Relationship between diversity of forest plant species and environmental gradient in eastern mountainous area of Heilongjiang Province, China

Twenty-three secondary forest communities with different structure were selected in Mao＇er Mountain National Park of Heilongjiang Province, China to study the relationship between diversity of forest plant species and environmental gradient. The forest plant species diversity was analyzed by the diversity index, and the environmental factors was quantified by the method of Whittaker＇s quantification of environmental gradient. Meanwhile, β-diversity indexes of communities were calculated with similar measurements. The results showed that the Shannon-wiener diversity index of forest plant species increased with the increase of the environmental gradient, and the β-diversity indexes of communities showed a liner increase along with the change of environmental gradient.

Plant biological diversity in natural secondary forests on Mao'er Mountains

The forest plant biological diversity investigations were conducted in Laoyeling Forest Ecological Experimental Station on Mao’er Mountains in eastern Heltongjiang Province. Sample plots were six different forest communities. Field works were divided into three seasons : spring, summer and autumn in one year. The results showed that forest plant biological diversity varied with seasons as well as growth forms. Herb species diversity values were the highest in the community growth forms. Diversity indices No, H’ and E1 were selected out as the best richness, diversity and evenness indices to indicate the biological diversity in forest community.

Community structure and species diversity dynamics of a subtropical evergreen broad-leaved forest in China:2005 to 2020

Here,we characterize the temporal and spatial dynamics of forest community structure and species diversity in a subtropical evergreen broad-leaved forest in China.We found that community structure in this forest changed over a 15-year period.Specifically,renewal and death of common species was large,with the renewal of individuals mainly concentrated within a few populations,especially those of Aidia canthioides and Cryptocarya concinna.The numbers of individual deaths for common species were concentrated in the small and mid-diameter level.The spatial distribution of community species diversity fluctuated in each monitoring period,showing a more dispersed diversity after the 15-year study period,and the coefficient of variation on quadrats increased.In 2010,the death and renewal of the community and the spatial variation of species diversity were different compared to other survey years.Extreme weather may have affected species regeneration and community stability in our subtropical monsoon evergreen broad-leaved forests.Our findings suggest that strengthening the monitoring and management of the forest community will help better understand the long-and short-term causes of dynamic fluctuations of community structure and species diversity,and reveal the factors that drive changes in community structure.

Tree species diversity and stand structure along major community types in lowland primary and secondary moist deciduous forests in Tripura,Northeast India

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.

Research on Species Diversity Characteristics of Chinese Endemic Plant Populus shanxiensis

[Objective] This study aimed at researching the species diversity of Populus shanxiensis community in Heichashan Mountain. [Method] Based on sampling methods, investigation in sampling spots was carried out according to the important indicator, the abundance index （N0）, Simpson index （λ）, Shannon-Weiner index （H＇） and homogeneity index （E1 and E5） were used for analysis. [Results] Species diversity index of Populus shanxiensis community was not only depended on the species compositions of communities, but also closely related to the important value of species. The order of abundance index and diversity index in each layer of Populus shanxiensis community was herb layershrub layertree layer, and the abundance index was positively related to the diversity index; while the variation trend of community homogeneity index was different from that of abundance index and diversity index, and the homogeneity had shown negative correlation with the dominance. [Conclusion] In this study, the growth status and conditions of Populus shanxiensis were further understood and researched, which had laid theoretical foundation for protecting the endangered species and provided basic information for the future studies of endangered species and related disciplines.

Topography and soil content contribute to plant community composition and structure in subtropical evergreen-deciduous broadleaved mixed forests

Topography and soil factors are known to play crucial roles in the species composition of plant communities in subtropical evergreen-deciduous broadleaved mixed forests.In this study,we used a systematic quantitative approach to classify plant community types in the subtropical forests of Hubei Province(central China),and then quantified the relative contribution of drivers responsible for variation in species composition and diversity.We classified the subtropical forests in the study area into 12 community types.Of these,species diversity indices of three communities were significantly higher than those of others.In each community type,species richness,abundance,basal area and importance values of evergreen and deciduous species were different.In most community types,deciduous species richness was higher than that of evergreen species.Linear regression analysis showed that the dominant factors that affect species composition in each community type are elevation,slope,aspect,soil nitrogen content,and soil phosphorus content.Furthermore,structural equation modeling analysis showed that the majority of variance in species composition of plant communities can be explained by elevation,aspect,soil water content,litterfall,total nitrogen,and total phosphorus.Thus,the major factors that affect evergreen and deciduous species distribution across the 12 community types in subtropical evergreendeciduous broadleaved mixed forests include elevation,slope and aspect,soil total nitrogen content,soil total phosphorus content,soil available nitrogen content and soil available phosphorus content.

Plant diversity patterns in different forests in Aershan,Inner Mongolia

Taking the communities of the sample sites in Aershan of Inner Mongolia as an investigation object, the indices affecting plant diversity were studied. The investigation was carried out in three different forest types （natural forests, plantations and regenerated forests after fire）. Results show that 95 plant species belonging to 19 families and 50 genera were identified in total. Of these species, nine were arbors, six were shrubs and the other 80 were herbs. We found some differences in the dominant species of different layers in three forest types. Natural forests had the largest importance value for the total number of species, followed by plantations and regenerated forests after fire. Plantations and natural forests had a similar change in richness indices. The largest value of richness indices was obtained in natural forests, while the lowest value was in regenerated forests after fire. Three diversity indices （Simpson＇s, Shannon-Wiener and Pielou＇s indices） indicate a similar trend in all sample plots. With an increase in elevation, values of diversity indices first increased and then decreased. In different forest types, similarity between natural forests was largest, while similarity between the regenerated forests and plantations was lowest.

Plant diversity and phenological pattern in the montane wet temperate forests of the southern Western Ghats,India

Plants diversity and phenological pattern of the trees were monitored in a montane wet temperate forest （shola） in the Kukkal Forest, Palni hills of the southern Western Ghats, India. Twelve random plots were selected for sampling the vegetation. For phenological studies, twenty-three fleshy fruit trees were identified in the study area and 10 individuals of each species were selected to record the phenological events fortnightly between April 2002 and April 2004. The phenological events were divided into vegetative and reproductive phases. A total of 2279 individuals were inventoried which belong to 83 species, 68 genera and 40 families. About 30% of the species were endemic to the Western Ghats. The most dominant species （〉 1 cm dbh） was Psychotria nilgiriensis var. astephana （Rubiaceae）, which accounted for 12% of the total sampled individuals. Lauraceae was the dominant family accounting for 20% of the individuals. Fruiting peak occurred in July 2003 and least in June 2002. During the peak period, fruits of 85 individuals of six species were observed. Syzygium tamilnadensis, Ilex wightiana and Beilschmiedia wightii fruited only once during the two years of study. The number of fruiting species showed no correlation with rainfall （r = 0.26, p = 0.2）, while a correlation was found with fruit abundance （r = 0.40, p 〈 0.05）. The results indicate that the montane wet temperate forest is unique in their diversity and a conspicuous display in phenology.

Plant Diversity of Maoershan National Forest Park

There are a wide variety of wild plants in Maoershan National Forest Park.According to a fiveyear survey,the plants are found to include 557 species belonging to 116 families and 335 genera.There are 10 dominant families,such as Asteraceae,Ranunculaceae,Rosaceae,Fabaceae,and Chenopodiaceae,including 251 species,accounting for 46.06% of the total.There are 9 dominant genera,such as Polygonum,Potentilla ,Viola ,Artemisia ,and Corydalis ,which include 82 species of plants,accounting for 14.72% of the total.This study statistically analyzed the diversity and function of plants in the park and classified useful plants to provide a basis for the conservation and development of plant resources in Maoershan National Forest Park.

Glade and Forest-Edge Plant Community Attributes for Three Glade Types in Arusha National Park, Tanzania

The aim of the study was to compare glade and forest-glade edge plant community attributes for man-made, upper and lower natural glades. Two plots were set up in twelve glades at 2.5, 12.5 m and three plots in thirteen glades at 2.5, 12.5 and 22.5 m depending on the size of the glade. The results showed that plants total abundance, percentage basal cover, species richness and species diversity for upper and lower natural glades differed significantly p < 0.05 and p < 0.01 respectively and species diversity for man-made glades p < 0.001. Plant species abundance, richness and diversity were highest at the forest-glade edge and decreased towards the glade interior. Plant species composition of the three glades types differed significantly (MRPP: T = -4.51, p < 0.001 and A = 0.17). Grasses’ total abundance and species richness and forbs species diversity differed significantly for man-made glades p < 0.01. For upper natural glades, grasses species richness was highly significant p < 0.001 while for forbs species richness and diversity were significant P < 0.01. Lower natural glades grasses and forbs’ total abundance, species richness and species diversity differed significantly p < 0.01 and p < 0.001 respectively. Growth forms in the lower natural glades were associated with the forest-glade edge or glade interior χ2 = 15.95, df = 4, p Eleusine jaegeri, Heterogon contortus, Senna mimisoides, Digitaria scalarum, Clutia abyssinica) were habitat indicators for disturbed areas, wet humid grey/black clay soils for upper natural glades and three (Solanum incanum, Senna didymobotrya, and Pennistem mezianum, were indicators of overgrazed areas and black clay soils for man-made glades. In conclusion, plant species abundance, richness and diversity were highest at the forest-glade edge and decreased towards the glade interior, while plant species composition differed significantly between the three-glade types. The plant growth form for lower natural glades was associated with forest-glade edge and glade interior.

Native Species Composition and Diversity of Valuable Woody Plants Regeneration during Fallow Period in Kamwatta, Moruca, Guyana

An intelligent method of shifting cultivation to regenerate vegetation after a long fallow period is critical information for restoration strategies. The literature review identified that the assessment of woody plant species on abandoned farmland has never been done before in Kamwatta, Moruca Region 1. In addition, more information should be available in indigenous communities and at the national level, including more documentation of the utilization of natural resources by the Warrau community. This study assessed the valuable woody plant species that grew during the fallow periods. Nine farmlands were randomly selected along a 100 m transect, each with varying fallow periods. In order to collect information on the age of farm abandonment, the researcher employed a mixed-methods approach. First, we found how long each farm had been fallow by administering a semi-structured questionnaire. Then, we conducted a flora survey to gain information on the variety and abundance of valuable plants using the age of farm abandonment as a dependent variable. The data analysis included the number of valuable woody trees with a diameter of >10 cm, seedlings and saplings with a diameter of <10 cm, the location of identified trees, and the uses of identified tree species. Microsoft Excel was used to code and analyze the questionnaire, while QGIS, Shannon’s Index of Diversity, and Simple Linear Regression were used to analyze the inventory data. The results showed that the respondents listed 38 valuable woody species, and 79% occurred in the studied area. The field verification revealed that the dominant family in the area was Mimosaceae. Species abundance increased with fallow up to 10 years before declining in the latter years. Plant diversity and abundance had a weak relationship with the age of abandoned farmlands for woody trees, while the seedlings and saplings showed no relationship.

Study on Plant Community Feature of Nanjing Temple Gardens

10 temple courtyards and 10 temple gardens were chosen as the research object in Nanjing.There were 146 species of vascular plants(including variety),which belong to 96 genera and 63 families.The Richness index,Simpson index,Species diversity and Similarity index of the plant community were analyzed.The results showed:①The dominant species of temple courtyards and temple gardens were all trees;the density of shrub layer(0.32 strains/m2) was greater than that of the tree layer(0.21 strains/m2).And the density of tree layer(2.4 strains/m2) and shrub layer(4.5 strains/m2) in temple gardens were totally higher than those of temple courtyards.②Both the Simpson index and the Species diversity in temple garden plots were higher than those of the temple courtyard plots;The Pielou index was at a higher level both in tree layer and shrub layer,which indicated that quantities of each tree species were on an average level.③The Similarity index in temple gardens was higher than that of the temple courtyards,both less than 50%,which indicated that the repetition rate of each tree species was obviously greater in temple gardens than in temple courtyards.

Elevational changes in vascular plants richness, diversity, and distribution pattern in Abune Yosef mountain range, Northern Ethiopia

The aim of this research is to investigate the patterns of vascular plant species richness,diversity,and distribution along an elevation gradient in the Abune Yosef mountain range,Ethiopia.Preferential systematic sampling was employed to collect vegetation and environmental data along the elevation gradient.We found that plant species richness declines monotonically from low to high elevations.Specifically,vascular plant species richness and diversity were lower in the Afroalpine grassland(high elevation)than in the Dry evergreen Afromontane forest and Ericaceous forest(low elevations).In contrast,endemic vascular plant richness was significantly higher in the Afroalpine grassland than in the Dry evergreen Afromontane forest and Ericaceous forest.Elevation showed a significant impact on the richness,diversity,and endemism of vascular plants.According to Sorensen's coefficient,the similarity between Dry evergreen Afromontane forest and Ericaceous forest vegetation types is higher(32%)than the similarity between Ericaceous forest and Afroalpine grassland(18%).Only 5%similarity was recorded between the Dry evergreen Afromontane forest and Afroalpine grassland.Growth forms showed different elevationai richness patterns.Trees and liana increased monotonically up to 3300 m.Shrub and herb richness patterns followed a hump-shaped and inverted hump-shaped pattern along the elevation gradient.The elevation patterns of vascular plant species richness,diversity,and growth form in the present study may be attributed to differences in management intensity,spatial heterogeneity,microclimatic variations,and anthropogenic disturbances.

Vertical patterns in plant diversity and their relations with environmental factors on the southern slope of the Tianshan Mountains(middle section)in Xinjiang(China)

The investigation of distribution patterns of species diversity is significant for successful biodiversity conservation. The spatial patterns of vegetation and different life-forms species diversity along an elevation gradient in the middle section of the southern slope of the Tianshan Mountains in Xinjiang, China were explored, using the detrended canonical correspondence analysis （DCCA） and the generalized additive model （GAM） methods based on a field survey of 53 sampling plots. In this work 158 species of seed plants were recorded, including 141 herbaceous, 14 shrub, and 2 tree species, in which the woody plants are very limited. 53 sampling plots were classified into 9 major plant communities. The results indicate that the herb communities were the most sensitive to changes in elevation gradient. The diversity indices of the community as a whole presented bimodal patterns. The peak values for the species diversities were found in the transition region between mountain steppe desert and mountain desert steppe （2,200-2,300m）, and in the alpine grassland region （2,900-3,100m）, while maximum species diversities were in the areas of intermediate environmental gradient. The main environmental factors on the distribution patterns in plant diversity were the elevation, soft water, total nitroeen, available nitrogen, organic matter, and total salt. The response tendency of the four diversity indices for the whole community to the soil environment was the same as that of the herb layers.

Hurricane disturbances, tree diversity, and succession in North Carolina Piedmont forests, USA

Windthrow plays a critical role in maintaining species diversity in temperate forests. Do large-scale strong wind events(i.e., tropical cyclones, including hurricanes,typhoons and severe cyclonic storms) increase tree diversity in severely damaged forest areas? Do hurricanes(tropical cyclones that occurs in the Atlantic Ocean and northeastern Pacific Ocean) lead to altered relative abundance of shade-tolerant and shade-intolerant species? Did historic hurricanes alter the succession trajectory of the damaged forests? We used nearly 70-year tree demographic data to assess the effects of two major hurricanes on woody species diversity in Piedmont forests, North Carolina, USA. Species richness(S) and Shannon–Wiener's diversity index(H') were used to evaluate the changes in tree diversity. The changes in composition were assessed with Nonmetric Multidimensional Scaling. The pre-hurricane successional phase can strongly influence both the damage severity and subsequent responses. Although there is often an immediate drop in diversity following a hurricane, understory tree diversity quickly increases to levels that exceed those prior to the disturbance. This leads to an increase in diversity in stands that were substantially damaged. Hurricanes significantly decrease the dominance of shade-intolerant canopy species while increasing preestablished, more shade-tolerant species. We conclude that large, and infrequent hurricanes help to maintain local tree diversity, but also accelerate the increase in dominance of understory species such as red maple and beech.

Trait variation and functional diversity maintenance of understory herbaceous species coexisting along an elevational gradient in Yulong Mountain,Southwest China

Characterizing trait variation across different ecological scales in plant communities has been viewed as a way to gain insights into the mechanisms driving species coexistence.However,little is known about how changes in intraspecific and interspecific traits across sites influence species richness and community assembly,especially in understory herbaceous communities.Here we partitioned the variance of four functional traits(maximum height,leaf thickness,leaf area and specific leaf area)across four nested biological scales:individual,species,plot,and elevation to quantify the scale-dependent distributions of understory herbaceous trait variance.We also integrated the comparison of the trait variance ratios to null models to investigate the effects of different ecological processes on community assembly and functional diversity along a 1200-m elevational gradient in Yulong Mountain.We found interspecific trait variation was the main trait variation component for leaf traits,although intraspecific trait variation ranged from 10% to 28% of total variation.In particular,maximum height exhibited high plasticity,and intraspecific variation accounted for 44% of the total variation.Despite the fact that species composition varied across elevation and species richness decreased dramatically along the elevational gradient,there was little variance at our largest(elevation)scale in leaf traits and functional diversity remained constant along the elevational gradient,indicating that traits responded to smaller scale influences.External filtering was only observed at high elevations.However,strong internal filtering was detected along the entire elevational gradient in understory herbaceous communities,possibly due to competition.Our results provide evidence that species coexistence in understory herbaceous communities might be structured by differential niche-assembled processes.This approach ee integrating different biological scales of trait variation ee may provide a better understanding of the mechanisms involved in the structure of communities.

Large-scale forest inventories of the United States and China reveal positive effects of biodiversity on productivity

Background： With the loss of species worldwide due to anthropogenic factors, especially in forested ecosystems, it has become more urgent than ever to understand the biodiversity-ecosystem functioning relationship （BEFR）. BEFR research in forested ecosystems is very limited and thus studies that incorporate greater geographic coverage and structural complexity are needed. Methods： We compiled ground-measured data from approx, one half million forest inventory sample plots across the contiguous United States, Alaska, and northeastern China to map tree species richness, forest stocking, and productivity at a continental scale. Based on these data, we investigated the relationship between forest productivity and tree species diversity, using a multiple regression analysis and a non-parametric approach to account for spatial autocorrelation. Results： In general, forests in the eastern United States consisted of more tree species than any other regions in the country. The highest forest stocking values over the entire study area were concentrated in the western United States and Central Appalachia. Overall, 96.4 % of sample plots （477,281） showed a significant positive effect of species richness on site productivity, and only 3.6 % （17,349） had an insignificant or negative effect. Conclusions： The large number of ground-measured plots, as well as the magnitude of geographic scale, rendered overwhelming evidence in support of a positive BEFR. This empirical evidence provides insights to forest management and biological conservation across different types of forested ecosystems. Forest timber productivity may be impaired by the loss of species in forests, and biological conservation, due to its potential benefits on maintaining species richness and productivity, can have profound impacts on the functioning and services of forested ecosystems.

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

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

Investigation and Study on Plant Communities in Baise Forest Park

Plant community structures of Baise Forest Park were analyzed through the field investigation. The results showed that there are 76 tree species of 69 genera and 41 families in the park. According to the species diversity analysis, among the 5 subareas recreational area has the highest diversity and evenness indexes, zoo has lower diversity index of plant community. Three-dimensional analysis of plant community shows that the community has simple structures, limited landscape layers and shrub coverage, a few lawn species and poor landscape effect. Analysis of its ecological habits shows that evergreen species in all 5 subareas of the park are more than deciduous species, and there are only a few ornamental tree species.

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

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