and wetland areas decrease.We analyzed spatiotemporal LUCC at the catchment scale of Daihai Lake,which has recently exhibited a dramatic loss of water area,and investigated the potential role of climatic changes and human activities in the wetland loss.From 1976 to 2015,the arable land and construction land increased by 71.72 and 15.81 km2,with ranges of 18.72% and 39.61%,respectively.Meanwhile,the wetland area decreased by 84.47 km2,accounting for 29.07% of the area in1976.From 1960 to 2015,the area of Daihai Lake decreased by 100.73 km^2,diminishing to 37.09% of the area in 1960,and the lake storage accordingly shrank from 12.9×10~8 to approximately 3.9×10~8 m^3.The lake level also rapidly declined.From 1962 to2014,the lake water mineralization,total nitrogen(TN),and total phosphorus(TP) increased by 2410,7.86,and 0.182 mg L-1,respectively.The pollution sources included not only mineral fertilizers and pesticides,but also livestock,poultry breeding,aquaculture,and rural household waste.The lake area decreased with increasing agricultural development,Daihai power plant(DHPP) water consumption,and catchment climatic dryness.Thus,the urgent implementation of effective restoration and mitigation measures are needed.

The Environmental Impact of Industrial Agriculture in Rwanda:The Case of Mulindi Tea Plantations

The aim of this study is to assess the impact of industrial agriculture on the environment in Rwanda taking Mulindi tea plantations as a case study.Tea is one of the three major crops of Rwandan industrial agriculture apart from coffee and pyrethrum.The results of this study show clearly the impact of tea plantations on the environment in Rwandan in all aspects.Soil samples collected in three zones

Major Elements in Lake Muhazi,Rwanda,East Africa

The aim of this study undertaken at Lake Muhazi in Rwanda was to determine and analyze the major elements present in water. The presence of many major elements （Al, As, Ba, C, Ca, Cu, Fe, H^＋, K, Mg, Mn, N, P, S, Si, and Zn） was determined by spectroscopic technique. The concentrations of the elements were measured in water samples taken from three different locations of the lake from May to August 2008. The lake is polluted by water flow from mountain sides surrounding the lake. Other causes of pollution could be the use of agrochemicals in the sugar land, which surrounds the lake, and human activities near the lake. Finally, we proposed the strategies that can be applied in order to ensure good conservation of the environment and to prevent augmentation of heavy materials into the lake.

Runoff variation and its response to climate change in Huolin River catchment,Northeast China

The Huolin River catchment(HRC)is located in the semi-arid region of Northeast China,which is very sensitive to climate change.The runoff in HRC is closely related to the recovery of local vegetation in the Greater Khingan Mountains and the survival of downstream wetlands.Dramatic runoff fluctuations and increasing no-flow days confirmed the water crisis in this area.Hence,it is extremely urgent to study the current situation and characteristics of runoff.In this study,hydrological and meteorological data of HRC during 1956-2018 were analyzed to elucidate the processes,characteristics,trends of the river runoff and revealed its response to climate change.The Mann-Kendall test and linear regression method showed that runoff in the HRC demonstrated a downward trend over the study period with a marked annual variation.The runoff in the high flow years was 100 times that of the low flow years,showing a typical continental climatic river characteristic.There are two runoff peak flows in the intra-annual runoff distribution in March and July,whereas two runoff valleys occurred around May and September to February.The runoff positively correlates with precipitation in summer and temperature in early spring.Snowmelt influenced by rising temperatures in April and precipitation in July is the main driving factor for the two peaks flow.Evaporation rose with precipitation decline and temperature increased,which may influence the runoff decrease.The annual runoff is well synchronized with the annual precipitation,and precipitation change is the main driving factor of variation and abrupt change points of annual runoff in the catchment.This study would be beneficial for water resource management in developing adaptation strategies to offset the negative impact of climate change in HRC.

Multi-Technique Characterization and Conservation of an Ancient Egyptian Fabric from King Khufu First Solar Ship

Textiles are among the most fragile artefacts in the world. They are difficult to preserve even in the best circumstances. Herein, we studied an artefacts fabric of a special nature in terms of usage. Despite the multiple applications of textiles, the piece understudy is one of the unique pieces that the ancient Egyptian used as fenders for King Khufu’s first solar boat, the second-largest discovery in Egypt history. The boat was discovered inside a limestone pit. It was disassembled and arranged in several layers. Four pillows of wrapped fabric were found in the first layer, which was used as boat fenders. This use is a great discovery of the role of textiles in the manufacture of ancient boats. Thus, we conducted tests and analytical studies of those fenders using scanning electron microscopy (SEM) and an optical microscope to identify the type and nature of fibers, spinning method, and aspects of damage. Both energy-dispersive X-ray (EDX) analysis and infrared analysis (FT-IR) were employed to explore the sample’s elemental content and study the functional groups of the fabric. These analytical processes were useful in carrying out the restoration and preservation work necessary for the artefact under study.

Abrupt change of winter temperature over the Mongolian Plateau during 1961-2017

Studying the abrupt change of winter temperature(ACWT)over the Mongolian Plateau(MP,including Inner Mongolia Autonomous Region and State of Mongolia)is of great significance for understanding the spatiotemporal distribution of temperature and the mechanism of global climate change.Monthly temperature data during 1961–2017was collected,and the abrupt change point was determined by the Mann–Kendall test and sliding ttest,to analyze the characteristics and causes of ACWT.The results showed that(a)The winter temperature has rapidly increased with a trend of 0.41℃/10a,which was significantly higher than that of the rest area of Chinese mainland,indicating that climate change in the MP was more sensitive to global warming.(b)The abrupt change point occurred in 1988,with temperature of-15.5℃and-14.1℃before and after abrupt change,respectively.The ACWT in 50°N was 1–3 years later than that in 40°N,and the isotherms of different temperatures moved northward by 10–200 km,especially-16℃isotherms moved approximately 200 km northward after 1988.(c)The Arctic Oscillation(AO)and Mongolian High(MH)anomaly affects winter temperature over the MP.When the AO is unusually strong,the MH and East Asian winter monsoon are weak,and southerly winds prevail in most regions,which is not conducive to the cold air developing southward,leading to higher winter temperature in the MP.Overwise,abnormally northerly winds prevail and temperature is low.Meanwhile,the abrupt change time of AO occurred in 1987 before winter temperature.It shows that the AO indirectly causes winter temperatures to rise by influencing the MH and is also the main driving factor of ACWT.

Morphodynamic development of the Terkhiin Tsagaan Lake Depression,Central Mongolia:Implications for the relationships of Faulting,Volcanic Activity,and Lake Depression Formation

Data on the origin and morphology of lake depressions caused by volcanism are scarce in Mongolia.Previous studies focused on climate change patterns based on Terkhiin Tsagaan Lake sediment.We present a result of existing reconstructions of lake depression development and changes in the hydrology system during the Khorgo volcanic activation and the Holocene environmental change.A depression of the Terkhiin Tsagaan Lake is formed by a lava flow barrier from the Khorgo volcano.However,the Khorgo volcanic eruption and the lake depression that could shape a large lake have arisen instead from a fault.The morphometric analysis and field measurements indicate that the derivation of the Terkhiin Tsagaan Lake depression and Khorgo volcano may have evolved from movement on a sinistral strike-slip fault,which is about 70 km long.The southern mountains and rivers were displaced from northwest to southeast along the Terkh Fault.The offset along Terkh Fault is 4.02-5.28 km in the depression of the Terkhiin Tsagaan Lake.After movement,a wide valley of the Terkh River developed in the present landscape.The active Khorgo Volcano formed along the Khorgo Fault.The Terkhiin Tsagaan Lake is formed by blocked water from the PaleoTerkh River after lava damming from the Khorgo Volcano.The initial paleo-lake area was about 195.7km^(2),which was three times larger than the modern lake.The current water volume of the Terkhiin Tsagaan Lake is 0.351 km^(3) while the volume of the paleo-lake was 2.248 km^(3).Based on this volume indicator the paleo-lake was 6.4 times larger than the current lake.Overflowing water from the lake depression formed the Suman River by a drying canyon through the lava plateau,but the canyon is along the Terkh Fault.Changes in the water volume of Terkhiin Tsagaan Lake and erosion of Suman River canyon are inversely related to each other.We present the morphometric relationships between the lava plateau of Khorgo Volcano and development of Terkhiin Tsagaan Lake depression.

Effect of invasive weed biochar amendment on soil enzymatic activity and respiration of coal mine spoil:a laboratory experiment study

Mining and excavation activities cause massive degradation of land,leading to complete loss of soil resources,vegetation,and biodiversity.Mine spoils support invasive weeds(predominantly Lantana)which can strive in these harsh conditions,causing allelopathy during plantation stage of reclamation.It is hypothesised that biochar produced from invasive weeds will enhance enzymatic activity,CO_(2)flux and overall fertility of coal mine spoil.A 6-month incubation study was conducted on the effect of biochar amendment(2 and 3%,w/w)on mine spoil enzymatic activities(dehydrogenase,invertase,amylase and cellulase),respiration and coal mine spoil fertility.The study showed that biochar significantly improved dehydrogenase(83%)and cellulase activity(78%)at 3%amendment.Geometric mean of enzymatic activities increased from 1.87 in control to 4.51 at 2%and 3.25 at 3%biochar amendment.Mine spoil physio-chemical properties such as soil organic carbon(65%),cation exchange capacity(54%),bulk density(25%)and water holding capacity(19%),were improved significantly com-pared to the unamended mine spoil.Biochar amendment reduced mine spoil CO_(2)flux at 2%(2.85μmol CO_(2)m^(−2)s^(−1))and 3%(2.60μmol CO_(2)m^(−2)s^(−1))compared to control(4.92μmol CO_(2)m^(−2)s^(−1)).The cost of biochar production and application(2%,w/w)in pit plantation during reclamation is estimated to be 844 USD t ha−1(plantation density:1600 trees ha−1).On the basis of present study,biochar preparation from invasive weeds can be used for sustainable reclamation of coal mine spoil.