Pielou Evenness Index Research Articles

Integrated Rice-Snail-Crayfish Farming System Shapes Soil Microbial Community by Enhancing pH and Microbial Biomass in South Subtropical China

Within the framework of sustainable agriculture, the integrated rice-snail-crayfish farming system has been recognized as a highly efficient agroecological approach that enhances crop production while minimizing the application of chemical fertilizers and pesticides. Nonetheless, the mechanisms by which this system influences soil microbial community composition to achieve these benefits remain unknown. In this study, we focused on traditional rice farming (TR), the integrated rice-snail-crayfish (R-S-C) farming system, and mono-rice farming (CK), and systematically examined the impacts of these farming systems on soil chemical properties, microbial biomass, enzyme activity, and microbial community composition. Our results showed that the R-S-C significantly increased soil pH, microbial biomass carbon (MBC), and the MBC/microbial biomass phosphorus (MBP) ratio compared to TR, as well as the peroxidase activity. Moreover, the R-S-C significantly increased soil total phospholipid fatty acid (PLFA), bacterial PLFAs, Gram-negative bacterial (GN) PLFAs, anaerobic bacteria PLFAs, arbuscular mycorrhizal fungi (AMF) abundances, and the bacteria/fungi ratio compared to the other two systems. However, the soil microbial α-diversity indices, including Shannon–Wiener index (H), Simpson index (D), and Pielou evenness index (J), were significantly lower in the R-S-C system than in the other two systems. Further exploration suggested that soil pH, microbial biomass nitrogen (MBN), the MBN/total nitrogen (TN) ratio, and the MBC/MBP ratio were critical factors governing microbial community composition under the three farming practices. Notably, soil pH alone accounted for 64.5% of the observed variation in microbial community composition. Path analysis using partial least squares structural equation modeling further revealed the pathways by which the R-S-C system enhanced total PLFAs, AMF, and gram-positive bacteria by regulating the soil pH and MBN/TN ratio. This study provides insights into the regulatory mechanisms driving soil microbial communities in the R-S-C system and offers a theoretical foundation for developing sustainable agricultural management practices.

Multivariate Environmental Factors and Seasonal Spatial Dynamics Affecting the Phytoplankton Community in Yazhou Bay, South China Sea

This study investigated phytoplankton and water environmental factors in Yazhou Bay, South China Sea, during the winter, spring, and summer of 2023. It examined phytoplankton community structure, subgroup heterogeneity, and key environmental drivers. Phytoplankton abundance ranged from 0.08 to 14.30 × 10⁴ cells·L−1, with high concentrations in estuary and nearshore zones. In summer, currents carry phytoplankton offshore, with stratification leading to high sedimentation in southern offshore waters. RDA results indicated that in winter and spring, inorganic nitrogen mainly influences phytoplankton distribution, while silicate is the primary factor in summer. Although seasonal differences in total phytoplankton abundance are minimal, significant horizontal and vertical distribution variations exist. Diverse preferences of different phytoplankton species for temperature, salinity, nitrogen, and phosphorus result in high species diversity. The Shannon–Wiener diversity index (H′) averages 3.96 ± 0.09, and the Pielou evenness index (J) averages 0.82 ± 0.01. Dominant species include Pseudo-nitzschia pungens, Skeletonema costatum, and Rhizosolenia sinica. Influenced by external oceanic water masses, estuary input, and islands, phytoplankton subgroups show regional and seasonal variations. Despite recorded harmful algal blooms (HABs) in adjacent waters, Yazhou Bay’s high biodiversity and low cell density suggest a low HAB risk, though future risks due to climate change and human activities remain.

Macrophyte Diversity and Ecosystem Services in Wetlands of Eastern Ranchi: A Multi-site Analysis of Abundance, Frequency, and Importance Value Index Patterns

Macrophytes, visible aquatic and semi-aquatic plants, are integral components of wetland ecosystems, playing crucial roles in maintaining biodiversity, providing ecosystem services, and ensuring ecological stability. This research examines the distribution, abundance, frequency, diversity, and ecosystem services of macrophytes in several wetlands (W1-W7) located in the eastern part of Ranchi district, Jharkhand, India. The study sites include Bundu Lake, Hindalco Pond, Choga Bada Talab, Raja Bandh, Kita Uparbandh, Tamar Bada Talab, and Rukka Dam. A quantitative assessment using quadrat sampling and phytosociological methods was conducted from September 2022 to March 2023 to ensure accurate data collection and analysis. The study documented 78 macrophyte species belonging to 33 families and 58 genera. Emergent macrophytes were found to be the dominant life form, constituting 69% of the recorded species. Several species demonstrated high frequency and abundance across multiple study sites, including Pontederia crassipes Mart., Alternanthera philoxeroides (Mart) Griseb., Hydrilla verticillata (L.f.) Royle, Ipomoea aquaticaForssk., and Nymphoides hydrophyllum (Lour.) kuntze. To assess the diversity and ecological characteristics of the macrophyte communities, various diversity indices were calculated. These included the Shannon-Wiener index, Simpson's index, Margalef index, and Pielou's Evenness index. The results of these analyses revealed high levels of macrophyte diversity and evenness within the studied wetlands. Twenty-one macrophytes were identified as key species and nine species as rare species based on their IVI (Importance Value Index) scores. The key species were found to provide essential ecosystem services, including erosion control, water quality improvement, nutrient cycling, carbon sequestration, and habitat provision for other organisms. This research contributes significantly to our understanding of macrophyte diversity patterns and traits-based ecosystem services in wetland ecosystems. The findings of this study have important implications for the development and implementation of effective conservation strategies for these vital wetland ecosystems in the eastern Ranchi (W1- W7).

Enhancing the Growth of Chili Plants and Soil Health: Synergistic Effects of Coconut Shell Biochar and Bacillus Sp. Strain Ya-1 on Rhizosphere Microecology and Plant Metabolism

To mitigate soil degradation and decrease dependency on chemical inputs in agriculture, this study examined the joint effects of coconut shell biochar and Bacillus strain Ya-1 on soil fertility, rhizosphere bacterial communities, and the growth of chili (Capsicum annuum L.). A controlled pot experiment with four treatments was conducted: control (CK), biochar only (C), Bacillus strain Ya-1 only (B), and a combination of both (BC). The BC treatment significantly enhanced the soil carbon and available phosphorus contents by approximately 20% and the soil nitrogen content and pH by 18% and 0.3 units, respectively, compared to the control. It also increased microbial biomass carbon and nitrogen by 25% and 30%, respectively, indicating improved soil microbial diversity as shown by the highest Pielou evenness index and Shannon index values. The combined application of biochar and the Ya-1 strain resulted in a 15% increase in chili plant height and a 40% improvement in root dehydrogenase activity, suggesting enhanced nutrient uptake and metabolism. Metabolic profiling showed shifts in stress response and nutrient assimilation under different treatments. Collectively, these results indicate the potential of biochar and microbial inoculants to significantly promote soil and plant health, providing a sustainable strategy to improve agricultural productivity and reduce reliance on chemical inputs.

An Ecological Survey of Chiggers (Acariformes: Trombiculidae) Associated with Small Mammals in an Epidemic Focus of Scrub Typhus on the China-Myanmar Border in Southwest China.

Chiggers (chigger mites) are a group of tiny arthropods, and they are the exclusive vector of Orientia tsutsugamushi (Ot), the causative agent of scrub typhus (tsutsugamushi disease). Dehong Prefecture in Yunnan Province of southwest China is located on the China-Myanmar border and is an important focus of scrub typhus. Based on the field surveys in Dehong between 2008 and 2022, the present paper reports the infestation and ecological distribution of chiggers on the body surface of rodents and other sympatric small mammals (shrews, tree shrews, etc.) in the region for the first time. The constituent ratio (Cr), prevalence (PM), mean abundance (MA), and mean intensity (MI) were routinely calculated to reflect the infestation of small-mammal hosts with chiggers. Additionally, the species richness (S), Shannon-Wiener diversity index (H), Simpson dominance index (D), and Pielou's evenness index (E) were calculated to illustrate the chigger community structure. Preston's log-normal model was used to fit the theoretical curve of species abundance distribution, and the Chao 1 formula was used to roughly estimate the expected total species. The "corrplot" package in R software (Version 4.3.1) was used to analyze interspecific relationships, and the online drawing software was used to create a chord diagram to visualize the host-chigger associations. From 1760 small-mammal hosts, a total of 9309 chiggers were identified as belonging to 1 family, 16 genera, and 117 species, with high species diversity. The dominant chigger species were Leptotrombidium deliense, Walchia ewingi, and Gahrliepia longipedalis, with a total Cr = 47.65% (4436/9309), among which L. deliense is the most important vector of Ot in China. The overall infestation indexes (PM, MA, and MI) and community parameters (S, H, and E) of chiggers in the mountainous areas and outdoors were higher than those in the flatland areas and indoors, with an obvious environmental heterogeneity. Leptotrombidium deliense was the dominant species in the flatland and indoors, while G. longipedalis was the prevalent species in the mountainous and outdoor areas. The species abundance distribution of the chigger community conformed to log-normal distribution with the theoretical curve equation: S(R)'=28e-[0.23(R-0)]2, indicating the existence of many rare species and only a few dominant species in the community. The expected total number of chigger species was roughly estimated to be 147 species, 30 more than the 117 species actually collected, suggesting that some uncommon species may have been missed in the sampling survey. The host-parasite association analysis revealed that one host species can harbor different chigger species, and one chigger species can parasitize different host species with low host specificity. A positive or negative correlation existed among different chigger species, indicating a cooperative or competitive interspecific relationship. The species diversity of chiggers is high in Dehong on the China-Myanmar border, and a large host sample is recommended to find more uncommon species. There is an obvious environmental heterogeneity of the chigger community, with different species diversity and dominant species in different environments. The low host specificity of chiggers and the occurrence of a large number of L. deliense in Dehong, especially in flatland areas and indoors, would increase the risk of persistent transmission of scrub typhus in the region.

Exploring the interplay between phytoplankton taxonomy, pigments, and optical properties in Ratnagiri coastal waters using a multi-parameter approach

This study presents a comprehensive analysis of phytoplankton diversity and optical properties in the coastal waters of Ratnagiri, India. Ratnagiri, located on the southern coast of Maharashtra, is one of the major centre for fishing activities in India as well as a developing hub for industrial activities. Given its ecological significance and the pressures it faces, the coastal waters of Ratnagiri present a valuable case for studying phytoplankton dynamics and their light absorption properties. We integrated parameters like phytoplankton taxonomy, pigment composition, Coloured Dissolved Organic Matter (CDOM), and phytoplankton absorption characteristics to give a comprehensive view of the phytoplankton community and its optical environment. Phytoplankton samples from Ratnagiri were analyzed with microscopy and high-performance liquid chromatography (HPLC) for taxonomy and pigment profiling, while CDOM and absorption properties were measured using spectrophotometry. Our findings reveal more or less spatial uniformity in phytoplankton composition (Pielou's Evenness Index (J’) ranged between 0.84 and 0.9), with significant diversity (Shannon Diversity Index (H’) ranged from 3.7 to 4.19) within the phytoplankton community. Pigment analysis revealed key marker pigments associated with various phytoplankton classes including bacillariophytes (diatoms), chlorophytes, cyanophytes, haptophytes and cryptophytes, providing insights into community structure. Concurrently, CDOM absorption coefficient (aCDOM (440)) that ranged between 0.08 and 0.3 m−1 indicated varying levels of dissolved organic matter, influencing light absorption and availability within the water column. The phytoplankton absorption data highlighted the specific wavelengths most affected by phytoplankton presence, notably those contributed by diatoms and cyanophytes, providing insights into the optical properties of Ratnagiri's coastal waters. This integrative approach underscores the importance of considering multiple parameters to accurately assess phytoplankton dynamics and their impact on the aquatic environment. The results contribute to a better understanding of the ecological processes governing coastal waters in Ratnagiri and offer valuable information for future monitoring and management efforts.

Influence of wildfires severity on tree composition and structure in Aberdare Afromontane forest ranges, Kenya

Wildfires strongly impacts on the forest ecosystems, with poorly understood consequences on the composition, diversity and structure within Afromontane forests of Eastern Africa. The impacts of wildfire on vegetation were investigated one year after the fire occurrence season. The burn severity was evaluated using Sentinel-2 satellite derived spectral index known as dNBR (difference Normalized Burn Ratio). This was used to delineate wildfire into low and high severity classes. We investigated the effects of wildfires using 36 plots of 15 m radius distributed in high and low burn severities while others were laid in unburnt areas. Our findings indicated that tree height, basal area and density were significantly different along severity classes (p = 0.003, p=0.007 and p<0.000 respectively). However, diameter at breast Height (DBH) was not significant along severity classes (p=0.185). The most ecologically important species based on Important Value Index (IVI) within the fire affected areas were Juniperus procera, Nuxia congesta, Olea europaea subsp. cuspidata, Protea kilimandscharicum and Scurtia myrtina. Among the five dominant tree species, the density of Protea kilimandscharicum and Olea europaea subsp. cuspidata were significant along the fire severities (p<0.05). Interaction of vegetation zones and wildfire severity indicated that only height was significant (p= 0.000) while all the other tree variables and species diversity index were not significant; DBH (p=0.053), basal area (p=0.606), tree density (p=0.389), Shannon diversity index (p=0.843), Simpson dominance index (p=0.490) and Pielou's evenness index (p=0.248). Whereas this study was on a short-term post-fire effects on vegetation, it has shown remarkable findings which can guide restoration and management of fire affected landscapes. The study recommends evaluation of long-term regeneration and recovery to guide integrated fire management within Afromontane Forest Ecosystems.

The native fish diversity with environmental influencing factors in the Daqing River basin, China

IntroductionInvestigating and assessing native fish diversity and conducting regional assessments of threats are vital for the conservation of aquatic biodiversity. For this specific study, the Daqing River basin in China was chosen as the research area. Field surveys were carried out between 2018 and 2019, supplemented by a review of pertinent literature and other records.MethodsTo evaluate fish diversity, the following parameters are selected for analysis: Relative abundance (Pi), Frequency of occurrence (Fi), Margalef richness index (D) , Shannon Wiener diversity index (H′) , and Pielou evenness index (J′).Relative abundance levels are categorized as follows: dominant species make up more than 10%, common species account for 1%–10%, and occasional species constitute less than 1%. Canoco 5.0 software was utilized to conduct Redundancy Analysis (RDA) on the fish species composition and environmental factors at 34 sampling sites.ResultsThe findings revealed that 85 fish species have been recorded in the basin, consisting of 78 freshwater species categorized into 8 orders, 17 families, and 59 genera, among which Cypriniformes comprised 64% of the total catch. The low proportion of threatened and endemic species was an important feature of the fish diversity of the Daqing River. Despite the theoretical presence of 85 species, field surveys managed to collect only 42 species, of which 33 were confirmed as naturally occurring within the basin. The average values of Margalef richness index, 22 Shannon Wiener diversity index and Pielou evenness index were 1.72, 2.04 and 0.80 respectively, signifying a low fish diversity with relatively uniform distribution across the sampled regions.DiscussionThis study found that the community structure and diversity of fish were closely related to environmental factors, particularly water quality. Among these factors, ammonia nitrogen emerged as a significant determinant of fish diversity. High concentrations of ammonia nitrogen inhibit fish growth, endanger health, and can even lead to death. Additionally, dams and other water infrastructure also impact fish community structure and diversity. This baseline study can provide a basis for the protection and ecological restoration of fish resources in the Daqing River.

Influence of some environmental variables on the diversity and distribution of aquatic oligochaetes (Clitellata: Annelida) in the Nyong estuary (Atlantic coast, southern Cameroon)

Tropical estuarine ecosystems are subject to strong anthropogenic pressures, with the direct consequence of declining or lost biodiversity. An essential and little-known biological component of these estuarine ecosystems is the population of oligochaete annelids, which play an indispensable role in energy transfer and the biodegradation of organic and chemical compounds. This study sheds light on the diversity and structure of oligochaetes in the Nyong estuary under the influence of some abiotic parameters. Based on hydrobiological standard techniques, 1016 individuals grouped into 3 orders (Tubificida, Haplotaxida and Lumbriculida), 5 families (Naididae, Tubificidae, Haplotaxidae, Glossoscolecidae and Lumbriculidae) and 5 species were collected and identified. Alma nilotica, positively correlated with dissolved oxygen (P = 0.033; n = 72), was the most abundant species (464 individuals), followed by Tubifex tubifex (216 individuals), positively correlated with salinity (P = 0.029; n = 72), pH (P = 0.037; n = 72) and temperature (P = 0.044; n = 72) Limnodrilus hoffmeisteri and Rhynchemis sp. showed no particular affinity with the abiotic component considered in this study. The Shannon-Weaver's (H') and Pielou's evenness (J) indices coupled with the species richness of all surveyed stations (S1 to S12) showed a greater diversity of taxa only at station S12, located in the lower estuary, 1 km from the mouth; during the dry season. This study shows that the spatial dynamics of oligochaetes in the Nyong estuary are strongly influenced by abiotic parameters and seasonal cycles.

Mangrove snail diversity as a tool for biomonitoring the mangrove based coastal habitats

Mangrove forests play a pivotal role in supporting mangrove associated snails by offering essential functions such as breeding grounds, nursery areas, food sources, and protection from predators. They play a particularly important role in nutrient cycling within mangrove ecosystems. Despite their significance, there has been a lack of studies conducted in Sri Lanka to explore the diversity of mangrove snails. Thus, the objective of this study was to assess the significance of snail species diversity in mangrove ecosystems on the western coast of Kandakuliya, Kalpitiya, Sri Lanka. Five sites were selected using purposive sampling technique at each location, and the sampling was conducted during low tide in daylight hours in both the non-rainy (February) and rainy (September) seasons of 2023. Transects (30 m) were established at each location, with six 1 m² quadrats placed along each transect at 5 m intervals as replicates. The study identified six snail species from three families, with Pirenella cingulata being the most widely distributed across all sites and exhibiting the highest abundance at site 3. Temporally, Pirenella cingulata displayed the highest number of individuals in both the rainy and dry seasons. Diversity indices indicated the highest values at site 1 for the Shannon-Wiener index (H´=1.14), site 5 for Pielou's evenness index (J=0.96), and site 1 for Simpson's diversity index (D=0.67). Pirenella cingulata recorded the highest total abundance at 85,840 individuals. Variations in these findings may be attributed to water quality factors such as temperature and dissolved oxygen, as well as mangrove dominance and climatic conditions. The study suggests that incorporation of environmental parameters could support to draw a more comprehensive understanding of the correlation of dynamics of environmental variables for mangrove snail population changes.

Seasonal variations in the structure of avian community in Zambezi riparian forest

Among the different biomes in southern Africa, tropical riparian forests appear to be especially rich in terms of biodiversity, but little is known about avian communities occupying these forests. In this paper, bird counts were conducted in May, July–August, and October–November in 2013 and 2014. The line transect method was used. A transect 16.6 km long was designed along the Zambezi River between S 17.4975 E 24.3478 and S 17.4874 E 24.447. In total, 146 bird species were recorded. The number of species detected each season varied from 95 to 100. The number of dominant species was consistently low, varying between 2 and 3 depending on the month. However, the cumulative dominance and the dominance index were much higher in the dry season (May–August) than in the wet season (October–November). Two species were dominant each month: Euplectes axillaris and Pycnonotus tricolor. Vidua macroura and Estrilda astrild were dominant only in October, while Streptopelia capicola was dominant only in May. The group of subdominants was much more diverse than dominants and included 13 species. The Shannon diversity index increased between July and November from 3.45 to 4.05 but Simpson's diversity index did not show any seasonal trend. Pielou's evenness index was higher in the wet season (0.82–0.88) than in the dry season (0.76–0.79). The proportions of the main feeding guilds were much the same throughout the year, except for November, when the proportion of insectivores markedly increased, while that of granivores decreased. Riparian forest corridors in urbanized environments may be viewed as main instruments for offsetting the negative effects of habitat loss and fragmentation. Dataset published through GBIF (DOI: 10.15470/0ssr1v)

Characterization of Bacterial Communities on Trout Skin and Eggs in Relation to Saprolegnia parasitica Infection Status.

We have investigated the changes in the microbial communities on the surface of trout eggs and the skin of adult trout in relation to the presence of Saprolegnia parasitica. This pathogen causes saprolegniosis, a disease responsible for significant losses in salmonid farms and hatcheries. It is known from other disease systems that the host-associated microbiome plays a crucial role in the defence against pathogens, but if the pathogen predominates, this can lead to dysbiosis. However, analyses of the effects of S. parasitica on the diversity, composition, and function of microbial communities on fish skin and eggs are scarce. Thus, we have collected skin swabs from injured and healthy trout (N = 12), which differed in S. parasitica load, from three different fish farms in Croatia (Kostanjevac, Radovan, and Solin), while trout egg samples (N = 12) were infected with S. parasitica in the laboratory. Illumina sequencing of the V4 region of the 16S rRNA marker gene showed that infection with S. parasitica reduced the microbial diversity on the surface of the eggs, as evidenced by decreased Pielou's evenness and Shannon's indices. We further determined whether the bacterial genera with a relative abundance of >5.0% in the egg/skin samples were present at significantly different abundances in relation to the presence of S. parasitica. The results have shown that some genera, such as Pseudomonas and Flavobacterium, decreased significantly in the presence of the pathogen on the egg surface. On the other hand, some bacterial taxa, such as Acinetobacter and Janthinobacterium, as well as Aeromonas, were more abundant on the diseased eggs and the injured trout skin, respectively. Finally, beta diversity analyses (weighted UniFrac, unweighted UniFrac, Bray-Curtis) have shown that the sampling location (i.e., fish farm), along with S. parasitica infection status, also has a significant influence on the microbial communities' composition on the trout skin and eggs, demonstrating the strong influence of the environment on the shaping of the host surface microbiome. Overall, we have shown that the presence of S. parasitica was associated with changes in the diversity and structure of the trout skin/egg microbiome. The results obtained could support the development of new strategies for the management of saprolegniosis in aquaculture.

Unveiling the effects of environmental factors and Yellow River inputs on the ichthyoplankton community structure in typical bays

To unravel the effects of environmental factors on fishery resources in the bay, we conducted six biological and environmental surveys in the Laizhou Bay between 2013 and 2020. The findings of our study illuminated several key aspects: (1) The annual discharge of water and sediment from the Yellow River to Laizhou Bay exhibited notable variations, while concurrently, environmental factors including temperature, salinity, and suspended particle matter underwent fluctuations, yet remained within a relatively stable range overall. (2) A total of 8318 eggs and larvae belonging to 10 orders, 16 families, and 19 genera were collected. Significant interannual fluctuations had been documented in the species composition, abundance, and biodiversity of ichthyoplankton. Notably, both Shannon-Wiener diversity index and Pielou evenness index were significantly negatively correlated with suspended particle matter concentration. (3) The water and sediment discharge significantly positively correlated with the number of cold-temperature species. However, the sediment input negatively correlated with the number of continental shelf benthopelagic fish. (4) Redundancy and correlation analyses confirmed the strong link between spatial and temporal distribution of fish communities and environmental factors, with salinity and dissolved oxygen key for ichthyoplankton abundance. Our research offers a scientific foundation for targeted fishery protection and management, which is crucial for preserving the ecological functions of spawning grounds in the bay.

The effect of the tidal cycle on the phytoplankton community assemblage in a mangrove-dominated tropical tidal creek.

A comparative assessment of phytoplankton dynamics during low tide (LT) and high tide (HT) was conducted from February 2022 to January 2023 in a tropical mesotidal creek, Manori, Mumbai, India. In total, 124 phytoplankton species were recorded. The HT resulted in greater species richness (124 species) and diversity indices (Shannon-Wiener's index) than the LT (102 species). The Pielou's evenness (J') and Simpson's dominance index (1-D) did not show significant fluctuations with the tides due to the marine phytoplankton species moving rhythmically in and out of the creek with the tides. Overall, the seasonal abundance was maximum during pre-monsoon at HT (5.79 × 103 u/L) and lowest in monsoon at LT (0.45 × 103 u/L), whereas spatial abundance was maximum at S1 (HT- 4.04 × 103 u/L) at HT and lowest at S3 (LT- 0.75 × 103 u/L) at LT. The diatoms dominated in their abundance (1.83 × 103 u/L and 3.82 × 103 u/L in HT) and diversity (77 in LT and 92 in HT). The species such as Coscinodiscus centralis, Coscinodiscus granii, Coscinodiscus radiatus, Triops furca, Melosira varians, Nitzchsia palea, Chaetoceros affinis, Skeletonema marinoi, Stephanocyclus meneghinianus, Planktoniella sol and Skeletonema costatumwere the dominant native residents in the creek. SIMPER analysis revealed that the maximum similarity was during the monsoon (47.65%), and the minimum was during the pre-monsoon (38.10%) at LT. However, in HT, the maximum similarity of phytoplankton shifted to post-monsoon (63.85%) and the minimum during the pre-monsoon (46.71%). The mean value of richness (d') and Shannon's diversity (H') showed a moderate phytoplankton diversity in the system. The environmental parameters (water temperature > pH > nitrate > salinity > DO > Alk > silicate) have a greater influence on the distribution of the phytoplankton community with tides as revealed by the Canonical correspondence analysis. Therefore, it has been found that tides play a significant role in the distribution and abundance of the phytoplankton community in a mesotidal creek environment.

Reduced Gut Bacterial Diversity in Early Life Predicts Feeding Intolerance in Preterm Neonates.

Microbiota plays a crucial role in intestinal maturation in preterm newborns. The clinical manifestation of the immaturity of the gastro-intestinal tract is called feeding intolerance (FI). This condition may resolve spontaneously or dramatically evolve into necrotizing enterocolitis. One of the most challenging tasks for the neonatologist is to identify those neonates that will develop the disease early in order to adequately provide nutrition to these patients, from the very first hours of life. A close interplay between the maturity of the gastro-intestinal tract and gut microbiota has been described; however, in preterm neonates, this relationship is still undefined. We analyzed the bacterial composition of stool samples, collected early in life, from 30 preterm newborns classified as intolerant or tolerant according to the degree of readiness of the gastro-intestinal tract to receive enteral nutrition. The Pielou evenness index was significantly increased in intolerant compared with tolerant newborns. Data corrected for confounding variables confirmed that the occurrence of gut maturation was independently influenced by Pielou evenness at birth. A lower bacterial diversity very early in life is associated with improved feeding tolerance in preterm newborns. The abundance analysis showed that neonates not ready to receive enteral nutrition for feeding intolerance show, after birth, an increased abundance of Proteobacteria, Lachnospiracae, Enterobacter and Acinetobacter. We can argue that those are the taxa that prevent the establishment of pioneer bacteria. A lower alpha-diversity, in the first days of life, may facilitate the seeding of beneficial pioneer bacteria that, in turn, drive healthy microbial colonization during neonatal life.

Anti-seasonal flooding drives substantial alterations in riparian plant diversity and niche characteristics in a unique hydro-fluctuation zone.

Human-induced disturbances such as dam construction and regulation have led to widespread alterations in hydrological processes and thus substantially influence plant characteristics in the hydro-fluctuation zones (HFZs). To reveal utilization of limited resources and mechanisms of inter-specific competition and species co-existence of plant communities based on niche breadth and overlap under the different HFZs of the Three Gorges Reservoir (TGR) in China, we conducted a field investigation with 368 quadrats on the effects of hydrological alterations on plant diversity and niche characteristics. The results showed anti-seasonal flooding precipitated the gradual disappearance of the original diverse niches, resulting in the reduction of plant species richness and functional diversity and more obvious competition among plant species with similar resource requirements. Annuals, perennials and shrubs accounted for 71.23%, 27.39% and 1.37%, respectively, suggesting that annuals and flood-tolerant riparian herbs were favored under such novel flooding conditions. A consistent increase in species number, Shannon-Wiener diversity index and Simpson dominance index with altitude was inconsistent with hump-shaped diversity-disturbance relationship of the intermediate disturbance hypothesis, while the opposite trend was observed for the Pielou evenness index. This species distribution pattern might be caused by several synergetic attributes (e.g., the submergence depth, plant tolerant capacity to flooding, life form, dispersal mode and inter-specific competition). Vegetation types shifted from xerophytes to mesophytes and eventually to hygrophytes with the increasing flooding time in the HFZs. Hydrological alterations proved to be the paramount driver of vegetation distribution in the different HFZs. The niche analysis provided the first insights on the mechanisms of resource utilization and inter-specific competition, of which annuals could germinate quickly after soil drainage to achieve the greatest competitive advantages and occupy a larger niche space than other plants. Vegetation was still in the early stage of primary succession in the novel riparian forests. Therefore, vegetation restoration strategies should be biased towards herbaceous plants, due to annuals with better environmental adaptability, supplemented by shrubs and small trees. To establish a complete reference system for vegetation restoration, natural vegetation monitory plots in the different succession stages should be established in the different HFZs of the TGR, and their environmental conditions, community structures and inter-specific relationships further analyzed.

Linear relationships between aboveground biomass and plant species diversity during the initial stage of degraded grassland restoration projects.

The relationship between aboveground biomass and plant diversity has been extensively examined to understand the role of biodiversity in ecosystem functions and services. Degraded grassland restoration projects can enhance carbon sequestration. However, the relationship between biomass and diversity remains one of the most actively debated topics regarding grassland ecosystems in degraded grassland restoration projects. We speculated that establishing the linear relationships between aboveground biomass and plant species diversity could contribute to enhancing the efficacy of degraded grassland restoration projects. This study sought to determine whether these relationships were linear during the initial stages of the restoration projects of degraded grasslands in Xing'an League, China. The investigations were based on an examination of seventy-six 1 × 1 m2 plots distributed among 15 areas in which the degraded grassland was at the initial stages of restoration. To quantify the species diversity of the degraded grassland communities, we used the species richness, Shannon-Wiener, inverse Simpson's reciprocal, and Pielou's evenness indices. Our analyses revealed that aboveground biomass had clear positive linear relationships with species richness during the initial stages of degraded grassland restoration. However, there were less pronounced associations with species diversity as assessed using the Shannon and inverse Simpson indices, based on regression models. Furthermore, weed biomass was found to have significant negative effects on species richness and Pielou's evenness. The weak linear relationship between aboveground biomass and species richness could be ascribed to an increase in weed biomass. We concluded that aboveground biomass and plant species diversity could be enhanced during the initial stages of degraded grassland restoration projects and suggest that the extent of weed biomass could serve as a key indicator of the efficacy of restoration from the perspective of plant species diversity and aboveground biomass in carbon sequestration projects.

Peripheral blood immune parameters, response, and adverse events after neoadjuvant chemotherapy plus durvalumab in early-stage triple-negative breast cancer.

We evaluated T- and B-cell receptor (TCR and BCR) repertoire diversity and 38 serum cytokines in pre- and post-treatment peripheral blood of 66 patients with triple-negative breast cancer (TNBC) who received neoadjuvant chemotherapy plus durvalumab and assessed associations with pathologic response and immune-related adverse events (irAEs) during treatment. Genomic DNA was isolated from buffy coat for TCR and BCR clonotype profiling using the Immunoseq platform and diversity was quantified with Pielou's evenness index. MILLIPLEX MAP Human Cytokine/Chemokine Magnetic Bead Panel was used to measure serum cytokine levels, which were compared between groups using moderated t-statistic with Benjamini-Hochberg correction for multiple testing. TCR and BCR diversity was high (Pielou's index > 0.75) in all samples. Baseline receptor diversities and change in diversity pre- and post-treatment were not associated with pathologic response or irAE status, except for BCR diversity that was significantly lower post-treatment in patients who developed irAE (unadjusted p = 0.0321). Five cytokines increased after treatment in patients with pathologic complete response (pCR) but decreased in patients with RD, most prominently IL-8. IFNγ, IL-7, and GM-CSF levels were higher in pre-treatment than in post-treatment samples of patients who developed irAEs but were lower in those without irAEs. Baseline peripheral blood cytokine levels may predict irAEs in patients treated with immune checkpoint inhibitors and chemotherapy, and increased post-treatment B-cell clonal expansion might mediate irAEs.

Spatio-temporal dynamics of phytoplankton community structure in the coastal waters of the Southern Beibu Gulf.

This study was conducted during October 2021 (autumn) and April 2022 (spring) to explore the phytoplankton community structure, their distribution characteristics, and the influence of environmental factors in the coastal waters of the Southern Beibu Gulf. The 15 sampling sites were grouped based on the difference in offshore distance to analyze the temporal and spatial differences in community structure and environmental driving in the investigated sea area of the coastal waters of the Southern Beibu Gulf. Permutational multivariate analysis of variance was conducted on the sample data in time and space, revealing that there is no significant difference in space (p > 0.05), but there is significant difference in time (p < 0.05). Notably, water pressure, pH, chemical oxygen demand, nitrite, and labile phosphate were higher in autumn, while total ammonia nitrogen, dissolved oxygen, and suspended solids were significantly higher in spring. Additionally, the study identified 87 phytoplankton species belonging to 6 phyla, dominating by Bacillariophyta, followed by Dinophyta and Cyanophyta. The phytoplankton density, Shannon Weiner's diversity index (H'), Pielou's evenness index (J), and Margalef's richness index (D) ranged from 84.88 to 4675.33 cells L-1, 0.56 to 2.58, 0.26 to 0.89, and 1.21 to 3.64, respectively. Permutational multivariate analysis of variance showed non-significant spatial differences in phytoplankton composition (p > 0.05) but seasonal differences (p < 0.05). Furthermore, canonical correspondence analysis (CCA) identified pH, dissolved oxygen, suspended solids, chemical oxygen demand, nitrite, and labile phosphate as key environmental factors influencing the phytoplankton community structure (p < 0.05). In this study, the dynamic changes of phytoplankton community structure and environmental factors in the southern coastal waters of Beibu Gulf were analyzed in detail from two aspects of time and space. The key environmental factors to protect the ecological environment in the southern coastal area of Beibu Gulf were found out. It provides a reference method and theoretical basis for the management and protection of Beibu Gulf and other tropical marine environment.

Impacts of rapidly urbanizing watershed comprehensive management on per- and polyfluoroalkyl substances pollution: Based on PFAS “diversity” assessment

The impact of watershed comprehensive management (WCM) on per- and polyfluoroalkyl substances (PFAS) pollution in rapidly urbanizing areas remains unclear. In a typical rapidly urbanizing watershed of Shenzhen, China, we investigated temporal variations in contamination level, primary source and ecological risk of 50 emerging and legacy PFAS, as well as the replacement trends of emerging PFAS before and after WCM during a six-year sampling campaign. We found that large-scale dredging was a non-negligible factor in abnormally increased PFAS concentrations (6.43 %–456.16 %) during WCM through their release from river sediments. To better characterize the diverse and complex PFAS contamination, a novel pollution assessment method, PFAS “diversity”, was adopted based on a modified Shannon–Weiner diversity index and Pielou evenness index, reflecting numbers of PFAS detected and how evenly each PFAS contributed to the total PFAS concentrations at specific sampling sites. Importantly, we found that the Pielou evenness index can indicate and quantify abnormal pollution sources (especially point sources) along the river. The results revealed that WCM did not effectively reduce total PFAS concentrations and diversity in the rapidly urbanizing watershed but obviously improved point source pollution. Furthermore, 6:2 polyfluorinated phosphate diesters and hexafluoropropylene oxide dimer acid (GenX) that posed high ecological risks emerged and the number of sampling sites with high risk increased from 16 to 20 after WCM. Finally, we summarize several important issues related to PFAS contamination during WCM and propose specific countermeasures, such as adopting environmental dredging and reducing the proportion of ecological water replenished by wastewater treatment plant effluent for better control of PFAS pollution. Our study highlighted the limited effectiveness of WCM in mitigating PFAS pollution and the importance of emerging contaminant regulation in rapidly urbanizing watersheds during WCM.