Bray-Curtis Similarity Index Research Articles

Assessing the external atmospheric input of microplastics: Two strategies based on polymer composition and aging characteristics

Microplastics (MPs) can be transported over long distances in the environment, hence, distinguishing between MPs generated locally and those introduced from external sources is necessary for regional MP pollution management. In this study, MPs pollution in the dust of Siziwang banner (Sizi), a sparsely populated area on the Mongolian Plateau, and Hohhot, a city with large populations, was observed. The high proportion of small MPs in Sizi (<25 μm), combined with the fact that most air masses reaching the area have undergone long-distance transport, supports the presence of external input through atmosphere. Based on the significantly different composition distributions and surface characteristics of the small sized MPs in Sizi and Hohhot, a composition-based Bray-Curtis similarity index (Comp-BCs) and a carbonyl index-based BCs index (CI-BCs) were established. Contributions of the external MPs input to small MPs in Sizi were estimated as 23–36 %, indicating that the role of atmospheric input on MPs pollution in sparsely populated areas should not be overlooked.

Spatial-temporal distributions of phytoplankton shifting, chlorophyll-a, and their influencing factors in shallow lakes using remote sensing

Understanding phytoplankton dynamics is crucial for assessing water ecosystem health. However, traditional in-situ investigations often fall short of capturing the spatial-temporal variations of phytoplankton community structure and biomass on large scales. This study introduces a novel approach that harnesses the power of machine learning models coupled with Sentinel-2 satellite data to predict phytoplankton shifting and chlorophyll-a (Chla) in three large shallow lakes in central China from 2016 to 2021. We employed an array of machine learning algorithms, including the extreme gradient boosting method (XGBoost), random forest (RF), support vector machine (SVM), and K-nearest neighbor (KNN) to retrieve Chla and phytoplankton groups clustered by hierarchical cluster analysis based on the Bray-Curtis similarity index (HCA). The influences of environmental factors, including meteorology and nutrients, on phytoplankton dynamics were then explored. Our results identified four distinct phytoplankton groups, each exhibiting unique structural characteristics according to the HCA. The RF and XGBoost, utilizing top-of-atmosphere reflectance, provided the most accurate estimations of phytoplankton shifting and Chla, respectively. The red edge-red ratio emerged as a key variable in both models, underlining the significance of red edge bands in phytoplankton monitoring. We mapped spatial-temporal patterns of phytoplankton group occurrence and average Chla concentration across the three lakes. Our findings indicated that eutrophication extended periods of cyanobacteria domination and algal blooms, particularly in bays and nearshore areas. Redundancy analysis and classification and regression tree model highlighted temperature as a significant driver of phytoplankton shifting, while nutrient levels exhibited stronger influences on Chla. Our study underscores the potential of integrating machine learning models with Sentinel-2 data to enhance the monitoring and prediction of phytoplankton dynamics in shallow lakes. This approach offers valuable insights for the early detection of algal blooms and informed management strategies, contributing to the preservation and sustainable management of aquatic ecosystems.

Variation and clustering analysis of several species of soursop family (Annonaceae) based on vegetative morphology characters

The Annonaceae family exhibited a high level of diversity and is spread over many regions. The designation of the names of several species of the Annonaceae family varies in each region. Therefore, characterization is needed to confirm and classify the taxonomy position of the species. This study aims to characterize the variation and analyze the clustering pattern of several species of the Annonaceae based on vegetative morphology characters. The type of method used in this research is exploratory descriptive, with seventeen specimen species consisting of ten Annonaceae studied in this research. Characters observed include tree age, stem diameter, plant height, stem color, type of sapling, type of branching, leaf shape, leaf tip shape, leaf base shape, leaf width, leaf length, leaf thickness, petiole length and thickness, leaf hairs , color of young and mature leaves, type of leaf edge, number of leaf veins, color of young branches, leaf hairs on young branches, and number of nodes on the stem per meter. These qualitative and quantitative characters were observed using Descriptors for Cherimoya (Annona cherimola Mill.) from Bioversity International and CHERLA. Data analysis was conducted in the Paleontological Statistics program with cluster analysis method (Bray-curtis similarity index) to produce a dendrogram topology. Results showed that there were variations in vegetative morphological characteristics among the ten species examined. Dendrogram topology was divided into 3 groups relatively following the tribe division, with similarity index 0.64 to 0.96. Xylopia sp. was separated from the others in Group 1 (Xylopiae). Group 2 (Uvariae) consisted of Fissistigma sp., Desmos chinensis, Artabotrys suaveolens, Uvaria purpurea, and Desmos sp. Group 3 (Annoneae) consisted of Annona muricata, Annona montana, Stelechocarpus burahol, and Annona glabra. Vegetative morphological characters have proven to be useful and effective in differentiating species in the Annonaceae family; it is recommended for initial identification of species, especially in the Annonoideae subfamily.

Species richness of living foraminifera in Sepetiba Bay (SE Brazil): a species checklist

AbstractThere is a gap in knowledge about the biodiversity of living foraminifera (protozoa) in Brazil, particularly in coastal environments. In Sepetiba Bay (SE Brazil), a coastal system highly impacted by anthropogenic activities, several previous studies have been carried out on foraminifera based on total (living + dead) assemblages and sub-fossil records. Thus, this study intends to analyze for the first time the species richness of living foraminifera (stained with Rose Bengal) in Sepetiba Bay. Based on the morphological characteristics, 214 living species were identified in 50 samples collected in Sepetiba Bay in May 2022. The number of living specimens was counted as 6548. Living foraminifera density was &lt; 252 specimens per gram of sediment and the species richness (S) ranged from 15 to 61 (mean 16.9 ± 15.5) in the analyzed stations. The main taxonomic classes found were Globothalamea and Tubothalamea. The main Globothalamea taxa belonged to the genus Ammonia, with Ammonia tepida, Ammonia buzasi, and Ammonia rolshauseni standing out, as well as the Bolivina, Buliminella, and Elphidium, represented mainly by Bolivina striatula, Buliminella elegantissima, and Elphidium excavatum. A non-Metric Multidimensional Scaling (nMDS) and cluster analysis based on a presence-absence matrix and Bray–Curtis similarity index allowed the identification of two main groups of stations: 1. Located in the innermost areas of Sepetiba Bay and surrounding the mainland and Marambaia Barrier Island, at shallower depths, with lower diversity; 2. an outermost group of stations with higher diversity in areas with greater oceanic influence. Compared with previous studies, the results of this work suggest an enlargement of the “innermost” zone with less diversity towards the oceanic region of Sepetiba Bay. This work shows that even using a matrix of presence/absence of living foraminifera and species richness, it is possible to distinguish environments in coastal systems. Data based on the living foraminifera is needed to understand current biodiversity to better characterize coastal environments and carry out biomonitoring studies.

Assessment of water quality of Kot Dam, Rajasthan, India, using water quality index

Aim: To assess the water quality of Kot Dam, located in the Jhunjhunu district of Rajasthan, India. Methodology: Physico-chemical parameters of water quality were monitored for two years (July 2021 to June 2023). The Water Quality Index (WQI), a widely accepted mathematical expression used to understand the trend in the quality of water bodies, was calculated based on the analysis of physicochemical parameters, including pH, total dissolved solids, hardness, alkalinity, dissolved oxygen, biological oxygen demand, chloride, sulphate, nitrate, calcium, magnesium, conductivity, and fluoride. Results: The site-wise and season-wise analysis of WQI revealed that Dam water was polluted due to organic pollutants, agricultural runoff, and waste disposal by local people, especially during summer (WQI=87.18) and monsoon seasons (WQI=85.38). Interpretation: Anthropogenic activities adversely affected the water quality at sample station (S1) of Kot Dam. Key words: Anthropogenic activities, Bray-Curtis Similarity Index, Dendrogram, Kot dam, Water quality

Alpha diversity of planktonic organisms across stream networks associated with mining activities in Southeast Sulawesi

Planktonic organisms are the main biotic components of the food chain of aquatic ecosystems. Little is known about the impact of multiple stressors on plankton community response in mining areas. This study aimed to elucidate the alpha diversity of zooplankton and phytoplankton in different stream networks associated with mining activities in the Molore watershed, Southeast Sulawesi. The research was carried out by taking samples for water quality and plankton analyses in four streams in November 2021 and November 2022. A rarefaction curve approach was used to assess the species richness and diversity trends of the region. Streams were clustered using the Bray-Curtis similarity index of alpha diversity indices, such as the Shannon-Wiener, Simpson, Margalef, Pielou, and Berger-Parker indices. We found six species of zooplankton only in three sites and 21 species of Phytoplankton in the class of Bacillariophyceae, Chlorophyceae, Cyanophyceae, Dinophyceae, and Euglenophyceae across the landscape gradient. The present study showed that the lowest value of the Shannon-Wiener diversity of the plankton community was 0.48, while the maximum expected value based on individuals’ rarefaction curve was 2.24. Species richness is in line with cluster analysis, which shows the similarity of stream groups according to the level of environmental pressure, indicating a valuable ecological indicator for stream management.

Effect of booster disinfection on the prevalence of microbial antibiotic resistance and bacterial community in a simulated drinking water distribution system

Booster disinfection was often applied to control the microorganism's growth in long-distance water supply systems. The effect of booster disinfection on the changing patterns of antibiotic resistance and bacterial community was investigated by a simulated water distribution system (SWDS). The results showed that the antibiotic resistance bacteria (ARB) and antibiotic resistance genes (ARGs) were initially removed after dosing disinfectants (chlorine and chloramine), but then increased with the increasing water age. However, the relative abundance of ARGs significantly increased after booster disinfection both in buck water and biofilm, then decreased along the pipeline. The pipe materials and disinfectant type also affected the antibiotic resistance. Chlorine was more efficient in controlling microbes and ARGs than chloramine. Compared with UPVC and PE pipes, SS pipes had the lowest total bacteria, ARB concentration, and ARB percentage, mainly due to higher disinfectant residuals and a smoother surface. The significant correlation (rs = 0.77, p < 0.001) of the 16S rRNA genes was observed between buck water and biofilm, while the correlations of targeted ARGs were found to be weak. Bray-Curtis similarity index indicated that booster disinfection significantly changed the biofilm bacterial community and the disinfectant type also had a marked impact on the bacterial community. At the genus level, the relative abundance of Pseudomonas, Sphingomonas, and Methylobacterium significantly increased after booster disinfection. Mycobacterium increased after chloramination while decreased after chlorination, indicating Mycobacterium might resist chloramine. Pseudomonas, Methylobacterium, and Phreatobacter were found to correlate well with the relative abundance of ARGs. These results highlighted antibiotic resistance shift and bacterial community alteration after booster disinfection, which may be helpful in controlling potential microbial risk in drinking water.

PSXI-30 Ruminal Bacterial Diversity Indexes of Grazing Beef Cattle Receiving Different Supplements Plus Phytogenic Additives

Abstract The addition of phytogenic compounds that have antimicrobial activity in cattle supplements can promote changes in ruminal bacterial diversity. This study aimed to evaluate the effect of two levels of supplementation plus a blend of phytogenic additives (essential oils, saponins, and spices) on the measures of alpha and beta diversity in the rumen of beef cattle grazing tropical pasture. The experiment was carried out in the Beef Cattle Sector of UNESP, Jaboticabal-BR. The trial lasted 84 days and nine castrated Nellore steers (body weight of 262 ± 31.2 kg) cannulated in the rumen were assigned in 3 simultaneous 3 × 3 Latin square designs. Animals were kept on the pasture of Urochloa brizantha cv. Marandu in the rainy season. The treatments were: ad libitum mineral supplementation (MS) as control group; added mineral supplementation, 0.1% of body weight per day plus Cargill phytogenic blend (AMSP); and energetic-protein supplementation, 0.3% of body weight per day plus Cargill phytogenic blend (EPSP). Ruminal samples were collected on day 26 of each experimental period. A mix of liquid and solid rumen content (6 mL) was taken before supplementation, placed in cryogenic tubes, and immediately frozen in liquid nitrogen. All samples were stored at −80 °C until DNA extraction and analysis. Total genomic DNA was extracted using the Quick-DNA Fecal/Soil Microbe Miniprep kit. The V3-V4 hypervariable regions of the bacterial 16S rRNA gene were amplified primers 341F (CCTACGGGNGGCWGCAG) and 806R (GGACTACHVGGGTWTCTAAT). The PCR fragments were submitted to sequencing on an Illumina NovaSeq 6000 PE 250 platform. The sequences were processed using mothur, grouped into operational taxonomic units (OTUs) using a similarity cut-off value of 97%, and the bacterial OTUs were classified using the SILVA database. Alpha diversity indices including Shannon, Simpson, Fisher, Chao1, and ACE, were calculated using the phyloseq package, while beta diversity was determined using the vegan package, both in Rstudio. Alpha diversity indices were compared between treatments using a non-parametric Kruskal–Wallis test and Wilcoxon’s post-hoc test. Beta diversity was tested using permutational multivariate analysis of variance (PERMANOVA) based on the Bray-Curtis similarity index. The AMSP and EPSP did not affect measures of alpha diversity (Figure 1), such as Shannon and Fisher indices (P = 0.219) as well as the richness index measured using Chao1 and ACE (P ≥ 0.363). A negative effect of supplementation on alpha diversity (P = 0.004) was only observed with Simpson’s Index of Diversity. Additionally, the supplementation did not change the beta-diversity of the ruminal bacterial community based on Bray–Curtis similarity index (P = 0.510; Figure 2). In conclusion, the addition of phytogenic compounds in the two levels of supplementation showed only a minor impact on the alpha diversity in the rumen of grazing beef cattle.

Reynolds phytoplankton functional classification approach helps evaluate the historical ecological status of the large European Southern Bug River (Ukraine)

AbstractThe phytoplankton functional group (FG) classification system sensu Reynolds enables evaluating the ecological status of rivers using the Q(r) compositional index. Here, we apply the Q(r) index to analyze the ecological conditions of the Southern Bug River, at the entire river length, in the early 20th century, testing it first on historic river phytoplankton data. Moreover, we combined the FG approach with the saprobic index and taxonomic richness to assess the ecological status of the river more reliably. The Bray–Curtis Similarity index highlighted the spatial clustering of river sites that corresponded well to the bioregions of the Eastern Lowlands and the Pontian Province. The Q(r) index revealed a higher variation in ecological status among sites than the saprobic index. Therefore, we argue that the FG approach provides a sensitive ecological status indication approach for river phytoplankton, including historical human impacts. The method may improve understanding of reference conditions and assessing the ecological status of Ukrainian rivers, as requested by the European Water Framework Directive.

Metal Mixture Toxicity of Ni, Cu, and Zn in Freshwater Algal Communities and the Correlation of Single-Species Sensitivities Among Single Metals: A Comparative Analysis.

The effects assessment of metals is mainly based on data of single metals on single species, thereby not accounting for effects of metal mixtures or effects of species interactions. Both of these effects were tested in combination, thereby hypothesizing that the sensitivity of a community to synergistic mixture toxicity depends on the correlation of single-species sensitivities among the single metals. Single-metal and metal-mixture effects were tested in full concentration-response experiments (fixed ray of 1:1:3 and 5:1:13 mass ratio Ni:Cu:Zn) on eight single freshwater algal species and 14 algal communities of four species each. The mean correlation of single-species median effect concentrations among the single metals (Ni-Cu, Cu-Zn, and Zn-Ni) for all species in a community ( ) ranged from -0.4 to 0.9 among the communities; most of these (12/14) were positive. Functional endpoints (total biomass) were overall less sensitive than structural endpoints (Bray-Curtis similarity index) for communities with positively correlated single-species sensitivities among the single metals ( ), suggesting that such correlations indicate functional redundancy under metal-mixture stress. Antagonistic metal-mixture interactions were predominantly found in single species, whereas metal-mixture interactions were antagonistic and surprisingly synergistic for the communities, irrespective of the reference mixture model used (concentration addition or independent action). The mixture interactions close to the carrying capacity (day 7) of communities gradually shifted from antagonism to more noninteractions with increasing correlation of single-species sensitivities among the single metals. Overall, this suggests that functional redundancy under mixed-metal stress comes at the cost of reduced biodiversity and that synergisms can emerge at the community level without any synergisms on the single-species level. Environ Toxicol Chem 2023;42:2666-2683. © 2023 SETAC.

Mucosal bacteriomes of rainbow trout (Oncorhynchus mykiss) intestines are modified in response to dietary phytase

Global aquaculture has seen an unprecedented expansion in recent years partly due to “functional feeds” that is known to improve feed utilization, fish growth performance and resilience to infectious disease. Nevertheless, a knowledge gap exists about how dietary phytase might influence intestinal bacteriomes of farmed fish. We therefore performed 16S rRNA gene-based community profiling. The remarkably uniform mucosal bacteriomes of rainbow trout (median Bray-Curtis similarity index 0.76 ± 0.09) fed the control diet were dominated by lactic acid bacteria (LAB) from putative phytase producing genera Lactococcus and Leuconostoc that likely originated from plant-based feed ingredients. Mucosal bacteriomes developed into uniform communities instead dominated by Mycoplasma-bacteria (median Bray-Curtis similarity index 0.55 ± 0.13) in response to the optimal amount of dietary phytase (0.15 g/kg feed). Both community types had a similar median species richness with 933 ± 301 and 1005 ± 678 bacterial taxa, respectively. A functional genomics analysis revealed that especially genes for amino acid and carbohydrate metabolism/transport were enriched in the LAB-dominated mucosal bacteriomes supporting their role as providers of otherwise inaccessible nutrients from for example dietary fibres. In contrast, only genes for energy production and conversion were marginally enriched in Mycoplasma-dominated communities. It is plausible that a combination of nutrient and mucosal space/attachment site competition is behind the observed shift in mucosal communities. Our results confirm previous reports that dietary phytase improve significantly both fish growth performance and feed utilization (p < 0.05). Moreover, dietary phytase is recommended for use in aquaculture as the enzyme apparently can facilitate the establishment of beneficial Mycoplasma-dominated bacteriomes in the intestinal mucosa of farmed rainbow trout.

New findings and two new species of the genus Colossendeis Jarzynsky, 1870 (Pycnogonida, Colossendeidae), with a morphometric analysis for species from the Southern Ocean

In this paper, specimens belonging to the pycnogonid genus Colossendeis Jarzynsky, 1870 collected during the Antarctic Polarstern XXIII/8 cruise (November 23, 2006, to January 30, 2007) were studied. In this collection, the following thirteen species have been identified, two of them being proposed as new species: Colossendeis frigida Hodgson, 1907, C. megalonyx Hoek, 1881, C. wilsoni Calman, 1915, C. engirmatica Turpaeva, 1974, C. arundorostris Fry & Hedgpeth, 1969, C. scotti Calman, 1915, C. lilliei Calman, 1915, C. drakei Calman, 1915, C. glacialis Hodgson, 1907, C. australis Hodgson, 1907, C. tortipalpis Gordon, 1932, C. pseudofrigida sp. nov., and C. bamberi sp. nov. All species are diagnosed and their taxonomic status discussed. C. frigida, C. engirmatica, and C. arundorostris extend their known depth range. C. arundorostris has been found for the first time outside the Ross Sea. The finding of C. engirmatica represents the first record after its original description. The new species are described, illustrated, and compared with their closest congeners. Finally, we carried out a cluster analysis (Bray-Curtis similarity index) based on a data-matrix of 49 Antarctic and Sub-Antarctic Colossendeis species and 26 morphological characters.

Diversity and Ant Community Composition in Some Algerian Islands

Abstract The present paper seeks to study the diversity and ant community composition of some Algerian islands. This study is considered as the first exhaustive survey of ant species of Algerian islands since 1957. The survey was carried out in the spring and summer seasons between April and July of two years 2014 and 2015. Vegetation richness, island area, mainland distance, and elevation variables were measured for each island. Relative abundance (RA), frequency of occurrence (FO), as well as species richness (S), Shannon’s diversity index (H), and equitability (E) for each island were used to compare the diversity pattern among islands. Patterns of species composition and community structure were compared among the sampling islands through ordination analysis (nonmetric multidimensional scaling [NMDS]). SIMPER analysis using a Bray–Curtis similarity index matrix was performed to determine the contribution of each ant species to the dissimilarities among islands. Canonical correspondence analysis (CCA) was performed to highlight the impact of environmental variables on the ant community. All analyses were computed by using PAST software. Two sampling methods (pitfall trap and hand collecting) were used, which led to the identification of 1039 individuals belonging to 16 species. Diversity indexes were different among islands. Ant community was significantly different between islands of the two regions Bejaia and Jijel. Three species contributed to 50.74% of the differences between islands of the two regions. Part of the ant community composition was influenced directly or indirectly by three environmental variables: vegetation richness, island area, and mainland distance. It is important to point out the absence of two invasive ants, Linepithema humile and Paratrechina longicornis, in our islands.

First data on testate amoebae associated with the endemic cave bivalve Congeria jalzici Morton &amp;amp; Bilandžija, 2013 with a description of Psammonobiotus dinarica sp. nov.

Testate amoebae are phylogenetically a very diverse group of eukaryotic microorganisms. They can be found in marine and freshwater habitats and in soil. Some of these single-celled organisms inhabit both surface and cave habitats, but their diversity in caves has barely been explored. Recent studies in the Dinaric region imply that testate amoebae in caves show a high diversity. The aim of this study was to identify the alpha diversity of testate amoebae in the Lika region (Dinaric karst, Croatia) and to compare the habitats of different caves based on testate amoebae assemblages. In eight caves we found more than 40 testate amoebae taxa, including a new testate amoeba species, Psammonobiotus dinaricasp. nov. The greatest diversity of testate amoebae was found in Markov ponor (27 taxa). The Bray-Curtis Similarity Index showed that testate amoebae assemblages in caves inhabited by the endemic and endangered cave bivalve Congeria jalzici (Markov ponor, Dankov ponor and Dražice ponor) differ from caves not inhabited by this species. This differentiation is attributed to the impact of the sinking Lika river, which occasionally completely submerges these caves, creating specific habitats for eukaryotic microorganisms. This study contributes to our understanding of the diversity, biogeography and ecology of testate amoebae in caves, as well as providing further insight into the conditions that sustain populations of C. jalzici.

Objective analysis of facial bone fracture CT images using curvature measurement in a surface mesh model

The human facial skeleton consists of multiple segments and causes difficulty during analytic processes. We developed image analysis software to quantify the amount of injury and validate the smooth curvature of the surface after facial bone reduction surgery. Three-dimensional computed tomography images of facial bone were obtained from 40 patients who had undergone open reduction surgery to treat unilateral zygomaticomaxillary fractures. Analytic software was developed based on the discrete curvature of a triangular mesh model. The discrete curvature values were compared before and after surgery using two regions of interest. For the inferior orbital rim, the weighted average of curvature changed from 0.543 ± 0.034 to 0.458 ± 0.042. For the anterior maxilla, the weighted average of curvature changed from 0.596 ± 0.02 to 0.481 ± 0.031, showing a significant decrement (P < 0.05). The curvature was further compared with the unaffected side using the Bray–Curtis similarity index (BCSI). The BCSI of the inferior orbital rim changed from 0.802 ± 0.041 to 0.904 ± 0.015, and that for the anterior maxilla changed from 0.797 ± 0.029 to 0.84 ± 0.025, demonstrating increased similarity (P < 0.05). In computational biology, adequate analytic software is crucial. The newly developed software demonstrated significant differentiation between pre- and postoperative curvature values. Modification of formulas and software will lead to further advancements.

Mine tailings storage dams modify upstream headwater fish assemblages

Riverscape connectivity is a critically important component determining the ecological condition of lotic ecosystems. We evaluated changes in fish assemblages caused by the loss of connectivity by mine tailings storage dams (TSDs), hypothesizing that headwater fish assemblages are restructured by TSDs located downstream, even though the upstream habitats are not altered. We used standard methods to collect fish in 24 first to third order sites, with half draining to TSDs (dammed) and the other half free from this impact (undammed). To identify differences between treatments, we used PERMANOVA to test both environmental variables and ichthyofauna composition (Bray-Curtis similarity index) and evaluated the biological metrics that most influenced assemblage composition change. As expected, we observed no difference between treatments for environmental variables, but we did observe differences in fish assemblage composition. We also observed five metrics with lower values in dammed streams (richness and abundance of intolerant species, siluriform richness, and abundance of Pareiorhaphis cf. proskynita and Trichomycterus brasiliensis) and two metrics with higher values in dammed streams (perciform richness and abundance of Oligosarcus argenteus). We believe these changes resulted from of stream fragmentation by TSDs, in addition to source-sink mechanisms and conclude that mine TSDs located downstream change headwater fish assemblages, an impact often neglected in biomonitoring and bioassessment studies.

Diversity of freshwater fish at Sago Palm Wetlands, Nakhon Si Thammarat Province, Thailand

Abstract. Suriya C, Satian C, Visut B, Supadha K. 2022. Diversity of freshwater fish at Sago Palm Wetlands, Nakhon Si Thammarat Province, Thailand. Biodiversitas 23: 6335-6344. Studies on the diversity of freshwater fish at Sago Palm Wetlands, Nakhon Si Thammarat Province, Thailand, were conducted in the period from March 2020 to November 2020. Fish samples were collected, encompassing the hot-dry season (March to June) and the rainy season (September to November) at 4 sampling zones, with 5 stations for each zone. Fish were caught using a seine net of 1 cm mesh size, 1.5m in length, and 1m in width. All data were analyzed to find out the fish diversity indices. The multivariate method was used to determine cluster analysis. A total of 3634 fish specimens, representing 62 species belonging to 24 families, were recorded during the sampling period. Cyprinidae was the major family, with Trichopsis vittatus containing the highest index of relative importance (IRI). The species diversity index of fish was in the range of 0.66 to 2.67; the evenness index was in the range of 0.64 to 0.95, and the species richness index ranged from 0.36 to 6.86, indicating an intermediate-low uniformity, with a medium species number in the area. The cluster analysis of the Bray-Curtis similarity index shows A division of the fish community into 2 clusters in the hot-dry season and 3 clusters in the rainy season, having a similarity percentage ranging between 42% and 95%, respectively. Also documented were one introduced species and one endangered fish species during sampling. The findings suggest that Sago Palm Wetlands is still inhabited by numerous fish species and should be conserved to ensure its aquatic animal richness for the future. This data provides information about the fish habitat in the Sago Palm Wetlands and can be used to update the checklists of fish species in the Tapi River, the Pak Phanang River, and the Trang River Basins. It also can be useful for the planning of fishing activities and the provision of guidelines for future research and conservation purposes.

Comparative Diversity of Bats in Two Contrasting Habitats in Terengganu

Differentiations in the habitat and resource utilisation lead to segregation and specialisation of niches for bats within the structurally complex tropical rainforest in Malaysia. This research aims to characterise chiropterans’ assemblages found in two different habitat types in Tasik Kenyir (dipterocarp forest) and Setiu (oil palm plantation). A total of 48 sampling nights were conducted within two years period from March 2017 to March 2019 which covered four sampling sites in Tasik Kenyir and four sites at Setiu. Two standard four-bank harp traps and 10 mist nets were deployed throughout the study at every site to capture bats at understory levels. This makes a total of 576 sampling efforts for both areas. Song Meter SM2bats and Echo Meter Touch from Wildlife Acoustic were used to record the echolocation of insectivorous bats. The total number of individuals and species observed were used to determine species diversity, richness, and evenness. Paleontological statistic software was used to generate the rank abundance and species accumulation curves. Bray-Curtis similarity index was used to generalise the index that represents the relative abundance of the sampling sites. A total of 835 individuals comprising 31 species from six families were captured at both study areas. Out of 835 individuals, 695 were captured within Tasik Kenyir comprising 27 species from six families (H = 2.381) while 140 individuals were captured in Setiu comprising 20 species from five families (H = 2.40). The diversity of bats in Tasik Kenyir was hypothesised to be higher than in Setiu as the habitat possess a larger undisturbed forest. However, the result showed the opposite in which no significant difference was detected from the diversity index calculated between these two areas. Detailed studies need to be conducted to determine if some areas are used as transient habitats for bats.

The Determination of Trophic Level of Küçükçekmece Lagoon Lake (İstanbul, Türkiye) by Using Some Environmental Variables with Indicator Benthic Macroinvertebrates Findings

In this study, to determine the trophic level of Küçükçekmece Lagoon Lake, water and sediment samplings were performed at five selected stations seasonally during a year between 2014-2015. The water samples were analyzed to determine some environmental variables (water temperature, pH, conductivity, DO (dissolved oxygen), TDS (total dissolved solids), and salinity. NO3-N, NO2-N, SO4-2, PO4-3, SiO2, chlorophyll-a, TP (total phosphorus), and Secchi disc light permeability) and benthic macroinvertebrates were examined to determine indicator organisms in the sampled sediment material. Bray-Curtis Similarity Index was used to the observed environmental results to determine the similarities of the sampling stations. According to this, station 1 (St. 1) located in the center of the lake, and St. 5 located near the sea were found to be different from other sampling stations while the stations located near the creeks were found to have much more similar to each other. In addition, to determine the trophy level of the lake, Carlson Trophic State Index (CTSI) was used to the obtained some physicochemical results (Secchi disc permeability, total phosphorus, chlorophyll-a) and it was found that the lake showed a eutrophic character during all seasons. According to the result of sediment sampling, an average of 350 individuals per m2 (44.3 % belonging Polychaeta group; 29.5 % belonging Chironomidae group; 19.7 % belonging Oligochaeta group; 6.5 % belonging Bivalvia group) in a total of 6 benthic macroinvertebrate taxa (Bivalvia, Polychaeta, Tubificoides benedii (Oligochaeta), Tubificoides sp. (immature Oligochaeta), Limnodrilus hoffmeisteri (Oligochaeta), and Chironomus salinarius (Chironomidae) were determined. Thus, it is observed that the presence of some indicator species supported eutrophic conditions qualitatively. As a result of this study, it was determined that Küçükçekmece Lagoon lake going on to expose the increasing pollution load.

Increased Soil Bacterial Abundance but Decreased Bacterial Diversity and Shifted Bacterial Community Composition Following Secondary Succession of Old-Field

Plant secondary succession is a very effective approach for the rejuvenation of degraded ecosystems. In order to comprehend alterations and driving mechanisms of soil bacterial communities under secondary succession of old-field and reveal their subsequent impacts on the decomposition and accumulation of soil organic carbon (SOC) and nitrogen (SON), we investigated changes in soil bacterial communities following ~160 years of old-field succession on the Loess Plateau of China through analyses of quantitative polymerase chain reaction (qPCR) and Illumina MiSeq DNA sequencing of 16S rRNA genes. Our results revealed that subsequent to secondary succession of old-field, soil bacterial abundance progressively increased, while bacterial richness and diversity significantly decreased. Principal component analysis and Bray–Curtis similarity index showed that bacterial community composition gradually shifted following old-field succession. Specifically, the relative abundances of Proteobacteria, Rokubacteria, and Verrucomicrobia progressively increased, while Actinobacteria and Firmicutes slightly decreased following old-field succession. The most enriched of Proteobacteria (e.g., Rhizobiales, Xanthobacteraceae, Gammaproteobacteria, Bradyrhizobium, Rhizobiaceae, and Mesorhizobiur) were found in a climax forest, while Chloroflexi and Gemmatimonadetes had the lowest relative abundances. Further, the most enriched members of Actinobacteria, including Geodermatophilaceae, Frankiales, Blastococcus, Micrococcales, Micrococcacea, Propionibacteriales, Nocardioidaceae, Nocardioide, and Streptomycetaceae, were exhibited in the farmland stage. Our results suggested that secondary succession of old-field greatly modified soil bacterial communities via the transformation of soil nutrients levels, altering plant biomass and soil physiochemical properties. Soil bacterial community composition was transformed from oligotrophic groups to copiotrophic Proteobacteria following old-field succession, which may promote SOC and SON accumulation through increasing the utilization of labile organic carbon (C) and nitrogen (N), while decreasing decomposition of recalcitrant organic C and N from the early- to late-successional stages.