Community Functional Diversity Research Articles

Soil Microbial Biomass and Functional Diversity of Microbial Communities in Native and Arable Soils of the Belogor’e Reserve

Soil Microbial Biomass and Functional Diversity of Microbial Communities in Native and Arable Soils of the Belogor’e Reserve

Atlantic Forest birds are more functionally and taxonomically diverse in valley bottoms relative to uplands

The theory behind metacommunity was recently reframed to incorporate the concepts of community ecology. Here we investigate how slight topographic variations might locally create habitat heterogeneity and a system of interchanging bird species (i.e., a metacommunity) in a continuous tropical forest. We studied the distribution of birds in a large and protected Neotropical Forest in southwestern Brazil to understand the influence of valley bottom sites on the taxonomic and functional diversity of the bird communities. As previous studies have shown that specialist species have spatially regular distribution when compared to generalists, in the present study we investigate if topography could influence those local patterns of distribution. We expected (1) to find higher taxonomic and functional diversity in communities of valley bottom areas and (2) lower beta taxonomic and functional diversity of the generalists at the valley bottom, but not of specialists, that should exhibit a somewhat consistent distribution. We gathered information on the composition of local bird communities by deploying eight automatic recording units, four in the valley bottoms and four in the uplands, along 4.3 km trail in the forest interior. Our data showed that bird diversity at the valley bottoms tended to be higher than that at the uplands. Specialist passerine assemblages presented high spatial stability and were regularly distributed throughout the forest. In contrast, generalist passerines have limited trait distribution due to valley bottoms. Because bird communities were distinct from each other, deforestation should have stronger impact in the system if only upland areas are left in the landscape. In this case, species dispersal and coexistence as well as complementary traits have predicted implications for the remaining forest fragments, and management actions should prioritize the conservation of forest fragments that include both bottom valleys and uplands areas.

Bacterial Communities in the Rhizosphere at Different Growth Stages of Maize Cultivated in Soil Under Conventional and Conservation Agricultural Practices.

ABSTRACTFarmers in Mexico till soil intensively, remove crop residues for fodder and grow maize often in monoculture. Conservation agriculture (CA), including minimal tillage, crop residue retention and crop diversification, is proposed as a more sustainable alternative. In this study, we determined the effect of agricultural practices and the developing maize rhizosphere on soil bacterial communities. Bulk and maize (Zea mays L.) rhizosphere soil under conventional practices (CP) and CA were sampled during the vegetative, flowering and grain filling stage, and 16S rRNA metabarcoding was used to assess bacterial diversity and community structure. The functional diversity was inferred from the bacterial taxa using PICRUSt. Conservation agriculture positively affected taxonomic and functional diversity compared to CP. The agricultural practice was the most important factor in defining the structure of bacterial communities, even more so than rhizosphere and plant growth stage. The rhizosphere enriched fast growing copiotrophic bacteria, such as Rhizobiales, Sphingomonadales, Xanthomonadales, and Burkholderiales, while in the bulk soil of CP other copiotrophs were enriched, e.g., Halomonas and Bacillus. The bacterial community in the maize bulk soil resembled each other more than in the rhizosphere of CA and CP. The bacterial community structure, and taxonomic and functional diversity in the maize rhizosphere changed with maize development and the differences between the bulk soil and the rhizosphere were more accentuated when the plant aged. Although agricultural practices did not alter the effect of the rhizosphere on the soil bacterial communities in the flowering and grain filling stage, they did in the vegetative stage.IMPORTANCE We studied the effect of sustainable conservation agricultural practices versus intensive conventional ones on the soil microbial diversity, potential functionality, and community assembly in rhizosphere of maize cultivated in a semiarid environment. We found that conservation agriculture practices increased the diversity of soil microbial species and functions and strongly affected how they were structured compared to conventional practices. Microbes affected by the roots of maize, the rhizobiome, were different and more diverse than in the surrounding soil and their diversity increased when the plant grew. The agricultural practices affected the maize rhizobiome only in the early stages of growth, but this might have an important impact on the development of maize plant.

Metagenomic Views of Microbial Communities in Sand Sediments Associated with Coral Reefs.

Reef sediments, the home for microbes with high abundances, provide an important source of carbonates and nutrients for the growth and maintenance of coral reefs. However, there is a lack of systematic research on the composition of microbial community in sediments of different geographic sites and their potential effect on nutrient recycling and health of the coral reef ecosystem. In combination of biogeochemical measurements with gene- and genome-centric metagenomics, we assessed microbial community compositions and functional diversity, as well as profiles of antibiotic resistance genes in surface sediments of 16 coral reef sites at different depths from the Xisha islands in the South China Sea. Reef sediment microbiomes are diverse and novel at lower taxonomic ranks, dominated by Proteobacteria and Planctomycetota. Most reef sediment bacteria potentially participate in biogeochemical cycling via oxidizing various organic and inorganic compounds as energy sources. High abundances of Proteobacteria (mostly Rhizobiales and Woeseiales) are metabolically flexible and contain rhodopsin genes. Various classes of antibiotic resistance genes, hosted by diverse bacterial lineages, were identified to confer resistance to multidrug, aminoglycoside, and other antibiotics. Overall, our findings expanded the understanding of reef sediment microbial ecology and provided insights for their link to the coral reef ecosystem health.

Functional diversity and species diversity in flooded and unflooded tropical forests

Functional diversity and species diversity provide information to understand differences between plant communities from a contrasting environment and the complementary on regional scale. Environmental variation determines which plants can persist in the community via species sorting processes; forest exposed to extended inundation each year has shown divergence in plant community composition, structure, and functional diversity, compared with unflooded dense forest. Here, we researched flooded and unflooded forests in the upper Magdalena River Valley (Colombia) to quantify and compare the plant species diversity and plant functional diversity. We calculated three components of functional diversity (i.e., functional richness, functional evenness, and functional divergence), we also used a measure of functional richness weighted by species abundance. Our results show that the plant community in the unflooded forest has higher stem density and lower basal area than flooded forests. Also, we show that tree communities in the flooded forests had higher specific leaf area, but lower wood density, suggesting an acquisitive resource strategy. Species diversity and functional diversity were higher in the plant community from the unflooded forest. Our findings of the functional traits and the functional diversity components reinforce the idea that the variation between flooded and unflooded forests is going beyond the species list in the plant communities. However, it is still unclear whether any general patterns exist regarding differences between flooded and unflooded tropical forests.

Soil pH: a key edaphic factor regulating distribution and functions of bacterial community along vertical soil profiles in red soil of pomelo orchard

BackgroundSoil microbes exist throughout the soil profile and those inhabiting topsoil (0–20 cm) are believed to play a key role in nutrients cycling. However, the majority of the soil microbiology studies have exclusively focused on the distribution of soil microbial communities in the topsoil, and it remains poorly understood through the subsurface soil profile (i.e., 20–40 and 40–60 cm). Here, we examined how the bacterial community composition and functional diversity changes under intensive fertilization across vertical soil profiles [(0–20 cm (RS1), 20–40 cm (RS2), and 40–60 cm (RS3)] in the red soil of pomelo orchard, Pinghe County, Fujian, China.ResultsBacterial community composition was determined by 16S rRNA gene sequencing and interlinked with edaphic factors, including soil pH, available phosphorous (AP), available nitrogen (AN), and available potassium (AK) to investigate the key edaphic factors that shape the soil bacterial community along with different soil profiles. The most dominant bacterial taxa were Proteobacteria, Acidobacteria, Actinobacteria, Chloroflexi, Crenarchaeota, and Bacteriodetes. Bacterial richness and diversity was highest in RS1 and declined with increasing soil depth. The distinct distribution patterns of the bacterial community were found across the different soil profiles. Besides, soil pH exhibited a strong influence (pH ˃AP ˃AN) on the bacterial communities under all soil depths. The relative abundance of Proteobacteria, Actinobacteria, Crenarchaeota, and Firmicutes was negatively correlated with soil pH, while Acidobacteria, Chloroflexi, Bacteriodetes, Planctomycetes, and Gemmatimonadetes were positively correlated with soil pH. Co-occurrence network analysis revealed that network topological features were weakened with increasing soil depth, indicating a more stable bacterial community in the RS1. Bacterial functions were estimated using FAPROTAX and the relative abundance of functional bacterial community related to metabolic processes, including C-cycle, N-cycle, and energy production was significantly higher in RS1 compared to RS2 and RS3, and soil pH had a significant effect on these functional microbes.ConclusionsThis study provided the valuable findings regarding the structure and functions of bacterial communities in red soil of pomelo orchards, and highlighted the importance of soil depth and pH in shaping the soil bacterial population, their spatial distribution and ecological functioning. These results suggest the alleviation of soil acidification by adopting integrated management practices to preserve the soil microbial communities for better ecological functioning.

Bacterial community structures and functional gene diversity of toluene denitrifying degraders in coking contaminated enrichments

Bacterial community structures and functional gene diversity of toluene denitrifying degraders in coking contaminated enrichments

Diversity and distribution patterns of macrofauna polychaetes (Annelida) in deep waters of the Southwestern Gulf of Mexico

The distribution and composition at the genus level of polychaetes greater than 500 μm of 54 sites in the southwestern Gulf of Mexico in a depth range of 185–3762 m were analyzed. Samples were collected on board the R/V Justo Sierra (Universidad Nacional Autónoma de México) in two cruises carried out in June 2015 and September 2016. Sixty-nine genera belonging to 33 families were recorded. The families with the highest abundance were: Spionidae, Paraonidae, Pilargidae and Capitellidae. Spionidae, Capitellidae and Paraonidae families presented the highest genus richness. The highest abundance was observed in the southern region of the study area and in the upper bathyal zone while the highest taxonomic richness was registered in the Campeche Bay, in the northwestern region of the study area and in intermediate depths. Polychaeta community functional diversity (bioturbation traits and feeding guilds) was also analyzed. A general decrease in functional diversity was observed as depth increased, presenting a partial biodiffusors and deposit-feeders dominance in the deepest zones. Distribution was highly related with depth, sediment granulometry, temperature and dissolved oxygen concentration of the bottom water.

两种镉积累型小麦根际微生物群落结构及功能多样性

PDF HTML阅读 XML下载 导出引用 引用提醒 两种镉积累型小麦根际微生物群落结构及功能多样性 DOI: 10.5846/stxb202104170997 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 安徽省自然科学基金项目（2008085MD120）；北京市农林科学院创新能力建设专项（KJCX20210439） Rhizosphere microbial community structure and functional diversity in two Cd-accumulating wheat cultivars Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为探究不同积累型小麦品种对根际微生物群落结构及功能多样性的影响，以镉低积累型小麦济麦22和镉高积累型小麦冀5265为研究材料，采用分离培养法和Biolog-Eco微平板法分析根际细菌数量、可培养优势群落结构以及微生物群落功能多样性。结果表明：污染土壤济麦22根际总细菌数量和抗Cd细菌数量均显著高于冀5265，而非污染土壤中两品种间无差异。污染土济麦22根际发现较多产脲酶和高镉抗性菌株（200 mg/L）。污染土济麦22根际优势菌多为Arthrobacter sp.和Bacillus sp.，冀5265根际优势菌主要为Streptomyces sp.；非污染土济麦22与冀5265根际优势菌群相似，均以Bacillus sp.为主。Biolog试验结果表明，两个小麦品种根际微生物群落对碳源的利用能力存在差异，济麦22根际微生物AWCD值、Mc Intosh指数、Shannon-Wiener指数、Simpson指数在污染土和无污染土中均显著高于冀5265。因此，污染土壤中不同积累型小麦品种根际微生物群落结构及功能多样性均存在差异，该研究结果对于揭示高低积累型小麦根际微生物机制提供了重要参考依据。 Abstract:In order to investigate the effects of the different accumulating wheat cultivars on rhizosphere microorganism community structure and functional diversity, low Cd-accumulating wheat Jimai 22 (JM22) and high Cd-accumulating wheat Ji 5265 (JI5265) were planted in pots filled with contaminated soil and non-contaminated soil and collected at the tillering stage of wheat. In total, four experimental treatments were set up, containing JM22 grown in contaminated soil (CJM), JI5265 grown in contaminated soil (CJI), JM22 grown in non-contaminated soil (NJM) and JI5265 grown in non-contaminated soil (NJI). The number of rhizosphere bacteria, community structure of culturable dominant bacteria and microbial community functional diversity were analyzed by traditional dilution plate culture method and Biolog-Eco microplate method. The results from the standard spread-plate method showed that the population of total bacteria and Cd-resistant bacteria in rhizosphere soil of JM22 were significantly higher than those of JI5265 in contaminated soil, but there was no significant difference in the population of total bacteria and Cd-resistant bacteria of rhizosphere soil between the two different accumulating wheat cultivars in non-contaminated soil. Studies on the biological characteristics of the isolated strains showed that more urease producing bacterial strains and Cd-resistant bacterial strains (200 mg/L) in rhizosphere soil of JM22 grown in contaminated soil were isolated than those of JI5265 grown in contaminated soil. Based on 16S rRNA gene sequences analysis, bacterial community composition was different in rhizosphere soil between cultivar JM22 and cultivar JI5265 in contaminated soil. Most of the dominant rhizosphere bacteria in JM22 were identified as Arthrobacter sp. and Bacillus sp., while Streptomyces sp. predominated in rhizosphere soil of wheat JI5265 in contaminated soil. The dominant rhizosphere bacteria in JM22 and JI5265 grown in non-contaminated soil were similar, and they were mainly Bacillus sp. The Biolog-Eco plate experiment results showed that there were differences in the utilization of carbon sources between the two wheat cultivars, and the average well color development (AWCD) values, Mc Intosh index, Shannon-Wiener index and Simpson index of rhizosphere microbes of wheat cultivar JM22 were significantly higher than those of cultivar JI5265 in both contaminated soil and non-contaminated soil after 120 h of incubation. Taken together, the community structure and functional diversity of rhizosphere microorganisms in the two Cd-accumulating wheat cultivars grown in contaminated soil were different. The results provide an important reference for understanding the rhizosphere microbial mechanism in high and low accumulating wheats. 参考文献 相似文献 引证文献

Responses of Soil Microbial Community Size, Respiration Rate and Functional Diversity to Invasive Plant Species Richness

Responses of Soil Microbial Community Size, Respiration Rate and Functional Diversity to Invasive Plant Species Richness

江西柘林水库鱼类群落结构及功能多样性分析

PDF HTML阅读 XML下载 导出引用 引用提醒 江西柘林水库鱼类群落结构及功能多样性分析 DOI: 10.5846/stxb202106031466 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划项目（2019YFD0900603）；财政部和农业农村部：国家现代农业产业技术体系资助（CARS-46）；中国水产科学研究院基本科研业务费院级湖库增殖渔业创新团队项目（2020TD57） Community structure and functional diversity of fishes in Zhelin Reservoir, Jiangxi Province Author: Affiliation: Fund Project: National Key Research and Development Program of China (No.No.2019YFD0900603); Supported by China Agriculture Research System of MOF and MARA（CARS-46）; Central Public-interest Scientific Institution Basal Research Fund，CAFS (NO.2020TD57) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为了解江西柘林水库鱼类群落结构和多样性的时空变化特征，研究鱼类物种多样性和功能多样性的关系，于2020年9月至2021年4月在该水库调查分析了鱼类物种组成、优势度及群落物种多样性和功能多样性。结果表明，共采集鱼类53种，分属于5目12科36属。其中，鲤形目（38种）种类最多，占调查物种数的71.69%，柘林水库上、中、下游库区分别采集到鱼类36、40和32种，各库区均以鲤形目鱼类为主，分别占采集物种数的72.97%、85.00%和75.00%。优势物种主要是䱗（Hemiculter leucisculus）、鳙（Aristichthys nobilis）和黄尾鲴（Xenocypris davidi），重要种主要是草鱼（Ctenopharyngodon idella）、鲢（Hypophthalmichthys molitrix）、鳊（Parabramis pekinensis）、鲫（Carassius auratus）、蒙古红鲌（Erythroculter mongolicus）等。鱼类群落结构季节性差异大于空间格局差异，主要表现为秋季和冬季之间；生物多样性指数Margalef和功能丰富度指数在上游修河水域相对较高，鱼类物种多样性和功能多样性空间格局差异性大于时间尺度下的差异性。物种多样性与功能多样性的回归分析结果显示，功能丰富度与物种多样性指数之间存在显著的正相关关系；功能冗余度与各物种多样性之间呈现负相关关系，说明物种数的增加导致了库区鱼类功能丰富度的增加和功能冗余度的降低，而功能均匀度未发生明显的变化，主要原因为调查区域内拥有不同功能性状的鱼类群体之间在个体数比例上呈现不均匀分布的模式，这一结果预示着拥有较多物种的群落生态位重叠度相对较低，生态系统受干扰后的恢复能力较差。总体而言，保护鱼类生物多样性和维护生态系统的稳定性应该通过调控鱼类种群结构达到提高鱼类群落冗余度以及资源和生境可用性的目的。 Abstract:To understand the spatial and temporal variation of fish assemblage structure and biodiversity, as well the relationships between fish taxonomical diversity and functional diversity, species compositions, the dominant species, taxonomical and functional diversity of fish communities which were captured from Zhelin Reservoir from September 2020 to April 2021 were investigated and analyzed. The results showed that a total of 53 fish species belonging to 5 orders, 12 families, and 36 genera were sampled with dominant Cyprinidae accounting for 71.69% of the total species. Among the reservoir spatial scales, 36, 40 and 32 fish species which accounting for 72.97%, 85.00% and 75.00% of the total sampled species were captured from upper-, middle- and low-reach, respectively. Hemiculter leucisculus, Aristichthys Nobilis and Xenocypris davidi were dominant species, while Ctenopharyngodon idella, Hypophthalmichthys molitrix, Parabramis pekinensis, Carassius auratus and Erythroculter mongolicus were main species in Zhelin Reservoir. The analysis of PERMANOVA (Permutational Multivariate Analysis of Variance) using the fish assemblage matrixes showed that the seasonal variation of species compositions was more significant than the spatial scale, and the variations were mainly performed between two seasons of antum and summer. Meanwhile, biodiversity indexes and functional diversity indexes of fish assembalges performed relative higher variations among spatial scales than temporal scales. Margalef index were relatively higher in the Xiuhe River than those in other water sites, while the indexes of Shannon, Simpson and Peilou indexes showed no variation among the reaches. Functional richness possessed relative higher level in upper reach than midlle and lower reaches, while functional evenness and functional disperse performed non changes among spatial scales. Functional redundancy had no variation among spatial and temporal scales. Regression analyses showed significant positive relationships between the biodiversity index of functional richenss and functional disperse with each taxonomical diversity index, while there were negative relationships between functional redundancy and taxonomical diversity indexes, which implying the increase of species richness led to the increase of the functional richness and decrease of functional redundancy. However, functional evenness did not change obviously which can mainly be explained by the disproportionate individuals of different fish functional groups. The results implied that interference resulted in a lower niche overlap of fish community with high species richness and lower ecosystem recovery ability. In general, the species diversity level of Zhelin Reservoir is lower and the anti-interference ability of this ecosystem is relatively weaker. To protect fish biodiversity and maintain the stability of the ecosystem, it is necessary to improve the fish community redundancy and the availability of resources and habitats by regulating the fish population structure. 参考文献 相似文献 引证文献

Changes in plant community composition and functional plant traits over a four-year period on an extensive green roof

Constructed ecosystems like green roofs are increasingly deployed in cities to mitigate issues associated with urbanization. To minimize the cost of green roof infrastructure, shallow growing media (substrate) for plants is often employed. Spatial heterogeneity in substrate depth has also been hypothesized to allow greater plant species diversity without adding to the weight. Stress and competition can change green roof plant communities after initial planting, but little is known about the long-term effects of spatial heterogeneity on vegetation composition and functional characteristics. Our goal was to determine how green roof plant communities and, in turn, functional plant traits, change over time in response to environmental stress and substrate heterogeneity. This four-year experiment used four substrate depth treatments: three with homogenous substrate depths of 5 cm, 10 cm, and 15 cm, and one treatment with a heterogenous substrate depth that varied between 5 cm and 15 cm (5/15 cm). The volume of the substrate in the 10 cm treatment and 5/15 cm treatment was equal. By the end of this four-year experiment, variation occurred between treatments for community composition and functional diversity, with the greatest species richness observed in the least stressful treatment (15 cm) and the greatest functional diversity and evenness observed in the most stressful treatment (5 cm). Additionally, each treatment had lower functional diversity after four years compared to the initially planted community. When the heterogenous 5/15 cm treatment was compared to the homogenous 10 cm treatment, there were no differences in the number of plant species, but the treatments contained two distinct plant communities. Furthermore, the 5/15 cm treatment supported taller species, a trait value associated with reduced stormwater runoff and substrate temperature. This finding indicates that creating green roofs with a heterogenous substrate depth could improve overall green roof function without increasing roof weight. Substrate depth can be manipulated by green roof designers to alter vegetation characteristics, but species and functional diversity showed opposite trends along the depth gradient.

Effects of Soil Properties, Temperature and Disturbance on Diversity and Functional Composition of Plant Communities Along a Steep Elevational Gradient on Tenerife

Elevational variation of vegetation has been of interest for centuries, and a prominent example for such pronounced vegetation changes can be found along the steep elevational gradient on Tenerife, Canary Islands, 200 km off the West-African cost. The 3,718-m ascent to the peak of the island volcano, Teide, offers a unique opportunity to investigate associated changes in vegetation. However, elevation is not a directly acting factor, but represents several natural environmental gradients. While the elevational variation of temperature is globally rather uniform and temperature effects on plant communities are well understood, much less is known about the region-specific elevational change of chemical soil properties and their impact on plant communities along elevational gradients. Because human interference takes place even at high-elevation areas, we considered human-induced disturbance as important third factor acting upon plant community assemblages. In our study, we compared the effects of soil properties, temperature and disturbance on species richness, functional identity and functional diversity of plant communities along the elevational gradient on Tenerife. We used pairs of study plots: directly adjacent to a road and in natural vegetation close by. In each plot, we did vegetation relevées, took soil samples, and installed temperature loggers. Additionally, we collected leaf samples to measure leaf functional traits of 80% of the recorded species. With increasing elevation, soil cation concentrations, cation exchange capacity (CEC) and pH decreased significantly, while the soil carbon to phosphorus ratio slightly peaked at mid-elevations. Temperature had the strongest effects, increasing species richness and favoring communities with fast resource acquisition. Species richness was higher at road verges, indicating the positive effect of reduced competition and artificially generated heterogeneity. However, we did not detect road effects on plant functional characteristics. Vice versa, we did not find soil effects on species richness, but increased concentrations of soil cations favored acquisitive communities. Surprisingly, we could not reveal any influence on community functional diversity. The importance of temperature aligns with findings from large-scale biogeographic studies. However, our results also emphasize that it is necessary to consider the effects of local abiotic drivers, like soil properties and disturbance, to understand variation in plant communities.

Anthropogenic activities and seasonal properties jointly drive the assemblage of bacterial communities in subtropical river basins

Anthropogenic activities have inevitably impacted riverine ecosystems, yet their overall contribution to the assemblage of bacterial communities at a large river basin scale remains unclear. In this study, 16S amplicon sequencing was implemented to investigate the bacterial ecosystems in paired water and sediment of North River and West River basins in South China., which contains various anthropogenic environments (e.g., rural/urban area, mining area and livestock area). Subsequently, the links between bacterial community and various types of emerging pollutants in river water were analyzed. The results show that the bacterial assemblage of water and sediment had their own properties that the bacterial community of sediment were mainly affected by seasonal properties, while the bacterial community of water were affected by both seasons and anthropogenic activities. Therein, the aquatic bacterial compositions and abundances were driven by changes in temperature, dissolved oxygen and the emerging pollutants. The dominant phyla Proteobacteria and Firmicutes exhibited adaptability to the mining-affected regions, therein many clades (e.g., Beijerinckiaceae, Acetobacteraceae and Mycobacteriaceae) were also prevalent in the livestock-affected and densely-populated regions. In addition, these two phyla presented associations to the antibiotic resistance in water. The levels of antibiotics, relative antibiotic resistance gens (ARGs) and non-antibiotic pharmaceuticals (NAPs) were closely related to bacterial community composition, diversity and functional diversity, indicating their drive in shifting bacterial communities. Collectively, this work provides a basis for understanding the contribution of anthropogenic activities in shifting bacterial community at a large river basin scale. Further, the results provide new insights for expansion of ecological assessment.

Does island ontogeny dictate the accumulation of both species richness and functional diversity?

AbstractAimThe accumulation of functional diversity in communities is poorly understood. Conveniently, the general dynamic model of island biogeography (GDM) makes predictions for how such diversity might accumulate over time. In this multiscale study of land snail communities on 10 oceanic archipelagos located in various regions of the globe, we test hypotheses of community assembly in systems where islands serve as chronosequences along island ontogeny.LocationTen volcanic archipelagos.Time periodFrom 23 Ma to the present.Major taxa studiedEndemic land snails.MethodsInitially, we assembled geological island characteristics of area, isolation and ontogeny for all studied islands. We then characterized island‐scale biotic variables, including the species diversity and functional diversity of snail communities. From these data, we assessed relationships between island and snail community variables as predicted by the GDM, focusing initially on the islands of the Galápagos archipelago and thereafter with a broader analysis of 10 archipelagoes.ResultsAs in other studies of island assemblages, in Galápagos we find a hump‐shaped curve of species richness, with depauperate snail faunas on early‐ontogeny islands, increasing species richness on mid‐ontogeny islands and low species richness on islands in late ontogeny. We find exceptionally low functional diversity on early‐ontogeny islands that increases through mid‐ontogeny, whereas late‐ontogeny islands exhibit a range of functional diversity. The analysis including all 10 archipelagos indicates a major role of archipelago‐specific factors. In both sets of analyses, functional diversity is exceptionally low on early‐ontogeny islands, and island ontogeny is a significant predictor of morphology.Main conclusionsConsistent patterns of functional diversity across island ontogeny on all examined archipelagos indicate a common role for habitat filtering, ecological opportunity and competition in a diversity of systems, leading to predictable changes in functional diversity and average morphology through island ontogeny, whereas patterns of species richness appear subject to archipelago‐specific factors.

Trap type affects dung beetle taxonomic and functional diversity in Bornean tropical forests

AbstractBaited pitfall traps (BPTs) and flight intercept traps (FITs) are the most common methods employed for sampling dung beetle communities. These methods vary in their efficacy and are affected by factors such as the bait types used and the dispersal abilities of different dung beetle species. We present the first quantitative comparison of the community composition, taxonomic and functional diversity of dung beetles caught in human dung BPTs and FITs in Bornean tropical forests. Functional diversity metrics were calculated based on the three functional traits of nesting method, body length, and diel activity. We show that BPTs and FITs captured complementary communities with different functional traits, and that BPTs captured more functionally diverse communities. We therefore recommend using a combination of both BPTs and FITs for studies assessing the composition of dung beetles across habitat types. Our results also highlight that it is important to consider how trap type affects the trait composition of communities when relating dung beetle communities and functional traits to ecological functioning. We suggest modifications to FITs based on the design of harp traps to increase their effectiveness in capturing larger‐bodied beetles.

30 Years of postdisturbance recruitment in a Neotropical forest.

QuestionsLong‐term community response to disturbance can follow manifold successional pathways depending on the interplay between various recruitment processes. Analyzing the succession of recruited communities provides a long‐term perspective on forest response to disturbance. Specifically, postdisturbance recruitment trajectories assess (a) the successive phases of postdisturbance response and the role of deterministic recruitment processes, and (b) the return to predisturbance state of recruits taxonomic/functional diversity/composition.LocationAmazonian rainforest, Paracou station, French Guiana.MethodsWe analyzed trajectories of recruited tree communities, from twelve forest plots of 6.25 ha each, during 30 years following a disturbance gradient that ranged from 10% to 60% of aboveground biomass removed. We measured recruited community taxonomic composition turnover, compared to whole predisturbance community, and assessed their functional composition by measuring the community weighted means for seven leaf, stem, and life‐history functional traits. We also measured recruited community taxonomic richness, taxonomic evenness, and functional diversity and compared them to the diversity values from a random recruitment process.ResultsWhile control plots trajectories resembled random recruitment trajectories, postdisturbance trajectories diverged significantly. This divergence corresponded to an enhanced recruitment of light‐demanding species that became dominant above a disturbance intensity threshold. After breakpoints in time, though, recruitment trajectories returned to diversity values and composition similar to those of predisturbance and control plots community.ConclusionsFollowing disturbance, recruitment processes specific to undisturbed community were first replaced by the emergence of more restricted, deterministic recruitment processes favoring species with efficient light use and acquisition. Then, a second phase corresponded to a decades‐long recovery of recruits predisturbance taxonomic and functional diversity and composition that remained unachieved after 30 years.

Functional redundancy of non‐volant small mammals increases in human‐modified habitats

AbstractAimHumans are rapidly altering natural habitats across much of the globe. Here we compared 264 globally distributed communities in natural and human‐modified habitats to detect changes in community richness and functional diversity with human influence.LocationGlobal.TaxonNon‐volant small mammals.MethodsWe calculated differences in observed to potential species richness (ΔSR) and observed to potential functional diversity (ΔFD) to account for regional pool differences. Then we determined the prevalence of four distinct scenarios of richness and functional diversity differences between human‐modified and natural habitats, and evaluated local and geographical variation in these differences. We obtained potential richness by calculating a probabilistic species pool and obtained potential functional diversity through the n‐dimensional hypervolume based on pool composition. We tested for differences in average ΔSR and ΔFD between habitats, and determined the most common scenario of ΔSR and ΔFD in human‐modified and natural habitats.ResultsWe found lower ΔSR in human‐modified than natural habitats, but no difference in ΔFD. Low ΔSR and high ΔFD predominated in human‐modified habitats, and high ΔSR and ΔFD in natural habitats. Low ΔSR and high ΔFD predominated in temperate forests, whereas high ΔSR and ΔFD in tropical forests and grasslands. Scenarios of low ΔSR and high ΔFD, and high ΔSR and low ΔFD, were most common in human‐modified and natural habitats of temperate grasslands.Main conclusionsA larger richness in human‐modified habitats does not result in larger functional diversity. Rather there seems to be an increase in functional redundancy because species which profit from human modification do not bring new functions into human‐modified habitats. While greater richness is found in human‐modified habitats from temperate biomes, this is not the case in extremely biodiverse tropical biomes. Assuming a positive relationship between richness, functional traits and ecosystem function, greater richness in modified habitats may not yield greater function.

The relationship between species diversity and functional diversity along aridity gradients in semi-arid rangeland

The relationship between community species diversity and functional diversity (SFDR) was suggested to reflect the degree of overlap in species functions and highlight the effects of environmental filters on community composition. Using a novel approach, categorizing individual plants into functional groups according to their plant biomass production (function level) and regardless of their taxonomic attribution, we tested the pattern of SFDR (e.g., linear correlation or other type) in a semiarid, annual plant community. Species abundance and biomass were monitored over four years among neighbouring topographic sites representing a range of aridity levels in the Northern Negev, Israel. All sampled plant individuals collected at flowering season were weighted and classified into ten functional groups according to their above-ground biomass. Functional group richness and species richness were calculated for each of the 16 research plots during the four research years. We examined the relationship between species richness and functional richness and the effects of year and topographic site on species richness within each of the functional groups. Species and functional richness varied considerably among years and topographic sites. Functional richness was found to be positively related to species richness throughout the entire studied aridity range. Under relatively humid conditions, species richness was high, and increasing aridity led mainly to loss of functional redundancy. Lost taxa were typically rare, large sized or drought intolerant species with low functional plasticity. Conversely, under relatively dry conditions, species richness was low and further increasing aridity led more to loss of functional richness than to loss of species richness. Typical species that drove this pattern were abundant, medium to low sized and drought tolerant species with high functional plasticity. These species decreased their plant biomass production while guaranteeing their existence under extreme drought.

Response and oil degradation activities of a northeast Atlantic bacterial community to biogenic and synthetic surfactants

BackgroundBiosurfactants are naturally derived products that play a similar role to synthetic dispersants in oil spill response but are easily biodegradable and less toxic. Using a combination of analytical chemistry, 16S rRNA amplicon sequencing and simulation-based approaches, this study investigated the microbial community dynamics, ecological drivers, functional diversity and robustness, and oil biodegradation potential of a northeast Atlantic marine microbial community to crude oil when exposed to rhamnolipid or synthetic dispersant Finasol OSR52.ResultsPsychrophilic Colwellia and Oleispira dominated the community in both the rhamnolipid and Finasol OSR52 treatments initially but later community structure across treatments diverged significantly: Rhodobacteraceae and Vibrio dominated the Finasol-amended treatment, whereas Colwellia, Oleispira, and later Cycloclasticus and Alcanivorax, dominated the rhamnolipid-amended treatment. Key aromatic hydrocarbon-degrading bacteria, like Cycloclasticus, was not observed in the Finasol treatment but it was abundant in the oil-only and rhamnolipid-amended treatments. Overall, Finasol had a significant negative impact on the community diversity, weakened the taxa-functional robustness of the community, and caused a stronger environmental filtering, more so than oil-only and rhamnolipid-amended oil treatments. Rhamnolipid-amended and oil-only treatments had the highest functional diversity, however, the overall oil biodegradation was greater in the Finasol treatment, but aromatic biodegradation was highest in the rhamnolipid treatment.ConclusionOverall, the natural marine microbial community in the northeast Atlantic responded differently to crude oil dispersed with either synthetic or biogenic surfactants over time, but oil degradation was more enhanced by the synthetic dispersant. Collectively, our results advance the understanding of how rhamnolipid biosurfactants and synthetic dispersant Finasol affect the natural marine microbial community in the FSC, supporting their potential application in oil spills.43fSDwbdHYX3Ei4X1BHK1YVideo abstract