evenness indices
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2021 ◽  
Vol 04 (04) ◽  
pp. 95-114
Author(s):  
Moses Fayiah ◽  
◽  
ShiKui Dong ◽  
Roberto Xavier Supe Tulcan ◽  
Sanjay Singh ◽  
...  

The constant biotic and abiotic interventions on the Qinghai Tibet Plateau (QTP) are seriously degrading the grasslands and, at the same time, restricting the active ecosystem function and grassland vegetation distribution on the plateau. This research analyses the dynamics of grassland vegetation composition across three land uses and counties. The degree of grassland degradation was divided into four land-use types based, i.e., healthy grassland (HG), restored grassland (RG), moderately degraded (MD) grassland, and severely degraded (SD) grassland. About 32 plant species were recorded in Tiebujia county, 28 in Maqin county, and 18 in Maduo county. Results showed Poa crymophila, Polygonum sibiricum, Leontopodium nanum and Oxytropis falcatabunge as the most abundant grassland species in all land-uses and counties. The richness of species ranged from 8 to 12 species per land-use, suggesting low richness and diversity in restored and degraded grassland. A positive non-significantly mean change (p<0.05) was detected for richness and evenness indices while a negative mean change (p<0.05) was detected for Simpson and Shannon indices in the alpine meadow and steppe in both Maqin and Maduo county. The results imply that degradation affects grassland vegetation, health, and distribution across the QTP. Plant total cover for the healthy grassland covered far more areas than other land-uses. Urgent mitigation measures to halt grassland degradation and decline in plant vegetation composition on the plateau should be adopted.


Author(s):  
A. A. Kuzemko

Using the big dataset (17,687 vegetation plots), a comparative analysis of grassland habitats of Ukraine in terms of species richness, Shannon and Simpson diversity indices and Pielou and Smith-Wilson evenness indices was performed. Leading positions of thermophilous forest fringe and hay meadows, especially mountain ones, in almost all indices were revealed. Instead, halophytic habitats show the lowest rates in the vast majority of analyzes. In addition to these general patterns, the analysis revealed the following trends: in almost all analyzes (except for the values of the Smith- Wilson index) habitats formed on carbonate rocks had greater richness and diversity than those formed on rocks of silicates; in almost all cases (except the Pielou index) oligotrophic wet grasslands were characterized by higher values of richness and diversity than eutrophic ones; in all analyzes, mountain habitats were characterized by higher values of richness and diversity than similar lowland habitats.


2021 ◽  
Vol 70 (1) ◽  
Author(s):  
Hans-Rolf Gregorius ◽  
Elizabeth M. Gillet

AbstractWhile evenness is understood to be maximal if all types (species, genotypes, alleles, etc.) are represented equally (via abundance, biomass, area, etc.), its opposite, maximal unevenness, either remains conceptually in the dark or is conceived as the type distribution that minimizes the applied evenness index. The latter approach, however, frequently leads to conceptual inconsistency due to the fact that the minimizing distribution is not specifiable or is monomorphic. The state of monomorphism, however, is indeterminate in terms of its evenness/unevenness characteristics. Indeed, the semantic indeterminacy also shows up in the observation that monomorphism represents a state of pronounced discontinuity for the established evenness indices. This serious conceptual inconsistency is latent in the widely held idea that evenness is an independent component of diversity. As a consequence, the established evenness indices largely appear as indicators of relative polymorphism rather than as indicators of evenness. In order to arrive at consistent measures of evenness/unevenness, it seems indispensable to determine which states are of maximal unevenness and then to assess the position of a given type distribution between states of maximal evenness and maximal unevenness. Since semantically, unevenness implies inequality among type representations, its maximum is reached if all type representations are equally different. For given number of types, this situation is realized if type representations, when ranked in descending order, show equal differences between adjacent types. We term such distributions “stepladders” as opposed to “plateaus” for uniform distributions. Two approaches to new evenness measures are proposed that reflect different perspectives on the positioning of type distributions between the closest stepladders and the closest plateaus. Their two extremes indicate states of complete evenness and complete unevenness, and the midpoint is postulated to represent the turning point between prevailing evenness and prevailing unevenness. The measures are graphically illustrated by evenness surfaces plotted above frequency simplices for three types, and by transects through evenness surfaces for more types. The approach can be generalized to include variable differences between types (as required in analyses of functional evenness) by simply replacing types with pairs of different types. Pairs, as the new types, can be represented by their abundances, for example, and these can be modified in various ways by the differences between the two types that form the pair. Pair representations thus consist of both the difference between the paired types and their frequency. Omission of pair frequencies leads to conceptual ambiguity. Given this specification of pair representations, their evenness/unevenness can be evaluated using the same indices developed for simple types. Pair evenness then turns out to quantify dispersion evenness.


Author(s):  
Damonmi E. Dkhar Afaq Majid Wani

The study and survey which was carried out to identify and assess diversity of plant species of sub tropical pine forest of Meghalaya was conducted during 2020-2021 at three different elevation stands located at 982 m (low-elevation stand), 1485 m (mid-elevation stand) and at 1816 m (high-elevation stand). Pinus kesiya was found to be the most dominant from all the three stand. A total of 34species of trees belonging to 19 families were recorded which consisted a total number of 857 individuals of trees, 14 species of shrubs belonging to 10 families recorded a total number of 866 individuals, and an overall occurrence of 20 species of herbaceous species belonging to 13 families recorded a total number of 670 individuals. Elaeagnus conferta was maximum for IVI in both high and mid elevation stand while Lantana camara showed maximum IVI in the low elevation. The herbaceous species diversity, richness and evenness indices was highest in high elevation and lowest in the low elevation, while herbaceous species of dominance showed a reverse trend. Tree and shrub species of the three elevation stand were quite similar in the mid and low elevation stand. The diversity richness of indigenous forest shows considerable variation in occurrence of species between different altitudes. Most of the species in the study area have medicinal value and socio-economic importance. Therefore, there is a need for necessary action towards sustainability of forest and conservation of species at large.


2021 ◽  
Vol 886 (1) ◽  
pp. 012047
Author(s):  
A Achmad ◽  
U Damayanti ◽  
R I Maulany

Abstract Lower mountain forest in the complex of Mount Bulusaraung Bantimurung Bulusaraung National Park, is a one of bird’s habitat in the South Sulawesi. This area is a tourist destination, especially mountain climbing activities. Thus, it is necessary to know the diversity of animals, especially birds on this hiking trail, so that the information can be used to support ecotourism activities. This study aims to analyze the diversity of bird species in the complex of Bulusaraung Mountain, Bantimurung Bulusaraung National Park in order to support ecotourism activities. This research was conducted from April to June 2018. Data was collected using the line transect method on three lines, namely the Balleanging, Kattokaddaro and Tompobulu lines. The second and third paths are hiking trails, while the rest are trails leading to community agricultural areas. The geographical position of the transect line was recorded using GPS. The GIS method was used to generate a bird watching trail map. Data analysis was carried out to calculate the individual density and frequency of bird presence. In addition, the species diversity indices, species evenness indices, and species richness indices were also calculated. The results showed that there were 44 species of birds found in the study area, which were 16 species in the Balleanging line, 27 species in the Kattokaddaro line and 37 species in the Tompobulu line. The highest bird species diversity indices value was found on the Tompobulu line (H' = 2.93), while on the Kattokaddaro line it was H' = 2.73 and the Balleanging H' = 2.55. The results of this study will support the management strategy in Bantimurung Bulusaraung National Park in order to harmonize the conservation of biological resources through ecotourism activities that involve local communities to increase their economic income.


2021 ◽  
Vol 25 (5) ◽  
pp. 829-834
Author(s):  
S.O. Olaoti-Laaro ◽  
D.M. Taiwo ◽  
K.A. Adeniji ◽  
S.A. Odewo ◽  
Z.T. Animashaun ◽  
...  

Anthropogenic activities has caused depletion of majority of Nigeria forest reserves, reducing forest lands to agricultural lands and grasslands. These prompted this study to consider the diversity of species as well as their species composition in the forest in February 2021. Four sub-plots were established in a cluster with an area of 50m by 50m, with 20m distance between each plots and 10m as edge effect. Twenty five tree species belonging to fifteen families were found in the study site. Family Malvaceae was the most represented. Triplochiton scleroxylon recorded the highest relative importance value (11.23). The diversity indices across the study plots assessed were species richness, evenness, Shannon index and dominance. Dominance indices across the study plots were low, asides for Plot 4 where. Triplochiton scleroxylon was dominant. Simpson index was highest in Plot 1 and lowest at Plot 4. Shannon index was highest, though in moderation in Plot 1 and relatively low in the remaining plots. Evenness indices across the four plots were high. However, the summarized diversity indices for the study site reflected dominance was generally low, Simpson index was high, Shannon index was moderate and Evenness index was moderate. The dendrogram depicted the relationship among the tree species population based on similarities and dissimilarities. Triplochiton scleroxylon belonged to a cluster while every other species with close similarity were categorized under cluster 2.


Author(s):  
Kourosh Arzamani ◽  
Abedin Saghafipour ◽  
Seyed Ahmad Hashemi ◽  
Hassan Vatandoost ◽  
Mohammad Alavinia ◽  
...  

Background: Ticks are considered as the main vectors for the transmission of various pathogens such as relapsing fever and CCHF to humans. This study was investigated the biodiversity indices and medically importance of ticks in North Khorasan Province, Northeast of Iran during 2015–2019. Methods: Specimens were captured from infested ruminants including cows, sheep, and goats. Additionally, tick col­lections also were performed on non-domesticated creatures such as turtles, rodents, and hedgehogs. Specimens were identified using valid identification keys. Species diversity, species richness and evenness indices have been calculated to estimate species biodiversity of ticks. Results: A total of 1478 adult ticks were collected. The specimens were from two families: Ixodidae (90.05%) and Ar­gasidae (9.95%), 6 genera and 17 species including: Rhipicephalus sanguineus (55.9%), Rhipicephalus bursa (13.4%), Hyalomma marginatum (9.5%), Hyalomma anatolicum (9.5%), Hyalomma asiaticum (0.2%), Hyalomma aegyptium (0.5%), Hyalomma scupense (1.3%), Hyalomma sp (1.2%), Haemaphysalis sulcata (0.7%), Haemaphysalis erinacea  (0.1%), Haemaphysalis inermis (0.1%), Haemaphysalis punctata  (0.2%), Haemaphysalis concinna (0.1% Boophilus annulatus (1.2), and Dermacentor marginatus (6.1%) among hard ticks as well as  Argas persicus (91.8%) and Argas reflexus (8.2%) amongst soft ticks. Rhipicephalus sanguineus, Rh. Bursa, Hy. marginatum and Hy. anatolicum were known as the most frequent species of hard ticks. Tick’s species richness, Shannon diversity index and Simpson index in this area were S= 17, H’= 1.69, D= 0.294 respectively. Conclusion: Based on tick distribution veterinary authority, public health organizations and other officials should act for implementation of disease prevention.  


2021 ◽  
Vol 9 ◽  
Author(s):  
Fei Ma ◽  
Lei Yang ◽  
Tian Lv ◽  
Zhenjun Zuo ◽  
Haocun Zhao ◽  
...  

The relationship between biodiversity and productivity (or biomass production) (BPR) has been a popular topic in macroecology and debated for decades. However, this relationship is poorly understood in macrophyte communities, and the mechanism of the BPR pattern of the aquatic macrophyte community is not clear. We investigated 78 aquatic macrophyte communities in a shallow mesotrophic freshwater lake in the middle and lower reaches of the Yangtze River in China. We analyzed the relationship between biodiversity (species richness, diversity, and evenness indices) and community biomass, and the effects of water environments and interspecific interactions on biodiversity–biomass patterns. Unimodal patterns between community biomass and diversity indices instead of evenness indices are shown, and these indicate the importance of both the number and abundance of species when studying biodiversity–biomass patterns under mesotrophic conditions. These patterns were moderated by species identity biologically and water depth environmentally. However, water depth determined the distribution and growth of species with different life-forms as well as species identities through environmental filtering. These results demonstrate that water depth regulates the biodiversity–biomass pattern of the aquatic macrophyte community as a result of its effect on species identity and species distribution. Our study may provide useful information for conservation and restoration of macrophyte vegetation in shallow lakes through matching water depth and species or life-form combinations properly to reach high ecosystem functions and services.


PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0249468
Author(s):  
Biniam T. Lakew ◽  
Adrian H. Nicholas ◽  
Stephen W. Walkden-Brown

Culicoides are one of the smallest hematophagous flies measuring 1–5 mm in size with only females seeking blood for egg development. The present study investigated spatio-temporal distribution of Culicoides species trapped between 1990 and 2018 at 13 sites in the New England region of NSW, Australia using automated light traps. Trapping locations were divided into three subregions (tablelands, slopes and plains). Nineteen Culicoides species were identified. Culicoides marksi and C. austropalpalis were the most abundant and widespread species. Culicoides brevitarsis, the principal vector of livestock diseases in New South Wales comprised 2.9% of the total catch and was detected in 12 of the 13 locations in the study. Abundance as determined by Log10 Culicoides count per trapping event for the eight most abundant species did not vary significantly with season but trended towards higher counts in summer for C. marksi (P = 0.09) and C. austropalpalis (P = 0.05). Significant geographic variation in abundance was observed for C. marksi, C. austropalpalis and C. dycei with counts decreasing with increasing altitude from the plains to the slopes and tablelands. Culicoides victoriae exhibited the reverse trend in abundance (P = 0.08). Greater abundance during the warmer seasons and at lower altitudes for C. marksi and C. austropalpalis was indicative of temperature and rainfall dependence in this region with moderate summer dominance in rainfall. The Shannon-Wiener diversity index of species was higher on the tablelands (H = 1.59) than the slopes (H = 1.33) and plains (H = 1.08) with evenness indices of 0.62, 0.46 and 0.39 respectively. Culicoides species on the tablelands were more diverse than on the slopes and plains where C. marksi and C. austropalpalis dominated. The temporal and spatial variation in abundance, diversity and evenness of species reported in this diverse region of Australia provides additional insight into Culicoides as pests and disease vectors and may contribute to future modelling studies.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wan-ying Li ◽  
Zhen Guo ◽  
Juan Li ◽  
Ji-chang Han

AbstractThe sandy soil leaks water and fertilizer, and the ecological degradation is serious. The structural characteristics of soft rock and sandy soil are complementary, and the improvement of sandy soil by adding soft rock is of great significance to improve soil fertility, restore biodiversity, and maintain sustainable development of the Mu Us sandy land region. In this study, total organic carbon (TOC), particulate organic carbon (POC), dissolved organic carbon (DOC), easily oxidized organic carbon (ROC), microbial biomass carbon (SMBC), bacterial community structure and crop yield were examined using soft rock:sand volume ratios of 0:1 (CK), 1:5 (C1), 1:2 (C2) and 1:1 (C3). Our results indicated that, compared with the CK treatment, TOC (9.66–22.34%), POC (85.65–120.41%) and ROC (114.12–192.31%) noticeably increased in C1, C2 and C3 treatments; SMBC in treatment C3 increased by 42.77%. The three dominant bacteria in the soil (Proteobacteria, Actinobacteria and Chloroflexi), as well as Proteobacteria abundance, greatly declined in the treatments with the addition of soft rock. Pseudarthrobacter was the dominant Genus in all treatments, having an abundance between 11.83 and 19.33%. Bacterial diversity, richness and evenness indices all recorded an increase under the treatments. POC, TOC and SMBC recorded the most significant effects on the bacterial community structure. The largest increases in wheat and corn yields were recorded in the C2 treatment (16.05% and 16.30%), followed by the C1 treatment (8.28% and 8.20%, respectively). Our findings indicate that a soft rock:sand ratio between 1:5 and 1:2 recorded the most improvement in the sandy soil environment.


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