This study investigates the weak-form efficiency and asymmetric multifractal scaling behavior of rare earth stock indices in the global,U.S.and Chinese markets during the trade war and the COVID-19 period.We examine t...This study investigates the weak-form efficiency and asymmetric multifractal scaling behavior of rare earth stock indices in the global,U.S.and Chinese markets during the trade war and the COVID-19 period.We examine the scaling behavior across overall,upward(bullish),and downward(bearish)market states from 2013 to 2021,employing an asymmetric multifractal detrended fluctuation analysis approach.Our findings indicate asymmetric multifractality in U.S.rare earth stock prices,caused by fat tails and long-range correlations.Weak-form price inefficiency and asymmetry in U.S.rare earth stock prices are prominent during market downturns,such as the trade war and COVID-19 periods.Chinese rare earth stocks demonstrate greater efficiency than U.S.and global stocks;thus,the latter markets provide arbitrage opportunities during upward and downward trends.展开更多
Sacred forests play a valuable role in the conservation of local biodiversity and provide numerous ecosystem services in Cameroon. The aim of this study was to estimate floristic diversity, stand structures and carbon...Sacred forests play a valuable role in the conservation of local biodiversity and provide numerous ecosystem services in Cameroon. The aim of this study was to estimate floristic diversity, stand structures and carbon stocks in the sacred forests of Bandrefam and Batoufam (western Cameroon). The floristic inventory and the stand structures were carried out in 25 m × 25 m plots for individuals with diameters greater than 10 cm;5 m × 5 m for individuals with diameters less than 10 cm. Carbon stocks were estimated using the non-destructive method and allometric equations. The floristic inventory identified 65 species divided into 57 genera and 30 families in the Bandrefam sacred forest and 45 species divided into 42 genera and 27 families in the Batoufam sacred forest. In the Bandrefam, the most important families are Phyllanthaceae (53.98%), Moraceae (21.69%), Lamiaceae (20.15%). At Batoufam, the most important families are Phyllanthaceae (39.73%), Fabaceae (28.47%), Araliaceae (23.77%). Malacantha alnifolia (55.14%), Vitex grandifolia (18.43%), Bosqueia angolensis (15.06%) were the most important species in Bandrefam. Otherwise, Malacantha alnifolia (28%), Polyscias fulva (22.73%), Psychotria sp. (21.28%) were the most important in Batoufam. The Bandrefam sacred forest has the highest tree density (2669 stems/ha). Total carbon stock is 484.88 ± 2.28 tC/ha at Batoufam and 313.95 ± 0.93 tC/ha at Bandrefam. The economic value varies between 5858.04 ± 27.62 USD/ha in Batoufam sacred forest and 3788.51 ± 11.26 USD/ha in Bandrefam sacred forest. The number of individuals and small-diameter trees has little influence on the carbon stocks in the trees. Medium-diameter trees store the most carbon, and very large-diameter trees, which are very poorly represented, store less carbon. In another way, wood density and the basal areas influence the carbon storage of the trees.展开更多
Collaborative forest management (CFM) is a form of forest governance in which local communities are involved in the management and decision-making processes related to forest resources. It is believed that forests und...Collaborative forest management (CFM) is a form of forest governance in which local communities are involved in the management and decision-making processes related to forest resources. It is believed that forests under such management are better in tree diversity and conservation status and thus hold more carbon stocks. The study assessed the impact of CFM on carbon stocks, tree species diversity & tree species density in Mabira Central Forest Reserve. Data were collected from plots that were systematically laid in the different purposively selected forest areas. The study findings show that there is no difference in stem density and carbon stocks between CFM and non-CFM areas. CFM areas had lower species richness compared to non-CFM areas. CFM areas, however, exhibited more species diversity than non-CFM areas. Climax colonization may favor a few dominant species over others, hence lowering species diversity despite the number of species being many in the understory, hence at the same time increasing species richness. Likewise, disturbance in CFM area may affect natural colonization and favor the emergency of many species either naturally or through assisted regeneration by reforestation, hence increasing diversity, whereas artificial selection of preferred species through harvesting may lower species richness, as observed. Recommendations for improving collaborative forest management (CFM) areas include implementing targeted interventions to enhance carbon sequestration, such as promoting reforestation and afforestation with high-carbon-storing species and strengthening monitoring and evaluation frameworks to assess carbon stock changes over time. Additionally, efforts should focus on enhancing biodiversity conservation by implementing more stringent protection measures and reducing human disturbance while encouraging community participation in biodiversity monitoring and conservation education.展开更多
Coastal wetlands are crucial for the‘blue carbon sink’,significantly contributing to regulating climate change.This study util-ized 160 soil samples,35 remote sensing features,and 5 geo-climatic data to accurately e...Coastal wetlands are crucial for the‘blue carbon sink’,significantly contributing to regulating climate change.This study util-ized 160 soil samples,35 remote sensing features,and 5 geo-climatic data to accurately estimate the soil organic carbon stocks(SOCS)in the coastal wetlands of Tianjin and Hebei,China.To reduce data redundancy,simplify model complexity,and improve model inter-pretability,Pearson correlation analysis(PsCA),Boruta,and recursive feature elimination(RFE)were employed to optimize features.Combined with the optimized features,the soil organic carbon density(SOCD)prediction model was constructed by using multivariate adaptive regression splines(MARS),extreme gradient boosting(XGBoost),and random forest(RF)algorithms and applied to predict the spatial distribution of SOCD and estimate the SOCS of different wetland types in 2020.The results show that:1)different feature combinations have a significant influence on the model performance.Better prediction performance was attained by building a model using RFE-based feature combinations.RF has the best prediction accuracy(R^(2)=0.587,RMSE=0.798 kg/m^(2),MAE=0.660 kg/m^(2)).2)Optical features are more important than radar and geo-climatic features in the MARS,XGBoost,and RF algorithms.3)The size of SOCS is related to SOCD and the area of each wetland type,aquaculture pond has the highest SOCS,followed by marsh,salt pan,mud-flat,and sand shore.展开更多
Agroforestry,as a platform for harmonizing agriculture and forestry is a win-win approach for the farming community and environmental sustainability.However,its potential is not well studied and quantified in Northwes...Agroforestry,as a platform for harmonizing agriculture and forestry is a win-win approach for the farming community and environmental sustainability.However,its potential is not well studied and quantified in Northwestern highland.Thus,this study aimed to investigate the woody species diversity,and carbon stock potential of traditional agroforestry practices in Northwestern Highlands(NWH)of Ethiopia.A total of 120 households were selected using stratified sampling for household(HH)surveys,and vegetation inventory was conducted in the winter season of 2023 on systematically laid 400 m2 sample quadrats.Shannon-Weiner diversity index(H’),Simpson’s diversity index(1-D)and Shannon evenness(E)were calculated to estimate woody species diversity.Variation in species diversity and carbon stock within and between agroforestry practices was assessed by 1-way ANOVA and rank differences were separated by post-hoc,Tukey HSD multiple comparison test.The result showed that four different agroforestry practices were identified,consisting of 44 woody species belonging to 23 families.Homegarden was the richest in terms of woody species composition(30),followed by boundary planting(25),while parkland agroforestry had the poorest species composition(12).The total carbon stock of the agroforestry practices in the study ranged from 92.51±29.21 to 143.52±47.83 Mg/ha),with soil organic carbon accounting for about 57.66%,followed by aboveground biomass carbon with 32.1%.Homegardens agroforestry had contributed more to the total carbon stocks than the other agroforestry practices.The total CO_(2)sequestration by above and below ground biomass of woody species in the traditional agroforestry practices of the NWH was estimated to be 519.97 and 104.01 Mg/ha,respectively.The study confirmed that the traditional agroforestry practices of the NWH of Ethiopia maintain a high diversity of woody species and are remarkably important for biodiversity conservation and climate change mitigation.展开更多
Natural forests are the primary carbon sinks within terrestrial ecosystems,playing a crucial role in mitigating global climate change.China has successfully restored its natural forest area through extensive protectiv...Natural forests are the primary carbon sinks within terrestrial ecosystems,playing a crucial role in mitigating global climate change.China has successfully restored its natural forest area through extensive protective measures.However,the aboveground carbon(AGC)stock potential of China's natural forests remains considerably uncertain in spatial and temporal dynamics.In this study,we provide a spatially detailed estimation of the maximum AGC stock potential for China's natural forests by integrating high-resolution multi-source remote sensing and field survey data.The analysis reveals that China's natural forests could sequester up to 9.880.10 Pg C by 2030,potentially increasing to 10.460.11 Pg C by 2060.Despite this,the AGC sequestration rate would decline from 0.190.001 to 0.080.001 Pg C·yr^(-1)over the period.Spatially,the future AGC accumulation rates exhibit marked heterogeneity.The warm temperate deciduous broadleaf forest region with predominantly young natural forests,is expected to exhibit the most significant increase of 26.36%by 2060,while the Qinghai-Tibet Plateau Alpine region comprising mainly mature natural forests would exhibit only a 0.74%increase.To sustain the high carbon sequestration capacity of China's natural forests,it is essential to prioritize protecting mature forests alongside preserving and restoring young natural forest areas.展开更多
Although the application of straw decomposing microorganism inoculants(SDMI)can accelerate straw decomposition,the underlying mechanisms affecting soil organic carbon(SOC)under different scenarios remain unclear.We co...Although the application of straw decomposing microorganism inoculants(SDMI)can accelerate straw decomposition,the underlying mechanisms affecting soil organic carbon(SOC)under different scenarios remain unclear.We conducted a meta-analysis using 226 observations from 86 studies on SOC changes under straw return with or without SDMI applications.Overall,our results indicated that straw with SDMI application increased the SOC stock by 1.51%at an initial carbon-to-nitrogen ratio(ICNR)>25(P<0.05),while the effect of ICNR≤25was insignificant.In particular,at ICNR>25,application of SDMI-treated straw increased SOC stocks in northern temperate continental areas(NTC)higher than in subtropical monsoon regions(STM).Furthermore,the straw with SDMI application increased higher SOC stocks in soils with pH>7.5 than those with pH≤7.5.In terms of agricultural management practices,SOC stocks were significantly higher in straw buried(SB),the experimental duration of straw return(EDSR)≥1 year,the straw return amount(SRA)>6,000 kg ha^(–1),and the SDMI application rate(SDMIR)>30 kg ha^(–1)conditions.The effect of straw with SDMI on SOC stocks under straw burying(SB)was significantly higher than that under straw mulching(SM)at ICNR≤25.At ICNR>25,EDSR,SDMIR,and the mean annual precipitation(MAP)were the main drivers of the effect of SDMI addition to straw on SOC stocks.Straw with SDMI induced SOC stock increases which increased with EDSR and decreased with increasing MAP.These findings provide a scientific basis for decision-makers and stakeholders to improve soil C management via the application of SDMI-amended straw at both regional and large scales.展开更多
In the last few decades, the Loess Plateau had experienced an extensive vegetation restoration to reduce soil erosion and to improve the degraded ecosystems. However, the dynamics of ecosystem carbon stocks with veget...In the last few decades, the Loess Plateau had experienced an extensive vegetation restoration to reduce soil erosion and to improve the degraded ecosystems. However, the dynamics of ecosystem carbon stocks with vegetation restoration in this region are poorly understood. This study examined the changes of carbon stocks in mineral soil （0-100 cm）, plant biomass and the ecosystem （plant and soil） following vegetation restoration with different models and ages. Our results indicated that cultivated land returned to native vegetation （natural restoration） or artificial forest increased ecosystem carbon sequestration. Tree plantation sequestered more carbon than natural vegetation succession over decades scale due to the rapid increase in biomass carbon pool. Restoration ages had different effects on the dynamics of biomass and soil carbon stocks. Biomass carbon stocks increased with vegetation restoration age, while the dynamics of soil carbon stocks were affected by sampling depth. Ecosystem carbon stocks consistently increased after tree plantation regardless of the soil depth; but an initial decrease and then increase trend was observed in natural restoration chronosequences with the soil sampling depth of 0-100 cm. Moreover, there was a time lag of about 15-30 years between biomass production and soil carbon sequestration in 0-100 cm, which indicated a long-term effect of vegetation restoration on deeper soil carbon sequestration.展开更多
This work studied the effects of tree species composition on soil carbon storage in five mixed stands dominated by oriental beech and grown in the western Caspian region in Guilan province, called Astara, Asalem, Fuma...This work studied the effects of tree species composition on soil carbon storage in five mixed stands dominated by oriental beech and grown in the western Caspian region in Guilan province, called Astara, Asalem, Fuman, Chere and Shenrud. The thickness of the litter layer, soil characteristics, tree composition and percentage of canopy coverage were measured in each stand. Total soil organic carbon differed significantly by stand. Total （organic） carbon stores at Fuman, which had the lowest tree species richness with 2 species and least canopy coverage （75%）, were significantly （p〈0.05） higher than at other locations. Carbon stor-age in topsoil （0-10 cm） was significantly lower in Shenrud, which had the highest tree species richness with 5 species and highest canopy cov-erage （95%）. The high percentage of canopy coverage in Shenrud proba-bly limited the conversion of litter to humus. However, in the second soil layer （10-25 cm）, Asalem, with high tree species richness and canopy coverage, had the highest carbon storage. This can be explained by the different rooting patterns of different tree species. In the Hyrcanian forest. According to the results, it can be concluded that not only tree composi-tion but also canopy coverage percentage should be taken under consid-eration to manage soil carbon retention and release.展开更多
Background: Forest management aims at obtaining a sustainable production of wood to be harvested to generate products or energy. However, the quantitative influence of forest management and of removals by harvest on b...Background: Forest management aims at obtaining a sustainable production of wood to be harvested to generate products or energy. However, the quantitative influence of forest management and of removals by harvest on biomass stocks has rarely been analysed on a large scale based on measurements. Two hypotheses prevail: management induces a reduction of wood stocks due to cuttings, versus no impact because of increased growth of the remaining trees. Using data collected for 2840 permanent plots across Romania from the National Forest Inventory representing^2.5 Mha, we have tested to what extent different management types and treatments can influence the biomass stock and productivity of beech forests, and attempt to quantify these effects both on the short and long terms. Three main types of beech forest management are implemented in Romania with specific objectives: intensive wood production in production forests, protection of ecosystem services (e.g. watersheds, avalanche protection) in protection forests, and protection of the forest and its biodiversity in protected forests. Production forests encompass two treatments differing according to the stand regeneration method: the age class rotation management and the group shelterwood management. Results: We show that forest management had little influence on the biomass stocks at a given stand age. The highest stocks at stand age 100 were observed in production forests (the most intensively managed forests). Consequences of early cuttings were very short-termed because the increase in tree growth rapidly compensated for tree cuttings. The cumulated biomass of production forests exceeded that of protected and protection forests. Regarding the treatment, the group shelterwood forests had a markedly higher production over a full rotation period. The total amount of deadwood was primarily driven by the amount of standing deadwood, and no management effect was detected. Conclusions: Given the relatively low-intensity management in Romania, forest management had no negative impact on wood stocks in beech forests biomass stocks at large scale. Stand productivity was very similar among management types or treatments. However cumulated biomass in production forests was higher than in protection or protected forests, and differed markedly according to treatments with a higher cumulated biomass in shelterwood forests.展开更多
Population genetics of the left-eyed flounder, Paralichthys olivaceus, including natural and cultured stocks distributed in the coastal waters near Qingdao of eastern maritime China, was analyzed in allozyme and RAPD....Population genetics of the left-eyed flounder, Paralichthys olivaceus, including natural and cultured stocks distributed in the coastal waters near Qingdao of eastern maritime China, was analyzed in allozyme and RAPD. The results showed that among total 29 gene loci of 15 isozymes, 9 and 7 were po- lymorphic in natural and cultured stocks, respectively. The status of genetic diversity in P. olivaceus is low in terms of polymorphic loci in chi-square test and genetic departure index of Hardy-Weinberg equi- librium. More alleles in IDHP, CAT, GDH and Ldh-C allozymes were found in the fish, which could be used as markers in assortive breeding and distinguishing stock, population or species evolution. Total 88 and 86 RAPD bands ranging from 200 to 2 500 bp were recognized individually in average of 7.8–8.0 bands per primer. The genetic diversity in cultured stock is lower than that in natural ones showing an ob- viously decreasing genetic divergence. Therefore, effective countermeasures must be taken to protect ge- netic resources of marine cultured fishes. The 2 markers have their own pros and cons. Combining the 2 markers to investigate the genetic variation of populations is suggested. The results provide basic data of this flounder and they are useful for studying genetic improvement and genetic resources of the fish.展开更多
Mangrove ecosystems have important ecological and economic values,especially their ability to store carbon.However,in recent years,human disturbance has accelerated mangrove degradation.Among them,the emission of poll...Mangrove ecosystems have important ecological and economic values,especially their ability to store carbon.However,in recent years,human disturbance has accelerated mangrove degradation.Among them,the emission of pollutants cannot be ignored.It is of great significance for carbon emission reduction and ecological protection to study the impacts of different pollutants on mangroves and their carbon stocks.Based on the remote sensing data of coastal areas south of the Yangtze River in China's Mainland,this paper builds the ensemble learning model Random Forest(RF)and Gradient Boosting Regression(GBR)to empirically analyse the relationship between industrial wastewater,industrial sulfur dioxide(SO2),PM2.5 and mangrove forests.The results show that the pollutant concentration of meteorological normalisation is more stable.The importance of pollutants presents regional heterogeneity.The area of mangroves in different cities and the corresponding total carbon stocks show different trends with the increase or decrease of pollutants,and there is a dynamic balance between urban pollutant discharge and mangrove growth in some cities.The research in this paper provides an analysis and explanation from the perspective of machine learning to explore the relationship between mangroves and pollutants and at the same time,provides scientific suggestions for the formulation of future pollutant emission policies in different cities.展开更多
Abstract： The water quality of Dianshan Lake in Shanghai Municipality, China, is impacted by nutrient losses from agricultural lands around the lake. In this study, nine types of agricultural land use were monitored ...Abstract： The water quality of Dianshan Lake in Shanghai Municipality, China, is impacted by nutrient losses from agricultural lands around the lake. In this study, nine types of agricultural land use were monitored in 2010 and 2011, and a correlation analysis between nutrient losses from agricultural non-point sources （NPS） and nutrient stocks in the lake was conducted over monthly and seasonal time periods. The results indicate that the monthly average concentration of total nitrogen （TN） ranged from 1.41 to 7.34 mg/L in 2010 and from 1.52 to 5.90 mg/L in 2011, while the monthly average concentration of total phosphorous （TP） ranged from 0.11 to 0.26 mg/L in 2010 and from 0.13 to 0.30 mg/L in 2011. The annual loss of TN from agricultural NPS was 195.55 tons in 2010 and 208.40 tons in 2011. The cultivation of water oat made the largest contribution to the loss of TN. The annual loss of TP was 44.58 tons in 2010 and 48.12 tons in 2011, and multi-vegetable cultivation made the largest contribution to the loss of TP. The results of correlation analysis show that the monthly stocks of TN and TP in the lake have a positive correlation with the monthly losses of TN and TP from agricultural NPS. According to the seasonal data, the stocks of TN and TP in the lake both have a much stronger correlation with the losses of TN and TP from agricultural NPS in summer than in other seasons. Agricultural NPS pollution control should be the main focus for the water resource conservation in this area.展开更多
Changes in land use cover, particularly from forest to agriculture, is a major contributing factor in increasing carbon dioxide（CO2） level in the atmosphere.Using satellite images of 1999 and 2011, land use and land...Changes in land use cover, particularly from forest to agriculture, is a major contributing factor in increasing carbon dioxide（CO2） level in the atmosphere.Using satellite images of 1999 and 2011, land use and land use changes in the Kumrat valley KPK, Pakistan, were determined： a net decrease of 11.56 and 7.46 % occurred in forest and rangeland, while 100 % increase occurred in agriculture land（AL）. Biomass in different land uses,forest land（FL）, AL, and range land（RL） was determined by field inventory. From the biomass data, the amount of carbon was calculated, considering 50 % of the biomass as carbon. Soil carbon was also determined to a depth of 0–15and 16–30 cm. The average carbon stocks（C stocks） in all land uses ranged from 28.62 ± 13.8 t ha-1in AL to486.6 ± 32.4 t ha-1in pure Cedrus deodara forest. The results of the study confirmed that forest soil and vegetation stored the maximum amount of carbon followed by RL. Conversion of FL and RL to AL not only leads to total loss of about 56 %（from FL conversion） and 37 %（RL conversion） of soil carbon in the last decades but also the loss of a valuable carbon sink. In order to meet the emissions reduction obligations of the Kyoto Protocol, Conservation of forest and RL in the mountainous regions of the Hindu Kush will help Pakistan to meet its emissions reduction goals under the Kyoto Protocol.展开更多
Data Mining (DM) methods are being increasingly used in prediction with time series data, in addition to traditional statistical approaches. This paper presents a literature review of the use of DM with time series da...Data Mining (DM) methods are being increasingly used in prediction with time series data, in addition to traditional statistical approaches. This paper presents a literature review of the use of DM with time series data, focusing on shorttime stocks prediction. This is an area that has been attracting a great deal of attention from researchers in the field. The main contribution of this paper is to provide an outline of the use of DM with time series data, using mainly examples related with short-term stocks prediction. This is important to a better understanding of the field. Some of the main trends and open issues will also be introduced.展开更多
Assessment of regional forest carbon stocks and underlying controls is critical for guiding forest management in the context of carbon sequestration. We investigated the variations in tree biomass carbon stocks relati...Assessment of regional forest carbon stocks and underlying controls is critical for guiding forest management in the context of carbon sequestration. We investigated the variations in tree biomass carbon stocks relating to forest types, and estimated the total tree biomass carbon stocks and projected gains through natural stand development by 2020 and 2050 in the Daqing Mountain Nature Reserve based on Category II data of the Forest Inventory of Inner Mongolia for the period ending 2008. Over a total area of 388,577 ha,this nature reserve currently stores an estimated 2221 Gg C in tree aboveground biomass alone, with potential to grow by more than 30 % to reach 2938 Gg C by 2020 and nearly double to 4092 Gg C by 2050 through natural development of the existing forest stands. The tree biomass carbon density and potential gain in tree biomass carbon stocks vary markedly among forest types and with stand development.The variations in the potential change of tree biomass carbon density for the periods 2008–2020 and 2008–2050 among forest types partly reflect the varying relationships of tree biomass carbon density with stand age for different tree species, and partly are attributable to variations in the stand age structure among different forest types. Of the major forest types, the ranking of projected changes in tree biomass carbon density are not consistent with variations in the relationship between tree biomass carbon density and stand age, neither are they explainable by variations in stand age structures, implying the interactive effect between forest type and stand dynamics on temporal changes in tree biomass carbon density. Birch rank highest for future biomass carbon sequestration because of its dominance in cover area and better age structure for potential gain in tree biomass carbon stocks. Poplar and larch were out-performers compared to other forest types given their greater contribution to total tree biomass carbon stocks relative to their distributional areas. Findings in this study illustrate that protection and proper management of under-aged forests can deliver marked gains in biomass carbon sequestration. This is of great importance to policy-makers as well as to scientific communities in seeking effective solutions for adaptive forest management and mitigation of anthropogenic greenhouse gases emissions using forest ecosystems.展开更多
The effects of apple dwarf stocks P22 and SH3 on the juvenile phase of Fuji seedlings were studied. The results showed that the juvenile phase could be shortened by more than two years when 2-year seedlings were graft...The effects of apple dwarf stocks P22 and SH3 on the juvenile phase of Fuji seedlings were studied. The results showed that the juvenile phase could be shortened by more than two years when 2-year seedlings were grafted on the dwarf stocks. The effects of P22 and SH3 were significantly different. Grafted on P22, the flowering node was less, the first flowing site was lower, and the juvenile phase was shorter than SH3. With the two stocks, the average first flowering site was more than 200 cm, the average flowering node was more than 100, and the lateral branch top bud was more than 50% in all first flowing seedlings.展开更多
Sturgeons are the most important principal market species in the Caspian Sea. In the present study, measurement of blood parameters was carried out with the aim of evaluating the normal value of hematological and seru...Sturgeons are the most important principal market species in the Caspian Sea. In the present study, measurement of blood parameters was carried out with the aim of evaluating the normal value of hematological and serum biochemical parameters of brood stocks Acipenser persicus during spawning season. Blood samples were collected from 36 brood stocks of A. persicus（18 males and 18 females） during the spawning season. Higher value of red blood cells, white blood cells, haemoglobin, haematocrit was observed in male breeders with significant differences between female breeders（p〉0.05）. Haemoglobin and haematocrit value in this study was within the range of 8.70 to 9.2 g/d L and 29.73% to 30.26%, respectively. The statistically significant differences between mean corpuscular volumes, mean corpuscular haemoglobin, lymphocyte and neutrophil percentages, aspartate aminotransferase, alkaline phosphatase and creatine kinase were observed in the male and female brood stocks.It is concluded from this study, some of the hematological and serum biochemical parameters of male and female A. persicus breeders were significantly varied from each other. In comparative investigation with earlier reports,the values of red blood cells, haemoglobin and haematocrit are highly varied due to age variations of fish.However, further studies are necessary to understand the impact of sexual, age, size, length, and season and habitat variation. Serum biochemical parameters can be used for confirming the maturity of A. persicus and monitoring any changes in the water quality parameters and soil.展开更多
Carbon is continuously being removed from the atmosphere by photosynthesis and stored in carbon pools(live,dead,and soil carbon)of forest ecosystems.However,carbon stock in dead wood and of trees with diameters at bre...Carbon is continuously being removed from the atmosphere by photosynthesis and stored in carbon pools(live,dead,and soil carbon)of forest ecosystems.However,carbon stock in dead wood and of trees with diameters at breast height(dbh)between 5 and 10 cm is often not considered in many studies carried out in the Congo Basin Forest.The relationship between tree diversity,life-forms and carbon stocks has received little attention.This study was carried out on the outskirts of Deng Deng National Park(DDNP)to determine tree diversity(dominant families,species richness and Shannon index),assess carbon stocks in the five carbon compartments(living tree,understory,fine roots,dead wood and litter)as well as to analyze the relationship between(1)carbon stocks and tree diversity;and,(2)between carbon stock and life-forms.The Shannon index of trees≥10 cm dbh ranged from 2.6 in riparian forest to 4.3 in secondary forest;and for the tree between 5 and 10 cm,it ranged to 1.56 in riparian forest to 3.68 in the secondary forest.The study site housed 16 species,7 genera and 3 families which are only found in trees of dbh between 5 and 10 cm.The average total carbon stock of the five compartments varied from 200.1 t ha-1 in forest residues to 439.1 t ha-1 in secondary forest.Dead wood carbon stock varied from 1.2 t ha-1 in riparian forests to 12.51t ha-1 in agroforests.The above ground carbon stocks for trees with diameter between 5 and 10 cm varied from 0.7 t ha-1 in young fallow fields to 5.02 t ha-1 in old secondary forests.This study reveals a low but positive correlation between species richness and total carbon stocks,as well as a significant positive relationship between life-forms and total carbon stocks.The findings highlight the need for more data concerning carbon content of dead wood,carbon of trees≥5 cm<10 cm dbh and the relationship between carbon stocks and tree diversity from other areas of the Congo Basin for a good understanding of the contribution of tropical forests to climate change mitigation.展开更多
文摘This study investigates the weak-form efficiency and asymmetric multifractal scaling behavior of rare earth stock indices in the global,U.S.and Chinese markets during the trade war and the COVID-19 period.We examine the scaling behavior across overall,upward(bullish),and downward(bearish)market states from 2013 to 2021,employing an asymmetric multifractal detrended fluctuation analysis approach.Our findings indicate asymmetric multifractality in U.S.rare earth stock prices,caused by fat tails and long-range correlations.Weak-form price inefficiency and asymmetry in U.S.rare earth stock prices are prominent during market downturns,such as the trade war and COVID-19 periods.Chinese rare earth stocks demonstrate greater efficiency than U.S.and global stocks;thus,the latter markets provide arbitrage opportunities during upward and downward trends.
文摘Sacred forests play a valuable role in the conservation of local biodiversity and provide numerous ecosystem services in Cameroon. The aim of this study was to estimate floristic diversity, stand structures and carbon stocks in the sacred forests of Bandrefam and Batoufam (western Cameroon). The floristic inventory and the stand structures were carried out in 25 m × 25 m plots for individuals with diameters greater than 10 cm;5 m × 5 m for individuals with diameters less than 10 cm. Carbon stocks were estimated using the non-destructive method and allometric equations. The floristic inventory identified 65 species divided into 57 genera and 30 families in the Bandrefam sacred forest and 45 species divided into 42 genera and 27 families in the Batoufam sacred forest. In the Bandrefam, the most important families are Phyllanthaceae (53.98%), Moraceae (21.69%), Lamiaceae (20.15%). At Batoufam, the most important families are Phyllanthaceae (39.73%), Fabaceae (28.47%), Araliaceae (23.77%). Malacantha alnifolia (55.14%), Vitex grandifolia (18.43%), Bosqueia angolensis (15.06%) were the most important species in Bandrefam. Otherwise, Malacantha alnifolia (28%), Polyscias fulva (22.73%), Psychotria sp. (21.28%) were the most important in Batoufam. The Bandrefam sacred forest has the highest tree density (2669 stems/ha). Total carbon stock is 484.88 ± 2.28 tC/ha at Batoufam and 313.95 ± 0.93 tC/ha at Bandrefam. The economic value varies between 5858.04 ± 27.62 USD/ha in Batoufam sacred forest and 3788.51 ± 11.26 USD/ha in Bandrefam sacred forest. The number of individuals and small-diameter trees has little influence on the carbon stocks in the trees. Medium-diameter trees store the most carbon, and very large-diameter trees, which are very poorly represented, store less carbon. In another way, wood density and the basal areas influence the carbon storage of the trees.
文摘Collaborative forest management (CFM) is a form of forest governance in which local communities are involved in the management and decision-making processes related to forest resources. It is believed that forests under such management are better in tree diversity and conservation status and thus hold more carbon stocks. The study assessed the impact of CFM on carbon stocks, tree species diversity & tree species density in Mabira Central Forest Reserve. Data were collected from plots that were systematically laid in the different purposively selected forest areas. The study findings show that there is no difference in stem density and carbon stocks between CFM and non-CFM areas. CFM areas had lower species richness compared to non-CFM areas. CFM areas, however, exhibited more species diversity than non-CFM areas. Climax colonization may favor a few dominant species over others, hence lowering species diversity despite the number of species being many in the understory, hence at the same time increasing species richness. Likewise, disturbance in CFM area may affect natural colonization and favor the emergency of many species either naturally or through assisted regeneration by reforestation, hence increasing diversity, whereas artificial selection of preferred species through harvesting may lower species richness, as observed. Recommendations for improving collaborative forest management (CFM) areas include implementing targeted interventions to enhance carbon sequestration, such as promoting reforestation and afforestation with high-carbon-storing species and strengthening monitoring and evaluation frameworks to assess carbon stock changes over time. Additionally, efforts should focus on enhancing biodiversity conservation by implementing more stringent protection measures and reducing human disturbance while encouraging community participation in biodiversity monitoring and conservation education.
基金Under the auspices of National Natural Science Foundation of China(No.42101393,41901375,52274166)Hebei Natural Science Foundation(No.D2022209005,D2023209008)Central Guided Local Science and Technology Development Fund Project of Hebei Province(No.236Z3305G,246Z4201G)Key Research and Development Program of Science and Technology Plan of Tangshan,China(No.22150221J)。
文摘Coastal wetlands are crucial for the‘blue carbon sink’,significantly contributing to regulating climate change.This study util-ized 160 soil samples,35 remote sensing features,and 5 geo-climatic data to accurately estimate the soil organic carbon stocks(SOCS)in the coastal wetlands of Tianjin and Hebei,China.To reduce data redundancy,simplify model complexity,and improve model inter-pretability,Pearson correlation analysis(PsCA),Boruta,and recursive feature elimination(RFE)were employed to optimize features.Combined with the optimized features,the soil organic carbon density(SOCD)prediction model was constructed by using multivariate adaptive regression splines(MARS),extreme gradient boosting(XGBoost),and random forest(RF)algorithms and applied to predict the spatial distribution of SOCD and estimate the SOCS of different wetland types in 2020.The results show that:1)different feature combinations have a significant influence on the model performance.Better prediction performance was attained by building a model using RFE-based feature combinations.RF has the best prediction accuracy(R^(2)=0.587,RMSE=0.798 kg/m^(2),MAE=0.660 kg/m^(2)).2)Optical features are more important than radar and geo-climatic features in the MARS,XGBoost,and RF algorithms.3)The size of SOCS is related to SOCD and the area of each wetland type,aquaculture pond has the highest SOCS,followed by marsh,salt pan,mud-flat,and sand shore.
基金financed by Debre Markose University Burie Campus.
文摘Agroforestry,as a platform for harmonizing agriculture and forestry is a win-win approach for the farming community and environmental sustainability.However,its potential is not well studied and quantified in Northwestern highland.Thus,this study aimed to investigate the woody species diversity,and carbon stock potential of traditional agroforestry practices in Northwestern Highlands(NWH)of Ethiopia.A total of 120 households were selected using stratified sampling for household(HH)surveys,and vegetation inventory was conducted in the winter season of 2023 on systematically laid 400 m2 sample quadrats.Shannon-Weiner diversity index(H’),Simpson’s diversity index(1-D)and Shannon evenness(E)were calculated to estimate woody species diversity.Variation in species diversity and carbon stock within and between agroforestry practices was assessed by 1-way ANOVA and rank differences were separated by post-hoc,Tukey HSD multiple comparison test.The result showed that four different agroforestry practices were identified,consisting of 44 woody species belonging to 23 families.Homegarden was the richest in terms of woody species composition(30),followed by boundary planting(25),while parkland agroforestry had the poorest species composition(12).The total carbon stock of the agroforestry practices in the study ranged from 92.51±29.21 to 143.52±47.83 Mg/ha),with soil organic carbon accounting for about 57.66%,followed by aboveground biomass carbon with 32.1%.Homegardens agroforestry had contributed more to the total carbon stocks than the other agroforestry practices.The total CO_(2)sequestration by above and below ground biomass of woody species in the traditional agroforestry practices of the NWH was estimated to be 519.97 and 104.01 Mg/ha,respectively.The study confirmed that the traditional agroforestry practices of the NWH of Ethiopia maintain a high diversity of woody species and are remarkably important for biodiversity conservation and climate change mitigation.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF1300203)the National Natural Science Foundation of China(Grant No.42371329s).
文摘Natural forests are the primary carbon sinks within terrestrial ecosystems,playing a crucial role in mitigating global climate change.China has successfully restored its natural forest area through extensive protective measures.However,the aboveground carbon(AGC)stock potential of China's natural forests remains considerably uncertain in spatial and temporal dynamics.In this study,we provide a spatially detailed estimation of the maximum AGC stock potential for China's natural forests by integrating high-resolution multi-source remote sensing and field survey data.The analysis reveals that China's natural forests could sequester up to 9.880.10 Pg C by 2030,potentially increasing to 10.460.11 Pg C by 2060.Despite this,the AGC sequestration rate would decline from 0.190.001 to 0.080.001 Pg C·yr^(-1)over the period.Spatially,the future AGC accumulation rates exhibit marked heterogeneity.The warm temperate deciduous broadleaf forest region with predominantly young natural forests,is expected to exhibit the most significant increase of 26.36%by 2060,while the Qinghai-Tibet Plateau Alpine region comprising mainly mature natural forests would exhibit only a 0.74%increase.To sustain the high carbon sequestration capacity of China's natural forests,it is essential to prioritize protecting mature forests alongside preserving and restoring young natural forest areas.
基金supported by the Key Science and Technology Project of Anhui Province,China(2023n06020056)the National Natural Science Foundation of China(32071628)the Colleges and Universities Science Foundation of Anhui Province,China(2024AH020002)。
文摘Although the application of straw decomposing microorganism inoculants(SDMI)can accelerate straw decomposition,the underlying mechanisms affecting soil organic carbon(SOC)under different scenarios remain unclear.We conducted a meta-analysis using 226 observations from 86 studies on SOC changes under straw return with or without SDMI applications.Overall,our results indicated that straw with SDMI application increased the SOC stock by 1.51%at an initial carbon-to-nitrogen ratio(ICNR)>25(P<0.05),while the effect of ICNR≤25was insignificant.In particular,at ICNR>25,application of SDMI-treated straw increased SOC stocks in northern temperate continental areas(NTC)higher than in subtropical monsoon regions(STM).Furthermore,the straw with SDMI application increased higher SOC stocks in soils with pH>7.5 than those with pH≤7.5.In terms of agricultural management practices,SOC stocks were significantly higher in straw buried(SB),the experimental duration of straw return(EDSR)≥1 year,the straw return amount(SRA)>6,000 kg ha^(–1),and the SDMI application rate(SDMIR)>30 kg ha^(–1)conditions.The effect of straw with SDMI on SOC stocks under straw burying(SB)was significantly higher than that under straw mulching(SM)at ICNR≤25.At ICNR>25,EDSR,SDMIR,and the mean annual precipitation(MAP)were the main drivers of the effect of SDMI addition to straw on SOC stocks.Straw with SDMI induced SOC stock increases which increased with EDSR and decreased with increasing MAP.These findings provide a scientific basis for decision-makers and stakeholders to improve soil C management via the application of SDMI-amended straw at both regional and large scales.
基金funded by the National Natural Science Foundation of China(4130161041501094+3 种基金41330858)the Key Research Program of the Chinese Academy of Sciences(KZZD-EW-04)the Natural Science Basic Research Plan in Shaanxi Province of China(2014JQ5170)the open foundation of State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau(A318009902-1510)
文摘In the last few decades, the Loess Plateau had experienced an extensive vegetation restoration to reduce soil erosion and to improve the degraded ecosystems. However, the dynamics of ecosystem carbon stocks with vegetation restoration in this region are poorly understood. This study examined the changes of carbon stocks in mineral soil （0-100 cm）, plant biomass and the ecosystem （plant and soil） following vegetation restoration with different models and ages. Our results indicated that cultivated land returned to native vegetation （natural restoration） or artificial forest increased ecosystem carbon sequestration. Tree plantation sequestered more carbon than natural vegetation succession over decades scale due to the rapid increase in biomass carbon pool. Restoration ages had different effects on the dynamics of biomass and soil carbon stocks. Biomass carbon stocks increased with vegetation restoration age, while the dynamics of soil carbon stocks were affected by sampling depth. Ecosystem carbon stocks consistently increased after tree plantation regardless of the soil depth; but an initial decrease and then increase trend was observed in natural restoration chronosequences with the soil sampling depth of 0-100 cm. Moreover, there was a time lag of about 15-30 years between biomass production and soil carbon sequestration in 0-100 cm, which indicated a long-term effect of vegetation restoration on deeper soil carbon sequestration.
文摘This work studied the effects of tree species composition on soil carbon storage in five mixed stands dominated by oriental beech and grown in the western Caspian region in Guilan province, called Astara, Asalem, Fuman, Chere and Shenrud. The thickness of the litter layer, soil characteristics, tree composition and percentage of canopy coverage were measured in each stand. Total soil organic carbon differed significantly by stand. Total （organic） carbon stores at Fuman, which had the lowest tree species richness with 2 species and least canopy coverage （75%）, were significantly （p〈0.05） higher than at other locations. Carbon stor-age in topsoil （0-10 cm） was significantly lower in Shenrud, which had the highest tree species richness with 5 species and highest canopy cov-erage （95%）. The high percentage of canopy coverage in Shenrud proba-bly limited the conversion of litter to humus. However, in the second soil layer （10-25 cm）, Asalem, with high tree species richness and canopy coverage, had the highest carbon storage. This can be explained by the different rooting patterns of different tree species. In the Hyrcanian forest. According to the results, it can be concluded that not only tree composi-tion but also canopy coverage percentage should be taken under consid-eration to manage soil carbon retention and release.
基金funding from the European Union Seventh Framework Program(FP7/2007–2013)under grant agreement n°244122support by a grant of the Romanian National Authority for Scientific Research,CNCS-UEFISCDI,project number PN-II-IDPCE-2011-3-0781support of the University of Antwerp Research Council through its Methusalem program
文摘Background: Forest management aims at obtaining a sustainable production of wood to be harvested to generate products or energy. However, the quantitative influence of forest management and of removals by harvest on biomass stocks has rarely been analysed on a large scale based on measurements. Two hypotheses prevail: management induces a reduction of wood stocks due to cuttings, versus no impact because of increased growth of the remaining trees. Using data collected for 2840 permanent plots across Romania from the National Forest Inventory representing^2.5 Mha, we have tested to what extent different management types and treatments can influence the biomass stock and productivity of beech forests, and attempt to quantify these effects both on the short and long terms. Three main types of beech forest management are implemented in Romania with specific objectives: intensive wood production in production forests, protection of ecosystem services (e.g. watersheds, avalanche protection) in protection forests, and protection of the forest and its biodiversity in protected forests. Production forests encompass two treatments differing according to the stand regeneration method: the age class rotation management and the group shelterwood management. Results: We show that forest management had little influence on the biomass stocks at a given stand age. The highest stocks at stand age 100 were observed in production forests (the most intensively managed forests). Consequences of early cuttings were very short-termed because the increase in tree growth rapidly compensated for tree cuttings. The cumulated biomass of production forests exceeded that of protected and protection forests. Regarding the treatment, the group shelterwood forests had a markedly higher production over a full rotation period. The total amount of deadwood was primarily driven by the amount of standing deadwood, and no management effect was detected. Conclusions: Given the relatively low-intensity management in Romania, forest management had no negative impact on wood stocks in beech forests biomass stocks at large scale. Stand productivity was very similar among management types or treatments. However cumulated biomass in production forests was higher than in protection or protected forests, and differed markedly according to treatments with a higher cumulated biomass in shelterwood forests.
基金Supported by the Natural Science Fundation of China (No. 30571445)Natural Science Fundation of Shandong Province of China
文摘Population genetics of the left-eyed flounder, Paralichthys olivaceus, including natural and cultured stocks distributed in the coastal waters near Qingdao of eastern maritime China, was analyzed in allozyme and RAPD. The results showed that among total 29 gene loci of 15 isozymes, 9 and 7 were po- lymorphic in natural and cultured stocks, respectively. The status of genetic diversity in P. olivaceus is low in terms of polymorphic loci in chi-square test and genetic departure index of Hardy-Weinberg equi- librium. More alleles in IDHP, CAT, GDH and Ldh-C allozymes were found in the fish, which could be used as markers in assortive breeding and distinguishing stock, population or species evolution. Total 88 and 86 RAPD bands ranging from 200 to 2 500 bp were recognized individually in average of 7.8–8.0 bands per primer. The genetic diversity in cultured stock is lower than that in natural ones showing an ob- viously decreasing genetic divergence. Therefore, effective countermeasures must be taken to protect ge- netic resources of marine cultured fishes. The 2 markers have their own pros and cons. Combining the 2 markers to investigate the genetic variation of populations is suggested. The results provide basic data of this flounder and they are useful for studying genetic improvement and genetic resources of the fish.
基金the Major Program of the National Fund of Philosophy and Social Science of China(Nos.21&ZD109).
文摘Mangrove ecosystems have important ecological and economic values,especially their ability to store carbon.However,in recent years,human disturbance has accelerated mangrove degradation.Among them,the emission of pollutants cannot be ignored.It is of great significance for carbon emission reduction and ecological protection to study the impacts of different pollutants on mangroves and their carbon stocks.Based on the remote sensing data of coastal areas south of the Yangtze River in China's Mainland,this paper builds the ensemble learning model Random Forest(RF)and Gradient Boosting Regression(GBR)to empirically analyse the relationship between industrial wastewater,industrial sulfur dioxide(SO2),PM2.5 and mangrove forests.The results show that the pollutant concentration of meteorological normalisation is more stable.The importance of pollutants presents regional heterogeneity.The area of mangroves in different cities and the corresponding total carbon stocks show different trends with the increase or decrease of pollutants,and there is a dynamic balance between urban pollutant discharge and mangrove growth in some cities.The research in this paper provides an analysis and explanation from the perspective of machine learning to explore the relationship between mangroves and pollutants and at the same time,provides scientific suggestions for the formulation of future pollutant emission policies in different cities.
基金supported by the Project of the Shanghai Science and Technology Committee(Grants No.08DZ1203200 and 08DZ1203205)
文摘Abstract： The water quality of Dianshan Lake in Shanghai Municipality, China, is impacted by nutrient losses from agricultural lands around the lake. In this study, nine types of agricultural land use were monitored in 2010 and 2011, and a correlation analysis between nutrient losses from agricultural non-point sources （NPS） and nutrient stocks in the lake was conducted over monthly and seasonal time periods. The results indicate that the monthly average concentration of total nitrogen （TN） ranged from 1.41 to 7.34 mg/L in 2010 and from 1.52 to 5.90 mg/L in 2011, while the monthly average concentration of total phosphorous （TP） ranged from 0.11 to 0.26 mg/L in 2010 and from 0.13 to 0.30 mg/L in 2011. The annual loss of TN from agricultural NPS was 195.55 tons in 2010 and 208.40 tons in 2011. The cultivation of water oat made the largest contribution to the loss of TN. The annual loss of TP was 44.58 tons in 2010 and 48.12 tons in 2011, and multi-vegetable cultivation made the largest contribution to the loss of TP. The results of correlation analysis show that the monthly stocks of TN and TP in the lake have a positive correlation with the monthly losses of TN and TP from agricultural NPS. According to the seasonal data, the stocks of TN and TP in the lake both have a much stronger correlation with the losses of TN and TP from agricultural NPS in summer than in other seasons. Agricultural NPS pollution control should be the main focus for the water resource conservation in this area.
文摘Changes in land use cover, particularly from forest to agriculture, is a major contributing factor in increasing carbon dioxide（CO2） level in the atmosphere.Using satellite images of 1999 and 2011, land use and land use changes in the Kumrat valley KPK, Pakistan, were determined： a net decrease of 11.56 and 7.46 % occurred in forest and rangeland, while 100 % increase occurred in agriculture land（AL）. Biomass in different land uses,forest land（FL）, AL, and range land（RL） was determined by field inventory. From the biomass data, the amount of carbon was calculated, considering 50 % of the biomass as carbon. Soil carbon was also determined to a depth of 0–15and 16–30 cm. The average carbon stocks（C stocks） in all land uses ranged from 28.62 ± 13.8 t ha-1in AL to486.6 ± 32.4 t ha-1in pure Cedrus deodara forest. The results of the study confirmed that forest soil and vegetation stored the maximum amount of carbon followed by RL. Conversion of FL and RL to AL not only leads to total loss of about 56 %（from FL conversion） and 37 %（RL conversion） of soil carbon in the last decades but also the loss of a valuable carbon sink. In order to meet the emissions reduction obligations of the Kyoto Protocol, Conservation of forest and RL in the mountainous regions of the Hindu Kush will help Pakistan to meet its emissions reduction goals under the Kyoto Protocol.
文摘Data Mining (DM) methods are being increasingly used in prediction with time series data, in addition to traditional statistical approaches. This paper presents a literature review of the use of DM with time series data, focusing on shorttime stocks prediction. This is an area that has been attracting a great deal of attention from researchers in the field. The main contribution of this paper is to provide an outline of the use of DM with time series data, using mainly examples related with short-term stocks prediction. This is important to a better understanding of the field. Some of the main trends and open issues will also be introduced.
基金funded by the Program for Public–Welfare Forestry of the State Forestry Administration of China(Grant No.201104008)
文摘Assessment of regional forest carbon stocks and underlying controls is critical for guiding forest management in the context of carbon sequestration. We investigated the variations in tree biomass carbon stocks relating to forest types, and estimated the total tree biomass carbon stocks and projected gains through natural stand development by 2020 and 2050 in the Daqing Mountain Nature Reserve based on Category II data of the Forest Inventory of Inner Mongolia for the period ending 2008. Over a total area of 388,577 ha,this nature reserve currently stores an estimated 2221 Gg C in tree aboveground biomass alone, with potential to grow by more than 30 % to reach 2938 Gg C by 2020 and nearly double to 4092 Gg C by 2050 through natural development of the existing forest stands. The tree biomass carbon density and potential gain in tree biomass carbon stocks vary markedly among forest types and with stand development.The variations in the potential change of tree biomass carbon density for the periods 2008–2020 and 2008–2050 among forest types partly reflect the varying relationships of tree biomass carbon density with stand age for different tree species, and partly are attributable to variations in the stand age structure among different forest types. Of the major forest types, the ranking of projected changes in tree biomass carbon density are not consistent with variations in the relationship between tree biomass carbon density and stand age, neither are they explainable by variations in stand age structures, implying the interactive effect between forest type and stand dynamics on temporal changes in tree biomass carbon density. Birch rank highest for future biomass carbon sequestration because of its dominance in cover area and better age structure for potential gain in tree biomass carbon stocks. Poplar and larch were out-performers compared to other forest types given their greater contribution to total tree biomass carbon stocks relative to their distributional areas. Findings in this study illustrate that protection and proper management of under-aged forests can deliver marked gains in biomass carbon sequestration. This is of great importance to policy-makers as well as to scientific communities in seeking effective solutions for adaptive forest management and mitigation of anthropogenic greenhouse gases emissions using forest ecosystems.
文摘The effects of apple dwarf stocks P22 and SH3 on the juvenile phase of Fuji seedlings were studied. The results showed that the juvenile phase could be shortened by more than two years when 2-year seedlings were grafted on the dwarf stocks. The effects of P22 and SH3 were significantly different. Grafted on P22, the flowering node was less, the first flowing site was lower, and the juvenile phase was shorter than SH3. With the two stocks, the average first flowering site was more than 200 cm, the average flowering node was more than 100, and the lateral branch top bud was more than 50% in all first flowing seedlings.
基金supported by Iranian Fisheries Research OrganizationTehran University
文摘Sturgeons are the most important principal market species in the Caspian Sea. In the present study, measurement of blood parameters was carried out with the aim of evaluating the normal value of hematological and serum biochemical parameters of brood stocks Acipenser persicus during spawning season. Blood samples were collected from 36 brood stocks of A. persicus（18 males and 18 females） during the spawning season. Higher value of red blood cells, white blood cells, haemoglobin, haematocrit was observed in male breeders with significant differences between female breeders（p〉0.05）. Haemoglobin and haematocrit value in this study was within the range of 8.70 to 9.2 g/d L and 29.73% to 30.26%, respectively. The statistically significant differences between mean corpuscular volumes, mean corpuscular haemoglobin, lymphocyte and neutrophil percentages, aspartate aminotransferase, alkaline phosphatase and creatine kinase were observed in the male and female brood stocks.It is concluded from this study, some of the hematological and serum biochemical parameters of male and female A. persicus breeders were significantly varied from each other. In comparative investigation with earlier reports,the values of red blood cells, haemoglobin and haematocrit are highly varied due to age variations of fish.However, further studies are necessary to understand the impact of sexual, age, size, length, and season and habitat variation. Serum biochemical parameters can be used for confirming the maturity of A. persicus and monitoring any changes in the water quality parameters and soil.
基金funded by a grant from the“Organisation pour la Conservation et le Developpement(OCD)”entitled“Forest Ecosystem Services”。
文摘Carbon is continuously being removed from the atmosphere by photosynthesis and stored in carbon pools(live,dead,and soil carbon)of forest ecosystems.However,carbon stock in dead wood and of trees with diameters at breast height(dbh)between 5 and 10 cm is often not considered in many studies carried out in the Congo Basin Forest.The relationship between tree diversity,life-forms and carbon stocks has received little attention.This study was carried out on the outskirts of Deng Deng National Park(DDNP)to determine tree diversity(dominant families,species richness and Shannon index),assess carbon stocks in the five carbon compartments(living tree,understory,fine roots,dead wood and litter)as well as to analyze the relationship between(1)carbon stocks and tree diversity;and,(2)between carbon stock and life-forms.The Shannon index of trees≥10 cm dbh ranged from 2.6 in riparian forest to 4.3 in secondary forest;and for the tree between 5 and 10 cm,it ranged to 1.56 in riparian forest to 3.68 in the secondary forest.The study site housed 16 species,7 genera and 3 families which are only found in trees of dbh between 5 and 10 cm.The average total carbon stock of the five compartments varied from 200.1 t ha-1 in forest residues to 439.1 t ha-1 in secondary forest.Dead wood carbon stock varied from 1.2 t ha-1 in riparian forests to 12.51t ha-1 in agroforests.The above ground carbon stocks for trees with diameter between 5 and 10 cm varied from 0.7 t ha-1 in young fallow fields to 5.02 t ha-1 in old secondary forests.This study reveals a low but positive correlation between species richness and total carbon stocks,as well as a significant positive relationship between life-forms and total carbon stocks.The findings highlight the need for more data concerning carbon content of dead wood,carbon of trees≥5 cm<10 cm dbh and the relationship between carbon stocks and tree diversity from other areas of the Congo Basin for a good understanding of the contribution of tropical forests to climate change mitigation.
