Ecological Network Analysis Research Articles

Longitudinal development of the airway metagenome of preterm very low birth weight infants during the first two years of life

Preterm birth is accompanied with many complications and requires severe therapeutic regimens at the neonatal intensive care unit. The influence of the above-mentioned factors on the premature-born infants’ respiratory metagenome or more generally its maturation is unknown. We therefore applied shotgun metagenome sequencing of oropharyngeal swabs to analyze the airway metagenome development of 24 preterm infants from one week postpartum to 15 months of age. Beta diversity analysis revealed a distinct clustering of airway microbial communities from hospitalized preterms and samples after hospital discharge. At nine and 15 months of age, the preterm infants lost their hospital-acquired individual metagenome signatures towards a common taxonomic structure. However, ecological network analysis and Random Forest classification of cross-sectional data revealed that by this age the preterm infants did not succeed in establishing the uniform and stable bacterial community structures that are characteristic for healthy full-term infants.

Structural and functional changes in Artificial Reefs ecosystem stressed by trophic modelling approach: Case study in the Bay of Biscay

Artificial Reefs (ARs) are commonly cited as a tool used for increasing fishery production and reinstating ecosystem functionalities. The assessment of ARs deployment is mostly based on analysis of the evolution of fish communities. Recently, studies have focused on trophic modelling to understand the functioning of such ecosystems in a more holistic approach. Trophic models are able to address this concern by describing the interaction between species at different trophic levels and based on the quantification of energy and matter flows through ecosystems. These models allow the application of numerical methods – also called Ecological Network Analysis (ENA) – to characterize emergent properties of the ecosystem. Usually, ENA indices are proposed as indicators of ecosystem health as they are sensitive to different impacts on marine ecosystems. In the present study, the Ecopath software is used to build an ecosystem model composed of 23 compartments, from detritus and phytoplankton to mammals, to describe the situation “before” and “after” the deployment of ARs in the south of the Bay of Biscay along the Landes coast. In addition, ENA indices are calculated for two periods, “before” and “after” the deployment of artificial reefs, to compare network functioning and the overall properties of the structural trophic network. Our results show little structural change in the ecosystem, with a rearrangement of the trophic levels and a simultaneous increase in biomass and system maturity. These preliminary results evidently need to be confronted with other environmental factors such as, for instance, substrate composition, proximity to natural reefs and larval supply. Nonetheless, we consider that the maturity index could be used as a new indicator to assess the evolution of ARs with specific management objectives.

Ecological indicators reveal historical regime shifts in the Black Sea ecosystem.

The Black Sea is one of the most anthropogenically disturbed marine ecosystems in the world because of introduced species, fisheries overexploitation, nutrient enrichment via pollution through river discharge, and the impacts of climate change. It has undergone significant ecosystem transformations since the 1960s. The infamous anchovy and alien warty comb jelly Mnemiopsis leidyi shift that occurred in 1989 is the most well-known example of the drastic extent of anthropogenic disturbance in the Black Sea. Although a vast body of literature exists on the Black Sea ecosystem, a holistic look at the multidecadal changes in the Black Sea ecosystem using an ecosystem- and ecology-based approach is still lacking. Hence, this work is dedicated to filling this gap. First, a dynamic food web model of the Black Sea extending from 1960 to 1999 was established and validated against time-series data. Next, an ecological network analysis was performed to calculate the time series of synthetic ecological indicators, and a regime shift analysis was performed on the time series of indicators. The model successfully replicated the regime shifts observed in the Black Sea. The results showed that the Black Sea ecosystem experienced four regime shifts and was reorganized due to effects instigated by overfishing in the 1960s, eutrophication and establishment of trophic dead-end organisms in the 1970s, and overfishing and intensifying interspecies trophic competition by the overpopulation of some r-selected organisms (i.e., jellyfish species) in the 1980s. Overall, these changes acted concomitantly to erode the structure and function of the ecosystem by manipulating the food web to reorganize itself through the introduction and selective removal of organisms and eutrophication. Basin-wide, cross-national management efforts, especially with regard to pollution and fisheries, could have prevented the undesirable changes observed in the Black Sea ecosystem and should be immediately employed for management practices in the basin to prevent such drastic ecosystem fluctuations in the future.

Environmental heterogeneity shapes the C and S cycling-associated microbial community in Haima's cold seeps.

Environmental heterogeneity in cold seeps is usually reflected by different faunal aggregates. The sediment microbiome, especially the geochemical cycling-associated communities, sustains the ecosystem through chemosynthesis. To date, few studies have paid attention to the structuring and functioning of geochemical cycling-associated communities relating to environmental heterogeneity in different faunal aggregates of cold seeps. In this study, we profiled the microbial community of four faunal aggregates in the Haima cold seep, South China Sea. Through a combination of geochemical and meta-omics approaches, we have found that geochemical variables, such as sulfate and calcium, exhibited a significant variation between different aggregates, indicating changes in the methane flux. Anaerobic methanotrophic archaea (ANME), sulfate-reducing, and sulfide-oxidizing bacteria (SRB and SOB) dominated the microbial community but varied in composition among the four aggregates. The diversity of archaea and bacteria exhibited a strong correlation between sulfate, calcium, and silicate. Interspecies co-exclusion inferred by molecular ecological network analysis increased from non-seep to clam aggregates and peaked at the mussel aggregate. The networked geochemical cycling-associated species showed an obvious aggregate-specific distribution pattern. Notably, hydrocarbon oxidation and sulfate reduction by ANME and SRB produced carbonate and sulfide, driving the alkalization of the sediment environment, which may impact the microbial communities. Collectively, these results highlighted that geofluid and microbial metabolism together resulted in environmental heterogeneity, which shaped the C and S cycling-associated microbial community.

Combined Application Effects of Arbuscular Mycorrhizal Fungi and Biochar on the Rhizosphere Fungal Community of Allium fistulosum L.

Arbuscular mycorrhizal fungi (AMF) are widespread soil endophytic fungi, forming mutualistic relationships with the vast majority of land plants. Biochar (BC) has been reported to improve soil fertility and promote plant growth. However, limited studies are available concerning the combined effects of AMF and BC on soil community structure and plant growth. In this work, a pot experiment was designed to investigate the effects of AMF and BC on the rhizosphere microbial community of Allium fistulosum L. Using Illumina high-throughput sequencing, we showed that inoculation of AMF and BC had a significant impact on soil microbial community composition, diversity, and versatility. Increases were observed in both plant growth (the plant height by 8.6%, shoot fresh weight by 12.1%) and root morphological traits (average diameter by 20.5%). The phylogenetic tree also showed differences in the fungal community composition in A. fistulosum. In addition, Linear discriminant analysis (LDA) effect size (LEfSe) analysis revealed that 16 biomarkers were detected in the control (CK) and AMF treatment, while only 3 were detected in the AMF + BC treatment. Molecular ecological network analysis showed that the AMF + BC treatment group had a more complex network of fungal communities, as evidenced by higher average connectivity. The functional composition spectrum showed significant differences in the functional distribution of soil microbial communities among different fungal genera. The structural equation model (SEM) confirmed that AMF could improve the microbial multifunctionality by regulating the rhizosphere fungal diversity and soil properties. Our findings provide new information on the effects of AMF and biochar on plants and soil microbial communities.

Microbial interactions and metabolisms in response to bacterial wilt and black shank pathogens in the tobacco rhizosphere.

Tobacco bacterial wilt (TBW) and black shank (TBS) are responsible for substantial economic losses worldwide; however, microbial interactions and metabolisms in response to TBW and TBS pathogens in the tobacco rhizosphere remain unclear. We explored and compared the response of rhizosphere microbial communities to these two plant diseases with the incidences in moderate and heavy degrees by sequencing of 16S rRNA gene amplicons and bioinformatics analysis. We found that the structure of rhizosphere soil bacterial communities was significantly (p < 0.05) changed from the incidences of TBW and TBS, which also led to decreased Shannon diversity and Pielou evenness. Compared with the healthy group (CK), the OTUs with significantly (p < 0.05) decreased relative abundances were mostly affiliated with Actinobacteria (e.g., Streptomyces and Arthrobacter) in the diseased groups, and the OTUs with significantly (p < 0.05) increased relative abundances were mainly identified as Proteobacteria and Acidobacteria. Also, molecular ecological network analysis showed that the nodes (<467) and links (<641) were decreased in the diseased groups compared with the control group (572; 1056), suggesting that both TBW and TBS weakened bacterial interactions. In addition, the predictive functional analysis indicated that the relative abundance of genes related to the biosynthesis of antibiotics (e.g., ansamycins and streptomycin) was significantly (p < 0.05) decreased due to incidences of TBW and TBS, and antimicrobial tests showed that some Actinobacteria strains (e.g., Streptomyces) and their secreted antibiotics (e.g., streptomycin) could effectively inhibit the growth of these two pathogens.

Bacteria rather than fungi mediate the chemodiversity of dissolved organic matter in a mudflat intertidal zone

Dissolved organic matter (DOM) in natural ecosystems is intimately associated with microbial communities. However, it remains unclear whether the diversity patterns followed by microbes can be transmitted to DOM compounds. Considering the structural properties of DOM compounds and the roles of microbes in ecosystems, we hypothesized that bacteria tended to be more closely associated with DOM compounds than fungi. To test the above hypothesis and bridge this knowledge gap, the diversity patterns and ecological processes for the DOM compounds, and the bacterial and fungal communities in a mudflat intertidal zone were comparatively investigated. As a result, spatial scaling patterns followed by microbes, including the diversity-area and distance-decay relationships, were also observed for DOM compounds. Lipid-like and aliphatic-like molecules comprised the major DOM compounds associated with environmental factors. Both the alpha- and beta-chemodiversity of DOM compounds were significantly associated with the diversity of bacterial communities, but not fungal communities. Co-occurrence ecological network analysis suggested that DOM compounds were more frequently associated with bacteria than fungi. Further, consistent community assembly patterns were observed for DOM and bacterial communities, but not fungal communities. Integrating multiple lines of evidence, this study demonstrated that bacteria rather than fungi mediated the chemodiversity of DOM in the mudflat intertidal zone. This study elucidates the spatial patterns of complex dissolved organic matter (DOM) pools in the intertidal ecosystem, shedding light on the intricate relationship between DOM compounds and bacterial communities.

Distribution Pattern of Bacterial Community in Soil Profile of Larix principis-rupprechtii Forest in Luya Mountain

Microbial communities are the key component to maintaining the structure and function of forest soil ecosystems. The vertical distribution of bacterial communities on the soil profile has an important impact on forest soil carbon pools and soil nutrient cycling. Using Illumina MiSeq high-throughput sequencing technology, we analyzed the characteristics of bacterial communities in the humus layer and 0-80 cm soil layer of Larix principis-rupprechtii in Luya Mountain, China, to explore the driving mechanisms affecting the structure of bacterial communities in soil profiles. The results showed that the α diversity of bacterial communities decreased significantly with increasing soil depth, and community structure differed significantly across soil profiles. The relative abundance of Actinobacteria and Proteobacteria decreased with increased soil depth, whereas the relative abundance of Acidobacteria and Chloroflexi increased with the increase in soil depth. The results of RDA analysis showed that soil NH+4, TC, TS, WCS, pH, NO-3, and TP were important factors determining the bacterial community structure of the soil profile, among which soil pH had the most significant effect. Molecular ecological network analysis showed that the complexity of bacterial communities in the litter layer and subsurface soil (10-20 cm) was relatively high, whereas the complexity of bacterial communities in deep soil (40-80 cm) was relatively low. Proteobacteria, Acidobacteria, Chloroflexi, and Actinobacteria played important roles in the structure and stability of soil bacterial communities in Larch. The species function prediction of Tax4Fun showed a gradual decline in microbial metabolic capacity along the soil profile. In conclusion, soil bacterial community structure showed a certain distribution pattern along the vertical profile of soil, the community complexity gradually decreased, and the unique bacterial groups of deep soil and surface soil were significantly different.

Urban industrial solid waste metabolism based on ecological network analysis: A case study of Tianjin

Urban industrial solid waste metabolism based on ecological network analysis: A case study of Tianjin

Native fungal community remains resilient during bioremediation of DBP pollution by exogenous Gordonia phthalatica QH-11T

Microbial bioremediation is a highly effective method to degrade phthalates in the environment. However, the response of native microbial communities to the exogenously introduced microorganism remains unknown. In this study, the native fungal community was monitored by amplicon sequencing of the fungal ITS region during the restoration process of the di-n-butyl phthalate (DBP)-contaminated soils with Gordonia phthalatica QH-11T. Our results showed that the diversity, composition, and structure of the fungal community in the bioremediation treatment did not differ from the control, and no significant correlations were found between number of Gordonia and variation of fungal community. It was also observed that DBP pollution initially increased the relative abundance of plant pathogens and soil saprotrophs first, but their proportions returned to the initial level. Molecular ecological network analysis showed that DBP pollution increased the network complexity, while the network was not significantly altered by bioremediation. Overall, the introduction of Gordonia was shown to not have a long-term impact on the native soil fungal community. Therefore, this restoration method can be considered safe in terms of soil ecosystem stability. The present study provides a deeper insight into the effect of bioremediation on fungal communities and provides an extended basis to further explore the ecological risks of introducing exogenous microorganisms.

Aedes albopictus microbiome derives from environmental sources and partitions across distinct host tissues.

The mosquito microbiome consists of a consortium of interacting microorganisms that reside on and within culicid hosts. Mosquitoes acquire most of their microbial diversity from the environment over their life cycle. Once present within the mosquito host, the microbes colonize distinct tissues, and these symbiotic relationships are maintained by immune-related mechanisms, environmental filtering, and trait selection. The processes that govern how environmental microbes assemble across the tissues within mosquitoes remain poorly resolved. We use ecological network analyses to examine how environmental bacteria assemble to form bacteriomes among Aedes albopictus host tissues. Mosquitoes, water, soil, and plant nectar were collected from 20 sites in the Mānoa Valley, Oahu. DNA was extracted and associated bacteriomes were inventoried using Earth Microbiome Project protocols. We find that the bacteriomes of A. albopictus tissues were compositional taxonomic subsets of environmental bacteriomes and suggest that the environmental microbiome serves as a source pool that supports mosquito microbiome diversity. Within the mosquito, the microbiomes of the crop, midgut, Malpighian tubules, and ovaries differed in composition. This microbial diversity partitioned among host tissues formed two specialized modules: one in the crop and midgut, and another in the Malpighian tubules and ovaries. The specialized modules may form based on microbe niche preferences and/or selection of mosquito tissues for specific microbes that aid unique biological functions of the tissue types. A strong niche-driven assembly of tissue-specific microbiotas from the environmental species pool suggests that each tissue has specialized associations with microbes, which derive from host-mediated microbe selection.

Ecosystem Quality Assessment and Ecological Restoration in Fragile Zone of Loess Plateau: A Case Study of Suide County, China

The Loess Plateau is the world’s largest loess landform region, characterized by a fragile ecosystem and frequent natural disasters that render it highly susceptible to ecological damage, highlighting urgent ecological restoration. We constructed a “Pattern-Service-Stress Ecosystem Quality Assessment Model” based on the connotation of ecosystem quality and the ArcGIS platform, then applied it to Suide County, a representative area of the Loess Plateau, as the research object. Next, using the dispersal ecology theory and the MCR model, we constructed an ideal ecological network. According to the quality assessment and ecological network analysis, we selected areas with low ecosystem quality within the scope of an ecological corridor as key areas for restoration. Finally, we proposed restoration strategies using regional ecological techniques. This study yielded the following results: The spatial pattern of ecosystem quality in Suide County exhibited a “high in the south and low in the north” pattern, with a high-value area of 823.87 km2, and a low-value area of 509.31 km2, accounting for 44.45% and 27.48% of the total area, respectively. In Suide County’s ecological network, the spatial distribution of ecological sources and corridors is dense in the south and sparse in the north, with a significant amount of path overlap within ecological corridors. Located on the southern ecological corridor of Suide County, forty-five key areas for restoration were classified into seven types. Eight problems were identified in the key areas, and twenty-three targeted restoration measures were proposed. These measures can result in 6.44 km2 of forest land and 5.26 km2 of grassland, improving the ecosystem quality of the key areas and even the entirety of Suide County. This study guides Suide County’s ecological restoration work and provides a paradigm for ecosystem quality assessment and ecological restoration on the Loess Plateau, pointing out directions. It has a certain radiation-driven effect and an important reference significance for ecological restoration in ecologically fragile areas.

Collaborative energy–water–carbon management based on energy substitution and multiple compound responses

Symbiotic consistency among several limited resources has become increasingly prominent. Dependence on fossil fuels, combined with energy consumption–induced water scarcity and excess carbon emissions, jeopardizes sustainable development. This study developed a provincial-scale energy substitution and response (ESR) model to (a) aggregate homogeneous regions and emphasize consistency of results; (b) formulate energy-substitution strategies based on ecological utility maximization; (c) explore responses from the threefold perspective of environmental improvement, economic utility, and system robustness; and (d) reveal the effects of the main factors and their interactions to support policymaking. An approach that combines the k-means algorithm, multiregional input–output analysis, ecological network analysis, and factorial analysis was applied to China to verify the models. It was found that the uneven transfer of interregional ecological flows across regions is not conducive to the health of metabolic mechanisms. Energy substitution can bring the multiple benefits of resource conservation, environmental improvement, profit growth, and sustainability enhancement. Regions I, IV, and V can take the lead in implementing substitutions while Regions II and III can adopt a joint substitution strategy to obtain compound effects. Natural gas and liquefied petroleum gas facilities should be built in more developed regions while clean energy subsidies should be supplemented in underdeveloped areas. This study's findings offer a new perspective for coordinating environmental, economic, and social development while avoiding high unemployment and regional population loss caused by energy system restructuring.

Effects of dam building on N2O-producing and N2O-reducing community structures in river sediments and the associated N2O emission potential

Dam construction is regarded as the greatest anthropogenic disturbance in aquatic ecosystems, and it promotes denitrification, through which large N2O emissions occur. However, the effect of dams on N2O producers and other N2O-reducing microorganisms (especially for nosZ II), and the associated denitrification rates remain poorly understood. This study systematically investigated the spatial variation of potential denitrification rates in dammed river sediments in winter and summer and the microbial processes driving N2O production and reduction. Sediments in the transition zone of dammed rivers were found to be critical for N2O emission potential, with lower potential denitrification rate and N2O production rate in winter than in summer. In dammed river sediments, the dominant N2O-producing microorganisms and N2O-reducers were nirS-harboring bacteria and nosZ I-harboring bacteria, respectively. Diversity analysis showed that diversity of N2O-producing did not differ significantly between upstream and downstream sediments, whereas the population size and diversity of N2O-reducing microbial communities in upstream sediments significantly decreased, leading to biological homogenization. Further ecological network analysis revealed that the ecological network of nosZ II microbes was more complex than that of nosZ I microbes, and both exhibited more cooperation in the downstream sediments than in the upstream sediments. Mantel analysis showed that the potential N2O production rate was mainly influenced by electrical conductivity (EC), NH4+, and TC content, and that higher nosZ II/nosZ I ratios contributed to improved N2O sinks in dammed river sediments. Moreover, the Haliscomenobacter genus from the nosZ II-type community in the downstream sediments contributed significantly to N2O reduction. Collectively, this study elucidates the diversity and community distribution of nosZ-type denitrifying microorganisms influenced by dams, and also highlights the non-negligible role played by nosZ II-containing microbial groups in mitigating N2O emissions from dammed river sediments.

To be or not to be controlled? The ecological role of the Guiana dolphin in its southernmost range

Several studies have explored dolphins feeding ecology in coastal ecosystems; However, research gauging the predatory effects of delphinid on ecosystems, which can be applied to management and conservation efforts, is still lacking. The northwestern section of the bay of Santa Catarina Island, locally known as North Bay, in Southern Brazil, inhabits the southernmost population of the Guiana dolphin (Sotalia guianensis). This small and resident population is structured in a single and highly cohesive group, using a small home range restricted to the western section of the bay. Like many other coastal dolphins, this dolphin population negatively interacts with fisheries, with frequent bycatch events or by sharing feeding resources. To explore the ecological role of dolphins in the North Bay ecosystem, we constructed an Ecopath food web model to estimate ecosystem and compartmental attributes. Mixed trophic impact and keystoneness index were used to assess the predatory effects of the species in the ecosystem. As a complementary approach to Ecopath, we used ecological network analysis (ENA) to determine the ecological role of the compartments using control analysis and the throughflow centrality. According to our model, North Bay is a mature detritus-based ecosystem. Dolphins showed the highest keystoneness index score among all functional groups, while control analysis showed they are also the most controlled component in the ecosystem. The dolphins rely mainly on the Whitemouth croaker (Micropogonias furnieri), a hub species showing the greatest centrality of flows. We concluded that the Guiana dolphin inhabiting the North Bay is a crucial compartment in the ecosystem. It shows the greatest ecosystem impact per biomass unit among all functional groups, while it is the most vulnerable compartment.

Ecological network analysis of traits reveals variable response capacity to stress.

Response diversity increases the potential 'options' for ecological communities to respond to stress (i.e. response capacity). An indicator of community response diversity is the diversity of different traits associated with their capacity to be resistant to stress, to recover and to regulate ecosystem functions. We conducted a network analysis of traits using benthic macroinvertebrate community data from a large-scale field experiment to explore the loss of response diversity along environmental gradients. We elevated sediment nutrient concentrations (a process that occurs with eutrophication) at 24 sites (in 15 estuaries) with varying environmental conditions (water column turbidity and sediment properties). Macroinvertebrate community response capacity to nutrient stress was dependent on the baseline trait network complexity in the ambient community (i.e. non-enriched sediments). The greater the complexity of the baseline network, the less variable the network response to nutrient stress was; in contrast, more variable responses to nutrient stress occurred with simpler networks. Thus, stressors or environmental variables that shift baseline network complexity also shift the capacity for these ecosystems to respond to additional stressors. Empirical studies that explore the mechanisms responsible for loss of resilience are essential to inform our ability to predict changes in ecological states.

Land carbon metabolism in Xiamen-Zhangzhou-Quanzhou region based on ecological network analysis.

Discovering the underlying mechanisms between carbon metabolism and carbon balance of human-natural system is of important theoretical and practical significance for reducing regional carbon emissions and promoting low-carbon development. Taking Xiamen-Zhangzhou-Quanzhou region from 2000 to 2020 as an example, we constructed the framework of spatial network model of land carbon metabolism based on carbon flow, and inquired into the spatial and temporal heterogeneity in the carbon metabolic structure, function and ecological relationships by using the ecological network analysis. The results showed that the dominant negative carbon transitions related with land use changes came from the conversion of cultivated land to industrial and transportation land, and that the high value areas of negative carbon flow were mainly distributed in the areas with relatively developed industries in the middle and east parts of Xiamen-Zhangzhou-Quanzhou region. Competition relationships were the dominant type and the spatial expansion was obvious, which led to the decreases of the integral ecological utility index and affected the regional carbon metabolic balance. The ecological network hierarchy of driving weight changed from a pyramid structure to a relatively more regular structure, with the producer contributing the most. The ecological network hie-rarchy of pull weight changed from a pyramid structure to an inverted pyramid structure, mainly due to the excessive increase of industrial and transportation land weights. Low-carbon development should focus on the sources of negative carbon transitions caused by land use conversion and its comprehensive impacts on carbon metabolic balance, to formulate differentiated low-carbon land use patterns and carbon emission reduction policies.

Performance of anammox enchanced by pulsed electric fields under added organic carbon sources using integrated network and metagenomics analyses

This paper aims to investigate the function of a pulsed electric field (PEF) in the anaerobic ammonia oxidation (anammox) process after adding certain chemical oxygen demand (COD) through integrated network and metagenomics analyses. The findings showed that the presence of COD was detrimental to anammox, but PEF could significantly reduce the adverse effect. The total nitrogen removal in the reactor for applying PEF was 16.99% higher on average than the reactor for only dosing COD. Additionally, PEF upgraded the abundance of anammox bacteria subordinate to the phylum Planctomycetes by 9.64%. The analysis of molecular ecological networks promulgated that PEF resulted in an increase in network scale and topology complexity, thereby boosting the potential collaboration of the communities. Metagenomics analyses demonstrated that PEF dramatically promoted anammox central metabolism in the presence of COD, specifically enhancing pivotal N functional genes (hzs, hdh, amo, hao, nas, nor and nos).

Distribution patterns and driving mechanism of soil protozoan community at the different depths of Larix principis-chinensis forest in the Luya Mountain, China.

To reveal the assembly mechanisms of soil protozoan community in subalpine forest ecosystems, we analyzed the composition and diversity of protozoan communities and their drivers at the six strata (the litter profile, humus profile, 0-10 cm, 10-20 cm, 20-40 cm and 40-80 cm) of soil profiles in subalpine Larix principis-rupprechtii forest in Luya Mountain using Illumina Miseq high-throughput sequencing technology. The results showed that protozoa in the soil profiles belonged to 335 genera, 206 families, 114 orders, 57 classes, 21 phyla, and 8 kingdoms. There were five dominant phyla (relative abundance >1%) and 10 dominant families (relative abundance >5%). The α diversity decreased significantly with increasing soil depth. Results of PCoA analysis showed that the spatial composition and structure of protozoan community differed significantly across soil depths. The results of RDA analysis showed that soil pH and soil water content were important factors driving protozoan community structure across soil profile. Null model analysis suggested that the heterogeneous selection dominated the processes of protozoan community assemblage. Molecular ecological network analysis revealed that the complexity of soil proto-zoan communities decreased continuously with increasing depth. These results elucidate the assembly mechanism of soil microbial community in subalpine forest ecosystem.

Editorial for the special issue “Control‐theoretic approaches for systems in the life sciences”

Editorial for the special issue “Control<scp>‐theoretic</scp> approaches for systems in the life sciences”