Variation In Species Composition Research Articles

Validation and development of eDNA metabarcoding primers for comprehensive assessment of Chinese amphibians.

Environmental DNA (eDNA) metabarcoding has emerged as a powerful, non-invasive tool for biodiversity assessments. However, the accuracy and limitations of these assessment techniques are highly dependent on the choice of primer pairs being used. Although several primer sets have been used in eDNA metabarcoding studies of amphibians, there are few comparisons of their reliability and efficiency. Here, we employed lab- and field-tested sets of publicly available and de novo-designed primers in amplifying 83 species of amphibian from all three orders (Anura, Caudata, and Gymnophiona) and 13 families present in China to evaluate the versatility and specificity of these primers sets in amphibian eDNA metabarcoding studies. Three pairs of primers were highly effective, as they could successfully amplify all the major clades of Chinese amphibians in our study. A few non-amphibian taxa were also amplified by these primers, which implies that further optimization of amphibian-specific primers is still needed. The simultaneous use of three primer sets can completely cover all the species obtained by conventional survey methods and has even effectively distinguished quite a number of species (n = 20) in the Wenshan National Nature Reserve. No single primer set could individually detect all of the species from the studied region, indicating that multiple primers might be necessary for a comprehensive survey of Chinese amphibians. Besides, seasonal variations in amphibian species composition were also revealed by eDNA metabarcoding, which was consistent with traditional survey methods. These results indicate that eDNA metabarcoding has the potential to be a powerful tool for studying spatial and temporal community changes in amphibian species richness.

Multi-year three-dimensional simulation of seasonal variation in phytoplankton species composition in a large shallow lake

Lake Erie has been negatively impacted by multiple stressors, including nutrient enrichment and climate change, that have exacerbated eutrophication and harmful algal blooms. Management of these long-term water quality problems requires numerical models that can be run over years to decades. The three-dimensional hydrodynamics and biogeochemistry models applied to date, however, have not been tested for continuous runs longer than one year and have not been shown to accurately reproduce seasonal variation in phytoplankton species composition (e.g., the development of harmful algal blooms) over decadal timescales. We simulated the three-dimensional nutrient and phytoplankton concentrations in western Lake Erie continuously from 2002 to 2014. Using a single parameter set, we were able to reproduce both seasonal and inter-annual variation in phytoplankton species composition. The model qualitatively reproduced the observed seasonal succession (i.e., variation in phytoplankton species composition), including the spring diatom bloom and late summer cyanobacterial growth. This study demonstrates that three-dimensional models can be applied for multi-year simulations of nutrients and phytoplankton to inform large lake research and management.

Above Ground Biomass and Carbon Sequestration of Urban Green Spaces in Danang City, Vietnam

Green space in cities is an essential component of the urban environment. Different forms of urban green spaces, with varying populations, plant communities, and roles, offer varying urban ecological advantages. Using the i-Tree Eco model, this study examined the structural characteristics of urban green trees and calculated the biomass storage capacity and carbon sequestration in urban green spaces in Da Nang City. The results revealed a considerable diversity of species composition among 7,513 trees belonging to 42 species of 20 families studied in four types of green spaces, with Terminalia catappa, Cyrtostachys renda, and Roystonea regia dominating. The average Shannon biodiversity index was 2.9, with the institution having the highest at 2.6 and the park having the lowest at 2.2. The total leaf biomass per hectare was 588.0 kg/ha, and the carbon sequestration rate was 2,845.30 kg/ha. Ficus subpisocarpa was the species with the highest value for these two advantages, and the park was the green space with the highest benefit in terms of biomass and carbon sequestration.

Determinants of taxonomic, functional, and phylogenetic beta diversity in breeding birds within urban remnant woodlots: Implications for conservation.

Examining beta diversity of animal assemblages in fragmented habitats, which measures variation in species composition among different fragments, is important for understanding the impact of habitat fragmentation on biodiversity. However, relying solely on taxonomic composition may not provide a comprehensive understanding. Incorporating measures of functional and phylogenetic diversities is essential for elucidating the ecological mechanisms underlying changes in community composition. In addition, prevailing studies often prioritize the evaluation of landscape characteristics within fragments as determinants of beta diversity, neglecting differences in habitat type and plant community composition. In this study, we surveyed birds in 26 remnant woodlot patches (ranging from 0.3 to 290.4 ha) in an urban landscape, southwest China, during the breeding season from 2017 to 2022. We recorded 70 bird species (excluding those recorded only once and high-flying birds, including raptors, swallows, and swifts), with the number of species per patch varying from 14 to 56. The overall bird taxonomic and phylogenetic beta diversities were primarily contributed by the turnover component, while functional beta diversity was dominated by the nestedness-resultant component. Patch area and perimeter area ratio significantly influenced the taxonomic, functional, and phylogenetic beta diversities, primarily mediated through the nestedness-resultant component, while inter-patch distance had a significant effect via the turnover component. In addition, there was a considerable correlation of bird taxonomic, functional, and phylogenetic beta diversities with habitat type and woody plant beta diversities, including their respective partitioned turnover and nestedness-resultant components. Our results suggest that bird assemblages in these patches may be regulated by selective extinction, interspecific competition, and environmental filtering. The findings have significant implications for sustainable landscape planning and habitat restoration. Conserving habitat patches of different sizes and maintaining or enhancing habitat heterogeneity between patches can facilitate the persistence of metacommunities.

Environmental DNA recovers fish composition turnover of the coral reefs of West Indian Ocean islands.

Islands have been used as model systems to study ecological and evolutionary processes, and they provide an ideal set-up for validating new biodiversity monitoring methods. The application of environmental DNA metabarcoding for monitoring marine biodiversity requires an understanding of the spatial scale of the eDNA signal, which is best tested in island systems. Here, we investigated the variation in Actinopterygii and Elasmobranchii species composition recovered from eDNA metabarcoding along a gradient of distance-to-reef in four of the five French Scattered Islands in the Western Indian Ocean. We collected surface water samples at an increasing distance from reefs (0 m, 250 m, 500 m, 750 m). We used a metabarcoding protocol based on the 'teleo' primers to target marine reef fishes and classified taxa according to their habitat types (benthic or pelagic). We investigated the effect of distance-to-reef on β diversity variation using generalised linear mixed models and estimated species-specific distance-to-reef effects using a model-based approach for community data. Environmental DNA metabarcoding analyses recovered distinct fish species compositions across the four inventoried islands and variations along the distance-to-reef gradient. The analysis of β-diversity variation showed significant taxa turnover between the eDNA samples on and away from the reefs. In agreement with a spatially localised signal from eDNA, benthic species were distributed closer to the reef than pelagic ones. Our findings demonstrate that the combination of eDNA inventories and spatial modelling can provide insights into species habitat preferences related to distance-to-reef gradients at a small scale. As such, eDNA can not only recover large compositional differences among islands but also help understand habitat selection and distribution of marine species at a finer spatial scale.

Larval dynamics suggest phenological strategies and positive effect of marine protected areas controlling indigenous and non-indigenous crab populations

The early life of most decapod crustaceans takes place in the water column as larvae before they settle in benthic habitats. The spatial and temporal variability in the settling of larval stages offers valuable insights into the potential recruitment of natural populations. To explore this, we studied megalopa assemblages at various segments of coastline on El Hierro and Lanzarote islands, both within and outside the Marine Protected Areas (MPAs) of each island. The study spanned four consecutive oceanographic periods in the Canary Islands (NW Africa), employing light traps for sample collection. The low number of recorded species suggested that light traps exhibit selectivity, particularly for megalopae belonging to Portunidae and Grapsidae. El Hierro, which experienced warmer sea surface temperatures, displayed higher megalopa abundance values than Lanzarote and distinct larval assemblages was observed between these two islands. Similarly, we identified significant variations in abundance and species composition between stratified and mixing seasons. These seasonal differences were influenced by the dominance of Achelous hastatus, Percnon gibessi, and Cronius ruber during the stratified season. In Lanzarote, C. ruber was not recorded during the mixing season, suggesting that the colder conditions there may constrain its reproduction. Interestingly, we observed that species traditionally harvested from the intertidal zone for human consumption (Plagusia depressa) or used as bait for recreational fishing (Pachygrapsus spp. and P. gibessi) exhibited higher megalopa abundances within the MPAs. In contrast, we noted lower megalopa densities of the non-indigenous species C. ruber within the protected areas. These results indicate a positive effect of MPAs controlling indigenous and non-indigenous crab populations. Moreover, the study provides novel data, showing that light traps are suitable for monitoring the temporal occurrence, abundance, and spatial distribution of non-indigenous and commercially exploited species. This is key for adopting an ecosystem-based approach to manage marine resources.

Seasonal species composition, abundance and public health importance of mosquito vectors (Diptera: Culicidae) in Huai Tha Khoei Reservoir, Ratchaburi, Thailand

Abstract. Chaiphongpachara T, Laojuna S. 2024. Seasonal species composition, abundance and public health importance of mosquito vectors (Diptera: Culicidae) in Huai Tha Khoei Reservoir, Ratchaburi, Thailand. Biodiversitas 25: 1264-1275. Mosquitoes are vectors for pathogens that cause life-threatening diseases in humans and animals. Significant mosquito-borne diseases include malaria, dengue, chikungunya, Zika, Japanese encephalitis, and filariasis. Anthropogenic environmental changes can significantly impact the dynamics of disease vector populations, which can lead to outbreaks of mosquito-borne diseases. This study investigated the seasonal variation in species composition and abundance of mosquito vectors around the Huai Tha Khoei Reservoir in Ratchaburi Province, Thailand, across cool, hot, and rainy seasons. A total of 1363 mosquitoes, representing 30 species from five genera, were collected. In particular, 25 of these species, accounting for 83.33% of the total, were identified as vectors of human pathogens. The most dominant species across all seasons was Culex tritaeniorhynchus Giles 1901, representing 39.47% (n=538) of the total, followed by Anopheles barbirostris Wulp 1884 s.l. (14.38%, n = 196) and Culex vishnui Theobald 1901 (9.02%, n=123). The Shannon diversity index was highest during the rainy season (H’= 2.144) and lowest in the hot season (H’=1.788). This is consistent with the results of the UPGMA tree based on beta diversity, indicating that mosquito diversity in the rainy season differs significantly from that in the cool and hot seasons. The findings enhance our understanding of the impact of seasonality on mosquito vectors in this region, which is crucial for developing effective disease control strategies. Additionally, this study serves as a valuable reference for understanding the diversity of mosquito vectors in other areas.

Beta diversity and regionalization of the western Atlantic marine biota

AbstractAimUnderstanding the factors determining marine community variations is important for biogeography and conservation. Beta diversity is a metric for mapping species composition variations between communities and regionalizing biota. Ecoregions are commonly used for regionalization, but their empirical testing has been limited. Our aim is to map marine species composition variations in the Western Atlantic, identify variables related to these variations, and regionalize areas based on community distribution. Additionally, we test whether currently proposed ecoregions represent unique biota units and specific environmental conditions.LocationWestern Atlantic Ocean.TaxonVertebrates, invertebrates and algae.MethodsWe constructed a large marine biodiversity database, including vertebrates, invertebrates, and algae, totalling over 4 million records. We used the generalized dissimilarity model (GDM) to identify variables most related to species composition variations and map beta‐diversity variations. We employed an unsupervised classifier for community regionalization. To test if the ecoregion regionalization boundaries are corroborated by species distribution data, we used the Sørensen index. To assess if ecoregions correspond to environmental units, we checked if areas had distinct environmental conditions using a PCA of 134 marine environmental variables.ResultsThe GDM explained a high variation in species composition, 61% in the complete database. Analysing vertebrates, invertebrates and algae separately also yielded relatively high results: 46%, 54%, and 33%, respectively. Coastal areas differed from open sea areas in composition. Environmental variables combined better explained beta diversity than isolated variables. The regionalization based on GDM was not congruent with ecoregion boundaries. Moreover, ecoregions showed no distinction in species composition or environmental conditions.Main ConclusionsThis study's regionalization is crucial for marine biodiversity conservation, focusing on understanding species composition patterns between coastal and open sea areas to develop tailored conservation strategies. Despite sampling limitations, the study advances marine biogeography knowledge by analysing over 4 million species records and 134 environmental variables. This comprehensive approach enhances understanding marine species distribution and diversity and aiding the development of effective conservation measures.

The Impact of Canopy on Nutrient Fluxes through Rainfall Partitioning in a Mixed Broadleaf and Coniferous Forest

Rainfall constitutes the primary input in the nutrient flux within forest ecosystems. The forest canopy modulates this flux by partitioning rainfall and selectively absorbing or adding nutrients. In mixed forests, variation in tree species composition regulates rainwater chemical composition, potentially leading to spatial heterogeneity in nutrient distribution and influencing nutrient cycling processes. This study examined the partitioning of rainfall into throughfall and stemflow, as well as their associated nutrient concentrations and fluxes, in a mixed broadleaf and coniferous forest on Changbai Mountain in Northeast China. We observed a rising trend in nutrient contents from rainfall to throughfall and then stemflow. The nutrient contents of stemflow varied largely with tree species due to the differences in canopy structure and bark morphological characteristics. The nutrient input contributed by throughfall and stemflow was 92.30 kg ha−1 during the observation period, and most elements underwent passive leaching through washout except for F− and Na+. We note that the nutrient fluxes in stemflow differed among tree species, with Pinus koraiensis (PK) delivering more acid group anions and Quercus mongolica (QM) providing more cations. Our research provides new insights into nutrient cycling within mixed forest canopies, sparking a transformative advancement in forest management and protection strategies through hydrochemistry-driven solutions.

Seagrass Biodiversity and its Drivers in the Kepulauan Banyak Marine Nature Park, Indonesia

Seagrasses are important marine plants that provide a variety of ecosystem services, including food and shelter for marine life, and protection from coastal erosion. This study investigated the biodiversity (alpha and beta diversity) of seagrass in the Kepulauan Banyak Marine Nature Park, Indonesia, with a specific focus on eight sites. Alpha diversity was calculated using Shannon's index, Simpson's index, and Pielou evenness. Beta diversity was determined using Bray-Curtis dissimilarity and Jaccard dissimilarity allowing us to examine the variations in species composition among different sites. Principal coordinate analysis and Partial distance-based redundancy analysis was used to visualize and investigate the impact of constraint variables to the structure of the seagrass communities. Alpha diversity varied among the sites, with the highest alpha diversity found at the Orongan and Matahari site and the lowest at the Ujung Lolok and Balai sites. The dominant substrate type (mud or sand) was found to be a significant (P≤ 0.01) determinant of seagrass alpha diversity, with mud substrates supporting higher diversity than sand substrates. The relationship between alpha diversity and constrain variables was only significant with closest distance to forest lost and longitude variables. The analysis found that water pH, closest distance to forest lost, mean distance to tourism spots, and closest distance to settlement collectively explained a significant (P≤ 0.001) portion (88.48%) of the variation in beta diversity of seagrass across the sites. The results of this study can be used to develop management strategies for the conservation of seagrass meadows in the park.

Elevation modulates the impacts of climate change on the Brazilian Cerrado flora

AbstractAimClimate change is causing species distribution to shift across the globe. Lowland taxa are moving upslope with warming, while montane species face extinction. We tested the hypothesis that elevation controls the future distribution of plant species in the Brazilian Cerrado, home of 3.5% of the Earth's flowering plants (c. 5000 endemic species) in just 0.4% of the planet's land surface.LocationCerrado region in Brazil.MethodsWe estimated geographical range shifts of 7398 angiosperm species by 2040 using species distribution models (SDMs). We stacked the SDMs to derive the temporal variations of species richness and composition over the Cerrado.ResultsOur results show that between 50 and 52% of the Cerrado flora will experience net range loss due to climate change. While montane species were more likely to lose range, range gain was more common among lowland taxa. We estimate that 68–73% of the Cerrado extent will face net species losses by 2040. Net species loss was more likely to occur below 743–798 metres above sea level. Virtually the entire Cerrado will experience some level of species replacement due to climate change and species turnover will intensify as elevation increases.Main ConclusionsOur findings suggest that upslope migration allows lowland plants to track climate change (‘winners’), whereas montane taxa do not (‘losers’). As species move upslope, lowlands become local extinction hotspots and mountains harbour novel plant assemblages. Therefore, elevation exerts a central role in shaping Cerrado flora responses to climate change and potentially the long‐term efficacy of conservation and restoration efforts.

Phytoplankton species composition as bioindicator in the largest fragmented channel of the Pearl River, China.

To test the serial discontinuity concept (SDC) predictions in a regulated river ecosystem, environmental parameters and phytoplankton community structure were determined in a subtropical river (China) which was regulated by 11 cascade dams. Our results showed that total phosphorus (TP) and silicate during the wet period in several dams supported the SDC predictions. Variations of phytoplankton species composition in several cascade dams, such as Datengxia (DTX) and Changzhou (CZ), also supported the SDC predictions. Moreover, the stations near the dams showed the maximum or minimum values of total species numbers in each cascade segment. Predictive model indicated that the types of phytoplankton decreased in the middle reaches, conforming to SDC predictions. In the whole system of cascading dams, an increase in silicate concentration and phytoplankton communities in the downstream was also consistent with SDC predictions. Therefore, these findings aligned with the SDC predictions in the aspects of both single dam and whole cascade dam system to some extent. In future research, our aim is to further investigate the effects of cascade damming on additional phytoplankton-related indices in this aquatic ecosystem. We hope to gather more comprehensive data to fully validate the SDC predictions.

Patterns of variability of species composition of catches from the russian fishing vessels in the south-eastern Pacific ocean for 2015–2022

The work provides information on the patterns of species composition of catches from the Russian fishing vessels conducted fishing of jack mackerel (Trachurus murphyi Nichols 1920), chub mackerel (Scomber japonicus Houttuyn 1782) and redbait (Emmelichthys spp.) in the South-Eastern Pacific Ocean outside the economic zones of the coastal States. According to scientific observations, an analysis of the composition of species caught by the Russian fishing vessels is given. When fishing in the pelagic zone over ocean depths, jack mackerel was the main target species, chub mackerel formed the bycatch. At the same time, the proportion of chub mackerel in catches in the northern parts was higher than in the southern ones. When fishing on seamounts of the Nazca Ridge, catches were dominated by redbait with jack mackerel and alfonsino (Beryx splendens Lowe, 1834) as bycatch. According to the similarity of the species composition of catches, three areas – 1) all the Southern and Central subareas and part of the Northern subarea; 2) seamounts of Nazca ridge; 3) part of the Northern subarea near the border of the EEZ of Peru between 17–20°S, were singled out using the cluster analysis method.

Spatiotemporal patterns of microclimatic buffering in relict alpine communities

AbstractQuestionsIn alpine landscapes, topography creates a mosaic of microclimatic niches that might prevent local extinctions, but the influence of this spatial heterogeneity on plant communities is largely unknown. Here we ask (1) how soil microclimatic variation is comparable at temporal and spatial scales, and (2) how such variation influences species composition and local extinctions in relict alpine communities.LocationPicos de Europa National Park, northern Spain.MethodsWe resurveyed permanent plots in four alpine sites following the recording of soil temperatures (temporal survey) for 10 years. We then sampled the spatial variation in species composition and microclimatic temperatures in 80 plots around the permanent plots (spatial survey). We evaluated the variation of six microclimatic indices between the temporal and the spatial surveys, and calculated the temporal trends observed in species cover. We finally predicted local extinction rates under microclimatic scenarios based on the observed microclimate–community relations.ResultsDespite high interannual variation, we found a 10‐year trend of temperature warming on (microridge) fellfields and (microvalley) snowbeds. Microclimatic variation was larger in space than in time, with little temperature variation in snowbeds and extreme low temperatures recorded in fellfields. Species composition was mainly influenced by growing degree days (GDD) and freezing degree days (FDD), which were both related to snow cover duration. Plant cover of 16 species (out of 36 frequent species) showed significant responses to microclimatic variation. Local extinctions were mainly predicted under relatively hotter and more freezing conditions.ConclusionsOur results support the idea that microclimatic spatial heterogeneity can reduce the negative influence of climate change on alpine plant communities. However, a continuous reduction of snow cover will result in a tipping point beyond which the buffer effect of this spatial heterogeneity will not be effective in protected microsites, leading to community homogenization. This process may have started in relict alpine communities where species from snowy microclimates are being outcompeted by species adapted to below‐zero winter temperatures.

Effects of the diet enrichment with β-glucan, sodium salt of butyric acid and vitamins on growth parameters and the profile of the gut microbiome of juvenile African catfish (Clarias gariepinus)

This study assessed the effect of the addition of active substances, i.e., β-glucan, sodium butyrate and vitamins (C, A, D3, E, K) to the diet of juvenile African catfish (Clarias gariepinus) on growth parameters and the intestinal microbiome. For this purpose, a four-week rearing of juveniles African catfish in a recirculating aquaculture system (RAS) under controlled conditions at 25°C was conducted. The fish were fed commercial feed (control group - C), which was enriched with various levels of sodium butyrate and β-glucan (FQV1 – FQV4). After the experiment, growth parameters such as weight gain (WG; g), length gain (LG; cm), specific growth rate (SGR; % d−1), condition factor (K) survival rate (SR; %) and cannibalism factor (CF; %) were determined. The profile of the intestinal microbiome was also determined using Next-Generation Sequencing (NGS) based on the analysis of the 16 S rRNA subunit. The obtained results indicated that feed supplementation with active substances in appropriate doses had a positive effect on the growth parameters of tested fish. Compared to the control group, statistically significant differences were obtained in WG (C - 7.62 g; FQV3 - FQV1 respectively 12.2–16.65 g), in WL (C - 6.23 cm; FQV3 - FQV1 respectively 7.59–8.74 cm), in SGR (C - 4.7%/d; FQV3 – V1 respectively 12.20 – 16.65 g), in K (C – 0.76; V3 – FQV4 respectively 0.80 – 0.84) (P <0.05). In addition, the control group had the highest value of CF (8.0%) compared to the research groups (P <0.05). The values of α-diversity metrics did not show statistically significant differences. However, the number of unique amplicon sequence variants (ASVs) in research groups confirmed that enriching the diet with the active substances increases the biodiversity of intestinal microbiome (C - 203; FQV4 - 373). In research groups and the control group, Firmicutes and Proteobacteria dominated, additionally, an increased number of beneficial lactic acid bacteria (LAB) of the Lactococcus and Bacillus genus was observed, while the number of potentially pathogenic bacteria of the Candidatus genus was reduced (P <0.05). Principal coordinate analysis (PCoA) determining β-diversity showed that the FQV3 was characterized by varied species composition compared to the other groups. The obtained results showed that a carefully selected composition of active ingredients used in the diet of juvenile African catfish has a beneficial effect on the profile and biodiversity of the intestinal microbiome, which indirectly improves resistance to infections and increases breeding indicators.

Beyond salinity: Plants show divergent responses to soil ion composition

AbstractAimIn salt‐affected environments, salinity shapes ecosystem functions and species composition. Apart from salinity, however, we know little about how soil chemical factors affect plant species. We hypothesized that specific ions, most of which contribute to salinity, co‐determine plant niche differentiation. We asked if the importance of ions differs for species with (halophytes) and without (associated species) physiological adaptations to saline soils.LocationCarpatho‐Pannonian region (Central and Eastern Europe).Time period2005–2021.Major taxa studiedVascular plants.MethodsWe recorded species occurrences and collected soil samples in 433 plots in saline habitats. We measured pH, salinity (electrical conductivity), and concentrations of Ca2+, K+, Mg2+, Na+, SO42− Cl−, CO32− and mineral nitrogen (mN) and calculated the sodium adsorption ratio (SAR). For 88 species, we fitted response curves with Huisman–Olff–Fresco (HOF) models. To study ions' effects on species composition and ions' variance, we compared unconstrained and constrained ordinations and performed a principal component analysis. We used random forests to analyse the importance of ions for individual species and created two‐dimensional species niche plots for key ions.ResultsIon concentration niches varied among species and did not necessarily correspond to soil salinity or alkalinity. We frequently observed monotonic, sigmoidal model responses, while skewed unimodal responses were rare. Ions explained a considerable proportion of species compositional variation. Particularly, Na+, SO42−, Cl−, and CO32− contributed to the ions' variance. Na+, followed by SO42−, Cl−, CO32−, Ca2+, Mg2+, and mN, was most important for the occurrence of individual species. Compared to associated species, Na+, SO42−, and mN were significantly less important for halophytes, whereas Cl− and CO32− played a significant role.Main conclusionsWe show that ion composition co‐determines niche differentiation in saline soils, suggesting evolved physiological adaptations in halophytes. Our study calls for incorporating high‐resolution data on soil ion composition in ecological research.

Weed infestation of narrow-leaved lupine crops in grain-grass-rowed crop rotation in the North-West of Russia

The results of the long term (2012–2018) study of weed infestation of green fallow fields with narrow-leaved lupin in the crop rotation including cereals, grasses and row crops in the North-West region of Russia (Leningrad region) are presented. The assessment of weediness in the narrow-leaved lupine variety Oligarch crops was carried out annually at 24 permanent survey sites (0.1 square meter). Based on the results of the surveys, the formation of a diverse and constant species composition of weeds (from 15 to 25 species), mainly of medium and severe degree of weediness (141–593 specimens per square meter), with the proportion of young plants ranging from 90.4 to 99.7 %. The mass species of weeds were lamb’s quarters, field pansy, corn spurry, hemp-nettles, fumitory, shepherd’s purse, prevalent perennial weeds were field sowthistle, coltsfoot, red sorrel, couch grass, marsh woundwort. The prevailing influence of weather conditions and individual characteristics on the weed infestation of narrow-leaved lupine crop has been determined. The combined effect of two factors was expressed by 47.7, 57.8 and 47.1 % in terms of species abundance, initial abundance and final phytomass of weeds, respectively. Long term application of mineral fertilizers led to an increase in the number of annuals (by 1.5–1.6 times) and a decrease in the density of growth of perennial weed species (by 1.6–1.9 times). The influence of the integrated plant protection system used in the crop rotation was manifested in a significant decrease in the density of perennial weed species (by 4.6 times) in narrow-leaved lupine crop.

Synthesis reveals approximately balanced biotic differentiation and homogenization.

It is commonly thought that the biodiversity crisis includes widespread declines in the spatial variation of species composition, called biotic homogenization. Using a typology relating homogenization and differentiation to local and regional diversity changes, we synthesize patterns across 461 metacommunities surveyed for 10 to 91 years, and 64 species checklists (13 to 500+ years). Across all datasets, we found that no change was the most common outcome, but with many instances of homogenization and differentiation. A weak homogenizing trend of a 0.3% increase in species shared among communities/year on average was driven by increased numbers of widespread (high occupancy) species and strongly associated with checklist data that have longer durations and large spatial scales. At smaller spatial and temporal scales, we show that homogenization and differentiation can be driven by changes in the number and spatial distributions of both rare and common species. The multiscale perspective introduced here can help identify scale-dependent drivers underpinning biotic differentiation and homogenization.

Effect of environmental factors on seminal microbiome and impact on sperm quality.

This review provides a comprehensive overview of the existing research on the seminal microbiome and its association with male infertility, while also highlighting areas that warrant further investigation. A narrative review was conducted, encompassing all relevant studies published between 1980-2023 on the male reproductive tract microbiome in humans. This review considered studies utilizing culture-based, polymerase chain reaction (PCR)-based, and next-generation sequencing (NGS)-based methodologies to analyze the microbiome. Data extraction encompassed sample types (semen or testicular tissue), study designs, participant characteristics, employed techniques, and critical findings. We included 37 studies comprising 9,310 participants. Among these, 16 studies used culture-based methods, 16 utilized NGS, and five employed a combination of methods for microorganism identification. Notably, none of the studies assessed fungi or viruses. All NGS-based studies identified the presence of bacteria in all semen samples. Two notable characteristics of the seminal microbiome were observed: substantial variability in species composition among individuals and the formation of microbial communities with a dominant species. Studies examining the testicular microbiome revealed that the testicular compartment is not sterile. Interestingly, sexually active couples shared 56% of predominant genera, and among couples with positive cultures in both partners, 61% of them shared at least one genital pathogen. In couples with infertility of known causes, there was an overlap in bacterial composition between the seminal and vaginal microbiomes, featuring an increased prevalence of Staphylococcus and Streptococcus genera. Furthermore, the seminal microbiome had discernible effects on reproductive outcomes. However, bacteria in IVF culture media did not seem to impact pregnancy rates. Existing literature underscores that various genera of bacteria colonize the male reproductive tract. These organisms do not exist independently; instead, they play a pivotal role in regulating functions and maintaining hemostasis. Future research should prioritize longitudinal and prospective studies and investigations into the influence of infertility causes and commonly prescribed medication to enhance our understanding of the seminal microbiota's role in reproductive health.

Factors acting on the floristic variability of the arboreal stratum: a review for the atlantic forest biodiversity hotspot

This study highlights the main factors influencing the distribution and composition of tree species in the Atlantic Forest. It aims to understand the influence of climatic factors in shaping composition patterns, as well as the influence of soil, topography and other environmental factors on the structure and dynamics of this biodiversity hotspot. The results of this systematic review revealed the important contribution of climatic factors such as rainfall and temperature to floristic differentiation in different regions of the Atlantic Rainforest. Edaphic and topographic factors, such as soil pH, soil water stress and altitude, also made important contributions to the distribution of tree species, both locally and on larger scales. Another component identified in the research was the complex interaction of environmental and spatial factors in composition patterns. This is a very recurrent component in the Atlantic Forest, due to latitudinal and longitudinal gradients, where specific ecological conditions create different niches for species. Despite advances, much of the variation in tree species composition remains unexplained, suggesting the existence of unknown factors or limitations in current analytical methods. Thus, this study highlights the need to further explore knowledge about the impact of climate change and anthropogenic activities on Atlantic Forest fragments. In addition, it suggests identifying new determinants and understanding the intrinsic interactions between vegetation and biotic predictors to aid effective management and conservation strategies for this unique and threatened ecosystem.