Background: The importance of structurally diverse forests for the conservation of biodiversity and provision of a wide range of ecosystem services has been widely recognised. However, tools to quantify structural div...Background: The importance of structurally diverse forests for the conservation of biodiversity and provision of a wide range of ecosystem services has been widely recognised. However, tools to quantify structural diversity of forests in an objective and quantitative way across many forest types and sites are still needed, for example to support biodiversity monitoring. The existing approaches to quantify forest structural diversity are based on small geographical regions or single forest types, typically using only small data sets.Results: Here we developed an index of structural diversity based on National Forest Inventory(NFI) data of BadenWurttemberg, Germany, a state with 1.3 million ha of diverse forest types in different ownerships. Based on a literature review, 11 aspects of structural diversity were identified a priori as crucially important to describe structural diversity. An initial comprehensive list of 52 variables derived from National Forest Inventory(NFI) data related to structural diversity was reduced by applying five selection criteria to arrive at one variable for each aspect of structural diversity. These variables comprise 1) quadratic mean diameter at breast height(DBH), 2) standard deviation of DBH, 3) standard deviation of stand height, 4) number of decay classes, 5) bark-diversity index, 6) trees with DBH ≥ 40 cm, 7) diversity of flowering and fructification, 8) average mean diameter of downed deadwood, 9) mean DBH of standing deadwood, 10) tree species richness and 11) tree species richness in the regeneration layer. These variables were combined into a simple,additive index to quantify the level of structural diversity, which assumes values between 0 and 1. We applied this index in an exemplary way to broad forest categories and ownerships to assess its feasibility to analyse structural diversity in large-scale forest inventories.Conclusions: The forest structure index presented here can be derived in a similar way from standard inventory variables for most other large-scale forest inventories to provide important information about biodiversity relevant forest conditions and thus provide an evidence-base for forest management and planning as well as reporting.展开更多
Structural diversity is the key attribute of a stand. A set of biodiversity measures in ecology was introduced in forest management for describing stand structure, of which Shannon information entropy (Shannon index) ...Structural diversity is the key attribute of a stand. A set of biodiversity measures in ecology was introduced in forest management for describing stand structure, of which Shannon information entropy (Shannon index) has been the most widely used measure of species diversity. It is generally thought that tree size diversity could serve as a good proxy for height diversity. However, tree size diversity and height diversity for stand structure is not completely consistent. Stand diameter cannot reflect height information completely. Either tree size diversity or height diversity is one-dimensional information entropy measure. This paper discussed the method of multiple-dimensional information entropy measure with the concept of joint entropy. It is suggested that joint entropy is a good measure for describing overall stand structural diversity.展开更多
The structural diversity in urban forests is highly important to protect biodiversity. In particular, fruit trees and bush species, cavity-bearing trees and coarse, woody debris provide habitats for animals to feed, n...The structural diversity in urban forests is highly important to protect biodiversity. In particular, fruit trees and bush species, cavity-bearing trees and coarse, woody debris provide habitats for animals to feed, nest and hide. Improper silvicultural practices, intensive recreational use and illegal harvesting lead to a decline in the structural diversity in forests within larger metropolitan cities. It is important to monitor the structural diversity at definite time intervals using effective technologies with a view to instituting the necessary conservation measures. The use of satellite images seems to be appropriate to this end. Here we aimed to identify the associations between the textural features derived from the satellite images with different spatial resolutions and the structural diversity indices in urban forest stands (Shannon-Wiener index, complexity index, dominance index and density of wildlife trees). RapidEye images with a spatial resolution of 5 m × 5 m, ASTER images with a spatial resolution of 15 m × 15 m and Landsat-8 ETM satellite images with a spatial resolution of 30 m × 30 m were used in this study. The first-order (standard deviation of gray levels) and second order (GLCM entropy, GLCM contrast and GLCM correlation) textural features were calculated from the satellite images. When associations between textural features in the images and the structural diversity indices were assessed using the Pearson correlation coefficient, very high associations were found between the image textural features and the diversity indices. The highest association was found between the standard deviation of gray levels (SDGL<sub>RAP</sub>) derived from RVI<sub>RAP</sub> of RapidEye image and the Shannon-Wiener index (H <sub>h</sub>) calculated on the basis of tree height (R <sup>2</sup> = 0.64). The findings revealed that RapidEye satellite images with a spatial resolution of 5 m × 5 m are most suitable for estimating the structural diversity in urban forests.展开更多
Four types of luminescent properties of metal-organic frameworks（MOFs） with formulas [Cd（1,2-BIYB）2（H2O）2]n·n（AQ-1,5-DAD）（1）, [Cd（AQ-1,5-DAD）（1,3-BIYB）2]n（2）, [Cd（1,3-BIYB）]n·n（AQ-1,5-DAD...Four types of luminescent properties of metal-organic frameworks（MOFs） with formulas [Cd（1,2-BIYB）2（H2O）2]n·n（AQ-1,5-DAD）（1）, [Cd（AQ-1,5-DAD）（1,3-BIYB）2]n（2）, [Cd（1,3-BIYB）]n·n（AQ-1,5-DAD）·n H2O（3）, and [Zn（1,4-BIYB）2]n·n（AQ-1,5-DAD）2·6H2O（4）,（Na2AQ-1,5-DAD = anthraquinone-1,5-disulfonic acid disodium, 1,2-BIYB = 1,2-bis（imidazol-1-ylmethyl）benzene, 1,3-BIYB = 1,3-bis（imidazol-1-ylmethyl）benzene, 1,4-BIYB = 1,4-bis（imidazol-1-ylmethyl）benzene） have been synthesized based on a rare sulfonate and imidazole Co-ligand system under different conditions. The structural features of four types of MOFs 1-4 are as follows： MOFs 1 show a 3D supramolecular compound in which the double one-dimensional chains are further cross-linked by hydrogen bonds. 2 exhibits a 2D network constructed by two different 1D chains. 3 features a 2D supramolecular network, in which the 1D chains and AQ-1,5-DAD are arranged alternately through hydrogen bonds. 4 posseses a 3D supramolecular structure constructed by a 2D network and one-dimensional hydrogen bonding chains. All compounds 1-4 are characterized by elemental analysis, infrared spectroscopy, and thermogravimetric analysis. The luminescence properties of 1-4 have been investigated.展开更多
Solvothermal reaction of manganese（II） salt with monosodium 2-sulfoterephthalate（2-NaH2stp） and two multi-pyridine N-containing auxiliary ligands results in the formation of two new complexes formulated with [Mn2...Solvothermal reaction of manganese（II） salt with monosodium 2-sulfoterephthalate（2-NaH2stp） and two multi-pyridine N-containing auxiliary ligands results in the formation of two new complexes formulated with [Mn2（Hstp）2（bpp）2（H2O）4]（1） and [Mn3（stp）2（tpy）3（H2O）]（H2O）5（2）（bpp = benz-2,3-pyrimidine-[2,3-f]-1,10-phenanthroline, tpy = 2,2＇：6＇,2＇＇-terpyridine）. X-ray diffraction structural analyses of two complexes reveal their structural diversity（0D and 1D） due to the difference of auxiliary ligands. 1 is a discrete structure, in which the Mn（Ⅱ） ion is hexa-coordinated with one stp, one bpp ligand and two water molecules. Complex 2 is a one-dimensional（1D） chain-like structure with three crystallographically independent Mn（Ⅱ） ions. The photoluminescent properties could be assigned to the π-π＊ transition of 2-sulfoterephthalate ligands.展开更多
Diversity-biomass relationships(DBRs)in terrestrial ecosystems tend to vary across spatial scales,but,particularly in hyperdiverse forests,the mechanisms driving these trends remain uncertain.Until now,few have simult...Diversity-biomass relationships(DBRs)in terrestrial ecosystems tend to vary across spatial scales,but,particularly in hyperdiverse forests,the mechanisms driving these trends remain uncertain.Until now,few have simultaneously investigated the connections between tree species diversity,stand structural diversity,mycorrhizal associations,and ecosystem functioning.In addition,DBRs have only been studied at limited spatial scales,with limited focus on the direct and indirect effects of environmental factors.We addressed these research gaps using a 30-ha forest dynamics plot located in Pu'er City,Southwest China.Through piecewise structural equation models,we quantified the direct effects of tree species diversity(α,β,γ),stand structural diversity,mycorrhizal associations(AM,EcM),and the environmental factors(soil fertility and topography),as well as the indirect effects of the environmental factors on aboveground tree biomass across spatial scales ranging from 400 to 230,400 m^(2).We hypothesized that complex interactions among these factors underpin the variation in DBRs in natural ecosystems across spatial scales.Our results showed that environmental conditions indirectly affected the tree biomass via changes in tree species diversity,and these effects became stronger as the spatial scale increased.At small to moderate spatial scales,environmental factors were more predictive of tree biomass than tree species diversity(or its components);the effects of stand structural diversity on biomass also gradually increased with spatial scale.Conversely,from the intermediate to the largest spatial scales,mycorrhizal associations gradually became the best predictors of DBR dynamics.Our research offers novel empirical evidence demonstrating the importance of environmental conditions,structural diversity,and mycorrhizal associations in shaping cross-scale DBRs.Future comprehensive studies should consider these factors to assess the mechanisms shaping scale-dependent DBRs in complex natural ecosystems.展开更多
The structural diversity of different tree-crop associations were studied at Gachabari Sal forest area of Madhupur Garh on Buffer and Peripheral Zone during 2006. The total density, basal area of trees in the Buffer a...The structural diversity of different tree-crop associations were studied at Gachabari Sal forest area of Madhupur Garh on Buffer and Peripheral Zone during 2006. The total density, basal area of trees in the Buffer and Peripheral Zone were 155.5 trees·hm^(-2), 795.4 trees·hm^(-2) and 3.9 m2·hm-2, 5.8 m^2·hm^(-2), respectively. No regeneration and natural trees were found in Peripheral Zone and the Zone is totally occupied by exotic species where the Buffer Zone comprised of both natural and exotic trees. The Peripheral Zone belonged to younger and smaller trees whereas the Buffer Zone belonged to mixture of smaller, taller, younger and mature trees simultaneously. For the practicing of different agroforestry systems both Zones have lost their original characters of Sal forest.展开更多
The original version of this article unfortunately contained three mistakes. （1） The spelling of the [A. Nishad＇] name was incorrect. The corrected spelling is given below.
We report the preparation,spectroscopic characterisation,crystal structure determination and cryomagnetic investigation of three cobalt(II)complexes of formula trans-[Co(bim)_(4)(NCS)_(2)](1),[Co(bim)_(2)(NCO)_(2)](_(...We report the preparation,spectroscopic characterisation,crystal structure determination and cryomagnetic investigation of three cobalt(II)complexes of formula trans-[Co(bim)_(4)(NCS)_(2)](1),[Co(bim)_(2)(NCO)_(2)](_(2))and[Co(bim)_(2)(N_(3))_(2)]_(n)(_(3))(bim=1-benzylimidazole).The structure of 1 is made up of neutral[Co(bim)_(4)(NCS)_(2)]mononuclear units,where the cobalt(II)ion is six-coordinate with four monodentate bim ligands in equatorial positions and two N-thiocyanato groups in the axial sites building a slightly compressed octahedron.展开更多
Dietary plant polysaccharides,which are natural,biocompatible,and functional macromolecules derived from plants,mushrooms,algae,and agri-food byproducts,have thus emerged as a focal point in the fields of food science...Dietary plant polysaccharides,which are natural,biocompatible,and functional macromolecules derived from plants,mushrooms,algae,and agri-food byproducts,have thus emerged as a focal point in the fields of food science,nutrition,and biomedical research.Driven by the global consumer demand for clean-label functional foods,natural nutraceut-icals,and sustainable health solutions,there has been a growing interest in these polysaccharides has surged,largely due to their diverse bio-logical activities and their potential to address pressing public health challenges,such as metabolic disorders,gut dysbiosis,and age-related diseases(Qin et al.,2021;Wang et al.,2024;Yang et al.,2025).展开更多
Multi-component chalcogenidometalates have garnered significant attention due to their promising applications in solar energy conversion devices,including photodetectors,solar cells,and photocatalysts.Photocurrent res...Multi-component chalcogenidometalates have garnered significant attention due to their promising applications in solar energy conversion devices,including photodetectors,solar cells,and photocatalysts.Photocurrent response is not only a fundamental property of photodetectors but also serves as a key indicator of the solar energy conversion efficiency in potential semiconductor devices.Despite the growing interest,a clear and universal guideline for designing chalcogenide materials with excellent photocurrent response remains elusive,primarily due to the substantial variations in their chemical compositions and crystal structures.In this review,we present a comprehensive compilation of reported multi-component chalcogenidometalates,including main group chalcogenides with binary and ternary anionic frameworks,and discuss their photocurrent response performance.Additionally,we also highlight other special chalcogenide systems,focusing on their photocurrent response characteristics.For the first time,we systematically summarize the intricate relationships between chemical composition,crystal structure,electronic band structure,and photocurrent response in these materials.Finally,we believe that this review provides a valuable structural perspective on the photocurrent response of multi-component chalcogenidometalates,offering useful insights for the design and application of advanced solar energy conversion materials.展开更多
A series of chalcogenide compounds with various compositions,i.e.,octanuclear or tetranuclear Zn-S clusters,have been synthesised in a straighforward manner.Different fused-ring aromatic ligands were used as capping l...A series of chalcogenide compounds with various compositions,i.e.,octanuclear or tetranuclear Zn-S clusters,have been synthesised in a straighforward manner.Different fused-ring aromatic ligands were used as capping ligands and the corresponding zero-dimensional(0D)products were obtained.On the other hand,use of bridging ligands led to a family of one-dimensional(1D)coordination polymers,and an in situ ligand reaction has been observed in[Zn_(8)S(SC_(6)H_(5))_(13)L_(1)(H_(2)O)]·2H_(2)O(L=3-carboxypryidyl)due to the hydrolysis of the cyano group of 3-pyridinecarbonitrile.A very rare 1D helical-chain structure was observed in[Zn_(4)(SC_(6)H_(5))_(8)L_(1)](L=4,4’-bipyridyl),providing evidence of the character of bridging organic ligands in the corresponding crystalline materials.First-principles calculations on[Zn_(4)(SC_(6)H_(5))_(8)L_(1)](L=4,4’-bipyridyl)further revealed that the two cluster units could rotate freely about the C-C single bond over a broad range,eventually leading to the formation of a one-dimensional helical structure.展开更多
Polyoxometalates(POMs)have demonstrated strong potential in various fields,such as catalysis,magnetism,medicine,photochemistry and materials science,mainly because of their remarkable physical and chemical properties....Polyoxometalates(POMs)have demonstrated strong potential in various fields,such as catalysis,magnetism,medicine,photochemistry and materials science,mainly because of their remarkable physical and chemical properties.In the broad area of POM chemistry,the study of metal carbonyl-based POMs,as an important type of organometallic POM,has been a rather attractive direction in recent years.展开更多
Linker conformation engineering provides opportunities for the structural diversity of coordination polymers(CPs);however,the approaches for modulating the synthesis solvents to influence linker conformation are very ...Linker conformation engineering provides opportunities for the structural diversity of coordination polymers(CPs);however,the approaches for modulating the synthesis solvents to influence linker conformation are very limited,and they are facing unpredictable challenges to date.Herein,through strategies of solvent-oriented structural self-assembly and solvent-induced single-crystal to single-crystal transformation,eight structurally distinct Cd-CPs were controllably synthesized with the same linkers for the first time.The decisive role of solvents in the self-assembly and transformations in CPs has been demonstrated in depth.Besides,rare reversible CP-based phase transition phenomena at low temperatures were observed.One of these represents the first example of an unprecedented turn-on–off CP-based Fe^(3+)ion sensor.展开更多
Decision trees are a kind of off-the-shelf predictive models, and they have been successfully used as the base learners in ensemble learning. To construct a strong classi- fier ensemble, the individual classifiers sho...Decision trees are a kind of off-the-shelf predictive models, and they have been successfully used as the base learners in ensemble learning. To construct a strong classi- fier ensemble, the individual classifiers should be accurate and diverse. However, diversity measure remains a mystery although there were many attempts. We conjecture that a deficiency of previous diversity measures lies in the fact that they consider only behavioral diversity, i.e., how the classifiers behave when making predictions, neglecting the fact that classifiers may be potentially different even when they make the same predictions. Based on this recognition, in this paper, we advocate to consider structural diversity in addition to behavioral diversity, and propose the TMD （tree matching diversity） measure for decision trees. To investigate the usefulness of TMD, we empirically evaluate performances of selective ensemble approaches with decision forests by incorporating different diversity measures. Our results validate that by considering structural and behavioral diversities together, stronger ensembles can be constructed. This may raise a new direction to design better diversity measures and ensemble methods.展开更多
Ribosomal RNAs are important because they catalyze the synthesis of peptides and proteins.Comparative studies of the secondary structure of 18S rRNA have revealed the basic locations of its many length-conserved and l...Ribosomal RNAs are important because they catalyze the synthesis of peptides and proteins.Comparative studies of the secondary structure of 18S rRNA have revealed the basic locations of its many length-conserved and lengthvariable regions.In recent years,many more sequences of 18S rDNA with unusual lengths have been documented in GenBank.These data make it possible to recognize the diversity of the secondary and tertiary structures of 18S rRNAs and to identify the length-conserved parts of 18S rDNAs.The longest 18S rDNA sequences of almost every known eukaryotic phylum were included in this study.We illustrated the bioinformatics-based structure to show that,the regions that are more length-variable,regions that are less length-variable,the splicing sites for introns,and the sites of A-minor interactions are mostly distributed in different parts of the 18S rRNA.Additionally,this study revealed that some length-variable regions or insertion positions could be quite close to the functional part of the 18S rRNA of Foraminifera organisms.The tertiary structure as well as the secondary structure of 18S rRNA can be more diverse than what was previously supposed.Besides revealing how this interesting gene evolves,it can help to remove ambiguity from the alignment of eukaryotic 18S rDNAs and to improve the performance of 18S rDNA in phylogenetic reconstruction.Six nucleotides shared by Archaea and Eukaryota but rarely by Bacteria are also reported here for the first time,which might further support the supposed origin of eukaryote from archaeans.展开更多
The relationship between Solidago canadensis L. invasion and soil microbial community diversity including functional and structure diversities was studied across the invasive gradients varying from 0 to 40%, 80%, and ...The relationship between Solidago canadensis L. invasion and soil microbial community diversity including functional and structure diversities was studied across the invasive gradients varying from 0 to 40%, 80%, and 100% coverage of Solidago canadensis L. using sole carbon source utilization profiles analyses, principle component analysis （PCA） and phospholipid fatty acids （PLFA） profiles analyses. The results show the characteristics of soil microbial community functional and structure diversity in invaded soils strongly changed by Solidago canadensis L. invasion. Solidago canadensis L. invasion tended to result in higher substrate richness, and functional diversity. As compared to the native and ecotones, average utilization of specific substrate guilds of soil microbe was the highest in Solidago canadensis L. monoculture. Soil microbial functional diversity in Solidago canadensis L. monoculture was distinctly separated from the native area and the ecotones. Aerobic bacteria, fungi and actinomycetes population significantly increased but anaerobic bacteria decreased in the soil with Solidago canadensis L. monoculture. The ratio of cyl9：0 to 18：1 co7 gradually declined but mono/sat and fung/bact PLFAs increased when Solidago canadensis L. became more dominant. The microbial community composition clearly separated the native soil from the invaded soils by PCA analysis, especially 18： lco7c, 16： lco7t, 16： lco5c and 18：2co6, 9 were present in higher concentrations for exotic soil. In conclusion, Solidago canadensis L. invasion could create better soil conditions by improving soil microbial community structure and functional diversity, which in turn was more conducive to the growth ofSolidago canadensis L.展开更多
This study aims to assess the impact of monospecific Tectona grandis forest plantation on the soil mite abundance and diversity. To achieve these objectives, two sites situated in Ivory Coast were investigated. The fi...This study aims to assess the impact of monospecific Tectona grandis forest plantation on the soil mite abundance and diversity. To achieve these objectives, two sites situated in Ivory Coast were investigated. The first, a primary forest was characterized by a very weak human activities whereas the second, a teak plantation was characterized by a high disturbance performed during the planting. After extracting, sorted and description, 116 mite species were described in the two sites. Mite densities were lower in teak plantation and also higher in the litter and decreased to the depth in both sites. Species richness re- corded in teak plantation （52 species） was significantly lower compared to primary forest （98 species）. The same trend was ob- served for Oribatida but not for Gamasida. The lower Oribatida （5 vs. 17） and higher Oribatida （24 vs. 41） were recorded respec- tively in teak plantation and primary forest. Mite Shannon index and evenness were significantly different between sites. High Jaccard index values and the appearance of exclusive species in both habitats showed that the sites are very distinct. Total number of species recorded corresponded to 58%-63% of the total number of species estimated by ACE and Chao 1＆2 estimators, indi- cating that the sampling effort was not sufficient. Mite abundance and diversity varied depending on the characteristics of habi- tats. Chemical element （Corn, Ctot, Ntot, and SOM） values were lower in teak plantation （disturbed habitat） and significantly dif- ferent to primary forest in the topsoil. Apart from litter height, soil depth, pH and C/N ratio, others variables were strongly corre- lated to mite abundance and diversity [Current Zoology 59 （5）： 633-643, 2013].展开更多
Tree species diversity and population structure at different community types were described and analyzed for primary and secondary lowland moist deciduous forests in Tripura. Overall 10,957 individual trees belonging ...Tree species diversity and population structure at different community types were described and analyzed for primary and secondary lowland moist deciduous forests in Tripura. Overall 10,957 individual trees belonging to 46 family, 103 genera and 144 species were counted at ≥30 cm DBH （diameter at breast height） using 28 permanent belt transects with a size of 1 ha （10 m × 1000 m）. Four different tree communities were identified. The primary forests was dominated by Shorea robusta （mean density 464.77 trees.ha^-1, 105 species） and Schima wallichii （336.25 trees.ha^-1, 82 species）, while the secondary forests was dominated by Tectona grandis （333.88 trees.ha^-1, 105 species） and Hevea brasiliensis （299.67 trees.ha^-1, 82 species）. Overall mean basal area in this study was 18.01m2.ha^-1; the maximum value was recorded in primary Shorea forest （26.21 m2.ha^-1）. Mean density and diversity indices were differed significantly within four different communities. No significant differences were observed in number of species, genera, family and tree basal cover area. Significant relationships were found between the species richness and different tree population groups across the communities. Results revealed that species diversity and density were increased in those forests due to past disturbances which resulted in slow accumu- lation of native oligarchic small tree species. Seventeen species were recorded with 〈2 individuals of which Saraca asoka （Roxb.） de Wilde and Entada phaseoloides （L.） Men＇. etc. extensively used in local ethnomedicinal formulations. The present S. robusta Gaertn dominated forest was recorded richer （105 species） than other reported studies. Moraceae was found more speciose family instead of Papilionaceae and Euphorbiaceae than other Indian moist deciduous forests. Seasonal phenological gap in such moist deciduous forests influenced the population of Trachypithecus pileatus and capped langur. The analysis of FIV suggested a slow trend of shifting the population of Lamiaceae group by Moraceae species in secondary T. grandis L. dominated community.展开更多
基金supported by a grant from the Ministry of Science,Research and the Arts of Baden-Württemberg(7533-10-5-78)to Jürgen BauhusFelix Storch received additional support through the BBW ForWerts Graduate Program
文摘Background: The importance of structurally diverse forests for the conservation of biodiversity and provision of a wide range of ecosystem services has been widely recognised. However, tools to quantify structural diversity of forests in an objective and quantitative way across many forest types and sites are still needed, for example to support biodiversity monitoring. The existing approaches to quantify forest structural diversity are based on small geographical regions or single forest types, typically using only small data sets.Results: Here we developed an index of structural diversity based on National Forest Inventory(NFI) data of BadenWurttemberg, Germany, a state with 1.3 million ha of diverse forest types in different ownerships. Based on a literature review, 11 aspects of structural diversity were identified a priori as crucially important to describe structural diversity. An initial comprehensive list of 52 variables derived from National Forest Inventory(NFI) data related to structural diversity was reduced by applying five selection criteria to arrive at one variable for each aspect of structural diversity. These variables comprise 1) quadratic mean diameter at breast height(DBH), 2) standard deviation of DBH, 3) standard deviation of stand height, 4) number of decay classes, 5) bark-diversity index, 6) trees with DBH ≥ 40 cm, 7) diversity of flowering and fructification, 8) average mean diameter of downed deadwood, 9) mean DBH of standing deadwood, 10) tree species richness and 11) tree species richness in the regeneration layer. These variables were combined into a simple,additive index to quantify the level of structural diversity, which assumes values between 0 and 1. We applied this index in an exemplary way to broad forest categories and ownerships to assess its feasibility to analyse structural diversity in large-scale forest inventories.Conclusions: The forest structure index presented here can be derived in a similar way from standard inventory variables for most other large-scale forest inventories to provide important information about biodiversity relevant forest conditions and thus provide an evidence-base for forest management and planning as well as reporting.
基金National Natural Science Foundation of China (Grant No. 30371157)
文摘Structural diversity is the key attribute of a stand. A set of biodiversity measures in ecology was introduced in forest management for describing stand structure, of which Shannon information entropy (Shannon index) has been the most widely used measure of species diversity. It is generally thought that tree size diversity could serve as a good proxy for height diversity. However, tree size diversity and height diversity for stand structure is not completely consistent. Stand diameter cannot reflect height information completely. Either tree size diversity or height diversity is one-dimensional information entropy measure. This paper discussed the method of multiple-dimensional information entropy measure with the concept of joint entropy. It is suggested that joint entropy is a good measure for describing overall stand structural diversity.
基金supported by the Scientific and Technological Research Council of Turkey(TBTAK)under the project no.114O015
文摘The structural diversity in urban forests is highly important to protect biodiversity. In particular, fruit trees and bush species, cavity-bearing trees and coarse, woody debris provide habitats for animals to feed, nest and hide. Improper silvicultural practices, intensive recreational use and illegal harvesting lead to a decline in the structural diversity in forests within larger metropolitan cities. It is important to monitor the structural diversity at definite time intervals using effective technologies with a view to instituting the necessary conservation measures. The use of satellite images seems to be appropriate to this end. Here we aimed to identify the associations between the textural features derived from the satellite images with different spatial resolutions and the structural diversity indices in urban forest stands (Shannon-Wiener index, complexity index, dominance index and density of wildlife trees). RapidEye images with a spatial resolution of 5 m × 5 m, ASTER images with a spatial resolution of 15 m × 15 m and Landsat-8 ETM satellite images with a spatial resolution of 30 m × 30 m were used in this study. The first-order (standard deviation of gray levels) and second order (GLCM entropy, GLCM contrast and GLCM correlation) textural features were calculated from the satellite images. When associations between textural features in the images and the structural diversity indices were assessed using the Pearson correlation coefficient, very high associations were found between the image textural features and the diversity indices. The highest association was found between the standard deviation of gray levels (SDGL<sub>RAP</sub>) derived from RVI<sub>RAP</sub> of RapidEye image and the Shannon-Wiener index (H <sub>h</sub>) calculated on the basis of tree height (R <sup>2</sup> = 0.64). The findings revealed that RapidEye satellite images with a spatial resolution of 5 m × 5 m are most suitable for estimating the structural diversity in urban forests.
基金supported by the National Natural Science Foundation of China(21503183)Yanan university field scientific research projects(YDBK2015-02)
文摘Four types of luminescent properties of metal-organic frameworks（MOFs） with formulas [Cd（1,2-BIYB）2（H2O）2]n·n（AQ-1,5-DAD）（1）, [Cd（AQ-1,5-DAD）（1,3-BIYB）2]n（2）, [Cd（1,3-BIYB）]n·n（AQ-1,5-DAD）·n H2O（3）, and [Zn（1,4-BIYB）2]n·n（AQ-1,5-DAD）2·6H2O（4）,（Na2AQ-1,5-DAD = anthraquinone-1,5-disulfonic acid disodium, 1,2-BIYB = 1,2-bis（imidazol-1-ylmethyl）benzene, 1,3-BIYB = 1,3-bis（imidazol-1-ylmethyl）benzene, 1,4-BIYB = 1,4-bis（imidazol-1-ylmethyl）benzene） have been synthesized based on a rare sulfonate and imidazole Co-ligand system under different conditions. The structural features of four types of MOFs 1-4 are as follows： MOFs 1 show a 3D supramolecular compound in which the double one-dimensional chains are further cross-linked by hydrogen bonds. 2 exhibits a 2D network constructed by two different 1D chains. 3 features a 2D supramolecular network, in which the 1D chains and AQ-1,5-DAD are arranged alternately through hydrogen bonds. 4 posseses a 3D supramolecular structure constructed by a 2D network and one-dimensional hydrogen bonding chains. All compounds 1-4 are characterized by elemental analysis, infrared spectroscopy, and thermogravimetric analysis. The luminescence properties of 1-4 have been investigated.
基金supported by the Postdoctoral Science Foundation of China(No.2014M562403)National Natural Science Foundation of China(No.21573189)
文摘Solvothermal reaction of manganese（II） salt with monosodium 2-sulfoterephthalate（2-NaH2stp） and two multi-pyridine N-containing auxiliary ligands results in the formation of two new complexes formulated with [Mn2（Hstp）2（bpp）2（H2O）4]（1） and [Mn3（stp）2（tpy）3（H2O）]（H2O）5（2）（bpp = benz-2,3-pyrimidine-[2,3-f]-1,10-phenanthroline, tpy = 2,2＇：6＇,2＇＇-terpyridine）. X-ray diffraction structural analyses of two complexes reveal their structural diversity（0D and 1D） due to the difference of auxiliary ligands. 1 is a discrete structure, in which the Mn（Ⅱ） ion is hexa-coordinated with one stp, one bpp ligand and two water molecules. Complex 2 is a one-dimensional（1D） chain-like structure with three crystallographically independent Mn（Ⅱ） ions. The photoluminescent properties could be assigned to the π-π＊ transition of 2-sulfoterephthalate ligands.
基金funded by Fundamental Research Funds of Chinese Academy of Forestry(No.CAFYBB2021ZA002).
文摘Diversity-biomass relationships(DBRs)in terrestrial ecosystems tend to vary across spatial scales,but,particularly in hyperdiverse forests,the mechanisms driving these trends remain uncertain.Until now,few have simultaneously investigated the connections between tree species diversity,stand structural diversity,mycorrhizal associations,and ecosystem functioning.In addition,DBRs have only been studied at limited spatial scales,with limited focus on the direct and indirect effects of environmental factors.We addressed these research gaps using a 30-ha forest dynamics plot located in Pu'er City,Southwest China.Through piecewise structural equation models,we quantified the direct effects of tree species diversity(α,β,γ),stand structural diversity,mycorrhizal associations(AM,EcM),and the environmental factors(soil fertility and topography),as well as the indirect effects of the environmental factors on aboveground tree biomass across spatial scales ranging from 400 to 230,400 m^(2).We hypothesized that complex interactions among these factors underpin the variation in DBRs in natural ecosystems across spatial scales.Our results showed that environmental conditions indirectly affected the tree biomass via changes in tree species diversity,and these effects became stronger as the spatial scale increased.At small to moderate spatial scales,environmental factors were more predictive of tree biomass than tree species diversity(or its components);the effects of stand structural diversity on biomass also gradually increased with spatial scale.Conversely,from the intermediate to the largest spatial scales,mycorrhizal associations gradually became the best predictors of DBR dynamics.Our research offers novel empirical evidence demonstrating the importance of environmental conditions,structural diversity,and mycorrhizal associations in shaping cross-scale DBRs.Future comprehensive studies should consider these factors to assess the mechanisms shaping scale-dependent DBRs in complex natural ecosystems.
文摘The structural diversity of different tree-crop associations were studied at Gachabari Sal forest area of Madhupur Garh on Buffer and Peripheral Zone during 2006. The total density, basal area of trees in the Buffer and Peripheral Zone were 155.5 trees·hm^(-2), 795.4 trees·hm^(-2) and 3.9 m2·hm-2, 5.8 m^2·hm^(-2), respectively. No regeneration and natural trees were found in Peripheral Zone and the Zone is totally occupied by exotic species where the Buffer Zone comprised of both natural and exotic trees. The Peripheral Zone belonged to younger and smaller trees whereas the Buffer Zone belonged to mixture of smaller, taller, younger and mature trees simultaneously. For the practicing of different agroforestry systems both Zones have lost their original characters of Sal forest.
文摘The original version of this article unfortunately contained three mistakes. （1） The spelling of the [A. Nishad＇] name was incorrect. The corrected spelling is given below.
基金supported by the Polish National Agency for Academic Exchange(PPN/BEK/2018/1/00239/U/00001/01)the Ministerio Español de Ciencia e Innovación(Projects CTQ2016-75068P and PID2019-109735GB-I00Unidad de Excelencia María de Maetzu MDM-2015-0538).
文摘We report the preparation,spectroscopic characterisation,crystal structure determination and cryomagnetic investigation of three cobalt(II)complexes of formula trans-[Co(bim)_(4)(NCS)_(2)](1),[Co(bim)_(2)(NCO)_(2)](_(2))and[Co(bim)_(2)(N_(3))_(2)]_(n)(_(3))(bim=1-benzylimidazole).The structure of 1 is made up of neutral[Co(bim)_(4)(NCS)_(2)]mononuclear units,where the cobalt(II)ion is six-coordinate with four monodentate bim ligands in equatorial positions and two N-thiocyanato groups in the axial sites building a slightly compressed octahedron.
文摘Dietary plant polysaccharides,which are natural,biocompatible,and functional macromolecules derived from plants,mushrooms,algae,and agri-food byproducts,have thus emerged as a focal point in the fields of food science,nutrition,and biomedical research.Driven by the global consumer demand for clean-label functional foods,natural nutraceut-icals,and sustainable health solutions,there has been a growing interest in these polysaccharides has surged,largely due to their diverse bio-logical activities and their potential to address pressing public health challenges,such as metabolic disorders,gut dysbiosis,and age-related diseases(Qin et al.,2021;Wang et al.,2024;Yang et al.,2025).
基金supported by the National Natural Science Foundation of China(Grants No.52202142,52171277,and 22175175)the Science and Technology Serving Enterprise Project in University and Colleges of Xi’an Science and Technology Bureau(Grant No.24GXFW0002)+1 种基金the Doctoral Scientific Research Startup Foundation of Shaanxi University of Science and Technology(2018BJ-07)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZR118).
文摘Multi-component chalcogenidometalates have garnered significant attention due to their promising applications in solar energy conversion devices,including photodetectors,solar cells,and photocatalysts.Photocurrent response is not only a fundamental property of photodetectors but also serves as a key indicator of the solar energy conversion efficiency in potential semiconductor devices.Despite the growing interest,a clear and universal guideline for designing chalcogenide materials with excellent photocurrent response remains elusive,primarily due to the substantial variations in their chemical compositions and crystal structures.In this review,we present a comprehensive compilation of reported multi-component chalcogenidometalates,including main group chalcogenides with binary and ternary anionic frameworks,and discuss their photocurrent response performance.Additionally,we also highlight other special chalcogenide systems,focusing on their photocurrent response characteristics.For the first time,we systematically summarize the intricate relationships between chemical composition,crystal structure,electronic band structure,and photocurrent response in these materials.Finally,we believe that this review provides a valuable structural perspective on the photocurrent response of multi-component chalcogenidometalates,offering useful insights for the design and application of advanced solar energy conversion materials.
基金Financial support from the NSFC(21401077 and 21371078)the start-up fund of Jiaxing University is gratefully acknowledged.
文摘A series of chalcogenide compounds with various compositions,i.e.,octanuclear or tetranuclear Zn-S clusters,have been synthesised in a straighforward manner.Different fused-ring aromatic ligands were used as capping ligands and the corresponding zero-dimensional(0D)products were obtained.On the other hand,use of bridging ligands led to a family of one-dimensional(1D)coordination polymers,and an in situ ligand reaction has been observed in[Zn_(8)S(SC_(6)H_(5))_(13)L_(1)(H_(2)O)]·2H_(2)O(L=3-carboxypryidyl)due to the hydrolysis of the cyano group of 3-pyridinecarbonitrile.A very rare 1D helical-chain structure was observed in[Zn_(4)(SC_(6)H_(5))_(8)L_(1)](L=4,4’-bipyridyl),providing evidence of the character of bridging organic ligands in the corresponding crystalline materials.First-principles calculations on[Zn_(4)(SC_(6)H_(5))_(8)L_(1)](L=4,4’-bipyridyl)further revealed that the two cluster units could rotate freely about the C-C single bond over a broad range,eventually leading to the formation of a one-dimensional helical structure.
基金supported by the National Natural Science Foundation of China(Grants 21571050,21573056,21771053,and 21771054).
文摘Polyoxometalates(POMs)have demonstrated strong potential in various fields,such as catalysis,magnetism,medicine,photochemistry and materials science,mainly because of their remarkable physical and chemical properties.In the broad area of POM chemistry,the study of metal carbonyl-based POMs,as an important type of organometallic POM,has been a rather attractive direction in recent years.
基金support of the National Natural Science Foundation of China(Project No.22061047)Yunnan Fundamental Research Projects(Project No.2016FB023)+1 种基金the Yunnan Provincial Department of Education for funding the research fund project(Project No.2023Y0239)the Advanced Analysis and Measurement Center of Yunnan University for the sample testing service.
文摘Linker conformation engineering provides opportunities for the structural diversity of coordination polymers(CPs);however,the approaches for modulating the synthesis solvents to influence linker conformation are very limited,and they are facing unpredictable challenges to date.Herein,through strategies of solvent-oriented structural self-assembly and solvent-induced single-crystal to single-crystal transformation,eight structurally distinct Cd-CPs were controllably synthesized with the same linkers for the first time.The decisive role of solvents in the self-assembly and transformations in CPs has been demonstrated in depth.Besides,rare reversible CP-based phase transition phenomena at low temperatures were observed.One of these represents the first example of an unprecedented turn-on–off CP-based Fe^(3+)ion sensor.
基金The authors would like to thank anonymous reviewers for their helpful comments and suggestions. This research was supported by the National Natural Science Foundation of China （Grant No. 61333014）.
文摘Decision trees are a kind of off-the-shelf predictive models, and they have been successfully used as the base learners in ensemble learning. To construct a strong classi- fier ensemble, the individual classifiers should be accurate and diverse. However, diversity measure remains a mystery although there were many attempts. We conjecture that a deficiency of previous diversity measures lies in the fact that they consider only behavioral diversity, i.e., how the classifiers behave when making predictions, neglecting the fact that classifiers may be potentially different even when they make the same predictions. Based on this recognition, in this paper, we advocate to consider structural diversity in addition to behavioral diversity, and propose the TMD （tree matching diversity） measure for decision trees. To investigate the usefulness of TMD, we empirically evaluate performances of selective ensemble approaches with decision forests by incorporating different diversity measures. Our results validate that by considering structural and behavioral diversities together, stronger ensembles can be constructed. This may raise a new direction to design better diversity measures and ensemble methods.
基金the National Education Project in Basic Science for Special Subjects(Insect Systematics)[grant No.J0630963]the National Science Foundation Project[Grant No.30970350]the National Science Foundation Project for Distinguished Young Scholars[Grant No.30725005].
文摘Ribosomal RNAs are important because they catalyze the synthesis of peptides and proteins.Comparative studies of the secondary structure of 18S rRNA have revealed the basic locations of its many length-conserved and lengthvariable regions.In recent years,many more sequences of 18S rDNA with unusual lengths have been documented in GenBank.These data make it possible to recognize the diversity of the secondary and tertiary structures of 18S rRNAs and to identify the length-conserved parts of 18S rDNAs.The longest 18S rDNA sequences of almost every known eukaryotic phylum were included in this study.We illustrated the bioinformatics-based structure to show that,the regions that are more length-variable,regions that are less length-variable,the splicing sites for introns,and the sites of A-minor interactions are mostly distributed in different parts of the 18S rRNA.Additionally,this study revealed that some length-variable regions or insertion positions could be quite close to the functional part of the 18S rRNA of Foraminifera organisms.The tertiary structure as well as the secondary structure of 18S rRNA can be more diverse than what was previously supposed.Besides revealing how this interesting gene evolves,it can help to remove ambiguity from the alignment of eukaryotic 18S rDNAs and to improve the performance of 18S rDNA in phylogenetic reconstruction.Six nucleotides shared by Archaea and Eukaryota but rarely by Bacteria are also reported here for the first time,which might further support the supposed origin of eukaryote from archaeans.
基金Project(2009QNA6015) supported by the Fundamental Research Funds for the Central Universities of ChinaProject(Y3110055)supported by the Natural Science Foundation of Zhejiang Province,ChinaProject(Y200803219) supported by the Foundation of Zhejiang Educational Committee of China
文摘The relationship between Solidago canadensis L. invasion and soil microbial community diversity including functional and structure diversities was studied across the invasive gradients varying from 0 to 40%, 80%, and 100% coverage of Solidago canadensis L. using sole carbon source utilization profiles analyses, principle component analysis （PCA） and phospholipid fatty acids （PLFA） profiles analyses. The results show the characteristics of soil microbial community functional and structure diversity in invaded soils strongly changed by Solidago canadensis L. invasion. Solidago canadensis L. invasion tended to result in higher substrate richness, and functional diversity. As compared to the native and ecotones, average utilization of specific substrate guilds of soil microbe was the highest in Solidago canadensis L. monoculture. Soil microbial functional diversity in Solidago canadensis L. monoculture was distinctly separated from the native area and the ecotones. Aerobic bacteria, fungi and actinomycetes population significantly increased but anaerobic bacteria decreased in the soil with Solidago canadensis L. monoculture. The ratio of cyl9：0 to 18：1 co7 gradually declined but mono/sat and fung/bact PLFAs increased when Solidago canadensis L. became more dominant. The microbial community composition clearly separated the native soil from the invaded soils by PCA analysis, especially 18： lco7c, 16： lco7t, 16： lco5c and 18：2co6, 9 were present in higher concentrations for exotic soil. In conclusion, Solidago canadensis L. invasion could create better soil conditions by improving soil microbial community structure and functional diversity, which in turn was more conducive to the growth ofSolidago canadensis L.
文摘This study aims to assess the impact of monospecific Tectona grandis forest plantation on the soil mite abundance and diversity. To achieve these objectives, two sites situated in Ivory Coast were investigated. The first, a primary forest was characterized by a very weak human activities whereas the second, a teak plantation was characterized by a high disturbance performed during the planting. After extracting, sorted and description, 116 mite species were described in the two sites. Mite densities were lower in teak plantation and also higher in the litter and decreased to the depth in both sites. Species richness re- corded in teak plantation （52 species） was significantly lower compared to primary forest （98 species）. The same trend was ob- served for Oribatida but not for Gamasida. The lower Oribatida （5 vs. 17） and higher Oribatida （24 vs. 41） were recorded respec- tively in teak plantation and primary forest. Mite Shannon index and evenness were significantly different between sites. High Jaccard index values and the appearance of exclusive species in both habitats showed that the sites are very distinct. Total number of species recorded corresponded to 58%-63% of the total number of species estimated by ACE and Chao 1＆2 estimators, indi- cating that the sampling effort was not sufficient. Mite abundance and diversity varied depending on the characteristics of habi- tats. Chemical element （Corn, Ctot, Ntot, and SOM） values were lower in teak plantation （disturbed habitat） and significantly dif- ferent to primary forest in the topsoil. Apart from litter height, soil depth, pH and C/N ratio, others variables were strongly corre- lated to mite abundance and diversity [Current Zoology 59 （5）： 633-643, 2013].
基金supported by DBT Network Project (BT/PR7928/NDB/52/9/2006)Department of Biotechnology(DBT),Govt. of India
文摘Tree species diversity and population structure at different community types were described and analyzed for primary and secondary lowland moist deciduous forests in Tripura. Overall 10,957 individual trees belonging to 46 family, 103 genera and 144 species were counted at ≥30 cm DBH （diameter at breast height） using 28 permanent belt transects with a size of 1 ha （10 m × 1000 m）. Four different tree communities were identified. The primary forests was dominated by Shorea robusta （mean density 464.77 trees.ha^-1, 105 species） and Schima wallichii （336.25 trees.ha^-1, 82 species）, while the secondary forests was dominated by Tectona grandis （333.88 trees.ha^-1, 105 species） and Hevea brasiliensis （299.67 trees.ha^-1, 82 species）. Overall mean basal area in this study was 18.01m2.ha^-1; the maximum value was recorded in primary Shorea forest （26.21 m2.ha^-1）. Mean density and diversity indices were differed significantly within four different communities. No significant differences were observed in number of species, genera, family and tree basal cover area. Significant relationships were found between the species richness and different tree population groups across the communities. Results revealed that species diversity and density were increased in those forests due to past disturbances which resulted in slow accumu- lation of native oligarchic small tree species. Seventeen species were recorded with 〈2 individuals of which Saraca asoka （Roxb.） de Wilde and Entada phaseoloides （L.） Men＇. etc. extensively used in local ethnomedicinal formulations. The present S. robusta Gaertn dominated forest was recorded richer （105 species） than other reported studies. Moraceae was found more speciose family instead of Papilionaceae and Euphorbiaceae than other Indian moist deciduous forests. Seasonal phenological gap in such moist deciduous forests influenced the population of Trachypithecus pileatus and capped langur. The analysis of FIV suggested a slow trend of shifting the population of Lamiaceae group by Moraceae species in secondary T. grandis L. dominated community.
