Variation In Community Structure Research Articles

Variation in coral rubble cryptofauna is scale-dependent and driven by small-scale habitat characteristics

Motile cryptofauna living in dead coral rubble represent some of the greatest biodiversity and basal energetic resources on tropical coral reefs. Yet we know relatively little about how and why coral rubble cryptofauna communities change over space and time. As human impacts increase the degradation of living hard corals to dead coral rubble on many reefs worldwide, understanding the communities that will succeed in these degraded environments and the factors paramount to their success becomes increasingly central to coral reef ecology and conservation. Using a remote and uninhabited oceanic atoll in the Pacific Ocean, we quantified the natural spatial variability in motile cryptofauna diversity and community structure in coral rubble across scales (m to km) and tested whether variability at smaller scales could be explained by gradients in microhabitat. We show that coral rubble cryptofauna communities are most variable at intra-site scales (m) rather than inter-site scales (100s m) or between reef zones (km scales). We also show that a substantial amount of variation in cryptofauna density (55%) and phyla-level community structure (31%) is explained by small-scale habitat characteristics, specifically the substrate type below the rubble and the variability in macroalgal cover on individual rubble pieces. Our findings highlight the need to study small-scale processes that are relevant to motile cryptofauna and their community interactions if we are to elucidate the structuring forces of these diverse cryptic assemblages on coral reefs.

Plant-specific microbial diversity facilitates functional redundancy at the soil-root interface

Abstract Aims Plant-specific microbial diversity reflecting host-microbe coevolution was frequently shown at the structural level but less on the functional scale. We studied the microbiome of three compartments at the soil root interface (root endosphere, rhizosphere, bulk soil) of medicinal plants cultivated under organic management in Egypt. The study aimed to examine the impact of the rhizosphere on microbial community composition and diversity in desert agricultural soil, as well as to identify specific functions associated with the rhizosphere. Methods The microbiome community structure, diversity, and microbial functioning were evaluated through the utilization of 16S rRNA gene amplicon and shotgun metagenome sequencing. Results We found the typical rhizosphere effect and plant-species-specific enrichment of bacterial diversity. The annual plants Calendula officinalis and Matricaria chamomilla (Asteraceae) were more similar than the perennial Solanum distichum (Solanaceae). Altogether, plant species explained 50.5% of the variation in bacterial community structures in the rhizosphere. Our results indicate a stronger effect of the plant species in terms of modulating bacterial community structures in the rhizosphere than in root endosphere samples. The plant-driven rhizosphere effect could be linked to redundant plant beneficial functions in the microbiome, while enrichment of specific genes related to amino acid ion transport and metabolism, carbohydrate transport and metabolism, defense mechanisms, and secondary metabolites biosynthesis were more specific. Conclusions The study explores the microbiome continuum at the soil-root interface of medicinal plant species, revealing significant bacterial community structure shifts and plant specificity. The study provides insights into the essential microbiome components contributing to rhizosphere functionality.

Floristic Checklist and Conservation Status of Woody Species in Relation to Gradient in Osomba Hills of Cross River National Park, Nigeria

Extant floristic data checklist and conservation status of woody species were determined in relationship with elevation gradient in Osomba hills of the Cross River National Park, Oban division. A total of 78 species of woody plants in 31 families were identified. The family Fabaceae recorded the highest number of species (13) followed by Malvaceae with 8 species, Annonaceae and Euphorbiaceae had 6 species each, Apocynaceae had 5 species, Irvingiaceae, Ochnaceae, and Olacaceae had 3 species each, Buseraceae, Clusiaceae, Combretaceae, Ebenaceae, Moraceae, Myristicaceae, Rubiaceae and Sapotaceae had 2 species each, Anacardiaceae, Anisophylleaceae, Asteraceae, Bombacaceae, Cecropioaceae, Gentianaceae, Hyperiaceae, Lecythiddaceae, Meliaceae, Passifloraceae, Polygalaceae, Rhizophoraceae, Rutaceae, Simaroubaceae and Violaceae had 1 species each. The investigation of the conservation status of the species using the IUCN redlist data revealed that 1 species (Berlinia korupensis Mackinder& Burgt) is critically endangered (CR), 6 species are near threatened (NT), 7 species are vulnerable (VU), 7 species are not evaluated (NE) and 54 species are of least concerned (LC). Life forms identified included 14 shrubs and 64 tree species in the study area. In the dry season, a total of 29 species including 5 shrubs and 24 trees were identified, while in the rainy season, a total of 57 species including 10 shrubs and 47 trees were identified. Plant diversity along elevation gradient was generally heterogeneous and could be influenced by many factors such as climate, spatial heterogeneity, biotic processes, and evolutionary history. Overall species richness of both shrubs and trees decreased along the elevation gradient whereas the tree species increased with the elevation. Anthropogenic factors and accessibility to the mountainous terrain could also contribute to the patterns of the plant diversity and tree community structure in the study area. Common anthropogenic activities observed were timber harvesting, firewood collections, and harvesting of plants for food and medicinal uses.

Seasonal dynamics shaping bacterial community structure and networks in a Multi Geomorphological Unit System (MGUS) within the eastern Ulansuhai Lake Basin, North China

Different geomorphological units such as mountains, forests, fields, grasslands, sands and water, despite their distinct morphologies, are interconnected through micro-ecosystems that collectively maintain the balance of regional ecology. However, there is a lack of research concerning the spatial correlation among different landscape micro-ecosystems within a catchment area, hindering a comprehensive understanding of watershed systematic evolution across various landscape micro-ecosystems. To address this gap, seasonal variations in bacterial community structure and ecological network connectivity were investigated across different geomorphological units in the eastern Ulansuhai Lake Basin, North China. Water and soil samples were collected in May (beginning of the growing season, 23 samples) and November (end of the growing season, 20 samples) 2021. The diversity of bacterial communities within the Multi Geomorphological Unit System (MGUS) comprising “mountain, forest, field, grassland, sand and water” increased from May to November due to precipitation and human cultivation influences. Environmental characteristics, such as water and soil variations, exert a greater influence on bacterial community structure than differences in landscape units. The stability of the macro-ecological network structure within the MGUS was relatively high, with “water” playing a pivotal role in connectivity (the average betweenness centrality value of “water” was more than twice that of the other landscape samples). This led to the gradual emergence of deterministic processes in the construction of the bacterial community, shifting from stochastic processes (90.8 % drift effect in May) to biotic interactions (29.2 % heterogeneous selection in November). Furthermore, the bacterial community structure exhibited “macroscopic stability, with ‘water’ assuming a central role, while also showing microscopic variations, reflecting fluctuations in the contribution of dominant bacterial genera to the network structure over time”. Our study offers a core information analysis aimed at characterizing the temporal and spatial evolution of microbial community structure within an MGUS, thereby addressing a gap in microbial macroecology.

Butterfly community dynamics in a monoculture‐dominated agricultural landscape

Abstract Understanding biodiversity dynamics in agricultural landscapes is essential for promoting sustainable land use and conserving wildlife. We examined butterfly communities in a monoculture‐dominated landscape, comparing remnant grassland sites surrounded by agricultural land (AGR), grasslands (GR), and forests (FOR). Data were collected from 30 sites across these three categories. We used non‐metric multidimensional scaling (NMDS) to assess community composition, rank abundance curves for community structure, and Hill numbers for alpha diversity. Generalised additive models (GAMs) identified key drivers of rare species richness and the abundance of the most common species, Coenonympha pamphilus. Results showed a few dominant species, with most having low abundances. Species richness was similar across all site categories, but differences in evenness and species dominance highlighted variations in community structure. GR and FOR sites had higher numbers of both rare and abundant species, indicating a more balanced distribution compared to AGR sites. NMDS revealed significant differences in composition, especially between FOR and AGR. The GAM results showed that the combination of agricultural land and forest cover enhances rare species richness, while agricultural cover alone had a negative impact. Even for the most common species C. pamphilus, high agricultural cover negatively impacts its population but shifts positively when combined with greater vegetation height in adjacent grasslands. These findings highlight the critical role of forest habitats within monoculture‐dominated landscapes in enhancing butterfly community diversity and stability. The adaptability of butterfly species to agricultural landscapes is limited to a small number of species and only up to a certain extent.

Diversity and Community Structure of Endophytic Fungi Isolated from the Brown Seaweed Sargassum thunbergii in Coastal Regions of Korea

This study investigated the diversity of endophytic fungi isolated from the brown seaweed, Sargassum thunbergia, collected from six coastal regions in Korea: Gangneung, Pohang, Buan, Taean, Tongyeong and Yeosu. A total of 154 fungal strains were isolated using ITS rDNA sequence analysis, resulting in 84 species across 43 genera. Species diversity, assessed based on the Shannon index, was highest in Tongyeong (H′=3.273), followed by Pohang (H′=3.209), Buan (H′=2.691), Yeosu (H′=2.649), Gangneung (H′=2.342), and Taean (H′=2.025). Principal Coordinates Analysis (PCoA) revealed that water temperature and dissolved oxygen are the primary environmental factors influencing the regional variation in fungal community structure. This study underscores the significance of environmental conditions in shaping the diversity and community composition of endophytic fungi in S. thunbergii.

Impact of continuous cropping on tobacco growth, stress resistance, and soil microecological structure

Tobacco fields have been continuously cropped for several years because of the high demand for tobacco leaves and limited land resources. To explore the effects of continuous cropping on tobacco growth and soil microecological community structure, this study compared the agronomic traits and physiological resistance characteristics of tobacco plants grown in noncontinuous cropping soil and soil with different continuous cropping years. High-throughput sequencing technology was used to analyze and predict the microbial community structure and functional gene variation patterns of tobacco soil. The results demonstrated that continuous cropping significantly impacted the average height, leaf area, and stem diameter of tobacco plants, as well as the contents of malondialdehyde, hydrogen peroxide, and glutathione in tobacco leaves that were continuously cropped. The relative abundances of Proteobacteria, Bacteroidetes, and Gemmatimonadetes in tobacco soil decreased with an increase in continuous cropping years, while relative abundance of Acidobacteria increased. The biodiversity index of tobacco soil samples showed a decreasing trend with an increase in continuous cropping years, with the sample with the longest continuous cropping year (33 years) having the lowest biodiversity index. Prediction of the potential functions of soil samples with different continuous cropping years revealed that the Z-scores of each pathway in noncontinuous cropping soil samples ranged from 1.12 to 0.078, while those in 33-year continuous cropping samples decreased from −0.10 to −1.41. Our findings indicate that continuous cropping has negative impacts on soil health and microecology, leading to a reduction in beneficial microbial population and microbial diversity.

Functional diversity of the above-ground fungal community under long-term integrated, organic and biodynamic Vineyard Management

BackgroundSustainable agriculture increasingly emphasizes the importance of microbial communities in influencing plant health and productivity. In viticulture, understanding the impact of management practices on fungal communities is critical, given their role in disease dynamics, grape and wine quality. This study investigates the effects of integrated, organic, and biodynamic management practices on the diversity and function of fungal communities in a vineyard located in Geisenheim, Germany, focusing on above-ground parts such as bark, leaves, and grapes.ResultsOur findings indicate that while overall fungal species richness did not significantly differ among management systems across various compartments, the composition of these communities was distinctly influenced by the type of management system. In particular, leaf and grape compartments showed notable variations in fungal community structure between integrated and organic/biodynamic management. No differences were observed between organic and biodynamic management. Integrated management demonstrated a significantly higher abundance of mycoparasites in comparison to organic and biodynamic management, primarily attributed to the increased presence of Sporobolomyces roseus, Sporobolomyces ellipsoideus and Rhodotorula glutinis.ConclusionsThe findings highlight the importance of management practices in shaping fungal community composition and function in vineyards. Although overall species richness remained unaffected, community composition and functional diversity varied, highlighting the potential for strategic microbiome management to enhance vineyard sustainability and plant health.

Biochar-induced changes in soil microbial communities: a comparison of two feedstocks and pyrolysis temperatures

BackgroundThe application of a biochar in agronomical soil offers a dual benefit of improving soil quality and sustainable waste recycling. However, utilizing new organic waste sources requires exploring the biochar’s production conditions and application parameters. Woodchips (W) and bone-meat residues (BM) after mechanical deboning from a poultry slaughterhouse were subjected to pyrolysis at 300 °C and 500 °C and applied to cambisol and luvisol soils at ratios of 2% and 5% (w/w).ResultsInitially, the impact of these biochar amendments on soil prokaryotes was studied over the course of one year. The influence of biochar variants was further studied on prokaryotes and fungi living in the soil, rhizosphere, and roots of Triticum aestivum L., as well as on soil enzymatic activity. Feedstock type, pyrolysis temperature, application dose, and soil type all played significant roles in shaping both soil and endophytic microbial communities. BM treated at a lower pyrolysis temperature of 300 °C increased the relative abundance of Pseudomonadota while causing a substantial decrease in soil microbial diversity. Conversely, BM prepared at 500 °C favored the growth of microbes known for their involvement in various nutrient cycles. The W biochar, especially when pyrolysed at 500 °C, notably affected microbial communities, particularly in acidic cambisol compared to luvisol. In cambisol, biochar treatments had a significant impact on prokaryotic root endophytes of T. aestivum L. Additionally, variations in prokaryotic community structure of the rhizosphere depended on the increasing distance from the root system (2, 4, and 6 mm). The BM biochar enhanced the activity of acid phosphatase, whereas the W biochar increased the activity of enzymes involved in the carbon cycle (β-glucosidase, β-xylosidase, and β-N-acetylglucosaminidase).ConclusionsThese results collectively suggest, that under appropriate production conditions, biochar can exert a positive influence on soil microorganisms, with their response closely tied to the biochar feedstock composition. Such insights are crucial for optimizing biochar application in agricultural practices to enhance soil health.

A Critical Evaluation of Network Approaches for Studying Species Interactions

Ecological networks of species interactions are popular and provide powerful analytical tools for understanding variation in community structure and ecosystem functioning. However, network analyses and commonly used metrics such as nestedness and connectance have also attracted criticism. One major concern is that observed patterns are misinterpreted as niche properties such as specialization, whereas they may instead merely reflect variation in sampling, abundance, and/or diversity. As a result, studies potentially draw flawed conclusions about ecological function, stability, or coextinction risks. We highlight potential biases in analyzing and interpreting species-interaction networks and review the solutions available to overcome them, among which we particularly recommend the use of null models that account for species abundances. We show why considering variation across species and networks is important for understanding species interactions and their consequences. Network analyses can advance knowledge on the principles of species interactions but only when judiciously applied.

Proactive monitoring of changes in the microbial community structure in wastewater treatment bioreactors using phospholipid fatty acid analysis

Diverse microbial community structures (MCS) in wastewater treatment plants (WWTPs) are vital for effectively removing nutrients and chemicals from wastewater. However, the regular monitoring of MCS in WWTP bioreactors remains unattractive owing to the skill and cost required for deploying modern microbial molecular techniques in the routine assessment of engineered systems. In contrast, low-resolution methods for assessing broad changes in the MCS, such as phospholipid fatty acid (PLFA) analysis, have been used effectively in soil studies for decades. Despite using PLFA analysis in soil remediation studies to capture the long-term effects of environmental changes on MCS, its application in WWTPs, where the microbial mass is dynamic and operational conditions are more fluid, remains limited. In this study, microbial communities in a controlled pilot plant and 12 full-scale activated sludge plants (ASPs) were surveyed over a two-year period using PLFA analysis. This study revealed that changes in the MCS in wastewater bioreactors could be detected using PLFA analysis. The MCS comprised 59 % Gram-negative and 9 % Gram-positive bacteria, 31 % fungi, and 1 % actinomycetes. The abundances of Gram-negative bacteria and fungi were strongly inversely correlated, with an R2 = 0.93, while the fatty acids cy17:0 and 16:1ω7c positively correlated (R2 = 0.869). Variations in temperature, solid retention time, and WWTP configuration significantly influenced the MCS in activated sludge reactors. This study showed that WWTP bioreactors can be routinely monitored using PLFA analysis, and changes in the bioreactor profile that may indicate imminent bioreactor failure can be identified.

Experimental Study on the Removal of Pollutants from Domestic Wastewater in a Strongly Constructed Wetland with an Applied Electric Magnetic Field

The addition of physical field enhancement measures to improve the purification effect of vertical flow artificial wetlands has gradually become popular. In this study, a vertical flow artificial wetland system reinforced by electric and magnetic fields was constructed. These fields were first optimized using finite element 3D simulation software to obtain the optimal electric and magnetic field parameters. Then, the pollutant removal effects and changes in microbial community structure were comparatively analyzed. The optimal electromagnetic field parameters (applied voltage of 15 V and applied magnetic field of 20 mT) resulted in significantly enhanced removal rates of chemical oxygen demand (COD), nitrate nitrogen (NH4+-N), total phosphorus (TP), and orthophosphorus (PO43−-P) in wastewater, with rates of 74.47%, 45.44%, 89.85%, and 90.04%, respectively. These rates were notably higher than those observed in the vertical flow artificial wetland system. The microbial community structure analysis revealed that the vertical flow constructed wetland with enhanced electric and magnetic fields exhibited (EM-VFCW) a more diverse and complex microbial community structure. Notably, the abundance of bacteria capable of removing NH4+-N and COD, including Aspergillus, Fusarium, and Actinobacteria, was significantly elevated.

Functional traits mediate the elevational patterns of functional diversity and community structure of mosses in a tropical mountain area

Functional diversity refers to the value, range, and distribution of functional traits within a community, such as the morphological, physiological and behavioral characteristics of species that determine the role a species plays in an ecosystem. Assessing the drivers of elevational pattern of functional diversity is crucial to predict the effects of global change on functional diversity and community structure. In our research, we collected mosses species data from 65 sampling sites and measured 11 functional traits that are related to their ecological functions. We applied double canonical correspondence analysis (DCCA) to analyze species responses to environmental conditions based on their traits. We applied generalized additive models with a Gaussian function of variance to determine the elevational patterns of functional trait composition, diversity and community structure. We applied and compared boosted regression trees (BRT) without considering functional traits and piecewise structural equation modelling (SEM) mediated with functional traits to relate environmental variables with functional diversity and functional community structure, respectively. We found the first DCCA axis accounted for the largest dissimilarities between the two groups of species and correlated mainly with the water-utilization traits. Although both functional diversity and community structure displayed negatively skewed pattern along the elevational gradient, habitat complexity and climatic variables contributed differently to their respective patterns. The SEM approach consistently outperformed the BRT approach in explaining the variations in both functional diversity and community structure. Our findings highlight the important role of functional traits in mediating the relationship between the environment and functional diversity metrics. Both biotic and abiotic processes play a significant role in shaping the community assemblages, with environmental variables having distinct impacts. Traits related to structure maintenance, water absorption, cell hydration, and nutrient acquisition were found to be key drivers of functional diversity, while water-utilization traits were mainly responsible for regulating functional community structure.

Dynamics of phytoplankton community in relation to environmental variables in tropical mangrove estuary, Sundarbans, India

Aim: To explore the spatio-temporal variation of phytoplankton diversity and community structure, in response to associated environmental variables in Matla estuary, Sundarbans, India. Methodology: Monthly sampling was carried out from August 2022 to July 2023 at three locations within the estuary. Plankton was identified and its dynamics were studied in relation to the environment variables. Results: A total of 38 genera of phytoplankton, belonging to 8 classes, were identified. Spatial diversity was high in the upper reaches of the estuary, while temporal diversity peaked during the monsoon season. The majority of the abundance (96%) was contributed by four classes: Coscinodiscophyceae (35%), Mediophyceae (27%), Bacillariophyceae (25%) and Dinophyceae (9%). Bacillariophyceae exhibited higher species richness, while Coscinodiscophyceae dominated in terms of density. Cluster analysis and non-metric multidimensional scaling revealed four separate groups with varying spatio-temporal attributes. Analysis of variance (ANOVA) post-hoc tests highlighted significant variations in environmental parameters across seasons. Various phytoplankton groups were positively correlated with the physio-chemical parameters such as temperature, alkalinity, free CO2, NO3, NO2, silicate, temperature, orthophosphate and chlorophyll-a. Biota-environment stepwise analysis (BIO-ENV) underscored the importance of air temperature and free CO2 (ρ= 0.4929) as key factors shaping phytoplankton distribution and community structure. Canonical Correspondence Analysis (CCA) further showed the significant influence of parameters such as temperature, silicate, nitrite and orthophosphate on the phytoplankton community. Interpretation: Finding of this study enriches our comprehension of estuarine ecosystem dynamics, and this information may serve as a baseline study and thereby aid in framing management measures for long-term conservation and management of both biotic and abiotic components within estuaries. Key words: Environmental variables, Estuary, Mangrove, Phytoplankton, Sundarbans

Feature analysis of 5G traffic data based on visibility graph

IntroductionAs 5G networks become widespread and their application scenarios expand, massive amounts of traffic data are continuously generated. Properly analyzing this data is crucial for enhancing 5G services.MethodsThis paper uses the visibility graph method to convert 5G traffic data into a visibility graph network, conducting a feature analysis of the 5G traffic data. Using the AfreecaTV dataset as the research object, this paper constructs visibility networks at different scales and observes the evolution of degree distribution with varying data volumes. The paper employs the Hurst index to evaluate the 5G traffic network and uses community detection to study the networks converted from 5G traffic data of different applications.ResultsExperimental results reveal significant differences in node degree distribution and topological structures of 5G traffic data across different application scenarios, such as star structures and multiple subnetwork structures. It is found that the node degree distribution of 5G traffic networks exhibits heterogeneity, reflecting the uneven growth of node degrees during network expansion. The Hurst index analysis discovers that the 5G traffic network retains the long-term dependence and trends of the original data. Through community detection, it is observed that networks converted from 5G traffic data of different applications exhibit diverse community structures, such as high centrality nodes, star-like community structures, modularity, and multilayer characteristics.DiscussionThese findings indicate that 5G traffic networks in different application scenarios exhibit complex and diverse characteristics. The heterogeneity of node degree distribution and differences in topological structures reflect the imbalance in node connection methods during network expansion. The results of the Hurst index show that the 5G traffic network inherits the long-term dependence of the original data, providing a basis for analyzing the dynamic characteristics of the network. The diverse community structures reveal the inherent modularity and hierarchy of the network, which helps to understand the performance and optimization directions of 5G networks in different applications.

The species diversity and phylogenetic structure patterns of desert plant communities in the Turpan-Hami region, Xinjiang

Desert plant communities play a crucial role in enhancing desert ecosystem productivity and stability but are highly susceptible to environmental changes owing to their limited resilience and resistance to disturbances, making it essential to understand the factors influencing their diversity patterns and community structure, particularly under the threat of climate change and intensifying droughts. This study focused on the Turpan-Hami desert region, a typical desert ecosystem in which diversity patterns and community structures remain unclear. We established 101 sampling sites ranging from elevations of −134–2056 m and recorded community information, including species composition, height, coverage, and density, using the sample plot method. The diversity patterns were analyzed using regression analysis, and the phylogenetic structure was assessed. Additionally, Canonical Correspondence Analysis, Mantel tests, and General Linear Models were used to identify the key factors affecting community structure. Our results demonstrated that the species richness and phylogenetic diversity of plant communities exhibited a monotonic increase with elevation, and the phylogenetic structure exhibited low clustering and high dispersion along the elevational gradient. The annual mean temperature emerged as the most significant factor influencing diversity patterns, with soil nutrients, such as total potassium and available phosphorus, also affecting the spatial distribution of diversity. Notably, no significant correlations were found between community phylogenetic structure and abiotic factors, highlighting the complex interactions that drive diversity in the Turpan-Hami region. This study offers valuable insights into the mechanisms shaping desert plant community diversity and is essential for biodiversity conservation efforts in fragile desert ecosystems amid climate change.

Community Structure and Species Diversity of Birds in Heterogenous Habitats of an East African Growing Agricultural Corridor

Community Structure and Species Diversity of Birds in Heterogenous Habitats of an East African Growing Agricultural Corridor

Variation in Community Structure and Abundance of Fish in Simple Structured Shallow Sandy Habitats

ABSTRACTSandy beaches and their surf zones characterise many of the world's open coastlines. They are important breeding, nursery and feeding areas for many species of fish. Despite the commonness and importance of sandy beach surf zones, the dynamics, space occupancy and diversity patterns of residing fish is in many places poorly understood. The aim of this study was to (1) characterise the fish community structure in 11 simple structured sandy surf zones of the northern Baltic Sea and (2) relate variation in fish abundance and community structure to a set of chosen abiotic variables. Using beach seine, weekly or biweekly sampling was conducted at fixed sites at 10 occasions throughout a summer season. A total of 60,006 fish individuals belonging to 20 species were recorded. Changes in abundance and community structure were mainly driven by the variation of only five species reflecting species‐specific recruitment patterns and different spatial responses to abiotic variables. Dominating groups were Gasterosteidae, Ammodytidae and Gobiidae that together formed 86% of the total adult fish catches. Larval numbers were completely dominated by Gobiidae. Multivariate analyses indicated species‐specific responses to measured environmental variables, most important being a combination of wave exposure, beach slope, bottom roughness, and temperature. The present study shows that changes in fish abundance on simple structured sandy sublittoral beaches in the northern Baltic Sea are large over the course of a breeding season. It also reveals that variation in adult and juvenile fish are driven by a set of abiotic factors that influence on the fish assemblage structure through mainly species‐specific, rather than through generic responses. Unravelling the degree to which the sandy shore fish community vary in the northern Baltic Sea will help in managing coastal environments that are increasingly being threatened by many anthropogenic stressors.

Megabenthic Diversity Patterns on a Seamount in the Philippine Sea: Implications for Conservation Planning on the Kyushu-Palau Ridge.

The oligotrophic tropical western Pacific region is characterized by a high density of seamounts, with the Kyushu-Palau Ridge (KPR) being the longest seamount chain here. Effective spatial management plans for seamount ecosystems necessitate an understanding of distribution patterns and key environmental factors influencing benthic communities. However, knowledge regarding deep-sea biodiversity patterns over intricate topography remains limited. In this study, we investigated a seamount with a water depth of 522 m at the summit located in the southern section of KPR. Survey transects were conducted from 522 m to 4059 m. By analyzing video-recorded data obtained by a human-occupied vehicle (HOV) during dives and environmental variables derived from bathymetry, distinct assemblages were identified through noise clustering. α- and β-diversity patterns within the seamount megabenthic community were analyzed across the depth gradient, along with investigation of their environmental drivers. A total of 10,596 megafauna individuals were documented, categorized into 88 morphospecies and statistically separated into six distinct community clusters using noise clustering analysis. Species abundance and richness were highest within the 700-800 m water depth range, declining notably beyond 2100 m, indicating a critical threshold for habitat classification in this region. The β-diversity of megabenthic communities was high (0.836). Although β-diversity patterns along the depth gradient were mostly dominated by differences in species richness, the contribution of species replacement increased with depth, becoming dominant at depths greater than 3000 m. Depth emerged as the primary driver of spatial variation in community structure, while near-bottom current velocity, topographic parameters (bathymetric position index, slope), and substrate type also influenced the formation of microhabitats. The study highlights the depth gradients, thresholds, and other intricate environmental factors shaping the spatial heterogeneity of these communities. It provides valuable insights for the future development of effective survey and conservation strategies for benthic biodiversity on the KPR.

Diversity of Orchid in Abies nephrolepis Nature Reserve in Shanxi, China.

Abies nephrolepis Nature Reserve has complex habitats and rich species diversity but lacks systematic ecological surveys. We focused on Orchid in Abies nephrolepis Nature Reserve, investigated and analyzed Orchid diversity and changes in community structure according to the characteristics of the alpine valleys in the study area, in terms of altitude gradient and habitat type, using the sample line method and the quadrat method. The results showed that 11 genera and 13 species of Orchidaceae were found in the survey, among which the species richness of Malaxis monophyllos was the highest, Neottia puberula was the second highest, and the species richness of Tulotis ussuriensis was the lowest, and the species with relative plurality ≥ 10% were Malaxis monophyllos (51.69%), Neottia puberula (14.77%), and Cypripedium guttatum (11.15%). The results of diversity analysis showed that Orchidaceae species were rich and the diversity index were the highest in the middle altitude area of 1950-2250 m; the distribution of Orchidaceae in the low altitude area was obviously clustered, and the similarity with the high altitude area was low. With the increase in altitude, the number of species showed an increase and then a decrease, showing a single-peak state, which was in line with the theory of "Intermediate altitude expansion hypothesis". The species and number of Orchidaceae in different habitats of Abies nephrolepis Nature Reserve also varied considerably, with Shannon-Wiener diversity index being the highest in EV4 (Abies nephrolepis + Picea meyeri + Picea wilsonii + Larix gmelinii var. principis-rupprechtii-Lonicera hispida-Carex lanceolata community) and EV5, and the smallest in EV1 habitats, Pielow evenness index being the highest in EV5 habitats and the lowest in EV1 habitats, and Simpson's index being the highest in EV5 habitats and the lowest in EV1 habitats. This study provides a scientific basis for strengthening regional monitoring of species diversity and protecting biodiversity.