Community Types Research Articles

Forest Flora of Nichlaul-III. Phytosociological Studies

The present paper deals with the phytosociological studies of Nichlaul forest. Important features of the forest concerning geographical location, topography, soil, climate and vegetational composition have been outlined. Eight types of plant communities have been recognised. The phytosociological characters noted in the field on visual estimation are dominance and sociability of perennial species. Only selected associates of the communities have been included in the table.The eight types of communities described appear to be interrelated floristically. The sociological values show that 17.8% of the species are common to all the eight communities indicating a high degree of congnuity.

Ecological Studies of Saurashtra Coast and Neighbouring Islands: I. Diu Island

The plant ecology of Diu, an island of irregular outline, situated in 20°43' N & 71°02' E and separated from the southern extremity of the peninsula of Saurashtra by a narrow channel on western shore of India is presented in this paper. Several plant communities are grouped into three ecosystems : Rock-strand, Strand and Inland sandy plain. The community type is a sub-division of an ecosystem, that is, it is recognised by the features of both its plant cover and its habitat. Plant communities under each of the three abovementioned ecosystems are described and also analysis of rocks and soils presented in tabular form to study soil features in relation to vegetation.

Characteristics of Vaginal Microbiota of Women of Reproductive Age with Infections.

The vaginal microbiota can be classified into five major community state types (CSTs) based on the bacterial content. However, the link between different CST subtypes and vaginal infection remains unclear. Here, we analyzed 2017 vaginal microbiota samples from women of a reproductive age with vaginal infections that were published in the last decade. We found that L. iners was the most dominant in 34.8% of the vaginal samples, followed by L. crispatus (21.2%). CST I was common in healthy individuals, whereas CST III and IV were associated with dysbiosis and infection. CST III-B, IV-A, IV-B, and IV-C0 were prevalent in patients with bacterial vaginosis (BV). Based on the relative abundance of bacteria at the (sub)genus level, a random forest classifier was developed to predict vaginal infections with an area under the curve of 0.83. We further identified four modules of co-occurring bacterial taxa: L. crispatus, Gardnerella, Prevotella, and Bacteroides. The functional prediction revealed that nucleotide biosynthesis pathways were upregulated in patients with human papilloma virus, and carbohydrate degradation pathways were downregulated in patients with BV. Overall, our study identified the bacterial signatures of healthy and infected vaginal microbiota, providing unique insights into the clinical diagnosis and health status prediction of women of a reproductive age.

Study on Master-Slave Game Optimization Operation of Integrated Energy Microgrid Considering PV Output Uncertainty and Shared Energy Storage

Integrated energy microgrids and shared energy storage have significant benefits in improving the energy utilization of the system, which is gradually becoming the current research hotspot. And the uncertainty of new energy output also significantly affects the stable and economic operation of integrated energy microgrid. So how to establish a set of integrated energy microgrids optimization operation model considering photovoltaic (PV) output uncertainty and shared energy storage is an urgent problem to be solved nowadays. Firstly, this paper introduces the framework of an integrated energy system microgrid containing a shared energy storage operator (ESO), and analyzes the scheduling method of the upper tier operator within the system as well as the economic benefits at the lower tier user end. Secondly, to address the randomness of PV output, Monte Carlo method is used to generate the scenarios, and then the scenarios are cut down by using the fast antecedent elimination technique. Then, an optimal operation model is established for micro grid operator (MGO) and user aggregator (UA), respectively, and based on the master-slave game relationship, so that the MGO is the leader and the UA is the follower, a Stackelberg game model is proposed to consider the integrated demand response of electricity and heat between the MGO and UA in the context of the participation of ESO in the auxiliary service of the UA. Finally, the proposed model is brought into a typical residential building community for simulation verification, and the results show that the model proposed in this paper can effectively balance the interests of MGOs and UAs, and realize win-win benefits for UA and ESO.

Reference ecosystem construction and adaptive restoration effect evaluation: A case study of a small watershed in the loess hilly region

AbstractThe loess hilly region is one of the most fragile areas in China. Many ecological restoration projects in this region are equivalent to simple afforestation and grass planting, with large investment and low benefits. Based on the concept of reference ecosystem, this study uses remote sensing data and vegetation community survey of Wanhuigou catchment, and applies methods such as redundancy analysis and GeoDetector to explore the characteristics of topography, soil, and vegetation of reference ecosystem, so as to provide restoration standards for damaged or degraded ecosystems in a small watershed. Thirteen typical and representative areas are selected to evaluate the degree of ecosystem damage and resilience, and divided into four categories according to the evaluation results and characteristics of ecosystems. Corresponding restoration measures such as protection and conservation, natural restoration, auxiliary regeneration, and ecological reconstruction are adopted for ecosystems under different scenarios with reference ecosystems as the target, and the effectiveness of implementation is assessed. The results show that the combination conditions of elevation and slope have a very important influence on the distribution of ecosystems. In the process of ecological restoration, it is necessary to deeply grasp the characteristics of soil and species diversity within the same community and among different communities, as well as their interrelationships. Adaptive restoration measures for ecosystems in different situations are conducive to the sustainability and effectiveness of ecosystem restoration. Given the complexity and diversity of habitat conditions and plant community types in Wanhuigou catchment, the results have certain universality, which can provide reference for the comprehensive management of other small watersheds in the loess hilly region, so as to achieve sustainable construction and restoration of ecosystems as well as harmonious development between humans and nature.

Habitat context and functional growth traits explain alien plant invader impacts on native vegetation communities

Examining context-dependency of ecological impacts of alien plant invasions is critical to further understand the mechanisms driving impacts. We examined how different regional and local habitat contexts influence the abundance-impact associations of an invasive ground-creeper, Tradescantia fluminensis, in native forests across eastern New South Wales (NSW), Australia. Invader impacts were assessed using surveys of resident vegetation at 97 monitoring plots (5 m × 2 m) located at 14 sites, representing a gradient of T. fluminensis abundance. We modelled the association of T. fluminensis invasion with native species richness (number per plot) and foliage cover across two different habitat types (remnant vs replanted forests), two vegetation community types (wet sclerophyll vs river oak forests), and two regions (northern vs. southern NSW). We also modelled variation in native species responses amongst different functional growth forms. The negative associations of T. fluminensis and native species communities was more strongly explained by local site variables (i.e., habitat type, community type, plant growth form) than regional scales. Native richness reduced with invasion in river oak but not wet sclerophyll forest. Native richness also declined in remnant forest, although no effect of invasion was observed in replanted forest. Surprisingly, native species growth forms most like T. fluminensis (ground layer herbs, ferns) were more resistant to reductions in native richness compared to divergent forms (shrub, tree and woody vine recruits). This study highlights the need to explicitly consider local community and habitat context and functional representation of resident species when considering invader impacts and site-level management plans.

Shifts in mycorrhizal types of fungi and plants in response to fertilisation, warming and herbivory in a tundra grassland.

Climate warming is severely affecting high-latitude regions. In the Arctic tundra, it may lead to enhanced soil nutrient availability and interact with simultaneous changes in grazing pressure. It is presently unknown how these concurrently occurring global change drivers affect the root-associated fungal communities, particularly mycorrhizal fungi, and whether changes coincide with shifts in plant mycorrhizal types. We investigated changes in root-associated fungal communities and mycorrhizal types of the plant community in a 10-yr factorial experiment with warming, fertilisation and grazing exclusion in a Finnish tundra grassland. The strongest determinant of the root-associated fungal community was fertilisation, which consistently increased potential plant pathogen abundance and had contrasting effects on the different mycorrhizal fungal types, contingent on other treatments. Plant mycorrhizal types went through pronounced shifts, with warming favouring ecto- and ericoid mycorrhiza but not under fertilisation and grazing exclusion. Combination of all treatments resulted in dominance by arbuscular mycorrhizal plants. However, shifts in plant mycorrhizal types vs fungi were mostly but not always aligned in their magnitude and direction. Our results show that our ability to predict shifts in symbiotic and antagonistic fungal communities depend on simultaneous consideration of multiple global change factors that jointly alter plant and fungal communities.

Response mechanism of rodent burrow density to natural environmental factors in desert areas based on multisource data

Timely and accurate prediction and early warning of rodent infestation are highly important for the sustainable development of desert ecosystems. This study combines data from 1376 UAV images of actual rodent burrows with natural environmental factor data, aiming to reveal the mechanism through which these factors affect rodent burrow density in the desert areas. The relationships between rodent burrow density and the 9 plant communities and 34 plant species in this area were analyzed by the K-W test and Spearman rank correlation analysis, respectively. The Boruta algorithm and the boosted regression trees (BRT) model were used to determine the six main factors influencing rodent burrow density from a total of 32 factors and to determine the distribution pattern of the burrows. The results show that (1) the density of rodent burrows in the Junggar Basin desert area gradually decreases from south to north and from west to east. (2) There were significant differences in rodent burrow density across the different plant community types (P = 0.048**). A total of 50.0 % of the species significantly influenced rodent burrow density at at least one level. (3) Among the 17 factors with lag effects, nine had the most significant correlation with rodent burrow density in April. Only two natural environmental factors demonstrated lag effects of less than one month. (4) The soil clay content, elevation, Normalized Difference Salinity Index (NDSI), vegetation cover, precipitation, and soil bulk density were the most important influencing factors on rodent burrow density. Considering the pairwise interactions among factors, the collective impact of these factors on rodent burrow density is at least sevenfold greater than the independent effect of a single factor. This study provides a theoretical basis for obtaining a timely and accurate understanding of the spatial distribution of rodent burrows, mitigating the degradation trend of desert ecosystems, and ensuring healthy and sustainable development.

Entrepreneurial thinking and Education 4.0 in communities with development gaps: an approach through the Sustainable Development Goals

Entrepreneurial thinking is considered a desirable competency in the profile of today’s professionals because it includes sub-competencies that strengthen individuals’ leadership capacity and stimulate the development of creative solutions that present a high impact on society. However, it has been detected that disadvantaged communities located in areas with underdeveloped conditions and rural areas present a significant disparity in access to training models, current infrastructure, and activities that promote entrepreneurship compared to developed communities frequently found in large cities. Through a comparative analysis with quantitative methods, we seek to argue the need that these types of communities have. In addition, the design of a training model based on the design framework for Education 4.0 is presented; this training model seeks to train in the sub-competences of entrepreneurial thinking using the “push and pull” technique with the Sustainable Development Goals (SDGs) as its central axis. This seeks to close the existing gap, provide affordable resources to these types of disadvantaged communities, and, at the same time, promote local solutions through the SDGs. The study is conducted in the eastern region of Michoacán, Mexico, and will present the preliminary results.

Q methodologist views on the future of Q: a study of a research community

It has been almost 90 years since William Stephenson’s 1935 letter to Nature that opened the door for Q methodology [Q]. Criticisms and excitement ensued and continue into the present within and outside of the Q research community. Yet, any research community contains researchers with different positionalities about the methodology’s philosophical framework, and best practices regarding data collection and/or data analysis. A relatively recent Q study indicated differences of opinion among Q methodologists when it comes to data analysis and its philosophical framework. Twenty years ago, Hurd and Brown uncovered four divergent viewpoints about the Q community’s view of the future of Q. Thus, especially with Q’s growing popularity, it seemed time to repeat that study with some change to the subjective statements used within the data collection phase, as many changes have occurred especially regarding technological advances for data collection and data analysis. Two viewpoints were uncovered, Tradition and Community, with a focus on the theoretical framework provided by Stephenson and the welcoming nature of the Q community, and Unorthodox with Expansion of Q, with a yearning to expand Q both physically and theoretically including a willingness to move beyond Stephenson’s vision. The discussion and conclusion focus on the implications of these perspectives and their shared consensus for the future of Q methodology as well as implications for other research methodologies. In other words, this study provides a demonstration of complementarity for understanding the behavior of all types of research communities.

Benthic Biodiversity by Baited Camera Observations on the Cosmonaut Sea Shelf of East Antarctica

A free-fall baited camera lander was launched for the first time on the Cosmonaut Sea shelf of East Antarctica at a depth of 694 m during the 38th Chinese National Antarctic Research Expedition (CHINARE) in 2022. We identified 31 unique taxa (23 were invertebrates and eight were fish) belonging to eight phyla from 2403 pictures and 40 videos. The Antarctic jonasfish (Notolepis coatsi) was the most frequently observed fish taxa. Ten species of vulnerable marine ecosystem (VME) taxa were observed, accounting for 32% of all species. The maximum number (MaxN) of Natatolana meridionalis individuals per image frame was ten, and they were attracted to the bait. The macrobenthic community type were sessile suspension feeders with associated fauna (SSFA), which was shaped by the muddy substrata with scattered rocks. Rocks served as the best habitats for sessile fauna. The study reveals the megafauna community and their habitat by image survey in the Cosmonaut Sea for the first time. It helped us obtain Antarctic biodiversity baselines and monitoring data for future ecosystem health assessment and better protection.

Exploring Wildfire Evacuation Strategies for Diverse Communities

Wildfire evacuations have become a persistent challenge all over the world in recent years. Studies have proposed various evacuation strategies, such as vehicle reduction, phased evacuation, and prohibition of on-street parking, which have demonstrated effectiveness in specific communities. However, a comprehensive study that generalizes the effectiveness and applicability of these strategies across different types of communities is lacking. This generalization could hold significant value for small, resource-strapped communities situated in wildland–urban interface zones (i.e., comprising a mix of residences and flammable vegetation) that lack the resources to conduct dedicated evacuation studies. In this study, two indicators, the ratio of background traffic volume to the number of evacuees (RBE), and the ratio of the capacity of the main evacuation roads to the number of evacuees (RCE) were derived to categorize communities into specific groups based on their characteristics during wildfire events. Through evacuation simulations of some typical real-world communities, the applicability and effectiveness of each strategy for each group was assessed. For the given scenarios considered, the findings revealed that for communities with high a RBE and low RCE, promoting carpooling with more than two people per vehicle, extending phased evacuation intervals with safety assurance for evacuees, and enforcing on-street parking prohibition made evacuations more effective. For other communities, encouraging families to use fewer vehicles and implementing a 15-min phased interval, if possible, could potentially be useful.

Temporal beta diversity and plant metacommunity structure dynamics over a 43-year period in an inter-tropical mexican arid region

Understanding the dynamics of metacommunity structure and temporal beta diversity is vital for comprehending ecological dynamics at local and regional scales; it is essential to evaluate impacts of factors such as climate change, dispersal, and biotic interactions. We examined changes in the composition and abundance of 199 perennial plant species in the semiarid Zapotitlán Valley, Mexico, over a 43-year period. We studied three local community types, scrubland, cardonal, and tetechera, with surveys conducted in 1980, 2003, 2018, and 2023. Shifts in species composition and abundance over time were analysed using the Temporal Beta Diversity Index distinguishing between species gains or losses. We investigated the metacommunity structure elements—coherence, turnover, and boundary clumping—in each survey. We observed pronounced temporal changes in species’ composition and abundance across all community types. These temporal changes stem from the losses and gains in species and individuals. Notably, 2023 showed significant losses in species occurrence and abundance, potentially attributable to an extended drought likely exacerbated by climate change. Surprisingly, the metacommunity structure remained Clementsian throughout our study, emphasising the stability of the cardonal in maintaining distinctions between local community types. This suggests that the metacommunity spatial structure is resistant to changes in local community compositions.

Composition and Structural Diversity of Woody Species in the Wof Ayzurish Forests, the Dry Afromontane Forest of the Northern EthiopiaI

Dry Afromontane Forest (DAF) is the largest Afromontane section and plays a fundamental role in preservation of species biodiversity. Despite its biodiversity, DAF is the most altered and threatened in the Ethiopian ecosystem. With the exception of a few isolated pockets left in some sacred places and protected areas of the country, most of forests are inaccessible. The scenario is not different for the present study forest. Therefore, the objective of the present study is to investigate woody species diversity, structure and regeneration status of Wof Ayzurish Forest, which is a dry Afromonatane in North Shewa of Ethiopia. A systematic method was employed whereby 67 quadrats set in 8 parallel lines transecting at 300-meter intervals and quadrats at 150-m distance. All trees and shrubs with diameters of breast height > 2.5 cm and height > 2 m were measured. The results revealed that Wof Ayzurish Forest harbors 76 species of woody plants that belong to 68 genera and 47 families, with Asteraceae, Fabaceae, and Solanaceae displaying the highest diversity. Shrubs had the highest composition than trees. The most abundant plants were Dodonaea viscosa subsp. angustifolia, Carissa spinarum, Juniperus procera, Olinia rochetiana and Olea europaea subsp. cuspidata. Dodonaea viscosa subsp. angustifolia was the most prominent plant, occurring in 98.5 % of all sample plots. The DBH and height classification pattern exhibited that the forest had a classic inverted J-shape, dominated by smaller trees and shrubs, indicating a secondary stage of regeneration. Total basal area (BA) for trees and shrubs DBH > 2.5 cm was 18.03 m2 ha−1. Remarkably, five species accounted for 57.45 % of the basal area, indicating that higher numbers of individuals concentrated in lower DBH classes. By using R software, agglomerative hierarchical cluster analysis and Canonical Correspondence Analysis (CCA) has done to identify plant community types and examine the relationship between plant community types and environmental variables, respectively. Three significantly different (p < 0.05) plant community types were identified. The CCA results showed that species diversity and community composition among community types were significantly influenced by altitude and human disturbance such as expansion of agriculture, cuttings, and grazing. Therefore, it is recommended that community-based methods and awareness creation should be devised in order to implement sustainable forest conservation.

The Ecological Risk Assessment of Foodborne Disease Outbreaks in Yazd Province, Iran

Background: Ecological conditions can change infection routes and increase the risks of outbreaks. The aim of this study is risk assessment of foodborne disease outbreaks based on dispersed regional climatic and demographic variables in Yazd Province, Iran. Methods: In this cross-sectional study, data of temporal climatic parameters and regional demographic factors linked to bacterial foodborne diseases were addressed. A multi-level regression analysis model was used to detect associations between the risk of outbreaks and ecological risk factors; the relationships were verified using (P&lt;0.05). Results: Significant associations were observed between the outbreaks and age )P&lt;0.001(, community type (P&lt;0.001), temperature (P=0.04), rainfall (P=0.03) and dust pollution (P&lt;0.001) in scattered parts of the province. The maximum rate of outbreaks was seen in spring, while the frequency of the outbreaks increased during April and October, compared to other months of the year (2012–2016). Conclusion: Consequences have revealed interventions of the environmental exposures in transmissions of microbial agents by complex ecological processes that caused the outbreaks.

Release from aboveground enemies increases seedling survival in grasslands

Abstract Plant enemies can influence plant community assembly and structure. However, it is unclear how insect herbivores and fungal pathogens affect seedling recruitment. Complex interactions with competition and resource availability make it difficult to isolate the effect of enemies. This uncertainty can impede understanding of community assembly drivers, species coexistence and trophic interactions; and limits hypothesis testing such as of the enemy release hypothesis, a key hypothesis in invasion biology. Using a novel species‐specific approach, we examine how enemies affect seedling survival and recruitment of 16 grassland species. We planted seedlings of 16 native species from two functional groups (C4 grasses and non‐legume forbs) into two grassland sites (early and mid‐succession). We hand‐painted 1512 individual seedlings with pesticides (insecticide and fungicide) over the course of one growing season to enforce aboveground species‐specific release from enemies and tested whether it enhanced survival relative to untreated controls. Applying treatments to individuals allowed us to test for the effect of enemies on plant performance while controlling for contexts such as competition from the resident community and resource levels. Release from insects increased seedling survival by 56% on average, with no additional benefit of release from fungal pathogens. This effect was observed for both forbs and C4 grasses across both sites and was strongest in resource‐acquisitive species. There was no effect of the mean phylogenetic distance between our target species and the resident plant community, or of light availability or soil moisture. Synthesis. The significant positive effect of release from insect herbivores on survival early in colonisation—a trend that held across functional groups and types of resident community—suggests insects play an important regulatory role in community assembly, especially for resource‐acquisitive species. As variation between species could be explained by traits but not by phylogeny, we emphasise the importance of trait‐based approaches to plant community ecology. Our results also support the key mechanism (increased performance following release from enemies) underlying the enemy release hypothesis. Enemy release may therefore aid initial recruitment of plants during the invasion process.

Using UAV images and deep learning in investigating potential breeding sites of Aedes albopictus

Aedes albopictus (Diptera: Culicidae) plays a crucial role as a vector for mosquito-borne diseases like dengue and zika. Given the limited availability of effective vaccines, the prevention of Aedes-borne diseases mainly relies on extensive efforts in vector surveillance and control. In multiple mosquito control methods, the identification and elimination of potential breeding sites (PBS) for Aedes are recognized as effective methods for population control. Previous studies utilizing unmanned aerial vehicles (UAVs) and deep learning to identify PBS have primarily focused on large, regularly-shaped containers. However, there has been a small amount of empirical research into their practical application in the field. We have thus constructed a PBS dataset specifically tailored for Ae. albopictus, including items such as buckets, bowls, bins, aquatic plants, jars, lids, pots, boxes, and sinks that were common in the Yangtze River Basin in China. Then, a YOLO v7 model for identifying these PBS was developed. Finally, we recognized and labeled the area with the highest PBS density, as well as the subarea with the most urgent need for source reduction in the empirical region, by calculating the kernel density value. Based on the above research, we proposed a UAV-AI-based methodological framework to locate the spatial distribution of PBS, and conducted empirical research on Jinhulu New Village, a typical model community. The results revealed that the YOLO v7 model achieved an excellent result on the F1 score and mAP(both above 0.99), with 97% of PBS correctly located. The predicted distribution of different PBS categories in each subarea was completely consistent with true distribution; the five houses with the most PBS were correctly located. The results of the kernel density map indicate the subarea 4 with the highest density of PBS, where PBS needs to be removed or destroyed with immediate effect. These results demonstrate the reliability of the prediction results and the feasibility of the UAV-AI-based methodological framework. It can minimize repetitive labor, enhance efficiency, and provide guidance for the removal and destruction of PBS. The research can shed light on the investigation of mosquito PBS investigation both methodologically and practically.

Cyanobacterial and moss biocrusts shape soil nematode community in dryland mountain ecosystems with increasing aridity

Soil nematodes are the most abundant animals on Earth and play critical roles in regulating numerous ecosystem processes, from enhancing primary productivity to mineralizing multiple nutrients. In dryland soils, a rich community of microphyte organisms (biocrusts) provide critical habitats for soil nematodes, but their presence is being threatened by increasing aridity induced by global climate change. Despite its importance, how types of biocrusts and aridity index influence soil nematode community in dryland mountain ecosystems remains largely unknown. To fill these knowledge gaps, we conducted a field survey with contrasting aridity indexes (0.2, 0.4, and 0.6) and three types of biocrusts (cyanobacterial, cyanobacterial-moss mixed, and moss crusts) in the topsoil (0–5 cm) from the northern Chinese Loess Plateau. We found that the abundance (number of individuals per gram of soil), richness (number of Operational Taxonomic Units; OTUs), and diversity (number of different species) of soil nematodes were remarkably higher under biocrusts than in bare soils, regardless of aridity index and types of biocrusts. Our results also showed that the same variables had the highest values in moss crusts compared to cyanobacterial and cyanobacterial-moss mixed crusts. Structural equation modelling further revealed that biocrust types and traits (i.e., biocrust thickness, chlorophyll content, shear force, and penetration resistance) are the most important factors associated with both nematode abundance and richness. Together, our findings indicate that biocrusts, especially moss cover, and less stressful aridity conditions favor soil nematodes community in dryland mountain regions. Such knowledge is critical for anticipating the distribution of these animals under climate change scenarios and, ultimately, the numerous ecosystem services supported by soil nematodes.

Impacts of Soil Properties on Species Diversity and Structure in Alternanthera philoxeroides-Invaded and Native Plant Communities.

Soil properties can affect plant population dynamics and the coexistence of native and invasive plants, thus potentially affecting community structure and invasion trends. However, the different impacts of soil physicochemical properties on species diversity and structure in native and invaded plant communities remain unclear. In this study, we established a total of 30 Alternanthera philoxeroides-invaded plots and 30 control plots in an area at the geographical boundary between North and South China. We compared the differences in species composition between the invaded and native plant communities, and we then used the methods of regression analysis, redundancy analysis (RDA), and canonical correspondence analysis (CCA) to examine the impacts of soil physicochemical properties on four α-diversity indices and the species distribution of these two types of communities. We found that A. philoxeroides invasion increased the difference between the importance values of dominant plant species, and the invasion coverage had a negative relationship with the soil-available potassium (R2 = 0.135; p = 0.046) and Patrick richness index (R2 = 0.322; p < 0.001). In the native communities, the species diversity was determined with soil chemical properties, the Patrick richness index, the Simpson dominance index, and the Shannon-Wiener diversity index, which all decreased with the increase in soil pH value, available potassium, organic matter, and ammonium nitrogen. However, in the invaded communities, the species diversity was determined by soil physical properties; the Pielou evenness index increased with increasing non-capillary porosity but decreased with increasing capillary porosity. The determinants of species distribution in the native communities were soil porosity and nitrate nitrogen, while the determinants in the invaded communities were soil bulk density and available potassium. In addition, compared with the native communities, the clustering degree of species distribution in the invaded communities intensified. Our study indicates that species diversity and distribution have significant heterogeneous responses to soil physicochemical properties between A. philoxeroides-invaded and native plant communities. Thus, we need to intensify the monitoring of soil properties in invaded habitats and conduct biotic replacement strategies based on the heterogeneous responses of native and invaded communities to effectively prevent the biotic homogenization that is caused by plant invasions under environmental changes.

Environmental heterogeneity caused by large-scale cultivation of Pyropia haitanensis shapes multi-group biodiversity distribution in coastal areas

The response of marine biodiversity to mariculture has long been a research focus in marine ecology. However, the effects of seaweed cultivation on biological community assembly are poorly understood, especially in diverse communities with distinct ecological characteristics. In this study, we used environmental DNA metabarcoding to investigate the spatial distribution patterns of bacterial, protistan, and metazoan diversity, aiming to reveal the mechanisms of community assembly in the Pyropia haitanensis cultivation zone along the Fujian coast, China. We found that, compared with the biological communities in control zones, those in P. haitanensis cultivation zones exhibited stronger geographic distance-decay patterns and displayed more complex and stable network structures. Deterministic processes (environmental selection) played a more important role in the assembly of bacterial, protistan, and metazoan communities in P. haitanensis cultivation zones, especially metazoan communities. Variance partitioning analysis showed that environmental variables made greater contributions to the diversity of the three types of communities within the P. haitanensis cultivation zones than in the control zones. Partial least squares path modeling analysis identified nitrate‑nitrogen (NO3-N), pH, particulate organic carbon (POC), and dissolved organic carbon (DOC) as the key environmental variables affecting biodiversity. Overall, the environmental heterogeneity caused by the large-scale cultivation of P. haitanensis could be the crucial factor influencing the composition and structure of various biological communities. Our results highlight the importance of the responses of multi-group organisms to the cultivation of seaweed, and provide insights into the coexistence patterns of biodiversity at the spatial scale.