Habitat Filtering Research Articles

Investigating the Biotic and Abiotic Drivers of Body Size Disparity in Communities of Non‐Volant Terrestrial Mammals

ABSTRACTAimThe species that compose local communities possess unique sets of functional and ecological traits that can be used as indicators of biotic and abiotic variation across space and time. Body size is a particularly relevant trait because species with different body sizes typically have different life history strategies and occupy distinct niches. Here we used the body sizes of non‐volant (i.e., non‐flying) terrestrial mammals to quantify and compare the body size disparity of mammal communities across the globe.LocationGlobal.Time PeriodPresent.Major Taxa StudiedNon‐volant terrestrial mammals.MethodsWe used IUCN range maps of 3982 terrestrial mammals to identify 1876 communities. We then combined diet data with data on climate, elevation and anthropogenic pressures to evaluate these variables' relative importance on the observed body size dispersion of these communities and its deviation from a null model.ResultsDispersion for these communities is significantly greater than expected in 54% of communities and significantly less than expected in 30% of communities. The number of very large species, continent, range sizes, diet disparity and annual temperature collectively explain > 50% of the variation in observed dispersion, whereas continent, the number of very large species, and precipitation collectively explain > 30% of the deviation from the null model.Main ConclusionsClimate and elevation have minimal predictive power, suggesting that biotic factors may be more important for explaining community body size distributions. However, continent is consistently a strong predictor of dispersion, likely due to it capturing the combined effects of climate, size‐selective human‐induced extinctions and more. Overall, our results are consistent with several plausible explanations, including, but not limited to, competitive exclusion, unequal distribution of resources, within‐community environmental heterogeneity, habitat filtering and ecosystem engineering. Further work focusing on other confounding variables, at finer spatial scales and/or within more causal frameworks is required to better understand the driver(s) of these patterns.

Co‐occurrence in snake and lizard sister species is unrelated to major ecomorphological traits

AbstractEnvironmental factors and interspecific interactions, such as competition and facilitation, can shape species' geographic ranges. Here, we tested the relationship between geographic range overlap of squamate sister species, and their divergence in body size, diel activity, and microhabitat use. Competition theory predicts that sister species with similar traits will overlap less geographically than sister pairs with dissimilar traits. However, similar distributions may present similar selective pressures and favour similar adaptations, such that habitat filtering may result in species with more similar traits in sympatry. Across 1434 sister species contrasts, we found little relationship between range overlap and niche divergence. In some models, the divergence in body size and microhabitat use marginally increased with sympatry, while in other models, sympatric sisters had similar activity times. However, the low R‐squared values of almost all these models lend only weak support to predictions from competition or habitat filtering theories. Sympatric sister species within the same biome showed more similar activity times than expected, lending some support to habitat filtering. Niche divergence in allopatry or sympatry, as calculated using a multi‐trait dissimilarity index, did not show a phylogenetic signal, and niches of sister species from different squamate clades did not deviate significantly from the null expectation. Overall, niche divergence or convergence, across the axes we explored, is not a prerequisite for regional species co‐occurrence. We suggest here that the lack of consistent support for either limiting similarity or habitat filtering may reflect that both these forces act as transient phenomena. More fine‐grained analyses, in space and time, would be needed to detect their fingerprints. Thus, coexistence in the face of competition can arise due to various evolutionary and biogeographic mechanisms, acting concurrently or asynchronously.

Deciphering microbial metabolic interactions and their implications for community dynamics in acid mine drainage sediments

The microbially-mediated reduction processes have potential for the bioremediation of acid mine drainage (AMD), which represents a worldwide environment problem. However, we know little about the microbial interactions in anaerobic AMD sediments. Here we utilized genome-resolved metagenomics to uncover the nature of cooperative and competitive metabolic interactions in 90 AMD sediments across Southern China. Our analyses recovered well-represented prokaryotic communities through the reconstruction of 2625 population genomes. Functional analyses of these genomes revealed extensive metabolic handoffs which occurred more frequently in nitrogen metabolism than in sulfur metabolism, as well as stable functional redundancy across sediments resulting from populations with low genomic relatedness. Genome-scale metabolic modeling showed that metabolic competition promoted microbial co-occurrence relationships, suggesting that community assembly was dominated by habitat filtering in sediments. Notably, communities colonizing more extreme conditions tended to be highly competitive, which was typically accompanied with increased network complexity but decreased stability of the microbiome. Finally, our results demonstrated that heterotrophic Thermoplasmatota associated with ferric iron and sulfate reduction contributed most to the elevated levels of competition. Our study shed light on the cooperative and competitive metabolisms of microbiome in the hazardous AMD sediments, which may provide preliminary clues for the AMD bioremediation in the future.

Phylogenetic indices and temporal and spatial scales shape the neighborhood effect on seedling survival in a mid-mountain moist evergreen broad-leaved forest, Gaoligong Mountains, Southwestern China.

Density dependence and habitat filtering have been proposed to aid in understanding community assembly and species coexistence. Phylogenetic relatedness between neighbors was used as a proxy for assessing the degree of ecological similarity among species. There are different conclusions regarding the neighborhood effect in previous studies with different phylogenetic indices or at different spatiotemporal scales. However, the effects of density dependence, neighbor phylogenetic relatedness, and habitat filtering on seedling survival with different phylogenetic indices or at different temporal and spatial scales are poorly understood. We monitored 916 seedlings representing 56 woody plant species within a 4-ha forest dynamics plot for 4 years (from 2020 to 2023) in a subtropical mid-mountain moist evergreen broad-leaved forest in the Gaoligong Mountains, Southwestern China. Using generalized linear mixed models, we tested whether and how four phylogenetic indices: total phylogenetic distance (TOTPd), average phylogenetic distance (AVEPd), relative average phylogenetic distance (APd'), and relative nearest taxon phylogenetic distance (NTPd'), three temporals (1, 2, and 3 years), and spatial scales (1, 2, and 4 ha) affect the effect of density dependence, phylogenetic density dependence, and habitat filtering on seedling survival. We found evidence of the effect of phylogenetic density dependence in the 4-ha forest dynamics plot. The effects of density dependence, phylogenetic density dependence, and habitat filtering on seedling survival were influenced by phylogenetic indices and temporal and spatial scales. The effects of phylogenetic density dependence and habitat filtering on seedling survival were more conspicuous only at 1-year intervals, compared with those at 2- and 3-year intervals. We did not detect any effects of neighborhood or habitat factors on seedling survival at small scales (1 and 2 ha), although these effects were more evident at the largest spatial scale (4 ha). These findings highlight that the effects of local neighborhoods and habitats on seedling survival are affected by phylogenetic indices as well as temporal and spatial scales. Our study suggested that phylogenetic index APd', shortest time scale (1 year), and largest spatial scales (4 ha) were suitable for neighborhood studies in a mid-mountain moist evergreen broad-leaved forest in Gaoligong Mountains. Phylogenetic indices and spatiotemporal scales have important impacts on the results of the neighborhood studies.

Environmental determinants of phylogenetic diversity in vernal pool habitats.

Phylogenetic diversity offers critical insights into the ecological dynamics shaping species composition and ecosystem function, thereby informing conservation strategies. Despite its recognized importance in ecosystem management, the assessment of phylogenetic diversity in endangered habitats, such as vernal pools, remains limited. Vernal pools, characterized by cyclical inundation and unique plant communities, present an ideal system for investigating the interplay between ecological factors and phylogenetic structure. This study aims to characterize the phylogenetic patterns of vernal pools and their associated vegetation zones, addressing questions about taxonomic and phylogenetic community discreteness, the role of flooding as a habitat filter, the influence of invasive species on phylogenetic structure, and the impact of seasonal variation on phylogenetic diversity. I find that zones-of-vegetation exhibit high between zone taxonomic and phylogenetic beta diversity whereas each zone forms a unique cluster, suggesting that zones are taxonomically and phylogenetically discrete units. Regions of high-inundation pressure exhibit phylogenetic clustering, indicating that flooding is a habitat filter in vernal pool habitats. Competition between native species conform to the 'competitive relatedness hypothesis' and, conversely, communities dominated by invasive Eurasian grass species are phylogenetically clustered. In addition, I find that phylogenetic diversity within zones fluctuates across the spring season in response to changing water levels, precipitation, and temperature. By analyzing three pools within the Merced Vernal Pool and Grassland Reserve, this research elucidates the phylogenetic dynamics of vernal pools. The findings underscore the need for tailored conservation strategies that account for the unique ecological characteristics of each vegetation zone within vernal pool habitats.

Extending trait dispersion across trophic levels: Predator assemblages act as top-down filters on prey communities.

Studies of community assembly typically focus on the effects of abiotic environmental filters and stabilizing competition on functional trait dispersion within single trophic levels. Predation is a well-known driver of community diversity and composition, yet the role of functionally diverse predator communities in filtering prey community traits has received less attention. We examined functionally diverse communities of predators (fishes) and prey (epifaunal crustaceans) in eelgrass (Zostera marina) beds in two northern California estuaries to evaluate the filtering effects of predator traits on community assembly and how filters acting on predators influence their ability to mediate prey community assembly. Fish traits related to bottom orientation were correlated with more clustered epifauna communities, and epifauna were generally overdispersed while fishes were clustered, suggesting prey may be pushed to disparate areas of trait space to avoid capture by benthic sit-and-wait predators. We also found correlations between the trait dispersions of predator and prey communities that strengthened after accounting for the effects of habitat filters on predator dispersion, suggesting that habitat filtering effects on predator species pools may hinder their ability to affect prey community assembly. Our results present compelling observational evidence that specific predator traits have measurable impacts on the community assembly of prey, inviting experimental tests of predator trait means on community assembly and explicit comparisons of how the relative effects of habitat filters and intraguild competition on predators impact their ability to affect prey community assembly. Integrating our understanding of traits at multiple trophic levels can help us better predict the impacts of community composition on food web dynamics as regional species pools shift with climate change and anthropogenic introductions.

Biotic and abiotic factors acting on community assembly in parallel anaerobic digestion systems from a brewery wastewater treatment plant

ABSTRACT Anaerobic digestion is a complex microbial process that mediates the transformation of organic waste into biogas. The performance and stability of anaerobic digesters relies on the structure and function of the microbial community. In this study, we asked whether the deterministic effect of wastewater composition outweighs the effect of reactor configuration on the structure and dynamics of anaerobic digester archaeal and bacterial communities. Biotic and abiotic factors acting on microbial community assembly in two parallel anaerobic digestion systems, an upflow anaerobic sludge blanket digestor (UASB) and a closed digester tank with a solid recycling system (CDSR), from a brewery WWTP were analysed utilizing 16S rDNA and mcrA amplicon sequencing and genome-centric metagenomics. This study confirmed the deterministic effect of the wastewater composition on bacterial community structure, while the archaeal community composition resulted better explained by organic loading rate (ORL) and volatile free acids (VFA). According to the functions assigned to the differentially abundant metagenome-assembled genomes (MAGs) between reactors, CDSR was enriched in genes related to methanol and methylamines methanogenesis, protein degradation, and sulphate and alcohol utilization. Conversely, the UASB reactor was enriched in genes associated with carbohydrate and lipid degradation, as well as amino acid, fatty acid, and propionate fermentation. By comparing interactions derived from the co-occurrence network with predicted metabolic interactions of the prokaryotic communities in both anaerobic digesters, we conclude that the overall community structure is mainly determined by habitat filtering.

Spatial distribution patterns and intraspecific and interspecific spatial associations of Quercus myrsinifolia population in Shennongjia, China

Quercus myrsinifolia is one of the dominant species in the evergreen broad-leaf forest on the southern slope of Shennongjia. The study of spatial distribution pattern and spatial correlation of Q. myrsinifolia population will help to understand population development and potential ecological processes, as well as the structure and biodiversity maintenance mechanism of evergreen broad-leaf forests at the northern edge of the subtropics. Based on forest dynamic monitoring data from one 1 hm2 permanent plot on the southern slope of Shennongjia, we employed pair correlation functions g(r) and marked correlation functions to analyze the diameter structure of the Q. myrsinifolia population, spatial distribution patterns at different diameter classes, and intraspecific and interspecific spatial associations. The results showed that diameter structure of Q. myrsinifolia population exhibited an inverted 'J'-shaped distribution, suggesting a healthy regeneration status and belonging to a growing population type. The spatial distribution showed a decreasing trend in aggregation with increasing diameter. Positive correlations among individuals strengthened with closer diameter classes, while weakening with larger diameter differences. Interspecific spatial associations showed an increasing correlation of Q. myrsinifolia with understory dominant species with increasing spatial scales, but no correlation was observed with canopy-dominant species. Our results suggested that the spatial pattern of Q. myrsinifolia populations on the southern slope of Shennongjia was mainly influenced by habitat filtering, seed dispersal limitation, and intraspecific and interspecific competition. Furthermore, the adaptive strategies of Q. myrsinifolia varied when they coexisted with different species.

Urbanization reduces Orthoptera diversity and changes community structure towards mobile species

Abstract Urban land use is regarded as one major driver for insect declines worldwide. We investigated how Orthoptera diversity and traits respond to the urban matrix and local vegetation parameters. Orthoptera were collected using a combined method of box‐quadrat sampling and pitfall trapping. We sampled 42 dry grasslands in Berlin, Germany, along gradients of urbanization (measured as proportion of sealed surface in the surrounding of the sites) and connectivity. We further included patch size and local vegetation parameters (plant richness, total vegetation cover, herb cover, neophyte cover) in our models. Urbanization was the main driver explaining Orthoptera species richness, Simpson diversity and functional diversity (functional dispersion), which all decreased with increasing proportion of sealed surface in the surrounding. Urbanization also influenced the Orthoptera species composition. Thereby, functional trait analyses revealed that the urban matrix acted as a habitat filter sorting towards mobile species. However, responses of the most common species showed that the effects of the urban matrix and vegetation parameters were species specific. Our results demonstrate predominantly negative effects of urbanization on Orthoptera diversity. Nevertheless, urban environments can provide important habitats, in particular for mobile species. Even small and isolated patches of dry grasslands can contribute to Orthoptera conservation in cities.

Variations in species diversity patterns and community assembly rules among vegetation types in the karst landscape.

The various vegetation types in the karst landscape have been considered the results of heterogeneous habitats. However, the lack of a comprehensive understanding of regional biodiversity patterns and the underlying ecological processes limits further research on ecological management. This study established forest dynamic plots (FDPs) of the dominant vegetation types (shrubland, SL; mixed tree and shrub forest, MTSF; coniferous forest, CF; coniferous broadleaf mixed forest, CBMF; and broadleaf forest, BF) in the karst landscape and quantified the species diversity patterns and potential ecological processes. The results showed that in terms of diversity patterns, the evenness and species richness of the CF community were significantly lower than other vegetation types, while the BF community had the highest species richness. The other three vegetation types showed no significant variation in species richness and evenness. However, when controlling the number of individuals of FDPs, the rarefied species richness showed significant differences and ranked as BF > SL > MTSF > CBMF > CF, highlighting the importance of considering the impacts of abundance. Additionally, the community assembly of climax communities (CF or BF) was dominated by stochastic processes such as species dispersal or species formation, whereas deterministic processes (habitat filtering) dominated the secondary forests (SL, MTSF, and CBMF). These findings proved that community assembly differs mainly between the climax community and other communities. Hence, it is crucial to consider the biodiversity and of the potential underlying ecological processes together when studying regional ecology and management, particularly in heterogeneous ecosystems.

Local factors and bionomic characteristics determining the occurrence of semiaquatic bugs in streams of Central Amazonia

Abstract Individual responses to changes in the environment by different species drive a better understanding of the dynamics of diversity and habitat filtering. Hypotheses based on functional and morphometric characteristics of the species are especially useful for accounting for different interpretations of biological responses. This study aimed to determine the responses of semiaquatic species of insects to habitat changes from the elaboration of hypotheses based on the importance of species traits facing environmental variations. We tested these hypotheses with maximum likelihood models to explain the occurrence of the species in streams of the central Amazon region. In a total of 17 collected Gerromorpha species, we used 14 to develop five predictive models of occurrence considering the bionomic characteristics of each species and their possible relationships with habitat changes in 33 streams in the central Amazon region. We used maximum likelihood models to assess the fit of the models to the observed occurrence, with environmental characteristics as covariates affecting the occurrence probability, and sampling effort affecting the detection probability. A total of five species exhibited changes in the probability of occurrence in streams related to an environmental condition (riparian forest disturbance, flow heterogeneity, and surface habitat heterogeneity). The probability of occurrence tended to reduce for four of the five species and increase for one with increase of environmental impacts. Furthermore, the sampling effort covariate did not affect the probability of detection in most species, indicating that the group showed a high detection. The use of functional characteristics of Gerromorpha species to develop ecological hypotheses proved relevant and indicated unexpected relationships, expanding our knowledge of this community of aquatic insects. Therefore, including the individual responses of organisms to environmental variations helps in studies on aquatic biodiversity, both for basic ecology and for conservation and bioassessment.

Distinct coral environments shape the dynamic of planktonic Vibrio spp.

BackgroundCoral reefs are one of the most biodiverse and productive ecosystems, providing habitat for a vast of species. Reef-building scleractinian corals with a symbiotic microbiome, including bacteria, archaea, viruses and eukaryotic microbes, are referred to coral holobionts. Among them, coral diseases, mainly caused by Vibrio spp., have significantly contributed to the loss of coral cover and diversity. Habitat filtering across the globe has led to a variety structure of marine bacterial communities. Coral species, quantity and characteristics are significant differences between the Xisha Islands and Daya Bay (Guangdong Province). Thus, the Vibrio communities may be distinct between coral rich and poor areas.ResultsThrough comparison of Vibrio dynamics between coral-rich (Xisha Islands) and coral-poor (Daya Bay) locations, we uncovered differences in Vibrio abundance, diversity, community composition and assembly mechanisms associated with corals. The higher abundance of Vibrio in coral rich areas may indicate a strong interaction between vibrios and corals. V. campbellii, Paraphotobacterium marinum and V. caribbeanicus were widely distributed in both coral rich and poor areas, likely indicating weak species specificity in the coral-stimulated growth of Vibrio. Random-forest prediction revealed Vibrio species and Photobacterium species as potential microbial indicators in the coral rich and coral poor areas, respectively. Ecological drift rather than selection governed the Vibrio community assembly in the Xisha Islands. Comparatively, homogenizing selection was more important for the Daya Bay community, which may reflect a role of habitat filtration.ConclusionThis study revealed the different distribution pattern and assembly mechanism of Vibrio spp. between coral rich and poor areas, providing the background data for the research of Vibrio community in coral reef areas and may help the protection of coral reef at the biological level. The main reasons for the difference were different number and species of corals, environmental (e.g., temperature) and spatial factors. It reflected the strong interaction between Vibrio and corals, and provided a new perspective for the investigation of Vibrio in coral reef ecosystem.

The owls are coming: positive effects of climate change in Northern ecosystems depend on grassland protection

Climate-driven migrations towards Northern latitudes are expected to reorganize biotic communities as result of range shift dynamics. However, the establishment of healthy populations of migrating species depends on habitat provision by receptor landscapes. Here, we ask if the rising temperatures and changes in precipitation regimes in western North America are likely to lead to an expansion of warm and dry-affiliated species, using the burrowing owl (Athene cunicularia) as a study case. This migratory species depends on grassland habitats for nesting and breeding, so we test for the effect of the lack of grasslands on the occupancy of future suitable environments. To estimate the burrowing owl's potential distribution, we used ecological niche models (ENMs) calibrated with climate and soil information and projected onto future scenarios of climate change (low versus high greenhouse gas emission). Then, we simulated environmental sorting using habitat filter masks derived from information on habitat use and forecasts of future land use change, focusing on grasslands as nesting and breeding habitat. We found that the burrowing owl could expand its geographic distribution by 3 to 10-fold towards Northern latitudes, especially under high-emission scenarios of climate change. However, nearly half of the suitable environments (up to 53,593 km2 of locations with suitable climate and soil) might not be covered by grasslands, due to conversion to agriculture and other human land uses which may prevent the establishment of breeding populations. Our results shed light on the pervasive effects of neglecting the preservation of grasslands across western North America, which could provide critically needed habitat for migrating species from lower latitudes. Enhancing and facilitating the colonization of novel species is a shift in the static paradigm of biodiversity conservation and a proactive measure for climate change adaptation.

Sporocarp nutrition of ectomycorrhizal fungi indicates an important role for endemic species in a high productivity temperate rainforest.

Endemic species of ectomycorrhizal fungi (EMF) are found throughout many biomes, but it is unclear whether their localized distribution is dictated by habitat filtering or geographical barriers to dispersal. We examined community composition (via long-read metabarcoding) and differences in sporocarp nutrition between endemic and cosmopolitan EMF species across perhumid temperate rainforests of British Columbia, characterized by soils with high nitrogen (N) supply alongside low phosphorus (P) and cation availability. Endemic EMF species, representing almost half of the community, had significantly greater sporocarp N (24% higher), potassium (+16%), and magnesium (+17%) concentrations than cosmopolitan species. Sporocarp P concentrations were comparatively low and did not differ by fungal range. However, sporocarp N% and P% were well correlated, supporting evidence for linkages in N and P acquisition. Endemics were more likely to occur on Tsuga heterophylla (a disjunct host genus) than Picea sitchensis (a circumpolar genus). The Inocybaceae and Thelephoraceae families had high proportions of endemic taxa, while species in Cortinariaceae were largely cosmopolitan, indicating some niche conservatism among genera. We conclude that superior adaptive traits in relation to perhumid soils were skewed toward the endemic community, underscoring the potentially important contribution of these localized fungi to rainforest nutrition and productivity.

Dispersal, habitat filtering, and eco-evolutionary dynamics as drivers of local and global wetland viral biogeography.

Wetlands store 20-30% of the world's soil carbon, and identifying the microbial controls on these carbon reserves is essential to predicting feedbacks to climate change. Although viral infections likely play important roles in wetland ecosystem dynamics, we lack a basic understanding of wetland viral ecology. Here 63 viral size-fraction metagenomes (viromes) and paired total metagenomes were generated from three time points in 2021 at seven fresh- and saltwater wetlands in the California Bodega Marine Reserve. We recovered 12,826 viral population genomic sequences (vOTUs), only 4.4% of which were detected at the same field site two years prior, indicating a small degree of population stability or recurrence. Viral communities differed most significantly among the seven wetland sites and were also structured by habitat (plant community composition and salinity). Read mapping to a new version of our reference database, PIGEONv2.0 (515,763 vOTUs), revealed 196 vOTUs present over large geographic distances, often reflecting shared habitat characteristics. Wetland vOTU microdiversity was significantly lower locally than globally and lower within than between time points, indicating greater divergence with increasing spatiotemporal distance. Viruses tended to have broad predicted host ranges via CRISPR spacer linkages to metagenome-assembled genomes, and increased SNP frequencies in CRISPR-targeted major tail protein genes suggest potential viral eco-evolutionary dynamics in response to both immune targeting and changes in host cell receptors involved in viral attachment. Together, these results highlight the importance of dispersal, environmental selection, and eco-evolutionary dynamics as drivers of local and global wetland viral biogeography.

Trait driven or neutral: understanding the change in functional trait diversity during early plant succession using Price partitions

Habitat filtering, species interactions and neutral colonization as well as extinction dynamics govern the sequence of community assembly and functional diversity (FD) during primary plant succession. To study the factors that influence changes in FD we here use data on plant seed size, seed numbers and specific leaf area from 107 study plots along a 7 year sequence of primary succession (2005–2011) in a 6 ha German artificial catchment. We show that the temporal variability in functional diversity can be partitioned into the effects of trait expression, species richness and plant cover. We observed a dominant role of species richness and community composition on FD. Trade-offs in the influence of species richness and plant cover tended to decrease the change in FD. Average FD steadily increased during the first 4 years of succession (2005–2008). The degree of annual changes in FD were highly plot specific. Average change in FD was comparatively low during the first 4 years and later high. Soil characteristics and light conditions did not significantly influence the detectable change in functional diversity. We conclude that the high plot-specific spatial variability of the annual changes in FD transformed the initially catchment-wide homogeneous distribution of plant species into a mosaic of very different local plant communities. Our partitioning results also indicate that the successional sequences in FD are in accordance with a hidden Markov series.

Low impact of forest conversion on biodiversity: Evidence from small mammals in contrasting forests of Mt. Liangshan

AbstractSecondary and plantation forests are the main alternative forests remaining after the deforestation of primary forests. Understanding the conservation value of secondary and plantation forests is important for biological conservation. To explore the impact of forest conversion on biodiversity, we compared multiple diversity metrics (taxonomic, phylogenetic, and functional diversity) and community structure of small mammals in the primary, secondary, and plantation forests in Mt. Liangshan, Sichuan Province, China. Three field surveys were conducted in each of the three forest types to characterize local small mammal assemblages from 2017 to 2020. We found that the taxonomic, phylogenetic, and functional diversity of small mammals in the three forest types were similar at the landscape scale, while all diversity metrics were lowest in the plantation forest and highest in the primary forests at the site scale. The community structure analysis showed that habitat filtering was the dominant process driving the assembly of small mammal communities across the three forest types, and there was no statistically significant difference in small mammal community structure among the three forest types. Our results indicated that secondary and plantation forests in the nature reserves, adjacent to the primary forest and exposed to little human disturbance, also can provide important habitats for small mammals.

Hidden worlds within flowers

There is a growing realization that ecological interactions take place at many scales, from acorns to forests, and that formerly overlooked community members, particularly microbes, can play outsized ecological roles. Beyond their primary function as the reproductive organs of angiosperms, flowers constitute resource-rich, ephemeral habitats teeming with flower-loving symbionts, or 'anthophiles'. The physical, chemical, and structural properties of flowers combine to create a habitat filter, selectively determining which anthophiles can reside there, and how, and when they interact. The microhabitats within flowers can provide shelter from predators or inclement weather, places to eat, sleep, thermoregulate, hunt, mate or reproduce. In turn, floral microhabitats contain the full range of mutualists, antagonists and apparent commensals, whose complex interactions impact how flowers look and smell, how profitable they are to foraging pollinators, and how selection feeds back upon the traits shaping those interactions. Recent studies suggest coevolutionary paths by which floral symbionts might be co-opted as mutualists and provide compelling examples in which ambush predators or florivores are recruited as floral allies. Unbiased studies that include the full roster of floral symbionts are likely to reveal novel links and additional nuance in the rich ecological communities hidden within flowers.

An Integrative Study of Mycobiome in Different Habitats from a High Arctic Region: Diversity, Distribution, and Functional Role.

In the Arctic ecosystems, fungi are crucial for interactions between soil and plants, the cycling of nutrients, and the transport of carbon. To date, no studies have been conducted to thoroughly examine the mycobiome and its functional role in various habitats of the High Arctic region. The aim was to unravel the mycobiome in the nine habitats (i.e., soil, lichen, vascular plant, moss, freshwater, seawater, marine sediment, dung, and marine alga) in the Ny-Ålesund Region (Svalbard, High Arctic) using a high-throughput sequencing approach. A total of 10,419 ASVs were detected. Among them, 7535 ASVs were assigned to unidentified phyla, while the remaining 2884 ASVs were assigned to 11 phyla, 33 classes, 81 orders, 151 families, 278 genera, and 261 species that were known. The distribution of the mycobiome was driven by habitat specificity, indicating that habitat filtering is a crucial factor influencing the fungal assemblages at a local scale in this High Arctic region. Six growth forms and 19 fungal guilds were found. The ecological guild (e.g., lichenized, ectomycorrhizal) and growth form (e.g., yeast, thallus photosynthetic) varied significantly among various habitats. In addition, the occurrence of 31 fungal species that are considered to be potential pathogens was determined. These results will increase our understanding of fungal diversity and its functional significance in this distinctive High Arctic area and thereby establish the groundwork for prediction about how the mycobiome will alter in various environments as a result of anticipated climate change.

From river to ocean: Connectivity and heterogeneity of aquatic ecosystems depicted by planktonic microeukaryotes

Understanding how the diverse habitats incubated a high diverse biosphere is a core question for biodiversity conservation. Community assembly of organisms in connected but different habitats could provide insight into this issue. As an important group of plankton, microeukaryotes are widely distributed in aquatic habitats and are sensible to ecological conditions. However, how the distribution of planktonic microeukaryotes from river to ocean are shaped by habitat connectivity and heterogeneity remains unclear. In order to assess the connectivity and heterogeneity of aquatic habitats, environmental DNA sequencing was used to profile the planktonic microeukaryotic communities in typical habitats throughout the major rivers, estuaries, coastal waters, and ocean of China, covering a geographic distance of 3530 km. The hypothesized “freshwater species pool (FSP)” and “marine species pool (MSP)” of planktonic microeukaryotes were confirmed by their significant dissimilarities in community composition. The planktonic microeukaryotic communities completed turnover of FSP-pattern and MSP-pattern within salinity range of 5–15 in estuaries of the river-to-ocean continuum. In this scale covering fresh and salty waters, the community assembly of planktonic microeukaryotes was driven primarily by habitat filtering rather than salinity nor geographic distance. Four types of habitat, i.e., river, estuary, tidal zone, and ocean, were outlined by their planktonic microeukaryotic communities, which depicted the habitat heterogeneity in this continuum. As to the constructive species in these habitats, 98.1 % of them were shared between at least two types of habitat and 41.3 % of them shared among all habitats. These shared constructive species depicted the habitat connectivity of aquatic ecosystems from river to ocean. The findings suggest that the assessment of planktonic microorganism assemblages is a potential approach to indicate habitat diversity in connected aquatic ecosystems.