Background： Estimation of tree diversity at broader scale is important for conservation planning. Tree diversity should be measured and understood in terms of diversity and evenness, two integral components to descri...Background： Estimation of tree diversity at broader scale is important for conservation planning. Tree diversity should be measured and understood in terms of diversity and evenness, two integral components to describe the structure of a biological community. Variation of the tree diversity and evenness with elevation, topographic relief, aspect, terrain shape, slope, soil nutrient, solar radiation etc. are well documented. Methods： Present study explores the variation of tree diversity （measured as Shannon diversity and evenness indices） of Majella National Park, italy with five available forest types namely evergreen oak woods, deciduous oak woods, blacWaleppo pine stands, hop-hornbeam forest and beech forest, using satellite, environmental and field data. Results： Hop-hornbeam forest was found to be most diverse and even while evergreen Oak woods was the lowest diverse and even. Diversity and evenness of forest types were concurrent to each other i.e. forest type which was more diverse was also more even. As a broad pattern, majority portion of the study area belonged to medium diversity and high evenness class. Conclusions： Satellite images and other GIS data proved useful tools in monitoring variation of tree diversity and evenness across various forest types. Present study findings may have implications in prioritizing conservation zones of high tree diversity at Majella.展开更多
In this paper,the relations between the parameters of stitch structure and the needle penetra-tion force,and the method by using the needle penetration force detected to evaluate the looplength and evenness of knitted...In this paper,the relations between the parameters of stitch structure and the needle penetra-tion force,and the method by using the needle penetration force detected to evaluate the looplength and evenness of knitted fabric indirectly are analysed and discussed.A microcomputer system with a needle sensor and author’s program are used as a pick up setcombined with a data analysis system,for sampling and analysing the needle penetration forcedata.A lot of experimental research work has been done for knitted fabric of some kinds of knittedstitch and loop length.As a summary of this study,some conclusions can be drawn from the linearregression between the needle penetration force and the loop length.Then,the size and evenness ofthe loop length of knitted fabric can be indicated indirectly by detecting the value and variance ofneedle penetration force.It offers an effective method to detect and evaluate the evenness of knit-ted fabric with an efficiently high speed.展开更多
Parameters influencing the evenness of the woollen cashmere yarn were analyzed, and fifty batches of yams with fineness of 38.5 tex were used to study the quality control parameters in relation to the evenness. Throug...Parameters influencing the evenness of the woollen cashmere yarn were analyzed, and fifty batches of yams with fineness of 38.5 tex were used to study the quality control parameters in relation to the evenness. Through statistical analysis, the models of yarn evenness were built. Moreover, the relationship between the evenness of spinning yarn and roving yarn was also investigated. The results showed that a positive correlation existed between them, and the mount of thin place per kilometer was the most important factor which could influence the evenness of woollen cashmere yam. The influence of the amount of neps and thick place on the yam evenness was indistinctive. The conclusions obtained would be helpful to improve the precontrol ability on yarn evenness.展开更多
Plant species diversity is one of the most widely used indicators in ecosystem management.The relation of species diversity with the size of the sample plot has not been fully determined for Oriental beech forests(Fag...Plant species diversity is one of the most widely used indicators in ecosystem management.The relation of species diversity with the size of the sample plot has not been fully determined for Oriental beech forests(Fagus orientalis Lipsky),a widespread species in the Hyrcanian region.Assessing the impacts of plot size on species diversity is fundamental for an ecosystem-based approach to forest management.This study determined the relation of species diversity and plot size by investigating species richness and abundance of both canopy and forest floor.Two hundred and fifty-six sample plots of 625 m^(2) each were layout in a grid pattern across 16 ha.Base plots(25 m×25 m)were integrated in different scales to investigate the effect of plot size on species diversity.The total included nine plots of 0.063,0.125,0.188,0.250,0.375,0.500,0.563,0.750 and 1 ha.Ten biodiversity indices were calculated.The results show that species richness in the different plot sizes was less than the actual value.The estimated value of the Simpson species diversity index was not significantly different from actual values for both canopy and forest floor diversity.The coefficient of variation of this index for the 1-ha sample plot showed the lowest amount across different plot sizes.Inverse Hill species diversity was insignificant difference across different plot sizes with an area greater than 0.500 ha.The modified Hill evenness index for the 1-ha sample size was a correct estimation of the 16-ha for both canopy and forest floor;however,the precision estimation was higher for the canopy layer.All plots greater than 0.250-ha provided an accurate estimation of the Camargo evenness index for forest floor species,but was inaccurate across different plot sizes for the canopy layer.The results indicate that the same plot size did not have the same effect across species diversity measurements.Our results show that correct estimation of species diversity measurements is related to the selection of appropriate indicators and plot size to increase the accuracy of the estimate so that the cost and time of biodiversity management may be reduced.展开更多
To explore the factors controlling human activity in Northeast Asia during the last deglaciation,this study synthesizes six pollen records from lakes and peatlands,alongside four paleotemperature records from terrestr...To explore the factors controlling human activity in Northeast Asia during the last deglaciation,this study synthesizes six pollen records from lakes and peatlands,alongside four paleotemperature records from terrestrial sedimentary sequences in this region.We simulated potential hunter-gatherer population densities using the Minimalist Terrestrial Resource Model(MTRM),and calculated vegetation openness,rate of change,and evenness based on pollen data.The results reveal a direct relationship between plant resources and hunter-gatherer populations from 20.9 to 10.2 ka BP.The synchronous increases in plant resources and population density from the Last Glacial(LG)to the B?lling-Aller?d(BA)warm period,as well as from the Younger Dryas(YD)to the early Holocene(EH),with stasis during the YD,suggest that resource availability was a key driver of human activity.Redundancy analysis(RDA)of pollen and paleotemperature records indicated that vegetation and plant resources were more closely linked to the mean annual air temperature,with winter characteristics,from the LG to the YD,whereas warm-season temperatures played a more significant role during the EH.This research emphasizes that variations in resource accessibility,rather than direct climate effects alone,were likely pivotal in shaping human activity responses to environmental changes.展开更多
Pavements are 3D in their shape. They can be captured in three dimensions by modern road mapping equipment which allows for the assessment of pavement evenness in a more holistic way as opposed to current practice whi...Pavements are 3D in their shape. They can be captured in three dimensions by modern road mapping equipment which allows for the assessment of pavement evenness in a more holistic way as opposed to current practice which divides into longitudinal and transversal evenness. It makes sense to use 3D vehicle models to simulate the effects of 3D surface data on certain functional criteria like pavement loading, cargo loading and driving comfort. In order to evaluate the three criteria mentioned two vehicle models have been created： a passenger car used to assess driving comfort and a truck-semitrailer submodel used to assess pavement and cargo loading. The vehicle models and their application to 3D surface data are presented. The results are well in line with existing single-track （planar） models. Their advantage over existing 1D/2D models is demonstrated by the example of driving comfort evaluation. Existing ＂geometric＂ limit values for the assessment of longi- tudinal evenness in terms of the power spectral density could be used to establish corre- sponding limit values for the dynamic response, i.e. driving comfort, pavement loading and cargo loading. The limit values are well in line with existing limit values based on planar vehicle models. They can be used as guidelines for the proposal of future limit values. The investigations show that the use of 3D vehicle models is an appropriate and meaningful way of assessing 3D evenness data gathered by modern road mapping systems.展开更多
The crevice corrosion of the reinforcing steel in the carbonated simulated concrete pore solutions(SCPSs)containing 0.04 mol/L chloride was investigated.In comparison,the steel without crevice covered on its surface w...The crevice corrosion of the reinforcing steel in the carbonated simulated concrete pore solutions(SCPSs)containing 0.04 mol/L chloride was investigated.In comparison,the steel without crevice covered on its surface was also studied.Results showed that the crevice corrosion in the uncarbonated SCPS was not triggered and the steel remained passivity by suppressing the anodic dissolution in the crevice interior.As SCPS was carbonated to have pH values of 10.5 and 11.5,the crevice corrosion was easier to be activated than the widely reported pitting corrosion owing to the rapid oxygen depletion within the crevice,but the crevice corrosion damage might be alleviated to a certain extent due to the relative compact surface film formed inside the crevice.The further carbonation led to the activation dissolution of both the crevice interior and exterior,causing the more serious corrosion damage.Corrosion process of the crevice corrosion was systematically analyzed by combining the electrochemical measurement results and Evens polarization diagram.展开更多
Heavy metal pollution poses a serious hazard to human health,and microbial remediation of heavy metals in soil has been widely studied.A group of ascomycetes classified as dark septate endophytes(DSEs)colonize plant r...Heavy metal pollution poses a serious hazard to human health,and microbial remediation of heavy metals in soil has been widely studied.A group of ascomycetes classified as dark septate endophytes(DSEs)colonize plant roots and benefit host plants under abiotic stress conditions.In this study,Phragmites australis,a common remediation plant in the Baiyang Lake in North China,was investigated.Soils and roots of P.australis were collected in typical heavy metal-contaminated sites,and the species diversity and community structure of DSEs in P.australis roots were studied.In addition,DSE strains were isolated,cultured,and tested for their tolerance to Cd stress.The results showed that DSEs occurred extensively in P.australis roots,forming typical dark septate hyphae,with a total colonization rate of 19.7%–83.1%.Morphological and internal transcribed spacer sequencing analyses were used to identify 10 species within 9 genera of DSE fungi.Among these fungi,6 strains with considerable resistance to Cd stress were identified.The biomasses of Poaceascoma helicoides,Alternaria doliconidium,and Acrocalymma vagum strains increased as the Cd levels increased.These results can not only help to understand plant-DSE interactions in wetland environments,but also provide a theoretical basis for making full use of DSE fungi to alleviate heavy metal contamination in soil.展开更多
Habitat quality is an important indicator for evaluating the quality of ecosystem.The Qinghai Province section of the Yellow River Basin plays an important role in the ecological protection of the upper reaches of the...Habitat quality is an important indicator for evaluating the quality of ecosystem.The Qinghai Province section of the Yellow River Basin plays an important role in the ecological protection of the upper reaches of the Yellow River Basin.To comprehensively analysis the alterations of habitat quality in the Qinghai Province section of the Yellow River Basin,this study utilized the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model to calculate the habitat quality index and analyze the spatio-temporal variation characteristics of habitat quality in the study area from 2000 to 2022,and calculated seven landscape pattern indices(number of patches,patch density,largest patch index(LPI),landscape shape index(LSI),contagion index(CONTAG),Shannon diversity index,and Shannon evenness index)to research the variation of landscape pattern in the study area.The results showed that the number of patches,patch density,LPI,LSI,Shannon diversity index,and Shannon evenness index increased from 2000 to 2022,while the CONTAG decreased,indicating that the landscape pattern in the Qinghai Province section of the Yellow River Basin changed in the direction of distribution fragmentation,shape complexity,and heterogeneity.The average value of the habitat quality index in the Qinghai Province section of the Yellow River Basin from 2000 to 2022 was 0.90.Based on the value of habitat quality index,we divided the level of habitat quality into five categories:lower(0.00-0.20),low(0.20-0.40),moderate(0.40-0.60),high(0.60-0.80),and higher(0.80-1.00).Most areas were at the higher habitat quality level.The lower habitat quality patches were mainly distributed in Longyang Gorge and Yellow River-Huangshui River Valley.From 2000 to 2022,the habitat quality in most areas was stable;the increase areas were mainly distributed in Guinan County,while the decrease areas were mainly distributed in Xining City,Maqen County,Xinghai County,Qumarleb County,and Darlag County.To show the extent of habitat quality variation,we calculated Sen index.The results showed that the higher habitat quality area had a decrease trending,while other categories had an increasing tendency,and the decreasing was faster than increasing.The research results provide scientific guidance for promoting ecological protection and high-quality development in the Qinghai Province section of the Yellow River Basin.展开更多
Mao抏rshan region is a representative natural secondary forested region in the eastern mountainous region, north-east of China. Under the support of ARC/INFO, the landscape pattern and landscape diversity of Maoerhsha...Mao抏rshan region is a representative natural secondary forested region in the eastern mountainous region, north-east of China. Under the support of ARC/INFO, the landscape pattern and landscape diversity of Maoerhshan region were studied by combining the forest type map (1:10000), which was drawn from the aerial photographs (1999), field investigation and land utilization map (1:10000). The selected indices included patch number, patch size, patch density index, richness index, dominance index, evenness index and diversity index. The results showed that the landscape dominant forest type in Mao抏rshan region was softwood broad-leaved forest. In all landscape types, the average patch area of natural secondary for-ests was bigger than that of artificial forest. The patch density index of each landscape formed in artificial forest was higher than that of natural secondary forest. The landscape diversity index and landscape evenness index of natural forest were highest, the landscape heterogeneity was also, but the landscape dominance was lower. In natural forest, the control effects of landscape elements on landscape-structure, function and its change were weakened. The artificial forest was on the contrary.展开更多
The research took different forest communities in Wenchang Satellite Launch Center as the research object and selected 8 forests to explore species diversity, evenness, and dominance of forests. The results showed tha...The research took different forest communities in Wenchang Satellite Launch Center as the research object and selected 8 forests to explore species diversity, evenness, and dominance of forests. The results showed that species diversity tended to be volatile upon forest communities; semi-mangrove species was the richest, as high as 2.38, followed by natural secondary forest and mixed forests. Plant evenness from high to low was as follows： herbaceous layer〉shrub layer〉tree layer. Natural secondary forest was higher in canopy density, and fewer in herbaceous plants; diversity and evenness were lower than shrub layer. Mangrove forests held lower dominance, and dominance showed insignificant differences among species.展开更多
Topography is the most factor that has the greatest impact of all factor that affect the distribution. To study the diversity of trees and shrub species in the Perc forest situated in Khorramabad, Lorestan, 140 circul...Topography is the most factor that has the greatest impact of all factor that affect the distribution. To study the diversity of trees and shrub species in the Perc forest situated in Khorramabad, Lorestan, 140 circular plots of 1200 m2 in a grid of 300 m × 250 m were surveyed, using a systematic random sampling method. In each plot, the Margalef richness index, Shannon-Wiener diversity index, Hill＇s N1 and Simpson indices and the evenness index of Simpson and Smith-Wilson were calculated and ordered on the basis of different classes of elevation, exposition and slope. The results indicated that slope did not have any significant effect on the indices. Exposition and elevation classes significant impacted the richness and diversity indices, but did not influence evenness. In general, the highest plant diversity was observed for slopes less than 15 %, northern aspects, without geographical direction, and elevations of 2100-2200 m. This information can be very useful in achieving the goals for sustainable management of forests. In addition to greater protection for regions with high diversity and reforestation （compatible species） in degraded area, we can help increase diversity in forests.展开更多
The concept of pedodiversity and its measurement methodology proposed and developed by Ibá?ez research term is introduced. An attempt to apply pedodiversity to analyze spatial soil variation and distribution patt...The concept of pedodiversity and its measurement methodology proposed and developed by Ibá?ez research term is introduced. An attempt to apply pedodiversity to analyze spatial soil variation and distribution patterns on the global scale is briefly demonstrated. Furthermore, constructive comments and criticisms on pedodiversity and its measurement from the noted pedologists and ecologists are outlined. Finally, potential applications of pedodiversity in soil science and other relevant disciplines are discussed.展开更多
[Objective] The diversity of soil erosion in the Meixi River watershed of the Three Gorges Reservoir Region was analyzed, in order to provide references for governance and protection of ecological environment of the s...[Objective] The diversity of soil erosion in the Meixi River watershed of the Three Gorges Reservoir Region was analyzed, in order to provide references for governance and protection of ecological environment of the study area. [Method] The soil erosion diversity index and evenness index of the Meixi River watershed in the Three Gorges Reservoir Region were studied based on the TM images in the year of 1988, 1999 and 2010, supported by GIS technology to extract various types of soil erosion in the area with different slope gradients and calculate soil erosion di- versity index and evenness index. [Result~ As slope gradients grew, the diversity in- dex and evenness index of soil erosion decrease after increasing with a turning point from 25~ to 35~. [Conchlsion] The proportion of light-erosion in the study area is 15.57%. Hence, the increase of diversity index and evenness index with gradients of 5^-35~ shows that the higher erosion intensity, the more uniform erosion types and the indexes decreased in gradients higher than 35°, suggesting that the lower erosion intensity, the better environment. Distribution and variation of different land types have close relation with soil erosion diversity and evenness indexes. Though soil erosion problems have been alleviated, by comparing soil erosion diversity index and evenness index, it can be concluded that changes of indexes are lower than 0.02, and soil erosion should be continued to be well controlled.展开更多
With the rapid development of economy and increase of population in the drainage areas, the nutrient loading has increased dramatically in the Changjiang estuary and adjacent coastal waters. To properly assess the imp...With the rapid development of economy and increase of population in the drainage areas, the nutrient loading has increased dramatically in the Changjiang estuary and adjacent coastal waters. To properly assess the impact of nutrient enrichment on phytoplankton community, seasonal microcosm experiments were conducted during August 2010-July 2011 in the coastal waters of Zhejiang Province. The results of the present study indicated that the chl a concentration, cell abundance, diversity indices, species composition and community succession of the phytoplankton varied significantly with different N/P ratios and seasons. Higher growth was observed in the 64：1 （spring）, 32：1 （summer）, 16：1 （autumn） and 128：1,256：1 （winter） treatments, respectively. The values of Shannon-Wiener index （H） and Pielou evenness index （J） were lower in the 8：1 and 16：1 treatments in autumn test, while H value was higher in the 128：1 and 8：1 treatments in winter test. A definite community succession order from diatoms to dinoflagel lares was observed in the autumn and winter tests, while the diatoms dominated the community throughout the culture in the spring and summer tests.展开更多
Plant diversity plays key ecological roles in forest ecosystems, including influencing succession, resilience and nutrient cycling. This study was conducted to investigate the effect of livestock grazing and human use...Plant diversity plays key ecological roles in forest ecosystems, including influencing succession, resilience and nutrient cycling. This study was conducted to investigate the effect of livestock grazing and human uses on herbaceous species diversity. We surveyed 50 ha of protected area and 50 ha of unprotected area to evaluate herbaceous species diversity in oriental beech （Fagus orientalis Lipsky） forests in northern Iran. We calculated and compared three indices each of diversity and evenness, and species richness between the two areas. Herbaceous cover was higher in the unprotected area while leaf litter depth and tree canopy cover were higher in the protected area. The diversity indices, H （Shan- non-Wiener index ）, N~ （McArthur index）, N2 （Hill＇s index）, EQ （Modified Nee index）, E,ar （Smith-Wilson index）, E5 （modified index of Hill） and R=S （species richness） and species richness R=S were greater in the protected area than in the unprotected area, suggesting that protection from grazing results in increased numbers of plants and species. The effect of land protection on plant diversity was more pronounced for evenness than for species richness and the positive correlation between diversity and evenness indices was higher than that between diversity and richness.展开更多
The finfish and shellfish resources were assessed quantitatively and qualitatively in regard to their abundance in creek waters at three sites within a period of two years, fi＇om January 1999 to December 2000, in the...The finfish and shellfish resources were assessed quantitatively and qualitatively in regard to their abundance in creek waters at three sites within a period of two years, fi＇om January 1999 to December 2000, in the western mangrove areas of Kachchh. The catch rate varied from 0.69 to 6.99kg·h^-1. It was low during monsoon （July to October）, which could be due to the freshwater-flow-induced salinity reduction in all the sites. Among 38 species recorded, 5 were shellfish and 33 were finfish. The spawning period of fishes was found to be during summer and early monsoon period （May to August）. Surface water temperatures varied from 17℃ to 37 ℃. Salinity values varied from 34 to 44 and the pH ranged between 7 and 8.9. Variation in dissolved oxygen content was from 3.42 to 5.85 mL L^-1. The high fishery densities in these semi arid mangrove creek areas were recorded during monsoon and early winter season.展开更多
Fire and pre-or post-fire management practices shape the distribution and richness of plant species.Here,the effects of pre-and post-fire management on vegetation recovery were studied at different times,up to 18 mont...Fire and pre-or post-fire management practices shape the distribution and richness of plant species.Here,the effects of pre-and post-fire management on vegetation recovery were studied at different times,up to 18 months after a wildfire.Two months after a 2015 wildfire,18 study plots were established(three 4-m^2 plots for each treatment),vegetation regrowth was monitored and vegetal species richness(S),evenness(IT),density(D),diversity(H0)and maximum diversity(HMax)after 2,10 and 18 months.The treatments were(1)control,unaffected by 2015 wildfire;(2)no treatment(NT),burned in 2015 wildfire and not managed;(3)managed in 2005 and burned in 2015(M05B);(4)managed in 2015,2 months before wildfire(M15B);(5)cut and manual removal after the 2015 wildfire(CR);(6)cut and no trunk removal randomly deposited on topsoil after the 2015 wildfire(CL).All the treatments were carried out in a Pinus halepensis Miller forest.At 10 and 18 months after the wildfire,vegetation recovery was greater in NT,CR and CL plots than in M05B and M15B the plots.By 18 months after the wildfire,Brachypodium retusum(Pers.)P.Beauv.and Rosmarinus officinalis L.were still dominant,especially in M15B,corroborating the belief that pre-fire treatment reduced ecosystem resilience and vegetal recovery compared to the NT and post-fire managed plots.Richness was significantly lower 10 months after wildfire in control plots,and IT was significantly higher in that inventory than previously in M15B.Eighteen months after the wildfire,H0 was significantly lower in M15B.Ten months post-wildfire,HMax was significantly lower in the control plots.Eighteen months after the wildfire,HMax,was significantly higher in CR,CL and M05B than in the control and M15B plots.Overall,pre-fire management was detrimental to post-fire vegetation recovery,while manual post-fire management proved beneficial.展开更多
Five indices of species richness, species diversity and species evenness were used to assess a diversity of four types of coniferous forests undergone different artificial regeneration time. The study was based on the...Five indices of species richness, species diversity and species evenness were used to assess a diversity of four types of coniferous forests undergone different artificial regeneration time. The study was based on the vertical structure of forests, involving growth-forms of total plants as well as vertical layers of woody plants. The results showed that, except for the fourth layer of woody plants, the vertical structure of the four forests exhibited significant difference in terms of their species richness, species diversity and species evenness, suggesting that a species diversity index provided more detailed information and was a better index reflecting the regeneration processes in this region. It was recommended that silvicultural management of artificially regenerated forests should be strengthened to conserve the biodiversity of the forests, optimize forest structure and, in the long run, promote sustainable development of forest ecosystems.展开更多
文摘Background： Estimation of tree diversity at broader scale is important for conservation planning. Tree diversity should be measured and understood in terms of diversity and evenness, two integral components to describe the structure of a biological community. Variation of the tree diversity and evenness with elevation, topographic relief, aspect, terrain shape, slope, soil nutrient, solar radiation etc. are well documented. Methods： Present study explores the variation of tree diversity （measured as Shannon diversity and evenness indices） of Majella National Park, italy with five available forest types namely evergreen oak woods, deciduous oak woods, blacWaleppo pine stands, hop-hornbeam forest and beech forest, using satellite, environmental and field data. Results： Hop-hornbeam forest was found to be most diverse and even while evergreen Oak woods was the lowest diverse and even. Diversity and evenness of forest types were concurrent to each other i.e. forest type which was more diverse was also more even. As a broad pattern, majority portion of the study area belonged to medium diversity and high evenness class. Conclusions： Satellite images and other GIS data proved useful tools in monitoring variation of tree diversity and evenness across various forest types. Present study findings may have implications in prioritizing conservation zones of high tree diversity at Majella.
文摘In this paper,the relations between the parameters of stitch structure and the needle penetra-tion force,and the method by using the needle penetration force detected to evaluate the looplength and evenness of knitted fabric indirectly are analysed and discussed.A microcomputer system with a needle sensor and author’s program are used as a pick up setcombined with a data analysis system,for sampling and analysing the needle penetration forcedata.A lot of experimental research work has been done for knitted fabric of some kinds of knittedstitch and loop length.As a summary of this study,some conclusions can be drawn from the linearregression between the needle penetration force and the loop length.Then,the size and evenness ofthe loop length of knitted fabric can be indicated indirectly by detecting the value and variance ofneedle penetration force.It offers an effective method to detect and evaluate the evenness of knit-ted fabric with an efficiently high speed.
文摘Parameters influencing the evenness of the woollen cashmere yarn were analyzed, and fifty batches of yams with fineness of 38.5 tex were used to study the quality control parameters in relation to the evenness. Through statistical analysis, the models of yarn evenness were built. Moreover, the relationship between the evenness of spinning yarn and roving yarn was also investigated. The results showed that a positive correlation existed between them, and the mount of thin place per kilometer was the most important factor which could influence the evenness of woollen cashmere yam. The influence of the amount of neps and thick place on the yam evenness was indistinctive. The conclusions obtained would be helpful to improve the precontrol ability on yarn evenness.
基金funded by Gorgan University of Agricultural Sciences and Natural Resources(grant number 9318124503).
文摘Plant species diversity is one of the most widely used indicators in ecosystem management.The relation of species diversity with the size of the sample plot has not been fully determined for Oriental beech forests(Fagus orientalis Lipsky),a widespread species in the Hyrcanian region.Assessing the impacts of plot size on species diversity is fundamental for an ecosystem-based approach to forest management.This study determined the relation of species diversity and plot size by investigating species richness and abundance of both canopy and forest floor.Two hundred and fifty-six sample plots of 625 m^(2) each were layout in a grid pattern across 16 ha.Base plots(25 m×25 m)were integrated in different scales to investigate the effect of plot size on species diversity.The total included nine plots of 0.063,0.125,0.188,0.250,0.375,0.500,0.563,0.750 and 1 ha.Ten biodiversity indices were calculated.The results show that species richness in the different plot sizes was less than the actual value.The estimated value of the Simpson species diversity index was not significantly different from actual values for both canopy and forest floor diversity.The coefficient of variation of this index for the 1-ha sample plot showed the lowest amount across different plot sizes.Inverse Hill species diversity was insignificant difference across different plot sizes with an area greater than 0.500 ha.The modified Hill evenness index for the 1-ha sample size was a correct estimation of the 16-ha for both canopy and forest floor;however,the precision estimation was higher for the canopy layer.All plots greater than 0.250-ha provided an accurate estimation of the Camargo evenness index for forest floor species,but was inaccurate across different plot sizes for the canopy layer.The results indicate that the same plot size did not have the same effect across species diversity measurements.Our results show that correct estimation of species diversity measurements is related to the selection of appropriate indicators and plot size to increase the accuracy of the estimate so that the cost and time of biodiversity management may be reduced.
基金National Key Research and Development Program of China,No.2020YFA0607700,No.2023YFF0804702National Natural Science Foundation of China,No.T2192954,No.42030507,No.42372352。
文摘To explore the factors controlling human activity in Northeast Asia during the last deglaciation,this study synthesizes six pollen records from lakes and peatlands,alongside four paleotemperature records from terrestrial sedimentary sequences in this region.We simulated potential hunter-gatherer population densities using the Minimalist Terrestrial Resource Model(MTRM),and calculated vegetation openness,rate of change,and evenness based on pollen data.The results reveal a direct relationship between plant resources and hunter-gatherer populations from 20.9 to 10.2 ka BP.The synchronous increases in plant resources and population density from the Last Glacial(LG)to the B?lling-Aller?d(BA)warm period,as well as from the Younger Dryas(YD)to the early Holocene(EH),with stasis during the YD,suggest that resource availability was a key driver of human activity.Redundancy analysis(RDA)of pollen and paleotemperature records indicated that vegetation and plant resources were more closely linked to the mean annual air temperature,with winter characteristics,from the LG to the YD,whereas warm-season temperatures played a more significant role during the EH.This research emphasizes that variations in resource accessibility,rather than direct climate effects alone,were likely pivotal in shaping human activity responses to environmental changes.
基金conducted as part of a research project funded by the German Federal Ministry of Transport and Digital Infrastructure (No. FE 04.0248/2011/DGB)
文摘Pavements are 3D in their shape. They can be captured in three dimensions by modern road mapping equipment which allows for the assessment of pavement evenness in a more holistic way as opposed to current practice which divides into longitudinal and transversal evenness. It makes sense to use 3D vehicle models to simulate the effects of 3D surface data on certain functional criteria like pavement loading, cargo loading and driving comfort. In order to evaluate the three criteria mentioned two vehicle models have been created： a passenger car used to assess driving comfort and a truck-semitrailer submodel used to assess pavement and cargo loading. The vehicle models and their application to 3D surface data are presented. The results are well in line with existing single-track （planar） models. Their advantage over existing 1D/2D models is demonstrated by the example of driving comfort evaluation. Existing ＂geometric＂ limit values for the assessment of longi- tudinal evenness in terms of the power spectral density could be used to establish corre- sponding limit values for the dynamic response, i.e. driving comfort, pavement loading and cargo loading. The limit values are well in line with existing limit values based on planar vehicle models. They can be used as guidelines for the proposal of future limit values. The investigations show that the use of 3D vehicle models is an appropriate and meaningful way of assessing 3D evenness data gathered by modern road mapping systems.
基金supported by the Fundamental Research Program of Shanxi Province(Grant Nos.202203021222188 and 202303021211166)Scientific Research Fund of Taiyuan University of Science and Technology(Grant No.20222073)+1 种基金Award Fund for Outstanding Doctors in Shanxi Province(Grant No.20232047)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(Grant No.2022L280).
文摘The crevice corrosion of the reinforcing steel in the carbonated simulated concrete pore solutions(SCPSs)containing 0.04 mol/L chloride was investigated.In comparison,the steel without crevice covered on its surface was also studied.Results showed that the crevice corrosion in the uncarbonated SCPS was not triggered and the steel remained passivity by suppressing the anodic dissolution in the crevice interior.As SCPS was carbonated to have pH values of 10.5 and 11.5,the crevice corrosion was easier to be activated than the widely reported pitting corrosion owing to the rapid oxygen depletion within the crevice,but the crevice corrosion damage might be alleviated to a certain extent due to the relative compact surface film formed inside the crevice.The further carbonation led to the activation dissolution of both the crevice interior and exterior,causing the more serious corrosion damage.Corrosion process of the crevice corrosion was systematically analyzed by combining the electrochemical measurement results and Evens polarization diagram.
基金supported by the National Natural Science Foundation of China(Nos.31800345 and 31770561)the National Science Foundation of Hebei Province,China(Nos.C2020201043 and 22E50029D)+1 种基金the Natural Science Interdisciplinary Research Program of Hebei University,China(No.DXK202311)the Post-graduate’s Innovation Fund Project of Hebei Province,China(No.CXZZSS2023010)。
文摘Heavy metal pollution poses a serious hazard to human health,and microbial remediation of heavy metals in soil has been widely studied.A group of ascomycetes classified as dark septate endophytes(DSEs)colonize plant roots and benefit host plants under abiotic stress conditions.In this study,Phragmites australis,a common remediation plant in the Baiyang Lake in North China,was investigated.Soils and roots of P.australis were collected in typical heavy metal-contaminated sites,and the species diversity and community structure of DSEs in P.australis roots were studied.In addition,DSE strains were isolated,cultured,and tested for their tolerance to Cd stress.The results showed that DSEs occurred extensively in P.australis roots,forming typical dark septate hyphae,with a total colonization rate of 19.7%–83.1%.Morphological and internal transcribed spacer sequencing analyses were used to identify 10 species within 9 genera of DSE fungi.Among these fungi,6 strains with considerable resistance to Cd stress were identified.The biomasses of Poaceascoma helicoides,Alternaria doliconidium,and Acrocalymma vagum strains increased as the Cd levels increased.These results can not only help to understand plant-DSE interactions in wetland environments,but also provide a theoretical basis for making full use of DSE fungi to alleviate heavy metal contamination in soil.
基金supported by the Demonstration Project of Integrated Ecological Rehabilitation Technology for Key Soil and Water Erosion Areas in the Yellow River Valley(2021-SF-134).
文摘Habitat quality is an important indicator for evaluating the quality of ecosystem.The Qinghai Province section of the Yellow River Basin plays an important role in the ecological protection of the upper reaches of the Yellow River Basin.To comprehensively analysis the alterations of habitat quality in the Qinghai Province section of the Yellow River Basin,this study utilized the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model to calculate the habitat quality index and analyze the spatio-temporal variation characteristics of habitat quality in the study area from 2000 to 2022,and calculated seven landscape pattern indices(number of patches,patch density,largest patch index(LPI),landscape shape index(LSI),contagion index(CONTAG),Shannon diversity index,and Shannon evenness index)to research the variation of landscape pattern in the study area.The results showed that the number of patches,patch density,LPI,LSI,Shannon diversity index,and Shannon evenness index increased from 2000 to 2022,while the CONTAG decreased,indicating that the landscape pattern in the Qinghai Province section of the Yellow River Basin changed in the direction of distribution fragmentation,shape complexity,and heterogeneity.The average value of the habitat quality index in the Qinghai Province section of the Yellow River Basin from 2000 to 2022 was 0.90.Based on the value of habitat quality index,we divided the level of habitat quality into five categories:lower(0.00-0.20),low(0.20-0.40),moderate(0.40-0.60),high(0.60-0.80),and higher(0.80-1.00).Most areas were at the higher habitat quality level.The lower habitat quality patches were mainly distributed in Longyang Gorge and Yellow River-Huangshui River Valley.From 2000 to 2022,the habitat quality in most areas was stable;the increase areas were mainly distributed in Guinan County,while the decrease areas were mainly distributed in Xining City,Maqen County,Xinghai County,Qumarleb County,and Darlag County.To show the extent of habitat quality variation,we calculated Sen index.The results showed that the higher habitat quality area had a decrease trending,while other categories had an increasing tendency,and the decreasing was faster than increasing.The research results provide scientific guidance for promoting ecological protection and high-quality development in the Qinghai Province section of the Yellow River Basin.
文摘Mao抏rshan region is a representative natural secondary forested region in the eastern mountainous region, north-east of China. Under the support of ARC/INFO, the landscape pattern and landscape diversity of Maoerhshan region were studied by combining the forest type map (1:10000), which was drawn from the aerial photographs (1999), field investigation and land utilization map (1:10000). The selected indices included patch number, patch size, patch density index, richness index, dominance index, evenness index and diversity index. The results showed that the landscape dominant forest type in Mao抏rshan region was softwood broad-leaved forest. In all landscape types, the average patch area of natural secondary for-ests was bigger than that of artificial forest. The patch density index of each landscape formed in artificial forest was higher than that of natural secondary forest. The landscape diversity index and landscape evenness index of natural forest were highest, the landscape heterogeneity was also, but the landscape dominance was lower. In natural forest, the control effects of landscape elements on landscape-structure, function and its change were weakened. The artificial forest was on the contrary.
基金Supported by Special Fund for Technology Research and Development of Hainan Province Scientific Research Institutes(No.KYYS-2015-16)~~
文摘The research took different forest communities in Wenchang Satellite Launch Center as the research object and selected 8 forests to explore species diversity, evenness, and dominance of forests. The results showed that species diversity tended to be volatile upon forest communities; semi-mangrove species was the richest, as high as 2.38, followed by natural secondary forest and mixed forests. Plant evenness from high to low was as follows： herbaceous layer〉shrub layer〉tree layer. Natural secondary forest was higher in canopy density, and fewer in herbaceous plants; diversity and evenness were lower than shrub layer. Mangrove forests held lower dominance, and dominance showed insignificant differences among species.
文摘Topography is the most factor that has the greatest impact of all factor that affect the distribution. To study the diversity of trees and shrub species in the Perc forest situated in Khorramabad, Lorestan, 140 circular plots of 1200 m2 in a grid of 300 m × 250 m were surveyed, using a systematic random sampling method. In each plot, the Margalef richness index, Shannon-Wiener diversity index, Hill＇s N1 and Simpson indices and the evenness index of Simpson and Smith-Wilson were calculated and ordered on the basis of different classes of elevation, exposition and slope. The results indicated that slope did not have any significant effect on the indices. Exposition and elevation classes significant impacted the richness and diversity indices, but did not influence evenness. In general, the highest plant diversity was observed for slopes less than 15 %, northern aspects, without geographical direction, and elevations of 2100-2200 m. This information can be very useful in achieving the goals for sustainable management of forests. In addition to greater protection for regions with high diversity and reforestation （compatible species） in degraded area, we can help increase diversity in forests.
文摘The concept of pedodiversity and its measurement methodology proposed and developed by Ibá?ez research term is introduced. An attempt to apply pedodiversity to analyze spatial soil variation and distribution patterns on the global scale is briefly demonstrated. Furthermore, constructive comments and criticisms on pedodiversity and its measurement from the noted pedologists and ecologists are outlined. Finally, potential applications of pedodiversity in soil science and other relevant disciplines are discussed.
基金Supported by Chongqing Municipal Commission of Education(KJ080818)National Natural Science Foundation of China(41161140352)~~
文摘[Objective] The diversity of soil erosion in the Meixi River watershed of the Three Gorges Reservoir Region was analyzed, in order to provide references for governance and protection of ecological environment of the study area. [Method] The soil erosion diversity index and evenness index of the Meixi River watershed in the Three Gorges Reservoir Region were studied based on the TM images in the year of 1988, 1999 and 2010, supported by GIS technology to extract various types of soil erosion in the area with different slope gradients and calculate soil erosion di- versity index and evenness index. [Result~ As slope gradients grew, the diversity in- dex and evenness index of soil erosion decrease after increasing with a turning point from 25~ to 35~. [Conchlsion] The proportion of light-erosion in the study area is 15.57%. Hence, the increase of diversity index and evenness index with gradients of 5^-35~ shows that the higher erosion intensity, the more uniform erosion types and the indexes decreased in gradients higher than 35°, suggesting that the lower erosion intensity, the better environment. Distribution and variation of different land types have close relation with soil erosion diversity and evenness indexes. Though soil erosion problems have been alleviated, by comparing soil erosion diversity index and evenness index, it can be concluded that changes of indexes are lower than 0.02, and soil erosion should be continued to be well controlled.
基金supported by the Ministry of Science and Technology of P.R.China under grant contracts (No.2010CB428903)the National Natural Science Foundation of China (No.41306112)+3 种基金the National Marine Public Welfare Research Project of China (Nos.201305043,200805069)the Zhejiang Provincial Natural Science Foundation (Nos.LY13D060004,Y5110131)the Marine Science Foundation of State Oceanic Administration for Youth (Nos.2013140,2013144)the Basic Scientific Research Fund of SIO,China (Nos.JG1311,JG1221)
文摘With the rapid development of economy and increase of population in the drainage areas, the nutrient loading has increased dramatically in the Changjiang estuary and adjacent coastal waters. To properly assess the impact of nutrient enrichment on phytoplankton community, seasonal microcosm experiments were conducted during August 2010-July 2011 in the coastal waters of Zhejiang Province. The results of the present study indicated that the chl a concentration, cell abundance, diversity indices, species composition and community succession of the phytoplankton varied significantly with different N/P ratios and seasons. Higher growth was observed in the 64：1 （spring）, 32：1 （summer）, 16：1 （autumn） and 128：1,256：1 （winter） treatments, respectively. The values of Shannon-Wiener index （H） and Pielou evenness index （J） were lower in the 8：1 and 16：1 treatments in autumn test, while H value was higher in the 128：1 and 8：1 treatments in winter test. A definite community succession order from diatoms to dinoflagel lares was observed in the autumn and winter tests, while the diatoms dominated the community throughout the culture in the spring and summer tests.
文摘Plant diversity plays key ecological roles in forest ecosystems, including influencing succession, resilience and nutrient cycling. This study was conducted to investigate the effect of livestock grazing and human uses on herbaceous species diversity. We surveyed 50 ha of protected area and 50 ha of unprotected area to evaluate herbaceous species diversity in oriental beech （Fagus orientalis Lipsky） forests in northern Iran. We calculated and compared three indices each of diversity and evenness, and species richness between the two areas. Herbaceous cover was higher in the unprotected area while leaf litter depth and tree canopy cover were higher in the protected area. The diversity indices, H （Shan- non-Wiener index ）, N~ （McArthur index）, N2 （Hill＇s index）, EQ （Modified Nee index）, E,ar （Smith-Wilson index）, E5 （modified index of Hill） and R=S （species richness） and species richness R=S were greater in the protected area than in the unprotected area, suggesting that protection from grazing results in increased numbers of plants and species. The effect of land protection on plant diversity was more pronounced for evenness than for species richness and the positive correlation between diversity and evenness indices was higher than that between diversity and richness.
文摘The finfish and shellfish resources were assessed quantitatively and qualitatively in regard to their abundance in creek waters at three sites within a period of two years, fi＇om January 1999 to December 2000, in the western mangrove areas of Kachchh. The catch rate varied from 0.69 to 6.99kg·h^-1. It was low during monsoon （July to October）, which could be due to the freshwater-flow-induced salinity reduction in all the sites. Among 38 species recorded, 5 were shellfish and 33 were finfish. The spawning period of fishes was found to be during summer and early monsoon period （May to August）. Surface water temperatures varied from 17℃ to 37 ℃. Salinity values varied from 34 to 44 and the pH ranged between 7 and 8.9. Variation in dissolved oxygen content was from 3.42 to 5.85 mL L^-1. The high fishery densities in these semi arid mangrove creek areas were recorded during monsoon and early winter season.
基金supported by POSTFIRE_CARE Project(CGL2016-75178-C2-2-R)sponsored by the Spanish Ministry of Economy and Competitiveness and AEI/FEDER,UE+1 种基金Support was also received from the FPU Program(FPU 014/00037)sponsored by the Ministry of Education,Culture and Sports,the EST16/00183 to a short stay in Mykolas Romeris University(Vilnius,Lithuania)to the Ministry of Education,Culture and Sports and project 2017SGR1344 of the Generalitat de Catalunya。
文摘Fire and pre-or post-fire management practices shape the distribution and richness of plant species.Here,the effects of pre-and post-fire management on vegetation recovery were studied at different times,up to 18 months after a wildfire.Two months after a 2015 wildfire,18 study plots were established(three 4-m^2 plots for each treatment),vegetation regrowth was monitored and vegetal species richness(S),evenness(IT),density(D),diversity(H0)and maximum diversity(HMax)after 2,10 and 18 months.The treatments were(1)control,unaffected by 2015 wildfire;(2)no treatment(NT),burned in 2015 wildfire and not managed;(3)managed in 2005 and burned in 2015(M05B);(4)managed in 2015,2 months before wildfire(M15B);(5)cut and manual removal after the 2015 wildfire(CR);(6)cut and no trunk removal randomly deposited on topsoil after the 2015 wildfire(CL).All the treatments were carried out in a Pinus halepensis Miller forest.At 10 and 18 months after the wildfire,vegetation recovery was greater in NT,CR and CL plots than in M05B and M15B the plots.By 18 months after the wildfire,Brachypodium retusum(Pers.)P.Beauv.and Rosmarinus officinalis L.were still dominant,especially in M15B,corroborating the belief that pre-fire treatment reduced ecosystem resilience and vegetal recovery compared to the NT and post-fire managed plots.Richness was significantly lower 10 months after wildfire in control plots,and IT was significantly higher in that inventory than previously in M15B.Eighteen months after the wildfire,H0 was significantly lower in M15B.Ten months post-wildfire,HMax was significantly lower in the control plots.Eighteen months after the wildfire,HMax,was significantly higher in CR,CL and M05B than in the control and M15B plots.Overall,pre-fire management was detrimental to post-fire vegetation recovery,while manual post-fire management proved beneficial.
文摘Five indices of species richness, species diversity and species evenness were used to assess a diversity of four types of coniferous forests undergone different artificial regeneration time. The study was based on the vertical structure of forests, involving growth-forms of total plants as well as vertical layers of woody plants. The results showed that, except for the fourth layer of woody plants, the vertical structure of the four forests exhibited significant difference in terms of their species richness, species diversity and species evenness, suggesting that a species diversity index provided more detailed information and was a better index reflecting the regeneration processes in this region. It was recommended that silvicultural management of artificially regenerated forests should be strengthened to conserve the biodiversity of the forests, optimize forest structure and, in the long run, promote sustainable development of forest ecosystems.
