Community Richness Research Articles

Variations in the Bacterial, Fungal, and Protist Communities and Their Interactions Within Sediment Affected by the Benthic Organism, Snail Bellamya purificata

In aquatic benthic environments, benthic organisms have been found to regulate important biogeochemical characteristics and perform key ecosystem functions. To further explore the ecological impact of the snail Bellamya purificata’s, presence on the benthic environment, we employed high-throughput sequencing technology to investigate its effects on the bacterial, fungal, and protist communities in sediment and their intrinsic interactions. Our findings revealed that B. purificata’s presence significantly enhanced the diversity and evenness of the fungal community while simultaneously decreasing the diversity and richness of the protist community, and it also altered the composition and relative abundance of the dominant phyla across the bacterial, fungal, and protist communities. The snail B. purificata considerably altered the co-occurrence networks of the microbial communities, particularly by enhancing the intrinsic complexity of the protist community and by strengthening the interconnections among the protist, bacterial, and fungal communities. Notably, the proportions of specialists within the sediment bacterial, fungal, and protist communities declined due to the snail B. purificata. Its presence also notably expanded the habitat niche breadth for sediment bacteria and protists. In terms of community assembly, B. purificata shifted the fungal community assembly from being dominated by stochastic processes to being dominated by deterministic processes, whereas the protist community assembly shifted from deterministic processes to being dominated by stochastic processes. The mainly altered ecological processes in the fungal and protist assemblies were drift and homogenizing selection. Additionally, the presence of B. purificata resulted in a notable reduction in the sediment ON level and a significant increase in the ammonia, FA, and EN concentrations. Sediment properties, particularly FA and nitrate, were strongly correlated with microbial communities and were key contributors to changes in microbial community dynamics. These research findings not only broadened our understanding of the ecological impacts of B. purificata on benthic microbial communities but also highlighted its substantial potential in enhancing microbial community stability.

МОНИТОРИНГ БИОРАЗНООБРАЗИЯ ЕЛЬНИКОВ ЕВРОПЕЙСКОЙ ЧАСТИ РОССИИ ПОСЛЕ ПРИРОДНЫХ И АНТРОПОГЕННЫХ «КАТАСТРОФ»

We analyzed the main trends of the change in the species richness of plant communities after catastrophic natural (catastrophicwindthrow, fires, large bark beetle outbreaks) and anthropogenic (clear felling) disturbances. The main factor determining the increase in species richness was the intensity of ecosystem disturbance after ca- tastrophes. The greatest disturbance was caused by clear-cut logging, when all timber was removed from the felling area by tractors. Fires also could totally destroy stands and all components of the forest ecosystem. Large- scale wind damage affected only the trees of the upper layer, while all other components of the plant communities were slightly damaged. The bark beetle outbreaks cause the death only of upper layer spruce trees, while the whole forest ecosystem remains unchanged. The degree of disturbance of stands, undergrowth, herb-dwarf scrubs layer, moss cover, litter and soil during the dieback of spruce forests as a result of ‘catastrophes’ determines the degree of vegetation recovery in disturbed areas. We studied the spruce forest in the zone of coniferous-broadleaved forests of the Moscow region, affected by an outbreak of typograph bark beetle.Dynamics of understory plant species richness was fundamentally different after stand salvage logging following beetle outbreaks and in unlogged standswith preserved deadwood. Monitor- ing observations of plant communities during 10 years on permanent sample plots revealed the main feature of the plant species succession after clear felling. For the first six years succession passed through the herb and the shrub stages with a sharp increase in species and structural diversity of plant communities. Only in the forest stage the species composition characteristic of the forest was restored. In the deadwood stand the forest communities was preserved and no differences in the dynamics of species richness of the original undisturbed forest were detected. Only dominance of species in the stand and herb-shrub layer changed. If man don't clear cut dead and wind- damaged areas of spruce forests, it will result in development of mixed forests with increased resistance to pests and forest diseases. Monocultures of spruce forests may be replaced by mixed forests, increasing the diversity of forests.

Hybrid Soybean as Green Manure for Improving Soil Properties and Subsequent Crop Growth

The rapid increase in fertilizer use has led to the degradation of soil quality, nutrient imbalances, reduced biodiversity, and soil compaction. To address these challenges, hybrid soybeans with efficient biological nitrogen fixation capabilities and broad environmental adaptability were selected as green manure to reduce fertilizer application, thereby improving soil fertility and structure. This study utilized the varieties “Forage Soybean S001” (S001), “Neinong S002 Forage Soybean” (S002), “Mengnong S003 Forage Soybean” (S003), “Mengnong S004 Forage Soybean” (S004), “Mengnong S005 Forage Soybean” (S005), and “Mengnong S006 Forage Soybean” (S006) as green manure materials. The clean tillage (CK) treatment served as the control, ensuring a residue-free soil surface while maintaining consistent practices in soil preparation, irrigation, and field management across all treatments. Field planting of green manure and subsequent crops was conducted at the M-Grass Ecology and Environment (Group) Company’s experimental site in Hohhot in early May of 2023 and 2024. The plots each measured 20 m2, with three replications arranged in a randomized block design. A combination of field experiments and laboratory analyses was utilized to investigate the effects of incorporating various hybrid soybean varieties as green manure on soil nutrient levels, soil enzyme activity, soil microbial communities, and the subsequent growth of oats. The results indicated that incorporating various hybrid soybean varieties as green manure into the soil significantly improved soil nutrient levels and enzyme activity. The diversity and richness of soil bacterial communities increased significantly, accompanied by alterations in community structure and composition. These changes enhanced soil fertility and optimized the microbial community structure, promoting the growth of subsequent crops. Among all the treatments, S001 and S004 were particularly effective in enhancing the soil environment, indicating their potential as superior green manure resources for broader application.

Difference in Community Structure and Function of Bacteria Attached to Stems and Leaves of Potamogeton crispus Compared to that of Bacteria in the Overlying Water and Sediment

The stems and leaves of submerged macrophytes usually grow below the water surface and could provide a good biological carrier for the colonization and growth of planktonic bacteria in water. Therefore, attached bacteria on the stem and leaf surfaces of submerged macrophytes are important components and play a crucial role in aquatic ecosystems. To further understand the structure characteristics and functional differences of the bacterial community attached to the stems and leaves of submerged macrophytes, the submerged macrophytes Potamogeton crispus and the overlying water and sediment were sampled and analyzed in this study. The results showed that a total of 10 320 OTUs were detected in the P. crispus samples, the overlying water samples, and the sediment samples. These OTUs included 64 phyla, 189 classes, 448 orders, 721 families, and 1 366 genera. The richness and diversity of bacterial communities in sediments were the highest, followed by the stem and leaves of P. crispus, and the alpha diversity index of planktonic bacteria in water was the lowest. Significant differences （P<0.05） were observed among the four alpha diversity indices of the three source samples. Bacterial communities with greater similarity were obtained from the same source samples, but there was more distinct community composition dissimilarity in bacteria collected from the submerged macrophytes and the overlying water and sediment samples （P<0.05）. At the level of phylum, order, and genus classification, the relative abundance of most dominant bacterial species, non-dominant species, and occasional species showed significant differences among the three source samples （P<0.05）. Proteobacteria, Actinobacteria, and Bacteroidetes were common dominant bacterial phyla for the three source samples, while Firmicutes were unique dominant phyla for attachment bacteria on the plant stem and leaves of P. crispus. There were differences in carbohydrate metabolism, energy metabolism, amino acid metabolism, cofactors, and vitamin metabolism among the three source samples （P<0.05）. The relative abundance of chemical heterotrophic and oxidative heterotrophic functional types in the stem and leaf samples of P. crispus was higher than that in the overlying water and sediment samples. In addition, higher nitrate reduction, nitrogen respiration, and nitric acid respiration functions were observed in sediment samples. To summarize, the stems and leaves have the potential to encourage bacterial colonization and create a unique bacterial community on the surface of submerged macrophytes. Submerged P. crispus macrophytes and their surroundings （water and sediment） play different roles in the biogeochemical cycling of nutrients in the freshwater ecosystem.

Effect of Nitrification Inhibitors on Soil Nitrogen Dynamics and Microbial Community Structure in Aerated Paddy Field

The aim of this study was to clarify the effects of nitrification inhibitors on the dynamic changes in the nitrogen and microbial community in paddy soil under aerated irrigation by using the indica hybrid rice Zhongzheyou 8 as experimental material. A trial with three treatments was conducted in 2023： conventional flooding irrigation （CF）, micro-nano bubble water aeration irrigation （MB）, and micro-nano bubble water aeration irrigation combined with nitrification inhibitor （MBNI）. The effects of nitrification inhibitors on the contents of NH4+-N and NO3--N and the apparent nitrification rate of soil under aerated irrigation were analyzed, as well as the characteristics of bacterial community diversity and its correlation with soil chemical factors. The results showed that compared with those in the CF treatment, the MB and MBNI treatment significantly increased the dissolved oxygen concentration, oxidation-reduction potential, pH, and soil NH4+-N content. Compared with that under the MB treatment, the MBNI treatment increased soil pH, reduced NH4+-N content in a short time after nitrogen fertilizer application, and later increased NO3--N content. Compared with that in the CF treatment, the MB and MBNI treatments could increase the diversity and richness of soil bacteria, while the relative abundance of Proteobacteria and Nitrospirota significantly increased, and the relative abundance of Bacteroidota decreased. The MBNI treatment reduced the diversity and richness of bacteria compared with that in the MB treatment and significantly decreased the relative abundance of Nitrospirota. Correlation analysis showed that soil chemical properties were significantly correlated with bacterial community structure. In conclusion, the combined application of nitrification inhibitors under aerated irrigation can improve soil nitrogen supply capacity, increase soil inorganic nitrogen content, improve soil chemical properties, and affect microbial community diversity and richness to optimize microbial community structure.

Removal of benzo[a]pyrene by a highly degradable microbial community immobilized by modified wheat straw biochar.

Benzo[a]pyrene (BaP), a high-molecular-weight polycyclic aromatic hydrocarbon (HMW-PAHs), is a prevalent organic pollutant. Due to various environmental factors, the viability and degradation capacity of PAHs-degrading bacteria in contaminated soil are significantly reduced. Therefore, it is imperative to maintain microbial activity and enhance degradation efficiency. This study aims to optimize BaP removal by utilizing biochar-immobilized BaP for the enhancement of microbial communities' degradative potential. The immobilization of modified wheat straw biochar (MWBC) significantly enhanced the removal efficiency of BaP by a highly efficient microbial community enriched from oil-contaminated soil, achieving a large removal efficiency of 75.18% for BaP (5-20mg/L) in a mineral salts medium in 12 d. The study also involved a detection of the species richness and intermediate metabolites of microbial community, as well as an assessment of the challenges and difficulties associated with managing real contaminated sites.

Salt stress affects the bacterial communities in rhizosphere soil of rice

Salt is a primary factor limiting the utilization of saline lands in coastal beach areas, with rhizosphere microorganisms playing a crucial role in enhancing crop stress resistance and exhibiting high sensitivity to environmental changes. Rice (Oryza sativa L.) is the preferred crop for reclaiming salinized soils. This study determined the microbial communities in rhizosphere soil of rice under different salt stress treatments by high-throughput sequencing. We found that salt stress changed the bacterial community diversity, structure and function in rhizosphere soil of rice. Salt stress significantly reduced the richness and diversity of bacterial communities in rhizosphere soil of rice. The bacterial community was characterized by higher abundance of the phyla Chloroflexi, Proteobacteria and Actinobacteria; the relative abundances of Firmicutes, Acidobacteriota and Myxococcota were decreased, while Bacteroidota and Cyanobacteria were increased under salt stress. The functions of bacterial communities in rhizosphere soil of rice mainly include chemoheterotrophy, aerobic_chemoheterotrophy, phototrophy etc., chemoheterotrophy and aerobic_chemoheterotrophy were significantly higher NS3 (adding 3‰ NaCl solution to the base soil) treatment than NS6 (adding 6‰ NaCl solution to the base soil) treatment. These findings provide a theoretical foundation for the development of specialized salt-tolerant microbial agents for rice cultivation and offer a viable strategy for improving the soil environment of saline coastal lands through the application of beneficial microorganisms.

Soil mite communities (Acari, Mesostigmata) in pure stands on post-agricultural lands: does season matter?

Post-agricultural land differs from typical forest land in physical, chemical and biological features. In addition, the environment of this land type is determined, among other things, by the introduced tree species. These differences may be revealed by the biodiversity and abundance of the soil fauna. We analysed the abundance, species richness and diversity of different instars of mesostigmatid mites inhabiting three different habitat types on post-agricultural land (shaped by pure Pinus sylvestris L., Tilia cordata Mill. and Betula pendula Roth stands). We collected 288 soil samples from eight plots in three stands. The collection was conducted in July and October in two consecutive vegetation seasons (2021 and 2022) for Mesostigmata mites community. Soil characteristics (determination of soil group and analysis of physical and chemical properties of soil and litter) were done in July 2021. In total, 399 individuals (266 females, 50 males and 83 juveniles) were classified into 38 taxa (33 species, five genera). Most individuals belonged to the Parasitidae, Laelapidae and Veigaiidae families. The most abundant species were Hypoaspis aculeifer (Canestini) (21.6% of all recorded mites), Veigaia nemorensis (C.L.Koch) (7.8%) and Trachytes aegrota (C.L.Koch) (7.0%). Abundance, species richness and diversity were shaped by collection month and Fe content in soil. The abundance was influenced by N litter content and was significantly lower in P. sylvestris stand in July (0.57 ± 0.23; mean ± SE) than in P. sylvestris (2.17 ± 0.54) and T. cordata (2.15 ± 0.48) stands in October. Moreover, abundance in P. sylvestris stand in October was higher than in B. pendula stand in July (0.78 ± 0.26). Similarly, species richness was significantly lower in P. sylvestris stand in July than in P. sylvestris and T. cordata stands in October (2.17 ± 0.54 and 2.15 ± 0.48, respectively). Higher Shannon’s diversity of mite communities was reported in P. sylvestris stand in October (0.40 ± 0.10) than in P. sylvestris and B. pendula stands in July (0.12 ± 0.06 and 0.14 ± 0.08, respectively). Large fluctuations of abundance, species richness and diversity of soil mite communities in P. sylvestris and B. pendula stands between collection months give the insights for creating mixed stands on post-agricultural land. It is worth noticing that the wet season creates the most favourable living environment for mesostigmatid mites in P. sylvestris litter.

The effect of Torreya grandis inter-cropping with Polygonatum sibiricum on soil microbial community.

Inter-cropping is a reasonable planting pattern between different plants. Inter-cropping of Torreya grandis with Polygonatum sibiricum is a relatively mature planting pattern in China, which has been applied to improve soil ecological environment and reduce the occurrence of pests and diseases in China. However, there is currently limited knowledge on the response of soil microbial communities to this practice. In this study, we employed Illumina MiSeq sequencing coupled with Functional Annotation of Prokaryotic Taxa (FAPROTAX) and Fungi Functional Guild (FUNGuild) analyses to investigate the dynamic changes in soil microbial communities across seven treated groups [the bulk soil of the T. grandis inter-cropping with P. sibiricum (IB), the bulk soil for mono-cropping of P. sibiricum (PB), the bulk soil for mono-cropping of T. grandis (TB), the P. grandis rhizosphere soil of the T. grandis inter-cropping with P. sibiricum (IPR), the rhizosphere soil for mono-cropping of P. sibiricum (PR), the T. grandis rhizosphere soil of the T. grandis inter-cropping with P. sibiricum (ITR), and the rhizosphere soil for mono-cropping of T. grandis (TR)]. The results showed that the rhizosphere soil of Torreya-Polygonatum inter-cropping exhibited higher microbial community richness, diversity and evenness than mono-cropping (ITR > TR, IPR > PR). Inter-cropping increased the abundance of Micrococcaceae, Xanthobacteraceae, Saitozyma, while decreased Bacillus, Burkholderia, Streptomyces, Cladosporium, and Gibberella significantly of the rhizosphere soil of T. grandis. Further, the abundance of pathogens, such as Fusarium and Neocosmospora, was higher in mono-cropping samples compared to inter-cropping. There existed distinct variations in bacterial and fungal communities among all groups except for IB and TB. The FAPROTAX and FUNGuild analyses results indicated that inter-cropping significantly enhanced soil microbial function associated with nutrient cycling and exhibited a consistent increase in the relative abundance of nitrogen-cycling and carbon-cycling bacteria, and decreased the abundance of plant pathogen guild in the inter-cropping sample ITR compared to the mono-cropping TR. Our findings suggest that T. grandis inter-cropping with P. sibiricum not only enhance the diversity of soil microbial communities, but also improve the nitrogen and carbon cycling functions. In addition, the inter-cropping can effectively reduce the relative abundance of some soil-borne pathogens for T. grandis and P. sibiricum, indicating that this intercropping method may alleviate the impact of pathogens on crops, thus providing assistance for plant disease prevention and sustainable management.

Effects of iodine content on the hydrochemical characteristics and microbial community structure of groundwater in coastal zone: A case study of Bailang River Basin.

Iodine is an important component of the thyroid gland, producing hormones. Excess iodine can trigger autoimmune thyroid disease. The salt-freshwater interaction zone of the coastal aquifer is affected by seawater intrusion, and the physical and chemical environment is constantly changing. Exploring the characteristics and influencing factors of high-iodine groundwater in coastal areas play an important role in the prevention and control of groundwater pollution. In this study, the hydrochemical characteristics of high-iodine groundwater were analyzed. The interrelationship between the water's chemical components was revealed, and the microbial community composition under different iodine concentration gradients in the groundwater was examined using 16sRNA high-throughput sequencing. The influence of water quality on microbial distribution was also explored. The results showed that the iodine content in the Bailang River Basin ranged from 31 to 1776 μg/L, and the high-iodine groundwater samples accounted for 67.7%, with uneven spatial distribution. Groundwater samples with different iodine concentrations were grouped and compared, and there was no significant difference in the diversity and richness of microbial communities. At the genus level, iodine concentrations were significantly correlated with Sediminibacterium and Thauera. In addition to iodine, nitrates and sulfates also have a significant effect on microbial communities. PRACTITIONER POINTS: Groundwater in the south bank of Laizhou Bay is predominantly alkaline, with uneven spatial distribution of iodine content. As the concentration of iodide increases, the groundwater chemical type tends towards Na-Cl type. The concentration of iodine has little effect on the richness and diversity of microbial communities. The concentrations of sulfate, nitrate, and nitrite also affect the microbial structure and species diversity of groundwater.

Light grazing increased but heavy grazing decreased the abundance and family richness of soil arthropods community in an alpine grassland in the Qinghai Lake Basin.

Soil arthropods are important biological components of the soil food web, which are highly sensitive to environmental disturbances and can rapidly respond to changes in the external environment, then reflect the stability and health of the soil ecosystem. We investigated the community structure of soil arthropod and their responses to grazing intensity along soil depth (from topsoil to subsoil) through a manipulated grazing treatment with four intensity levels (no grazing, light grazing, moderate grazing and heavy grazing) in an alpine grassland in the Qinghai Lake basin. The results showed that: (1) Collembola was the dominant group in the experimental site. (2) Nearly two-thirds of the individuals were distributed in the topsoil (0-10 cm), and grazing did not cause soil arthropods to migrate from the topsoil to deeper soil layers. (3) Light grazing had a positive effect on increasing the individual number, family richness and diversity of soil arthropods, while heavy grazing had the opposite effect, exerting a negative impact on the soil arthropod community. (4) When the grazing intensity did not exceed moderate grazing (i.e. stocking rate of 3.86 Tibetan sheep·hm-2), grazing would have a positive effect on the soil arthropod community. In summary, light grazing is the intensity of disturbance that has a positive effect on the soil arthropod community in this region. This study not only revealed the impact of grazing on the community structure of soil arthropods but also aided in assessing the potential effects of grazing activities on the stability of soil ecosystems, providing scientific evidence for the sustainable management of alpine grasslands.

Macroalgal diversity drives abundance and richness of amphipod community

Macroalgal diversity drives abundance and richness of amphipod community

Production of polyhydroxybutyrate with photosynthetic bacteria treating artificial kitchen waste: Effect of light intensity

Kitchen waste can be used as a cheap carbon source for photosynthetic bacteria (PSB) to produce polyhydroxybutyrate (PHB). Light intensity is one of the most important factors in PSB growth. This paper investigated the efficiency and mechanism of PSB growth and PHB production from fermented kitchen waste under different light intensities. Results showed that PSB could grow well and produce PHB within the light intensity range of 1000-4000 lux using fermented kitchen waste as substrate. The 2000 lux was the optimal for PHB production, and PHB content and concentration reached 41.6% dry cell weight and 675.3mg/L, respectively, much higher than other light intensities. The corresponding PHB yield and productivity were 0.33g PHB/g chemical oxygen demand (COD) and 51.9mg/L/d, respectively. Removal of COD and NH4+ were 89.6% and 44.7%, respectively. Microbial community analysis showed that diversity and richness of bacterial community increased with time, and Rhodopseudomona and unclassified_f_Enterobacteriaceae were the dominant bacterial genera at the 2000 lux. Metabolic characteristics in fatty acid degradation, tricarboxylic acid cycle, pyruvate metabolism, photosynthesis, and pyruvate metabolism increased at the 2000 lux. Also, the key enzyme (PhaC, butyryl-CoA dehydrogenase, etc.) for synthesizing PHB was highly expressed, which corresponded to the large amount of PHB accumulation. This study provides a theoretical reference for treatment of kitchen waste with PSB for PHB production.

A study of family climate and Academic Achievements of tribal secondary school students in Seraikela -Kharaswan district of Jharkhand

India's newly formed state Jharkhand (15 Nov 2000) is identified by its tribal population. In which Jharkhand is ranked sixth in the country. Our Jharkhand is a green state full of minerals and rich communities. Despite this, our state is a backward state. The purpose of this study was to determine whether there is a connection between the family climate and academic achievement in tribal secondary school students. With reference to their gender and locality. Further, it was also intended to find out the difference between the boy and girl students in terms of academic achievement. The researcher adopted a correlational research design for the study. 80 tribal secondary school students of class X consisting of 40 boys and 40 girls from rural and urban areas were taken as a sample by random sampling technique. The research tools used for the study were Family Climate Scale and the student's academic achievement scores. data were analyzed by using Mean, standard deviation, Person product- moment correlation and t-test. The findings showed that gender and location were positively correlated with the family climate of tribal secondary school students as well as their academic success. Moreover, the family climate of boy and girl tribal students at secondary school did not different significantly.

Expanding Soil Invertebrate Knowledge in Panama: The Genus Lepidocyrtus (Collembola, Entomobryidae) in the Parque Natural Metropolitano as a Study Case

Panama, located in the heart of the Mesoamerican hotspot, harbors an extraordinary species diversity across the Tree of Life. The Collembola species of the genus Lepidocyrtus play an important role in soil biological processes such as decomposition, being used to monitor soil health and functional parameters. However, the limitation of morphological characters and molecular resources hampers the evaluation of local soil diversity. Here, using 30 Lepidocyrtus specimens collected in the Parque Natural Metropolitano (PNM), we unravel the diversity of this Panamanian protected area through molecular tools and new taxonomic traits. Our phylogenies, in combination with species delimitation analyses, indicate that the PNM harbors an extremely rich community of Lepidocyrtus species, two of them cited in Panama for the first time, and three of them potentially new to science. We highlight that the presence of the dental tubercle and pseudopores on the BP4 region are not monophyletic and, therefore, can be used as supplementary characters to morphologically resolve species complexes. Overall, this study sheds light on the Lepidocyrtus richness of the PNM, which acts as a shelter for Panamanian and the Mesoamerican hotspot species.

Effects of a Vegetable Eel Co-Culture System on the Soil Ammonia-Oxidizing Microbial Community

(1) Background: A vegetable eel co-culture system is an economically efficient way of agricultural cultivation, which can have an impact on the soil microbial environment and play a pivotal role in the soil nutrient cycle, but there is little research on its impact on soil ammonia-oxidizing microorganisms. (2) Methods: NovaSeq platform sequencing was employed to investigate the richness, structure, and diversity of soil ammonia-oxidizing microbial communities, exploring the effects of a vegetable eel co-culture system on soil nitrogen cycling. Four different planting treatments were set up: unfertilized without vegetable eel (CCK), fertilized without vegetable eel (CRT), unfertilized with vegetable eel (ICK), and fertilized with vegetable eel (IRT). (3) Results: A vegetable eel co-culture system significantly increased soil pH and decreased bulk density under fertilization conditions. The soil nitrification potential rate was enhanced by a vegetable eel co-culture system to an average of 26.3%. A vegetable eel co-culture system significantly altered the community structure of all ammonia-oxidizing microorganisms, with a significant increase in the richness and diversity of ammonia-oxidizing bacteria (AOB) and comammox clade-A, while fertilization significantly increased the diversity of all ammonia-oxidizing microbial communities. Structural equation modeling (SEM) analysis showed that the main environmental factors affecting the structure of the ammonia-oxidizing microbial community were nitrate and total nitrogen. The number of amoA genes in AOB and comammox clade-B was significantly positively correlated with the soil potential N nitrification rate (PNR), which played a leading role in the nitrification of alkaline vegetable soil. The network analysis revealed that a vegetable eel co-culture system improved the modularity of AOB and comammox clade-B by 13.14% and 5.66%. (4) Conclusions: This study showed that the vegetable eel co-culture system stimulated the evolution of ammonia-oxidizing microbial communities by changing the physicochemical properties, which in turn promoted the soil nitrification reaction.

Thousands of Years of Pastoralism Don’t Count: Coprophagous Beetles Prefer Exotic Alpaca Dung to That of Cattle

Dung beetles mostly feed on mammal dung. Throughout the European Alps, the dung produced by local domestic ungulates attracts many species of dung beetles, giving rise to rich and diversified communities that play an important role in the Alpine agricultural ecosystem. There is, therefore, understandable concern about the introduction of exotic livestock, such as alpacas (Vicugna pacos (Linnaeus, 1758)), into the region. This research studied dung beetle assemblages in an Alpine valley where both cattle and alpacas are raised. We used standardized pitfall traps baited with alpaca or cow dung along altitudinal transects to assess the “attractiveness” of the two resources to dung beetles. Most species entered both trap types. The average number of species per trap did not vary significantly and the nMDS trap ordination largely overlapped, but the total number of individuals and the average number of individuals per trap were higher in traps baited with alpaca dung. This difference was largely due to the preference of the dominant species Euheptaulacus carinatus (Germar, 1824) for alpaca dung-baited traps. Moreover, both the abundance and specific richness changed with altitude, being greatest in alpaca traps during July at intermediate altitudes. IndVal analyses showed that eight out of nine species (all Aphodiinae) showed a preference for alpaca traps. Since the microclimatic conditions (i.e., temperature) of the two trap types were virtually the same, it is reasonable to consider trophic preferences as the source of the observed differences. Finally, we also sampled the beetles present in the alpaca latrines and cow dung pats deposited on pastures, providing confirmation that dung beetles do indeed visit the dung of both species. Our results emphasize the usefulness of polyphagia and the trophic flexibility of dung beetles, providing evidence that the long history of pastoralism in the Alps has not led local species to adapt to the dung of domestic ungulates. The results also suggest that alpaca breeding could be a sustainable activity since, thanks to the work of dung beetles which feed upon and move the dung into their tunnels (as occurs with cattle dung), there is less need for farmers to remove the dung from pastures.

Comparative effects of non-fermented and Lacticaseibacillus paracasei-fermented pomelo juice on gut microbiota composition and short-chain fatty acid production: An in vitro colonic model

Pomelo juice, especially from the Tubtim Siam cultivar, may offer prebiotic benefits by promoting beneficial gut bacteria. This study evaluated the impact of non-fermented and Lacticaseibacillus paracasei (L. paracasei)-fermented pomelo juice on gut microbiota using an in vitro colonic fermentation model. The L. paracasei-fermented juice significantly increased lactobacilli levels compared to the non-fermented juice, while both treatments similarly suppressed coliforms within 24 h. Microbiota analysis revealed increased richness and significant community shifts in both treatments. Moreover, the fermented juice demonstrated a greater decrease in the Firmicutes/Bacteroidetes ratio, indicating a greater impact on gut metabolism. Fermented juice promoted beneficial bacteria like L. paracasei, Bifidobacterium longum, and Faecalibacterium prauznitzii while inhibiting pathogens. These changes coincided with higher production of short-chain fatty acids (SCFAs), including acetic, propionic, and n-butyric acids. Therefore, fermenting pomelo juice with L. paracasei improves its ability to beneficially influence the gut microbiota, suggesting its potential for gut health enhancement.

Addition of bacterial-feeding nematodes contributes to soil phosphorus availability by affecting the mineralization of moderately labile organic phosphorus

Improving the soil residual organic phosphorus (P) utilization rate is important for alleviating P resource shortages and reducing water pollution. Bacterial-feeding nematodes can impact soil alkaline phosphomonoesterase (AlP) activity and mediated organic P mineralization through affecting AlP-producing bacteria that harbor the phoD gene. However, it is unclear which organic P fraction mineralization is promoted with increasing AlP activity after bacterial-feeding nematodes are added, and whether this promotion effect varies with fertilization regimes. Microcosm experiments without (control; -Nematode) and with adding bacterial-feeding nematode Eucephalobus (+Nematode) were carried out in the present study to investigate impacts of bacterial-feeding nematodes on organic P mineralization by using soils collected from four fertilization regimes: non-fertilized control (CK), chemical nitrogen (N), P and potassium (K) fertilizers (NPK), crop straw plus chemical fertilizers (SNPK), pig manure plus chemical fertilizers (MNPK). After 30 days, +Nematode treatment significantly increased soil AlP activity under all the fertilization regimes, and also increased the richness index of AlP-producing bacteria as well as the relative abundances of the gram-positive (G+) bacteria Actinomycetia, Streptomyces and Amycolatopsis. Meanwhile, these three G+ bacteria showed a significant positive correlation with AlP activity, and contributed the most to the different AlP-producing bacterial community compositions under -Nematode treatment versus +Nematode treatment. Moreover, +Nematode treatment only significantly increased the labile organic P (NaHCO3-Po) content in CK and SNPK soils, and the moderately labile organic P (NaOH I-Po) content in SNPK soil. Correlation analysis showed that the AlP activity had positive relationships with the AlP-producing bacterial richness index, community composition and NaOH I-Po, water-soluble P (NH4Cl-Pi) contents. Partial least squares structural equation modeling (PLS-SEM) revealed that NaOH I-Po, under the direct influence of AlP, indirectly and positively influenced NH4Cl-Pi by affecting moderately labile inorganic P (NaOH I-Pi). Overall, this study increases our understanding of the effect mechanism of bacterial-feeding nematodes on organic P mineralization, and finds that the addition of bacterial-feeding nematodes under straw returning may have a better effect in improving the soil P availability compared with their addition under other fertilization regimes.

Understorey-nesting bird community responses to land use in the Korup National Park, an Afrotropical rainforest in South-Western Cameroon

Tropical forest biodiversity is under immense pressure due to a combination of global and local factors, including climate change and intensive land use. Birds play an important role in tropical forest ecosystems, contributing significantly to various ecosystem services. This study examined the impact of deforestation on the richness and abundance of understorey-nesting bird communities along a land-use intensification gradient in the peripheral zone of Korup National Park, Southwest Cameroon. We selected 30 sampling plots, each covering 4 ha, across five habitat types: near-primary forest, secondary forest, disturbed forest, cocoa/coffee plantations, and annual food crop fields. A total of 236 understorey bird nests were identified, representing 16 species. Our findings revealed that land use intensity significantly influenced bird species richness and abundance. Primary and secondary forests provided 75% of the nesting species and 71% of the nests. However, 19% of the species either appeared or increased in cocoa/coffee plantations and annual crop fields. Among the feeding groups, frugivores were the most sensitive group to deforestation. This study corroborates the adverse effects of forest destruction on birds communities and highlights the urgent need to address the rapid and extensive forest conversion occurring within Korup National Park. Allowing secondary forests to regenerate and preserving large patches of primary forest are essential strategies to help understorey-nesting bird communities mitigate the impacts of global changes.