Variation In Species Abundance Research Articles

Study on the Diversity and Distribution of Spider Fauna at Sree Krishna College Campus of Thrissur District, Kerala, India

Field survey was conducted to record the diversity of spiders at different sites in the Sree Krishna College Campus of Thrissur district during September 2022 to February 2023. Around 51 species of spiders belonging to 36 genera under 14 families were recorded. Salticidae family was represented with twelve species followed by Araneidae (10 sps.), Oxyopidae (5 sps.), Theridiidae (4 sps.), Lycosidae, (3 sps.), Tetragnathidae (3 sps.) and Sparassidae (3 sps.), Thomisidae (2 sps.), Pholcidae (2 sps.). But, Hersilidae, Linyphiidae, Uloboridae, Cheiracanthiidae and Sicariidae family members were very less. Spider population in different sites exhibited variation in species abundance and richness. Shannon index, Simpson index, Margalef Richness index, Berger-Parker index and Menhinick’s Index evaluated were 3.423, 0.9580, 9.540, 0.9101and 3.709 respectively. The abundance and percent occurrence of different spider species revealed variation in their distribution. For the study the entire campus has been surveyed, by dividing the area into four sites, Site A, Site B, Site C and Site D. Species composition and diversity indices studies revealed that more diversity in the site C followed by Site D, Site B and Site A. These types of surveys are important for the study of the prevalence of the spider population in given habitats and to create a biodiversity database of spider.

Distribution of Macrozoobenthos of Flowing Water Bodies by Altitudinal Belts of the Nakhchivan Autonomous Republic

Spatial distribution, species structure and ecological indicators of macrozoobenthos of flowing water bodies by altitude belts of Nakhchivan Autonomous Republic were studied. Macrobenthos fauna of the rivers of the region is formed in psammoreophilic, phytoreophilic and peloreophilic biocenoses with a great advantage of lithoreophilic biocenosis. The lithoreophilic biocenosis of rivers of the mountain and high-mountain belts is characterized by extensive area and abundance of species diversity. The core of the lithoreophilic biocenosis is composed of populations of rheophilic organisms such as moths, mayflies, vernal pools and simulids; its usual inhabitants are also rheophilic larvae of chironomids of the genus Polypedilum, Endochironomus, Eukiefferiella, Cricotopus and Orthocladius. The family composition of the fauna was found to be relatively stable along the rivers. Differences in the species composition of macrobenthos fauna, change of dominant species in biocenoses are related to biological features of the main species, anthropic and anthropogenic impacts, as well as different time of research. The species composition of macrozoobenthos of the rivers of the autonomous republic decreases from the source to the mouth.

Molecular physiology of Antarctic diatom natural assemblages and bloom event reveal insights into strategies contributing to their ecological success.

In the Southern Ocean, phytoplankton must cope with harsh environmental conditions such as low light and growth-limiting concentrations of the micronutrient iron. Using metratranscriptomics, we assessed the influence of oceanographic variables on the diversity of the phytoplankton community composition and on the metabolic strategies of diatoms along the Western Antarctic Peninsula, a region undergoing rapid climate change. We found that cross-shelf differences in oceanographic parameters such as temperature and variable nutrient concentrations account for most of the differences in phytoplankton community composition and metabolism. We opportunistically characterized the metabolic underpinnings of a large bloom of the centric diatom Actinocyclus in coastal waters of the WAP. Our results indicate that physicochemical differences from onshore to offshore are stronger than between southern and northern regions of the WAP; however, these trends could change in the future, resulting in poleward shifts in functional differences in diatom communities and phytoplankton blooms.

Go with the flow: Impacts of high and low flow conditions on freshwater mussel assemblages and distribution.

Understanding the drivers of distribution and assemblage composition of aquatic organisms is an important aspect of management and conservation, especially in freshwater systems that are inordinately facing increasing anthropogenic pressures and decreasing biodiversity. For stream organisms, habitat conditions during high flows may be impossible to measure in the field, but can be an important factor for their distribution, especially for less mobile organisms like freshwater mussels. Hence, the objective of this study was to use a two dimensional HEC-RAS model to simulate hydraulic conditions during high and baseline flows (flows approx. 10-600 x and 0.7 x median daily flows respectively) in a 20 km segment in the San Saba River, Texas in combination with existing mussel survey data from 200 sites (collected every 100m) to 1) examine whether hydraulic conditions differed between areas of increased mussel richness and diversity (referred to as hotspots) and other sites, and 2) understand how well site occupancy and species abundance could be explained by hydraulic conditions occurring under different flow conditions. The results showed that richness and diversity hotspots occurred in deeper areas with lower shear stress, stream power, and Froude number during both high and low flows. Occupancy could be predicted with 67-79% accuracy at the site scale and 60-70% accuracy at the mesohabitat scale (∼20 to 1200 m long). In addition, hydraulic conditions across flow scenarios explained up to 55% of variation in species abundances, but predictions were less successful for species often observed to occupy micro-scale flow refuges such as bedrock crevices. The results indicate that pools may serve as important refuge for all species during both high and low flow events, which may be relatively unique to bedrock-dominated systems. Understanding hydraulic conditions that occur at extreme flows such as these is important given that the frequency and magnitude of such events are increasing due to climate change.

Habitat suitability maps for Australian flora and fauna under CMIP6 climate scenarios.

Spatial information about the location and suitability of areas for native plant and animal species under different climate futures is an important input to land use and conservation planning and management. Australia, renowned for its abundant species diversity and endemism, often relies on modeled data to assess species distributions due to the country's vast size and the challenges associated with conducting on-ground surveys on such a large scale. The objective of this article is to develop habitat suitability maps for Australian flora and fauna under different climate futures. Using MaxEnt, we produced Australia-wide habitat suitability maps under RCP2.6-SSP1, RCP4.5-SSP2, RCP7.0-SSP3, and RCP8.5-SSP5 climate futures for 1,382 terrestrial vertebrates and 9,251 vascular plants vascular plants at 5 km2 for open access. This represents 60% of all Australian mammal species, 77% of amphibian species, 50% of reptile species, 71% of bird species, and 44% of vascular plant species. We also include tabular data, which include summaries of total quality-weighted habitat area of species under different climate scenarios and time periods. The spatial data supplied can help identify important and sensitive locations for species under various climate futures. Additionally, the supplied tabular data can provide insights into the impacts of climate change on biodiversity in Australia. These habitat suitability maps can be used as input data for landscape and conservation planning or species management, particularly under different climate change scenarios in Australia.

Quantitative studies on the microstructure evolution and its impact on the viscosity of a molten Al2O3-Na3AlF6 system by Raman spectroscopy and theoretical simulations

The microstructure of the molten alumina-cryolite system is an important aspect in the dissolution behavior of alumina (α-Al2O3) in cryolite (Na3AlF6) molten salt and impacts the physical properties of the molten system. In this work, the symmetric stretching vibrational wavenumbers of aluminum nonbridging fluorine (AlFx3-x) and aluminum-oxygen-fluorine (Al2OFy4-y, and Al2O2Fz2-z) bonds in the high wavenumber range, as well as their corresponding Raman scattering cross sections (RSCS), were first analyzed and determined by quantum chemistry (QC) ab initio calculations. The species in binary Al2O3-Na3AlF6 melts with varying Al2O3 contents from 0 to 6.0 wt% were then qualitatively and quantitatively analyzed using in situ high-temperature Raman spectroscopy in conjunction with first principles calculation from room temperature to melt. The species of AlF4-, AlF52- and AlF63- were found to be present and predominant in the melts with Al2O3 contents ranging from 0 to 6.0 wt%. The content of Al2OF62- species tended to increase with Al2O3 content from 0 to 3.0 wt%, while Al2O2F42- species only existed in the melts with an Al2O3 concentration of more than 3.0 wt%. Finally, the abundance of various species in the molten Al2O3-Na3AlF6 system was further correlated to the melt viscosity. The contribution to viscosity was primarily determined by the distribution of AlFx3-x (x = 4, 5, and 6) and Al2OF62- species, and the contribution ability of corresponding species to viscosity was Al2OF62-, AlF63-, AlF52- and AlF4- from largest to smallest.

The Impact of Goat Milk Pretreatment with Pulsed Electric Fields on Cheese Quality.

To reduce the microbial load in goat's milk, which is less thermally stable than cow's milk, an alternative processing method was used in this study. This involved treating the milk with pulsed electric fields (PEFs) (at 10 kV·cm-1, with 50 µs pulses for 3 Hz) and then heat-treating it at 63 °C for 6.0 s, as well as using heat treatment alone at 75 °C for 3.4 s. Cheeses were made using both types of milk treatment, and samples were collected after 5, 15, and 25 days of ripening for DNA extraction and purification, followed by high-throughput sequencing on the MiSeq Illumina sequencing platform. Analysis of the bacterial populations in the two types of cheese using various diversity indices revealed no significant differences in species richness and abundance, although there was a trend for the PEF-treated cheese to have a less diverse set of species with an uneven distribution of relative abundance. However, when examining the composition of the microbial communities in the two types of cheese using Weighted UniFrac analysis and Analysis of Similarities, there were significant differences in the presence and abundance of various species, which could have implications for the development of starter cultures. Concerning physicochemical properties (pH, aw, moisture content, total acidity and L, and a and b color parameters), the results also reveal that, generally, no significant differences were found, except for the color parameter, where cheeses treated with PEF demonstrated more whiteness (L) and yellowness (b) during ripening. Sensory scores for typicity (caprylic, goaty, and acetic) increased over time, but between treatments, only small differences were perceived by panellists in cheese with 5 days of ripening. Concerning texture firmness and cohesiveness, the PEF+HT samples presented lower values than the HT samples, even over storage time. In general, concerning quality parameters, similar behavior was observed between the treatments during the ripening period.

Short-term functional response to post-fire vegetation dynamic: A case study in a Mediterranean Pinus halepensis forest

Wildfire events significantly affect plant communities. Understanding the post-fire vegetation dynamics and how native and alien species interact to shape the composition and structure of the community is crucial to address conservation policy. Dispersal mechanisms and resource exploration strategies are two functional strategies which can explain variability in species response to disturbance. Here, we investigated how functional traits shape the short-term dynamic after a wildfire event in a Mediterranean pine forest. We collected plant co-occurrences and abundances in permanent plots of 100 m2 across four distinct sampling sessions (from late winter to early autumn, every 2 months). Functionally relevant traits including leaf traits and dispersal-related traits were also retrieved for the recorded species. We then derived the Grime's strategies of the recorded species from the collected leaf traits, and we computed the dispersal ability of each species as a function of the corresponding dispersal traits. To compare Grime's strategies and leaf traits across the monitoring cycles, we calculated the community weighted mean for each cycle as the average of species trait values in each plot. Further, we estimated variations in species abundances and species composition within each plot by using temporal turnover analysis, which showed a continuous post-fire increase in community-level vegetation cover and a strong compositional change driven by a spread of alien species. Associating these patterns to the recorded functional traits revealed that dispersal ability is crucial in post-fire recolonization. Moreover, ruderal species, being the most represented strategy soon after the fire, give way over time to more competitive species showing higher leaf area. Thus, short-term vegetation recovery involves different species-specific strategies that shape the ecological succession over time. Our case study highlights that knowledge about how functional traits drive plant colonization strategies is critical to assess the post-fire restoration status of Mediterranean pine forests.

Comparative Floristic Analysis of Angiosperms of Bundi District– A Part of Haroti Plateau (Rajasthan)

Plant diversity plays an important role in the life of human beings, by way of providing many valuables produces. They help in maintaining the biodiversity in an ecosystem. Abundant species diversity is essential for wealth of natural ecosystems and environment of the area. The present paper highlights comprehensive data on the current status of angiosperms diversity of Bundi district. The flora of Bundi comprises 629 species of angiosperms belonging to 381 genera under 104 families. The area shows much diversity of geographical forms and ecosystem ranges. This district is rich in scenic beauty and biodiversity. The ten dominant families of the area have been compared with those of adjacent areas as well as Upper-gangetic plain, North Gujrat and Delhi. The present work provides comparative analysis among angiosperms families, genera and species.

The difference in the composition of gut microbiota is greater among bats of different phylogenies than among those with different dietary habits.

Bats have a very long evolutionary history and are highly differentiated in their physiological functions. Results of recent studies suggest effects of some host factors (e.g., phylogeny and dietary habit) on their gut microbiota. In this study, we examined the gut microbial compositions of 18 different species of bats. Results showed that Firmicutes, Gammaproteobacteria, and Actinobacteria were dominant in all fecal samples of bats. However, the difference in the diversity of gut microbiota among bats of different phylogenies was notable (p = 0.06). Various species of Firmicutes, Actinobacteria, and Gammaproteobacteria were found to contribute to the majority of variations in gut microbiota of all bats examined, and Aeromonas species were much more abundant in bats that feed on both insects and fish than in those of insectivores. The abundance of various species of Clostridium, Euryarchaeota, and ancient bacterial phyla was found to vary among bats of different phylogenies, and various species of Vibrio varied significantly among bats with different dietary habits. No significant difference in the number of genes involved in various metabolic pathways was detected among bats of different phylogenies, but the abundance of genes involved in 5 metabolic pathways, including transcription; replication, recombination, and repair; amino acid transport and metabolism; and signal transduction mechanisms, was different among bats with different dietary habits. The abundance of genes in 3 metabolic pathways, including those involved in stilbenoid, diarylheptanoid, and gingerol biosynthesis, was found to be different between insectivorous bats and bats that feed on both insects and fish. Results of this study suggest a weak association between dietary habit and gut microbiota in most bats but a notable difference in gut microbiota among bats of different phylogenies.

Vegetation restoration after a fire on the territory of the Barguzin Nature Reserve

Forest fires are increasingly becoming the cause of the destruction of a particular ecosystem or landscape, the restoration of which takes quite a long time. Research on pyrogenic succession is one of the urgent tasks in modern science. In the course of this work, an analysis of vegetation restoration on the territory of the Barguzin Nature Reserve was carried out. After a grass-roots fire on the ecological trails of the Shumilikha River valley and on the Davshinsky pillars, the course of pyrogenic succession was monitored from 2016 to 2019. The study of the progress of vegetation restoration was carried out on the laid test sites on each of the trails. In the course of the work, geobotanical descriptions were made, an abundance of species diversity was revealed, and the total projective cover was also taken into account. In the first year after the fire, such species as Chamerion angustifolium L., Calamagrostis korotkyi L., Bergenia crassifolia (L.) Fritsch., Calamagrostis obtusata Trin., etc. were found on trial sites. During the first three years of succession, it was revealed that the species composition and wealth were not constant and changed every year. At the same time, there was an increase in the projective coverage during the first three years (from 10 to 30% in the valley of the Shumilikha River, from 15 to 45% on the Davshinsky pillars). An increase in the total projective coverage in the studied areas indicates a general restoration of the landscape.

Functional trait trade-offs define plant population stability across different biomes.

Ecological theory posits that temporal stability patterns in plant populations are associated with differences in species' ecological strategies. However, empirical evidence is lacking about which traits, or trade-offs, underlie species stability, especially across different biomes. We compiled a worldwide collection of long-term permanent vegetation records (greater than 7000 plots from 78 datasets) from a large range of habitats which we combined with existing trait databases. We tested whether the observed inter-annual variability in species abundance (coefficient of variation) was related to multiple individual traits. We found that populations with greater leaf dry matter content and seed mass were more stable over time. Despite the variability explained by these traits being low, their effect was consistent across different datasets. Other traits played a significant, albeit weaker, role in species stability, and the inclusion of multi-variate axes or phylogeny did not substantially modify nor improve predictions. These results provide empirical evidence and highlight the relevance of specific ecological trade-offs, i.e. in different resource-use and dispersal strategies, for plant populations stability across multiple biomes. Further research is, however, necessary to integrate and evaluate the role of other specific traits, often not available in databases, and intraspecific trait variability in modulating species stability.

Interspecific variation in plant abundance can contribute to the diversity and evolutionary assembly of floral communities

Angiosperms show remarkable floral diversity in pollinator use. However, how this diversity evolves in a community context remains poorly understood. In this article I propose that different plant species abundances promote adaptation to different pollinators and different degrees of specialization. In this view, interspecific variation in species abundance can foster floral diversity. I develop a mathematical model of pollen transfer considering the interaction of several pollination processes – pollen removal and carryover, intra‐ and interspecific competition for pollinator visitation, and interspecific pollen transfer – that are linked to floral abundance. I integrate the model to an adaptive dynamic framework to simulate the evolutionary assembly of pollination networks. The model demonstrates that different pollinator attributes and degrees of generalization are favored at different plant relative abundances. Within communities, interspecific variation in plant abundance increased diversity in pollinator use and degree of generalization while also promoting the evolution of pollination networks with higher nestedness and lower connectance, leading to networks more consistent with natural pollination networks. The model helps understand the evolutionary assembly of flower communities and suggests a new mechanism by which floral diversity can be generated, contributing to our understanding of floral evolution and diversification.

The unmarked R package: Twelve years of advances in occurrence and abundance modelling in ecology

AbstractSpecies distribution models (SDMs) are widely applied to understand the processes governing spatial and temporal variation in species abundance and distribution but often do not account for measurement errors such as false negatives and false positives.We describeunmarked, a package for the freely available and open‐source R software that provides a complete workflow for modelling species distribution and abundance while explicitly accounting for measurement errors. Here we focus on recent advances inunmarkedfunctionality to support multi‐species, multi‐state, and multi‐season data, as well as support for fitting models with random effects.For illustration, we present an analysis of Acadian FlycatcherEmpidonax virescensabundance on Roanoke River National Wildlife Refuge, North Carolina, USA, over 18 years. We found that Acadian Flycatcher abundance was initially greater in hardwood plantation habitat relative to bottomland hardwood forest along river levees but that abundance declined over time in both habitats.We plan forunmarkeddevelopment to keep pace with advances in hierarchical modelling in ecology, including better handling of continuous‐time data from camera trap and automated recording units and integrated models for multiple data streams.

Abstract 2364: Gut microbiome interacts with clinical characteristics on all-cause mortality of colorectal cancer patients

Abstract Background: Gut microbiota has been introduced to involve in the migration and invasion stage of metastasis of colorectal cancer (CRC) cells and interact with both the pharmacokinetics and pharmacodynamics of chemotherapeutic agents and immune checkpoint inhibitors. In this study, we examined microbiome features in association with all-cause mortality of CRC patients and examined their interactions with clinical factors. Methods: We performed 16S rRNA sequencing for 331 preoperative fecal samples of CRC patients at Seoul National University Hospital, Korea. Multiple Cox proportional hazard model was applied to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for the risk of all-cause mortality due to microbiome features (within-sample diversity indices, species patterns, genus abundance, and taxonomic co-occurrence networks) and clinical factors (tumor grade and stage, surgical methods, neoadjuvant and adjuvant therapies, and invasion). We added the multiplicative term into the model to test the interaction between gut microbiota and clinical characteristics. Results: During a median follow-up of 3.7 years, deaths from any causes were reported in 46 patients. From 172 species, the principal component analysis identified 4 patterns, which explained a total 66.1% variation in species abundance. Of 77 genera, 9 co-occurrence networks were identified by the SParse InversE Covariance Estimation for Ecological Association Inference. For genus level, the risk of death was positively associated with Butyricicoccus (HR=1.54, 95% CI=1.17-2.04), but inversely associated with Lactococcus (HR=0.60, 95% CI=0.37-0.95), Acidaminococcus (HR=0.57, 95% CI=0.34-0.96), Megasphaera (HR=0.79, 95% CI=0.64-0.99), Mitsuokella (HR=0.75, 95% CI=0.57-0.99). All-cause mortality was associated with well or moderately differentiated adenocarcinoma (HR=3.84, 95% CI=1.83-8.07), neoadjuvant therapy (HR=4.10, 95% CI=1.40-12.0), tumor stage IV (HR=8.64, 95% CI=3.42-21.8), and presence of venous invasion (HR=2.32, 95% CI=1.08-4.97). Among clinical pathological factors associated with all-cause mortality, Bacteroides abundance significantly interacted with both tumor stage (pinteraction=0.013) and venous invasion (pinteraction=0.001). Conclusion: Our study identified several microbiome features in links with either increasing or decreasing mortality from any causes. Interactions between the gut microbiome and clinical factors might inform insights on how the gut microbiota modulates the effect of clinical factors on CRC prognosis after the curative operation. Further research using postoperative information is needed to confirm our findings. Citation Format: Tung Hoang, Min Jung Kim, Ji Won Park, Seung-Yong Jeong, Aesun Shin. Gut microbiome interacts with clinical characteristics on all-cause mortality of colorectal cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2364.

Annotation-free discovery of functional groups in microbial communities.

Recent studies have shown that microbial communities are composed of groups of functionally cohesive taxa whose abundance is more stable and better-associated with metabolic fluxes than that of any individual taxon. However, identifying these functional groups in a manner that is independent of error-prone functional gene annotations remains a major open problem. Here we tackle this structure-function problem by developing a novel unsupervised approach that coarse-grains taxa into functional groups, solely on the basis of the patterns of statistical variation in species abundances and functional read-outs. We demonstrate the power of this approach on three distinct datasets. On data of replicate microcosms with heterotrophic soil bacteria, our unsupervised algorithm recovered experimentally validated functional groups that divide metabolic labour and remain stable despite large variation in species composition. When leveraged against the ocean microbiome data, our approach discovered a functional group that combines aerobic and anaerobic ammonia oxidizers whose summed abundance tracks closely with nitrate concentrations in the water column. Finally, we show that our framework can enable the detection of species groups that are probably responsible for the production or consumption of metabolites abundant in animal gut microbiomes, serving as a hypothesis-generating tool for mechanistic studies. Overall, this work advances our understanding of structure-function relationships in complex microbiomes and provides a powerful approach to discover functional groups in an objective and systematic manner.

Habitat–trait interactions that control response to climate change: North American ground beetles (Carabidae)

AbstractAimAs one of the most diverse and economically important families on Earth, ground beetles (Carabidae) are viewed as a key barometer of climate change. Recent meta‐analyses provide equivocal evidence on abundance changes of terrestrial insects. Generalizations from traits (e.g., body size, diets, flights) provide insights into understanding community responses, but syntheses for the diverse Carabidae have not yet emerged. We aim to determine how habitat and trait syndromes mediate risks from contemporary and future climate change on the Carabidae community.LocationNorth America.Time period2012–2100.Major taxa studiedGround beetles (Carabidae).MethodsWe synthesized the abundance and trait data for 136 species from the National Ecological Observatory Network (NEON) and additional raw data from studies across North America with remotely sensed habitat characteristics in a generalized joint attribute model. Combined Light Detection and RAnging (LiDAR) and hyperspectral imagery were used to derive habitat at a continental scale. We evaluated climate risks on the joint response of species and traits by expanding climate velocity to response velocity given habitat change.ResultsHabitat contributes more variations in species abundance and community‐weighted mean traits compared to climate. Across North America, grassland fliers benefit from open habitats in hot, dry climates. By contrast, large‐bodied, burrowing omnivores prefer warm‐wet climates beneath closed canopies. Species‐specific abundance changes predicted by the fitted model under future shared socioeconomic pathways (SSP) scenarios are controlled by climate interactions with habitat heterogeneity. For example, the mid‐size, non‐flier is projected to decline across much of the continent, but the magnitudes of declines are reduced or even reversed where canopies are open. Conversely, temperature dominates the response of the small, frequent flier Agonoleptus conjunctus, causing projected change to be more closely linked to regional temperature changes.Main conclusionsCarabidae community reorganization under climate change is being governed by climate–habitat interactions (CHI). Species‐specific responses to CHI are explained by trait syndromes. The fact that habitat mediates warming impacts has immediate application to critical habitat designation for carabid conservation.

Hard-Bottom Polychaetes Exposed to Multiple Human Pressure along the Mediterranean Coast of Egypt

The complex mixture of anthropogenic pressure determines the impact on the marine biota, hampering the ecosystem’s functioning. The coast of Alexandria, Egypt, experiences multiple human pressure, including sewage discharge, engineering activities (urbanization) for armoring purposes, and beach nourishment. Hard-bottom polychaete assemblages are demonstrated to reflect coastal areas’ environmental status, though their use in monitoring programs is uncommon. The sensitivity of hard-bottom polychaete assemblages in depicting variations in environmental conditions of two sites exposed to the discharge of polluted water and three sites exposed to urbanization was analyzed. The high spatial and temporal variation in species abundance and diversity probably hid differences among the assemblages exposed to the two forms of pressure while highlighting differences among sites exposed to the same impact form. In addition, changes in the algal substrate probably influenced the observed pattern. Temporal variation of salinity and differences in biological oxygen demand (BOD) and the organic matter appeared to indirectly affect polychaete abundance and diversity by favoring tolerant algal taxa such as Ulva sp. Contrary to what was expected, assemblage variation due to site-specific environmental features accounted for more than the variations due to the two forms of human pressure in shaping differences among polychaete assemblages.

Habitat attributes mediate herbivory and influence community development in algal metacommunities.

Understanding the drivers and impacts of spatiotemporal variation in species abundance on community trajectories is key to understanding the factors contributing to ecosystem resilience. Temporal variation in species trajectories across patches can provide compensation for species loss and can influence successional patterns. However, little is known about the underlying mechanisms that lead to patterns of species or spatial compensation and how those patterns may be mediated by consumer-resource relationships. Here we describe an experiment testing whether habitat attributes (e.g., structural complexity and spatial heterogeneity) mediate the effects of herbivory on tropical marine macroalgal communities by reducing accessibility and detectability, respectively, leading to variable trajectories among algal species at community (within patch) and metacommunity (i.e., among patch) scales. Reduced accessibility (greater habitat complexity) decreased the effects of herbivory (i.e., depressed consumption rate, increased algal species richness), and both accessibility and detectability (spatial heterogeneity) influenced algal community structure. Moreover, decreased accessibility at the community scale and a mosaic of accessibility at the metacommunity scale led to variation in community assembly. We suggest that habitat attributes can be important influencers of consumer-resource interactions on coral reefs, which in turn can increase species diversity, promote species succession, and enhance stability in algal metacommunities.

The impact of Traditional Chinese Medicine on mouse gut microbiota abundances and interactions based on Granger causality and pathway analysis.

The intestinal microbiota is essential in absorbing nutrients and defending against pathogens and is associated with various diseases, including obesity, type 2 diabetes, and hypertension. As an alternative medicine, Traditional Chinese Medicine (TCM) has long been used in disease treatment and healthcare, partly because it may mediate gut microbiota. However, the specific effects of TCM on the abundance and interactions of microbiota remain unknown. Moreover, using TCM ingredients and data detailing changes in the abundance of gut microorganisms, we developed bioinformatic methods that decipher the impact of TCM on microorganism interactions. The dynamics of gut microorganisms affected by TCM treatments is explored using a mouse model, which provided the abundance of 70 microorganisms over time. The Granger causality analysis was used to measure microorganism interactions. Novel "serial connection" and "diverging connection" models were used to identify molecular mechanisms underlying the impact of TCM on gut microorganism interactions, based on microorganism proteins, TCM chemical ingredients, and KEGG reaction equations. Codonopsis pilosula (Dangshen), Cassia twig (Gui Zhi), Radices saussureae (Mu Xiang), and Sijunzi Decoction did not cause an increase in the abundance of harmful microorganisms. Most TCMs decreased the abundance of Bifidobacterium pseudolongum, suggesting a Bifidobacterium pseudolongum supplement should be used during TCM treatment. The Granger causality analysis indicated that TCM treatment changes more than half the interactions between the 70 microorganisms, and "serial connection" and "diverging connection" models suggested that changes in interactions may be related to the reaction number connecting species proteins and TCM ingredients. From a species diversity perspective, a TCM decoction is better than a single herb for healthcare. The Sijunzi Decoction only significantly increased the abundance of Bifidobacterium pseudolongum and did not cause a decrease in the abundance of other species but was found to improve the alpha diversity with the lowest replacement rate. Because most of the nine TCMs are medicinal and edible plants, we expect the methods and results presented can be used to optimize and integrate microbiota and TCMs into healthcare processes. Moreover, as a control study, these results can be combined with future disease mouse models to link variations in species abundance with particular diseases.