Quantifyingα-diversity as a continuous function of location——a case study of a temperate forest

α-diversity describes species diversity at local scales.The Simpson’s and Shannon-Wiener indices are widely used to characterizeα-diversity based on species abundances within a fixed study site(e.g.,a quadrat or plot).Although such indices provide overall diversity estimates that can be analyzed,their values are not spatially continuous nor applicable in theory to any point within the study region,and thus they cannot be treated as spatial covariates for analyses of other variables.Herein,we extended the Simpson’s and Shannon-Wiener indices to create point estimates ofα-diversity for any location based on spatially explicit species occurrences within different bandwidths(i.e.,radii,with the location of interest as the center).For an arbitrary point in the study region,species occurrences within the circle plotting the bandwidth were weighted according to their distance from the center using a tri-cube kernel function,with occurrences closer to the center having greater weight than more distant ones.These novel kernel-basedα-diversity indices were tested using a tree dataset from a 400 m×400 m study region comprising a 200 m×200 m core region surrounded by a 100-m width buffer zone.Our newly extendedα-diversity indices did not disagree qualitatively with the traditional indices,and the former were slightly lower than the latter by<2%at medium and large band widths.The present work demonstrates the feasibility of using kernel-basedα-diversity indices to estimate diversity at any location in the study region and allows them to be used as quantifiable spatial covariates or predictors for other dependent variables of interest in future ecological studies.Spatially continuousα-diversity indices are useful to compare and monitor species trends in space and time,which is valuable for conservation practitioners.

Diversity Analysis of Chlorophyll, Flavonoid, Anthocyanin, and Nitrogen Balance Index of Tea Based on Dualex

The chemical compositions of tea(Camellia sinensis)are affected by numerous factors,such as cultivar,climate,leaf position,and cultivation pattern.However,under the same conditions,the chemical compositions are mainly determined by varieties.Therefore,we investigated the genetic diversity of chemical compositions of tea tree resources in China to screen excellent germplasm resources.Three chemical compositions index(including chlorophyll index,flavonoid index,and anthocyanin index)and the nitrogen balance index of tea leaves were measured in 102 tea germplasms planted in Chinese Tea Plants Improved Variety Germplasm Resources Nursery(CTPIVGRN)by Dualex on April 152019.Results showed that the chlorophyll,flavonoid,and anthocyanin contents and the nitrogen balance index significantly differed between the 102 tea germplasms.The genetic diversity index values were 2.005,2.246,1.599,and 1.838,and the average genetic diversity was 1.922.The 102 tea germplasms can be divided into four categories by cluster analysis under the genetic distance threshold of 11.These results suggest that the genetic diversity of tea germplasm resources in China is rich.This study’s results can serve as a basis for the diversified development and utilization of tea plant.

The Rich-Gini-Simpson quadratic index of biodiversity

The Gini-Simpson quadratic index is a classic measure of diversity, widely used by ecologists. As shown recently, however, this index is not suitable for the measurement of beta diversity when the number of species is very large. The objective of this paper is to introduce the Rich- Gini-Simpson quadratic index which preserves all the qualities of the classic Gini-Simpson index but behaves very well even when the number of species is very large. The additive partitioning of species diversity using the Rich-Gini- Simpson quadratic index and an application from island biogeography are analyzed.

ANALYSIS OF HABITAT PATTERN CHANGE OF RED-CROWNED CRANES IN THE LIAO HE DELTA USING SPATIAL DIVERSITY INDEX

Habitat pattern change of red-crowned cranes (Grus japonensis) in t he Liaohe Delta between 1988 and 1998 was analyzed with the help of Spatial Dive rsity Index based on remote sensing data and field investigation. The result sho wed that the influence from human activities on the wetland habitat of red-crow ned cranes was prominent with the development of oil and agricultural exploitati on, and the habitat pattern of red-crowned cranes had been obviously changed by the human disturbance during the ten years. The areas with high Spatial Diversi ty values (SD≥0.65) and that with mid-high values (0.5≤SD< 0.65), which const ituted the main part of suitable habitat of red-crowned cranes,had reduced to 9142ha and 5576ha respectively, with the shrinking of natural land cover, such a s reed and Suaeda community. The habitat pattern became more fragmented, which w as caused by roads and wells during oil exploration. It was indicated that the s uitability and quality of habitat for red-crowned cranes in the Liaohe Delta we re degraded in the last decade. The results also showed that diversity index cou ld reflect the habitat suitability of red-crowned cranes quantitatively and des cribe the spatial pattern of the habitat explicitly. This study will provide a s cientific basis for habitat protection of red-crowned cranes and other rare spe cies in wetlands.

The weighted quadratic index of biodiversity for pairs of species: a generalization of Rao’s index

The distribution of biodiversity at multiple sites of a region has been traditionally investigated through the additive partitioning of the regional biodiversity, called γ-diversity, into the average within-site biodiversity or α-diversity, and the biodiversity among sites, or β-diversity. The standard additive partitioning of diversity requires the use of a measure of diversity which is a concave function of the relative abundance of species, like the Shannon entropy or the Gini- Simpson index, for instance. When a phylogenetic distance between species is also taken into account, Rao’s quadratic index has been used as a measure of dissimilarity. Rao’s index, however, is not a concave function of the distribution of relative abundance of either individual species or pairs of species and, consequently, only some nonstandard additive partitionings of diversity have been given using this index. The objective of this paper is to show that the weighted quadratic index of biodiversity, a generalization of the weighted Gini-Simpson index to the pairs of species, is a concave function of the joint distribution of the relative abundance of pairs of species and, therefore, may be used in the standard additive partitioning of diversity instead of Rao’s index. The replication property of this new measure is also discussed.

Phenotypic diversity in Ethiopian durum wheat(Triticum turgidum var.durum)landraces

The phenotypic diversity of 274 Ethiopian durum wheat accessions was analyzed, taking their geographic origins into account. The aim was to assess the extent and patterns of agronomically important phenotypic variation across districts of origin and altitude classes for major qualitative traits using diversity index and multivariate methods. Eight qualitative and three quantitative traits were scored for 2740 plants and analyzed for diversity. The Shannon–Weaver diversity(H′) index was used to estimate phenotypic diversity. The estimated H′ ranged from monomorphic for glume hairiness to highly polymorphic for other traits. The highest(0.86) H′ was obtained for seed degree of shriveling, possibly indicating the differential responses of the genotypes to water deficit during later growth stages. With respect to district of origin, the highest(0.72) and lowest(0.44) H′ values were obtained for the Bale and SNNP districts, respectively. With respect to altitude, the highest(0.76) and lowest(0.62) H′ values were recorded for altitudes 1600–2000and > 3000 m above sea levels, respectively. Principal components analysis explained substantial variation contributed by district of origin and altitude range. Genotypes were clustered into three groups by districts of origin and altitude class, with relatively strong bootstrap values of 57 and 62 for the former and latter, respectively. It could be concluded that Ethiopian durum wheat landraces are very diverse both within and among districts of origin and altitude classes. This wealth of genetic diversity should be exploited for wheat improvement of yield and for resistance to biotic and abiotic stresses, particularly terminal drought.

Thinning intensity affects microbial functional diversity and enzymatic activities associated with litter decomposition in a Chinese fir plantation

Microbial functional diversity and enzymatic activities are critical to maintaining material circulation during litter decomposition in forests.Thinning,an important and widely used silvicultural treatment,changes the microclimate and promotes forest renewal.However,how thinning affects microbial functional diversity and enzymatic activities during litter decomposition remains poorly understood.We conducted thinning treatments in a Chinese fir plantation in a subtropical region of China with four levels of tree stem removal（0,30,50,and 70%）,each with three replicates,and the effects of thinning on microbial functional diversity and enzymatic activities were studied 7 years after treatment by collecting litter samples four times over a 1-year period.Microbial functional diversity and enzymatic activities were analyzed using Biolog Ecoplates（Biolog Inc.,Hayward,CA,USA）based on the utilization of 31 carbon substrates.Total microbial abundance during litter decomposition was lower after the thinning treatments than without thinning.Microbial functional diversity did not differ significantly during litter decomposition,but the types of microbial carbon-source utilization did differ significantly with the thinning treatments.Microbial cellulase and invertase activities during litter decomposition were significantly higher under the thinning treatments due to changes in the litter carbon concentration and the ratios of carbon and lignin to nitrogen.The present study demonstrated the important influence of thinning on microbial activities during litter decomposition.Moderate-intensity thinning may maximize vegetation diversity and,in turn,increase the available substrate sources for microbial organisms in litter and promote nutrient cycling in forest ecosystems.

Diversity and structural composition of species in dipterocarp forests:a study from Fasiakhali Wildlife Sanctuary, Bangladesh

Fasiakhali Wildlife Sanctuary is a protected area composed of tropical remnant rainforest that harbor substantial number of large,old Garjan（Dipterocarpus spp.）trees.The present study assessed composition,structure and diversity of the species in this protected area.A total of 32 trees species were recorded with DBH ≥ 11 cm belonging to 24 genera and 19 families.The forest is low in plant diversity as represented by Shannon–Wiener diversity and Simpson Dominance indices.Dipterocarpus turbinatus was the most dominant species with maximum relative density,frequency,dominance,and importance value index.Syzygium firmum and Tectona grandis followed in terms of dominance.The structural composition indicated higher number of individuals in the medium growth classes（41 to 〈 511 cm DBH and 16–20 m height ranges）,whereas D.turbinatus was the only species that dominated most of the growth classes.Poor stem density in lower growth classes indicated meager recruitment of regeneration which may be due to lower annual precipitation,increased grazing and encroachments.This study will help to understand the patterns of tree species composition and diversity in the remnant dipterocarp forests of Bangladesh.It will also contribute to identifying threatened plants to undertake D.turbinatus based conservation and sustainable management of the Fasiakhali Wildlife Sanctuary.

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.

Quantifying forest structural diversity based on large-scale inventory data:a new approach to support biodiversity monitoring

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.

Woody plant diversity,structure and regeneration in the Ambo State Forest,South Gondar Zone,Northwest Ethiopia

For this study in the Ambo State Forest on woody plant diversity, structure and regeneration, 70 quadrats, each 25 m by 25 m, were selected using a systematic random sampling technique and intervals of 100 m along a transect line. For assessing seedlings and saplings, two 2 × 10 m sub quadrats were set upon opposite sides of each main quadrat. Data on species diversity, abundance, structure, basal area, density, frequency and regeneration status were collected and analyzed using standard procedures and programs. Of 58 woody plant species identified, 69 % were trees, 16 % were shrubs, 12 % were tree/shrubs and 4 % were climbers. Fabaceae was the most speciesrich family comprising 17 species. The Shannon-Weiner diversity index was 2.73, and evenness was 0.67. The population structure in the cumulative diameter class frequency distribution revealed an interrupted and inverted J-shape with a very high decrease in higher diameter class. Acacia lahai （49 %） was the most important woody species with the highest importance value index. To maintain balanced structure, enhanced regeneration and protecting the forest from selective cutting are recommended.

Assessing the influence of harvesting intensities on structural diversity of forests in south-west Germany

Background: To increase ecosystem resilience and biodiversity, the maintenance and improvement of structural and compositional diversity of forests has become an important goal in forest management for many forest owners and jurisdictions. At the same time, future harvesting intensity (HI) may increase to meet the demand for woody biomass by an increasing bioeconomy sector. Yet, the influence of HI on forest structural diversity is largely unknown. Here, we address this issue by analyzing the relationship between HI and structural diversity based on large-scale national forest inventory (NFI) data, where the latter is quantified using a previously developed Forest Structure Index and HI is expressed as wood volume removal during the period 2002-2012 for the same inventory plots. Results: Our results show a surprisingly small impact of harvesting intensity on changes in structural diversity for most of the analysed types of forests. Only intense harvesting (> 80%-90% of initial growing stock) led to a significant reduction in structural diversity. At low to moderate HI most aspects of structural diversity were positively influenced. Only the quadratic mean DBH and the volume of large trees (≥ 40 cm DBH) were substantially negatively influenced at HI > 60% and 70% of initial growing stock, respectively. Conclusions: In several forest types, HI could be increased without a reduction in overall structural diversity. Hence, structural diversity in these selectively managed forests appears to be a very resistant forest property in relation to HI. Other indicators at stand and landscape scale may be needed to adjust levels of HI that are suited to maintain forest biodiversity.

Spatial pattern of tree diversity and evenness across forest types in Majella National Park,Italy

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.

Effect of exclosure ages on woody plant structure,diversity and regeneration potential in the western Tigray region of Ethiopia

Exclosure is a method of rehabilitating degraded lands by protecting them from the interference of animals and from human encroachment, and is used to regenerate native vegetation as a way to reduce soil erosion, increase rain water infiltration and provide fodder and woody biomass in degraded grazing lands. Therefore, we studied woody plant structure, diversity and regeneration potentials in 5-and 10-year grazing exclosures in comparison with open grazed sites in a semi-arid environment. Data on species diversity, abundance, structure, basal area, frequency, density, and regeneration status were collected from 270 sample plots. Forty-one woody species representing 20 families were identified, with 18, 28 and 38 species found in open grazed areas, and in 5-and 10-year grazing exclosures, respectively. The 10-year grazing exclosures had a higher(P <0.05) species richness and plant densities compared to the 5-year grazing exclosures and the open grazed areas. The population structure and regeneration status of woody species in both grazing exclosures showed an inverted J-shape, indicating a healthy regeneration status, whereas hampered regeneration was observed in open grazed areas. The establishment of grazing exclosures had positive effects in restoring woody plant diversity and improving vegetation structure and regeneration potentials of degraded grazing lands.

Stand Structure, Diversity and Regeneration Status of Woody Species in Open and Exclosed Dry Woodland Sites around <i>Molapo</i>Farming Areas of the Okavango Delta, Northeastern Botswana

Stand structure, diversity and regeneration status of woody species were investigated in open and exclosed dry woodland sites in Island Safari, Shorobe and Xobe, northeastern Botswana. A total of 105, 111 and 130 quadrats, measuring 20 × 20 m each, were laid down along parallel line transects in the three sites, respectively, to collect data. A total of 47 species, representing 16 families and 24 genera, were recorded in the study sites. Of these, 33 species representing 13 families and 20 genera, 41 species representing 15 families and 23 genera and 27 species representing 10 families and 14 genera were encountered in Island Safari, Shorobe and Xobe, respectively. The most diverse family was Fabaceae followed by Combretaceae and Tiliaceae at all the three sites. The most diverse genus was Acacia, followed by Combretum and Grewia. The diversity of woody species in the study sites were 2.18, 2.15 and 1.5 in Shorobe, Island Safari and Xobe, respectively, while their corresponding evenness values were 0.6, 0.6 and 0.5, respectively. The mean densities of the woody species encountered in Island Safari, Shorobe and Xobe were 2629, 4271 and 2745 individuals ha&#451, respectively. The five densest species were Colophospermum mopane, Dichrostachys cinerea, Acacia tortilis, Philenoptera violacea and Terminalia prunioides in Island Safari, C. mopane, A. tortilis, A. erioloba, P. violacea and D. cinerea in Shorobe and Acacia mellifera, A. tortilis, P. nelsii, A. luederitzii and A. erubescens in Xobe. The highest important value index values were exhibited by C. mopane, D. cinerea, A. tortilis, P. violacea and T. prunioides in Island Safari, C. mopane, A. erioloba, A. tortilis, P. violacea and C. imberbe in Shorobe, and A. mellifera, A. tortilis, P. nelsii and A. luederitzii in Xobe. The alarming result was the fact that 71%, 80% and 85% of the woody species recorded in Island Safari, Shorobe and Xobe, respectively, exhibited hampered regeneration and, thus, unhealthy population structures. Therefore, there is an urgent need to address the observed unhealthy population structures of the woody species through investigation of the major causes of their hampered regeneration, and also designing measures that will facilitate natural and artificial regeneration of these species at the three study sites.

Evaluation of Broadleaf Tree Diversity at the Basin Scale—In Case of Artificial <i>Chamaecyparis obtusa</i>Forests

In recent years, the various functions required of forests, especially the conservation of biodiversity, have been attracting increasing attention in Japan and worldwide. In Japan, 67% of national land is covered by forest, 41% of which is artificial forest (i.e., plantations). Therefore, forest biodiversity conservation efforts should also target artificial forests. In this paper, we seek to promote sustainable forest management that considers biodiversity conservation by examining indices that can be used by forest managers to evaluate the diversity of broadleaf trees. The result was that evaluation of broadleaf tree diversity in artificial forests at a basin scale was possible by combining several types of indicators.

Diversity and Dynamics of Soil Free-Living Nematode Populations in a Mediterranean Agroecosystem

To determine the effect of agricultural management on the dynamics and functional diversity of soil nematode communities in a carrot field at Kibbutz Ramat Hakovesh, Israel, soil samples from 0-10 cm and 10-20 cm depths were collected during the growing season of carrot. Indices were used to compare and assess the response of soil free-living nematode communities to agricultural management. Eighteen nematode families and 20 genera were observed during the growing period, with Cephalobus, Rhabditidae, Aphelenchus, Tylenchus, and Dorylaimus being the dominant genera/families.During the planting, mid-season and post-harvest periods the total number of nematodes at both depths was significantly lower (P ＜ 0.01) in the carrot treatment than in the control plots, while during the harvest period at both depths total nematodes and bacterivores were significantly higher in the treatment plots (P ＜ 0.01). The values of the maturity index (MI) at both depths were found to be significantly lower in the treatment plots than in the control plots during the pre-planting period (P ＜ 0.05). Overall, WI, MI and PPI were found to be more sensitive indicators than other ecological indices for assessing the response of nematode communities to agricultural management in a Mediterranean agroecosystem.

Impact of tree litter identity, litter diversity and habitat quality on litter decomposition rates in tropical moist evergreen forest

Background:Attempts to restore degraded highlands by tree planting are common in East Africa.However,up till now,little attention has been given to effects of tree species choice on litter decomposition and nutrient recycling.Method:In this study,three indigenous and two exotic tree species were selected for a litter decomposition study.The objective was to identify optimal tree species combinations and tree diversity levels for the restoration of degraded land via enhanced litter turnover.Litterbags were installed in June 2019 into potential restoration sites(disturbed natural forest and forest plantation)and compared to intact natural forest.The tested tree leaf litters included five monospecific litters,ten mixtures of three species and one mixture of five species.Standard green and rooibos tea were used for comparison.A total of 1,033 litters were retrieved for weight loss analysis after one,three,six,and twelve months of incubation.Results:The finding indicates a significant effect of both litter quality and litter diversity on litter decomposition.The nitrogen-fixing native tree Millettia ferruginea showed a comparable decomposition rate as the fast decom-posing green tea.The exotic conifer Cupressus lusitanica and the native recalcitrant Syzygium guineense have even a lower decomposition rate than the slowly decomposing rooibos tea.A significant correlation was observed be-tween litter mass loss and initial leaf litter chemical composition.Moreover,we found positive non-additive ef-fects for litter mixtures including nutrient-rich and negative non-additive effects for litter mixtures including poor leaf litters respectively.Conclusion:These findings suggest that both litter quality and litter diversity play an important role in decom-position processes and therefore in the restoration of degraded tropical moist evergreen forest.

Global comparisons of beta diversity among mammals,birds,reptiles,and amphibians across spatial scales and taxonomic ranks

Beta diversity is the change in species composition among areas in a geographic region. The proportion of species shared between two areas often decreases when the distance separating them increases, leading to an increase in beta diversity. This study compares beta diversity among four classes of terrestrial vertebrates （mammals, birds, reptiles, and amphibians） at both regional （biogeographic realm） and global extents, using the same sets of faunal sample units for all four groups in each comparison. Beta diversity is lower for the two endothermic taxa （birds and mammals） than for the two ectothermic taxa （reptiles and amphibians） in all six biogeographic realms examined. When the four taxa in the six biogeographic realms are combined, beta diversity at the species rank is higher than that of the genus rank by a factor of 1.24, and is higher than that of the family rank by a factor of 1.85. The ratio of beta diversity at the genus rank to that at the family rank is 1.50. Beta diversity is slightly higher for ecoregions of 5000-99,999 km^2 than for ecoregions of 100,000-5,000,000 km^2.