Diversity Of Dominant Species Research Articles

Genetic diversity of a dominant plant alters interspecific interactions between two subordinate species and facilitates their coexistence

Environmental heterogeneity of various kinds can promote species coexistence. We hypothesized that greater genetic diversity of a competitively dominant species in a plant community can promote coexistence of subordinate species. To test this hypothesis, we grew the duckweeds Lemna minor and Spirodela polyrhiza apart and together without or with 1, 2, and 4 genotypes of a much larger, co-occurring species, Hydrocotyle verticillata. The presence of H. verticillata strongly reduced the growth of both duckweed species, consistent with its dominance. The presence of S. polyrhiza significantly increased biomass of L. minor and this effect did not depend on the presence or absence of H. verticillata or its genotypic richness. Without H. verticillata, the presence of L. minor drastically reduced biomass (-94%) of S. polyrhiza. However, the inhibitory effect of L. minor on S. polyrhiza became much weaker in the presence of one and two genotypes of H. verticillata and completely disappeared in the presence of four genotypes of H. verticillata. These results suggest that both the presence of H. verticillata and its genotypic richness can alter interspecific interactions between the two duckweed species. We conclude that genetic diversity of a single, highly dominant species may promote coexistence of subordinate species when they differ strongly in the ability to compete with each other. We suggest testing further for effects of genetic diversity of dominant species on subordinate species with similar competitive abilities.

Testing the hierarchy of predictability in grassland restoration across a gradient of environmental severity.

Ecological restoration is critical for recovering degraded ecosystems but is challenged by variable success and low predictability. Understanding which outcomes are more predictable and less variable following restoration can improve restoration effectiveness. Recent theory asserts that the predictability of outcomes would follow an order from most to least predictable from coarse to fine community properties (physical structure > taxonomic diversity > functional composition > taxonomic composition) and that predictability would increase with more severe environmental conditions constraining species establishment. We tested this "hierarchy of predictability" hypothesis by synthesizing outcomes along an aridity gradient with 11 grassland restoration projects across the United States. We used 1829 vegetation monitoring plots from 227 restoration treatments, spread across 52 sites. We fit generalized linear mixed-effects models to predict six indicators of restoration outcomes as a function of restoration characteristics (i.e., seed mixes, disturbance, management actions, time since restoration) and used variance explained by models and model residuals as proxies for restoration predictability. We did not find consistent support for our hypotheses. Physical structure was among the most predictable outcomes when the response variable was relative abundance of grasses, but unpredictable for total canopy cover. Similarly, one dimension of taxonomic composition related to species identities was unpredictable, but another dimension of taxonomic composition indicating whether exotic or native species dominated the community was highly predictable. Taxonomic diversity (i.e., species richness) and functional composition (i.e., mean trait values) were intermittently predictable. Predictability also did not increase consistently with aridity. The dimension of taxonomic composition related to the identity of species in restored communities was more predictable (i.e., smaller residuals) in more arid sites, but functional composition was less predictable (i.e., larger residuals), and other outcomes showed no significant trend. Restoration outcomes were most predictable when they related to variation in dominant species, while those responding to rare species were harder to predict, indicating a potential role of scale in restoration predictability. Overall, our results highlight additional factors that might influence restoration predictability and add support to the importance of continuous monitoring and active management beyond one-time seed addition for successful grassland restoration in the United States.

Long-term performance of ZVI-stimulating anaerobic/aerobic system - PEI modified ceramic membrane SMBR in reusing food wastewater for irrigation: An industrial project and microbial community shift

A large-scale project was carried out using an integrated treatment system composed of anaerobic and aerobic unit followed by ceramic membrane SMBR for reclaiming 200 m3/d of food wastewater for the purpose of irrigation. Utilization of ZVI technology to facilitate the organic contaminants degradation in UASB and aerobic unit in the operation of successive 240 days was investigated. A membrane flux of around 30 LMH was stably attained in a novel PEI-modified flat sheet ceramic membrane SMBR equipped with in situ intensive mechanical cleaning bush system. The ceramic MBR system investigated had significantly alleviated membrane fouling and no severe membrane fouling occurred throughout the whole filtration process. Overall, the combined treatment system can produce high quality reusable water for irrigation and the final effluent had a COD of around 120 mg/L and BOD5 of around 32 mg/L, respectively. Finally, variations in dominant species in both initial sludge Day-1 and sludge Day-240 in ZVI assisting UASB and aerobic unit was further unraveled by the high throughput sequencing analysis.

Laminar burning velocity, emissions, and flame structure of dimethyl ether-hydrogen air mixtures

The present work reports experimentation and numerical simulations of laminar burning velocity, emission analysis, and flame structure of dimethyl ether-hydrogen mixtures. The volumetric hydrogen addition is considered into the DME fuel for a range of mixture equivalence ratios (0.6<ϕ < 1.7). The initial mixture temperature is raised to 373 K at constant atmospheric pressure of 1.0 bar. The heat flux method is utilized to investigate the laminar burning velocity in laminar premixed planar adiabatic flames. The laminar burning velocity (LBV), along with the flame position and emission measurements, are extracted from these flames. The computations were performed with freely propagating flames (LBV, species, sensitivity, etc. data), and the burner stabilizes flames (flame position and emission analysis) for the same mixture and initial conditions using various detailed mechanisms. An emphasis is paid to a newly developed Shrestha mechanism, which includes a radiation model and NO sub-mechanism. Both experimental data and competition results were validated against the pure DME air mixture data available in the existing literature, and further analysis was carried out. It is observed that planar flames can be stabilized only up to a hydrogen addition of 40%. Adding hydrogen enhanced the flame temperature, heat release rates, and burning velocity while reducing the CO and NO emissions. A slight shift of peak burning velocity on the rich side of the equivalence ratio (from 1.05 to 1.2) is observed with hydrogen addition (0–40%). The mixture temperature also enhances the flame temperature and laminar burning velocity. It is interesting to note that hydrogen-added mixtures show a relatively lower dependency on initial mixture temperature. The variation of dominant species and heat release rates are also discussed in detail. The sensitivity analysis is carried out to get information on dominant reactions participating in the combustion of DME hydrogen mixtures.

Cyanobacteria and Their Metabolites in Mono- and Polidominant Shallow Eutrophic Temperate Lakes.

Monodominant (one species dominates) or polidominant (multiple species dominate) cyanobacterial blooms are pronounced in productive freshwater ecosystems and pose a potential threat to the biota due to the synthesis of toxins. Seasonal changes in cyanobacteria species and cyanometabolites composition were studied in two shallow temperate eutrophic lakes. Data on cyanobacteria biomass and diversity of dominant species in the lakes were combined with chemical and molecular analyses of fifteen potentially toxin-producing cyanobacteria species (248 isolates from the lakes). Anatoxin-a, saxitoxin, microcystins and other non-ribosomal peptides formed the diverse profiles in monodominant (Planktothrix agardhii) and polidominant (Aphanizomenon gracile, Limnothrix spp. and Planktolyngbya limnetica) lakes. However, the harmfulness of the blooms depended on the ability of the dominant species to synthesize cyanometabolites. It was confirmed that P. agardhii produced a greater amount and diverse range of MCs and other NRPs. In the polidominant lake, isolates of the co-dominant A. gracile, L. planctonica and P. limnetica synthesized no or only small amounts of cyanometabolites. In general, the profile of cyanometabolites was greater in cyanobacteria isolates than in environmental samples, indicating a high potential for toxic cyanobacteria bloom.

Metagenomics analysis of antibiotic resistance genes, the bacterial community and virulence factor genes of fouled filters and effluents from household water purifiers in drinking water

The aim of this study was to explore the influence and removal of household water purifiers (HWPs) on emerging contaminants in drinking water, and their distribution characteristics. The antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), virulence factor genes (VFGs) and bacterial communities were profiled in the fouled filters, influents, and effluents from HWPs with five steps of filtration after 150 days operation, using metagenomics. The results showed that the diversity of dominant species in Poly Propylene 1 μm (PP1) and nanofiltration membrane (NM) was significantly higher than that in other filters. Post-activated carbon (AC) was used to detect low species richness or diversity, and the highest proportion of dominant species, which contributes to the greater microbial risk of HWPs effluents in drinking water. The number of dominant bacterial genera in the filters disinfected with chloramine was higher than that in the same group disinfected with chlorine. The bacterial species richness or diversity in water was reduced by the purification of HWPs because the filter elements effectively trapped a variety of microorganisms. The relative abundance of Antibiotic efflux in the effluents of chlorinated and chloraminated HWPs was 5.58 × 10−3 and 4.60 × 10−3, respectively, which was the main resistance mechanism. High abundance of VFGs was found in HWPs effluents and the relative abundance of aggressive VFGs was significantly higher than those of defensive VFGs. Based on the co-occurrence results, 243 subtypes of ARGs co-occurred with VFGs, and a variety of bacteria were thought to be possible ARGs hosts, which indicated that the host bacteria of VFGs in HWP effluents had a stronger attack ability. The effluent of HWPs with only filtration processes is exposed to the risk of ARGs and VFGs. This study helps to understand the actual purification effect of HWPs and provides a theoretical reference for the management and control of ARGs pollution in domestic drinking water.

Adaptive genetic diversity of dominant species contributes to species co-existence and community assembly

The synthesis of evolutionary biology and community ecology aims to understand how genetic variation within one species can shape community properties and how the ecological properties of a community can drive the evolution of a species. A rarely explored aspect is whether the interaction of genetic variation and community properties depends on the species' ecological role. Here we investigated the interactions among environmental factors, species diversity, and the within-species genetic diversity of species with different ecological roles. Using high-throughput DNA sequencing, we genotyped a canopy-dominant tree species, Parashorea chinensis, and an understory-abundant species, Pittosporopsis kerrii, from fifteen plots in Xishuangbanna tropical seasonal rainforest and estimated their adaptive, neutral and total genetic diversity; we also surveyed species diversity and assayed key soil nutrients. Structural equation modelling revealed that soil nitrogen availability created an opposing effect in species diversity and adaptive genetic diversity of the canopy-dominant Pa. chinensis. The increased adaptive genetic diversity of Pa. chinensis led to greater species diversity by promoting co-existence. Increased species diversity reduced the adaptive genetic diversity of the dominant understory species, Pi. kerrii, which was promoted by the adaptive genetic diversity of the canopy-dominant Pa. chinensis. However, such relationships were absent when neutral genetic diversity or total genetic diversity were used in the model. Our results demonstrated the important ecological interaction between adaptive genetic diversity and species diversity, but the pattern of the interaction depends on the identity of the species. Our results highlight the significant ecological role of dominant species in competitive interactions and regulation of community structure.

A direct comparison of the effects and mechanisms between species richness and genotype richness in a dominant species on multiple ecosystem functions.

Both species (interspecific) richness and genotype (intraspecific) richness of dominant species have significant effects on ecosystem functioning directly or indirectly by regulating plant community functional structure. However, the similarities and differences of the effects between inter‐ and intraspecific levels are poorly understood. In this study, we selected the main species in the semi‐arid Eurasian typical steppe as study objects and simultaneously carried out a species richness experiment and a genotype richness experiment of Stipa grandis which is one of the dominant species in this region. We investigated how plants at each of the two richness levels affected multiple ecosystem functions (biomass, soil C, N and P cycles) directly and indirectly by regulating community functional structure, including community‐weighted mean trait values (CWM) and functional dispersion (FDis). Both species richness and genotype richness showed significant direct effects on soil P cycle, and FDis significantly mediated the responses of aboveground biomass and soil N cycle to the changes of species richness and the response of belowground biomass to the changes of genotype richness in S. grandis. CWM showed significant effects on biomass in the species richness experiment and soil nutrient cycles in the genotype richness experiment, independently of the levels of plant richness. These findings provide experimental insights of intraspecific richness effects into the relationships between biodiversity and ecosystem functioning, and highlight the importance of conserving the intraspecific diversity of dominant species in the semi‐arid steppe regions.

Functional Diversity Can Predict Ecosystem Functions Better Than Dominant Species: The Case of Desert Plants in the Ebinur Lake Basin

Studying the impact of biodiversity on ecosystem multifunctionality is helpful for clarifying the ecological mechanisms (such as niche complementary effects and selection) of ecosystems providing multiple services. Biodiversity has a significant impact on ecosystem versatility, but the relative importance of functional diversity and dominant species to ecosystem functions needs further evaluation. We studied the desert plant community in Ebinur Lake Basin. Based on field survey data and experimental analysis, the relationship between the richness and functional diversity of dominant species and the single function of ecosystem was analyzed. The relative importance of niche complementary effect and selective effect in explaining the function of plant diversity in arid areas is discussed. There was no significant correlation between desert ecosystem functions (soil available phosphorus, organic matter, nitrate nitrogen, and ammonium nitrogen) and the richness of the dominant species Nitraria tangutorum (p &lt; 0.05). Soil organic matter and available phosphorus had significant effects on specific leaf area and plant height (p &lt; 0.05). Functional dispersion (FDis) had a significant effect on soil available phosphorus, while dominant species dominant species richness (SR) had no obvious effect on single ecosystem function. A structural equation model showed that dominant species had no direct effect on plant functional diversity and ecosystem function, but functional diversity had a strong direct effect on ecosystem function, and its direct coefficients of action were 0.226 and 0.422. The results can help to explain the response mechanism of multifunctionality to biodiversity in arid areas, which may provide referential significance for vegetation protection and restoration for other similar areas.

The late Miocene Beli Breg Basin (Bulgaria): palaeoecology and climate reconstructions based on pollen data

Late Miocene sediments from the Beli Breg Coal Basin, Western Bulgaria, were investigated using spore-pollen analysis. Based on palynological characteristics, we describe dynamics and development of vegetation in the studied basin. The main types of palaeocoenoses are distinguished. The fossil flora is characterised by a variable structure of plant communities and diversity of dominant species. In general, the warm temperate representatives of the genera Quercus, Castanea, Corylopsis, Ulmus, and Carya dominated the composition of mixed mesophytic forest palaeocoenoses. Climate data reconstructed using the Coexistence Approach method show that the climate was of a moderately warm type, with a mean annual temperature of ca. 16 °C and temperatures ca. 4 °C by mean in the winter season, thus providing very favourable climatic conditions for the distribution of warm temperate vegetation. The established values for precipitation of about 1000 mm annually indicate the presence not only of a warm but also humid climate, with low seasonality and relatively short dry period.

Species diversity and abundance of scorpions in Ahvaz city, Southwest Iran

Abstract. Mansouri NJS, Akbarzadeh K, Jahanifard E, Vazirianzadeh B, Rafinejad J. 2021. Species diversity and abundance of scorpions in Ahvaz city, Southwest Iran. Biodiversitas 22: 763-768. Arthropods are one of the most important and diverse phyla of the animal kingdom. This phylum includes several classes of insects and arachnids, which are of medical and veterinary importance. Scorpions are at the top of the group of venomous arthropods in terms of having venomous bites and causing death. Scorpions live mainly in tropical and subtropical regions of the world and therefore have higher diversity and richness in these regions. This study aimed to investigate the biodiversity and abundance of scorpions in Ahvaz city, Khuzestan province, Iran. It has the highest species diversity and species richness in Iranian scorpions. Scorpions were collected from five regions in Ahvaz using various methods. In total 237 scorpions were collected and identified. They belonged to two families, seven genera and seven species: Mesobuthus eupeus (65%), Hemiscorpius lepturus (23.2%), Androctonus crassicauda (3.8%), Compsobuthus rugosulus (3.4%), Orthochirus zagrosensis (2.5%), Apistobuthus susanae (1.7%), Buthacus macrocentrus (0.4%). Except for H. lepturus (Hemiscorpiidae), other species belonged to the Buthidae family. That all of them were non-burrowing. M. eupeus was the dominant species diversity analysis indicated higher species richness and species diversity for summer (Margalef = 1.07; Shannon = 1.55). Logistic regression analysis showed that the variables of geographical location, humidity, and temperature had a significant relationship with the abundance of scorpion species, while height had no statistically significant.

Effects of landscape composition and site land-use intensity on secondary succession in a tropical dry forest

Regenerating forests after agricultural land abandonment are increasingly common in human-modified tropical landscapes. These secondary forests preserve biodiversity and provide multiple ecosystem services, but such important roles depend on their recovery rates, which can be difficult to predict. Recovery is expected to occur faster when landscape composition favors seed dispersal to the regenerating site, and when previous land-use does not significantly reduce propagule bank or future plant growth. Here, we test such expectations for the recovery of a Mexican tropical dry forest during secondary succession. For this purpose, we measured several indicators of landscape composition and site land-use intensity in 30 regenerating sites located along gradients of age of abandonment and amount of surrounding forest. Generalized linear models and redundancy analysis were fitted to test if values of four vegetation properties (aboveground biomass, total and dominant species diversity, and species composition) were indicative of such effects. We found evidence that, as expected, species richness recovers faster in sites surrounded by higher forest cover, while aboveground biomass recovers slower as surrounding pasture cover increases. Species composition was also significantly but poorly explained by the interaction between age of abandonment and the amount of forest cover. Contrary to our expectations, we found weak evidence on the impact of site land-use intensity on all vegetation properties, except on the number of dominant species, which showed higher values in sites with higher land-use intensity. Our findings show that landscape context plays a major role in structuring successional plant communities in this tropical dry region, even stronger than site land-use intensity. This seems to be related to the influence of landscape patterns on dispersal and recruitment limitation, but also on the likelihood of further human disturbances. Therefore, conserving landscape quality is paramount to enhance forest recovery and its contribution to the preservation of biodiversity and ecosystem services.

Nonlinear drought plasticity reveals intraspecific diversity in a dominant grass species

Abstract Intraspecific diversity of dominant species in native plant communities can modulate ecosystem function under both optimal and stressful conditions. Yet, few genotype by environment interaction studies quantify differences in the shape of plasticity functions or phenotypic breakpoints across genotypes in natural populations. Using three genotypes with a history of drought selection, we performed a greenhouse study on the dominant tallgrass prairie species Andropogon gerardii. We investigated phenotypic plasticity and recovery differences among genotypes across a water availability gradient, measuring growth‐related, instantaneous and cumulative phenotypes. To further understand genotype by environment effects, we quantified plasticity functions and breakpoints among genotypes. Like other studies, we found strong evidence for phenotypic and plasticity differences among genotypes. However, we also found nonlinear plasticity functions and breakpoints were common across phenotypes, especially relative growth rates, biomass allocation and root architecture. Drought selected genotypes were also more likely to flower during recovery, but all genotypes were resilient to drought across treatments. We demonstrate that plasticity functions may help explain intraspecific diversity, patterns of selection and nonlinear community responses to more variable rainfall within an experimental population. In particular, plasticity functions can help disentangle drought/variability tolerance versus acquisitive strategies. A better understanding of intraspecific diversity in this grass species will provide more mechanistic insight into its ability to buffer ecosystem changes and provide resiliency in the tallgrass prairie under future droughts. A free Plain Language Summary can be found within the Supporting Information of this article.

Structure peculiarities of Pinus sylvestris L. consortium

The structure of Pinus sylvestris L. consortium of various ontogenetic conditions in the regions of the Republic of Mari El and the city of Yoshkar-Ola in the territory of Russia is described. Based on modern methods of collecting arthropod animals in tree crowns and studying the structure of consortium, data analysis has been performed. With P. sylvestris coenopopulations, 73 species of Insecta and Arachnida are associated. The dominant species diversity is Coleoptera. The trophic groups of Insecta and Aranei, the groups in the breadth of the range of nutrition and harmfulness are characterized. It is shown that the diversity of Insecta and Aranei complexes in P. sylvestris coenopopulations is determined by the age features of the tree and the ecological conditions of the study areas. Consideration of the ontogenetic state of the determinant of the consortium and analysis of the formation of different types of integumentary tissue contributes to the prediction of the stages of colonization and damage to trees by harmful Insecta. It was suggested that for the detailed characterization of the consortium, it is necessary to organize a long-term monitoring of the state of tree stands and the composition of their consorts using the population-ontogenetic approach.

Increased fish diversity over day and night in structurally complex habitats of artificial reefs

A major goal of ecology is to understand how spatial heterogeneity determines patterns of species diversity and composition. Studies have demonstrated positive relationship between environmental heterogeneity and diversity, but evidence from marine ecosystems is controversial and scarce in terms of how spatial heterogeneity and diel period mediate this relationship. We used fish communities from four Southwestern Atlantic vessel reefs to assess whether positive heterogeneity-diversity relationships (HDR) hold for these mobile organisms and whether the relationships weaken with nightfall. We sampled fishes in three habitats of contrasting structural complexity (high, low and control), over day and night, and employed two complementary diversity frameworks: partitioning of gamma diversity into independent alpha and beta components (Jost's approach) and partitioning of beta diversity into turnover and nestedness components (Baselga's approach). We recorded 5005 fishes belonging to 76 species and 31 families. As expected, the mean alpha diversity of rare species (0D) doubled from control to high complexity areas and decreased by half from day to night. The diversity of typical species (1D) also doubled from control to high complexity areas, but did not reduce at night. Complexity and diel period did not have significant effect on the diversity of dominant species (2D). No relationship between complexity and alpha diversity was weakened at night. Beta diversity of the three diversity orders significantly differed from 1 (totally homogeneous vessel reef), indicating that complexity underlies patterns of beta diversity. This effect was consistent in both diel periods, contradicting expectations of weaker influence of complexity at night. The turnover component of beta diversity was consistently greater than nestedness at day and nigth (2.8 and 1.9-fold, respectively). Our findings support positive HDR for the diversity of rare and typical species. Dominant species also respond to heterogeneity by replacing each other across the complexity gradient, but not by becoming more numerous in high complexity areas. Diel changes did not affect the strenght of HDR, revealing an uninterrupted role of environmental heterogenity on fish communities. Conserving heterogeneous, structurally complex habitats is crucial for conserving marine fish diversity.

内蒙古典型草原建群种羊草基因型多样性抑制群落物种多样性的生态功能

PDF HTML阅读 XML下载 导出引用 引用提醒 内蒙古典型草原建群种羊草基因型多样性抑制群落物种多样性的生态功能 DOI: 10.5846/stxb201711021964 作者: 作者单位: 南开大学生命科学学院植物生物学和生态学系,南开大学生命科学学院植物生物学和生态学系,南开大学生命科学学院植物生物学和生态学系,南开大学生命科学学院植物生物学和生态学系,南开大学生命科学学院植物生物学和生态学系,南开大学生命科学学院植物生物学和生态学系,南开大学生命科学学院植物生物学和生态学系,南开大学生命科学学院植物生物学和生态学系 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（2016YFC0500706）；国家自然科学基金项目（31570427，31770505） Genotypic diversity of a dominant species Leymus chinensis inhibited ecological function of species diversity in the Inner Mongolia Steppe Author: Affiliation: College of Life Science,Nankai University,College of Life Science,Nankai University,College of Life Science,Nankai University,College of Life Science,Nankai University,College of Life Science,Nankai University,College of Life Science,Nankai University,College of Life Science,Nankai University,College of Life Science,Nankai University Fund Project: The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan) 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:植物群落的物种多样性以及群落建群种的基因型多样性对群落生态功能是否存在交互影响已成为群落生态学研究的热点内容。以内蒙古典型草原群落内常见物种为研究对象，研究了群落物种多样性与建群种羊草（Leymus chinensis）基因型多样性及其交互作用对群落生物量生态功能特性的影响。结果表明：（1）羊草基因型多样性、物种多样性及其交互作用对群落地上、地下和总生物量无显著影响（P > 0.05）；（2）羊草基因型多样性、物种多样性及其交互作用对多样性效应（净多样性效应、互补效应和选择效应）有显著影响（P < 0.05）。羊草基因型多样性抑制多样性净效应的发挥，且主要抑制互补效应；而物种多样性则促进多样性净效应的发挥，主要表现为选择效应对地上生物量的正效应；（3）互补效应对群落生物量多样性净效应起主要贡献。实验所得结果不仅为探讨多样性效应在物种水平以及群落水平上对群落生物量的影响因素提供了重要启示，而且为内蒙古草原种质资源的保护及合理利用，乃至生态系统的恢复和重建提供理论指导。 Abstract:Community ecologists have focused on whether there exists an interactive effect between species diversity and genotypic diversity of dominant species on community ecological function in recent years. In the present study, we selected some common species in the Inner Mongolia Steppe as study objects, and examined how the genotypic diversity of the dominant species, the species diversity of common species and their interactions influenced the community biomass. (1) Genotypic diversity of Leymus chinensis, species diversity, and their interactions did not significantly influence the community aboveground, belowground, or total biomass (P > 0.05). (2) The genotypic diversity of L. chinensis, species diversity, and their interactions significantly influenced diversity effects (net diversity effect, complementarity effect, and selection effect) on community biomass (P < 0.05). The genotypic diversity of L. chinensis inhibited the net diversity effect, mainly complementarity effect. However, species diversity promoted the net diversity effect, in particular, selection effect on aboveground biomass. (3) The net diversity effect on ecological function of the community biomass was mainly due to complementarity effect. The above results provided not only an important message for exploring whether species diversity or genotypic diversity of dominant species plays a more important role in influencing the diversity effect on community biomass, but also proper guides for protection and rational utilization of seed resources, and moreover, for the ecosystem recovery and re-establishment in the Inner Mongolia Steppe. 参考文献 相似文献 引证文献

Functional diversity is more sensitive to biotic filters than phylogenetic diversity during community assembly

AbstractEcologically important functional traits and phylogenetic relatedness may provide mechanistic insight into biotic filters influencing community assembly. To assess this, we examined the relationship between functional diversity (FD, functional trait relatedness) and phylogenetic diversity (PD, evolutionary relatedness) during grassland restoration. Temporal changes in FD and PD were used to examine the effect of two biotic filters during community assembly: intraspecific variation in dominant species (different population sources) and interspecific variation among subordinate species (phylogenetically distinct species pools). The experimental grassland restoration contained whole plots sown with either cultivars or local ecotypes of three dominant grasses (Sorghastrum nutans, Andropogon gerardii, and Schizachyrium scoparium). Each whole plot contained subplots sown with three phylogenetically distinct pools of subordinate species. Cover of all species was measured in permanent sampling areas for ten years, and 10 functional traits were measured for 88 species, allowing calculation of PD and FD, respectively. Overall, the communities establishing with local ecotypes of the dominant grasses were functionally more dissimilar than when established with cultivars, particularly among the Asteraceae, suggesting competitive exclusion of functionally dissimilar species by cultivars. This result was opposite to our prediction that cultivars through limiting similarity would exclude more similar species more so than would local ecotypes. The effect of the dominant grass population source was contingent upon interactions with species pools. A supplemental propagule addition of functionally dissimilar species four years since initial sowing increased FD, but this effect varied among species pools. A lack of relationship between FD and PD in this system indicated that measuring PD alone without inclusion of functional traits may miss additional factors affecting species coexistence. In addition, the variation in FD between population sources and among species pools indicated that the measured traits were more sensitive to these factors than to their phylogenetic relationships. This analysis of long‐term data from a field experiment showed new consequences of using different seed sources and species pools (as biotic filters), and supplemental seeding on PD and FD of restored grassland. Quantifying relevant functional traits in a phylogenetic framework could help identify plant population sources that enhance coexistence of desirable species.

Constancy despite variability: Local and regional macrofaunal diversity in intertidal seagrass beds

The importance of seagrass habitat for the diversity of benthic fauna has been extensively studied worldwide. Most of the information available is, however, about α diversity while little consideration has been given to β diversity. To fill the knowledge gaps regarding the variability of epifaunal and infaunal seagrass assemblages at large spatial and temporal scales, we scrutinized an extensive dataset covering five years of monitoring of eight intertidal Zostera marina meadows around Brittany (France). High species richness arose at the regional scale from the combination of high local diversity of the meadows and substantial among-meadows β diversity. Epifauna and infauna appeared as distinct self-communities as they displayed different spatial and temporal patterns and varied in their responses to local hydrological conditions. Infauna had higher total β diversity than epifauna due to a tighter link to the great variability of local environmental conditions in the region. Both exhibited substantial variations in species composition and community structure with variations of dominant species that were accompanied by extensive change in numerous rare species. The dominant epifaunal species were all grazers. Changes in species composition were induced mostly by species replacement and rarely by richness differences between meadows. Indeed, species richness remained within a narrow range for all seagrass beds, suggesting a potential carrying capacity for species richness of the meadows. Overall, all meadows contributed equally to the regional turnover of seagrass macrofauna, emphasizing high variability and complementarity among beds at the regional scale. The implications of this substantial within-seagrass variability for the functioning of benthic ecosystems at broad scale and for conservation purposes in habitat mosaics warrant further investigations but our results clearly advocate taking into account within-habitat variation when evaluating the diversity of benthic habitats and the potential effect of habitat loss.

Investigating the effects of forest structure on the small mammal community in frequent-fire coniferous forests using capture-recapture models for stratified populations

Small mammals comprise an important component of forest vertebrate communities. Our understanding of how small mammals use forested habitat has relied heavily on studies in forest systems not naturally prone to frequent disturbances. Small mammal populations that evolved in frequent-fire forests, however, may be less restricted to specific habitat conditions due to the instability of these resources in time and space. We investigate how canopy cover and the volume of coarse woody debris (CWD), covariates that are considered important for small mammals, impact abundance and body mass of eight small mammal species. Based on live-trapping data collected across 23 sites over three years in a frequent fire forest in the Sierra Nevada we apply capture-recapture models for stratified populations, a statistically rigorous, rarely used framework that allows joint modeling of detection, abundance and its response to covariates. Canopy cover had a strong negative association with the abundance of yellow-pine chipmunks and California ground squirrels, and a strong positive association with deer mice. CWD had a strong negative association with the abundance of golden-mantled ground squirrels, yellow-pine and long-eared chipmunks, and a strong positive association with deer mice. Whereas canopy cover influenced abundance and body mass similarly, CWD had a positive association with body mass and a negative association with abundance in some species. These patterns could arise if suitable habitat is monopolized by socially dominant individuals. Despite these habitat associations, the small mammal community in our study was dynamic and diverse, with spatial and temporal variation in dominant species suggesting that species were flexible in their use of habitat. This study suggests that it is important to understand the disturbance regimes when investigating habitat requirements, coexistence and evolutionary ecology of small mammal species.

Nighttime transpiration in a seasonally dry tropical montane cloud forest environment

Key message Highly variable nighttime transpiration, with higher rates generally observed after preceding fog, is prevalent in dominant tree species of the nutri- ent-poor tropical montane cloud forest environment of central Veracruz, Mexico. Abstract Although nighttime transpiration (En) is pre- valent in a wide range of species from cloud-affected for- ests, its magnitude relative to total daily transpiration (Ed) as reported in the literature is generally small (En/Ed is 0.12 on average). In the present study, we observed high dry- season En/Ed ratios with large night-to-night variation in dominant species from the tropical montane cloud forest (TMCF) zone of central Veracruz, Mexico: 0.22 ± 0.18 for Quercus lancifolia (old-growth TMCF); 0.26 ± 0.14 and 0.16 ± 0.16 for Alchornea latifolia and Alnus jorull- ensis, respectively (regenerating post-fire TMCF); and 0.30 ± 0.20 to 0.12 ± 0.21 for Pinus patula (young and mature pine plantations). En was determined as the dif- ference between observed nocturnal sap flow and estimated refilling of stem water storage, the latter of which was on average: 21-25 % of nocturnal sap flow for Q. lancifolia ;6 and 5 % for A. latifolia and A. jorullensis, respectively; and 21-23 % for P. patula. Night-to-night variation in En was mostly due to large variation in vapor pressure deficit (VPD) related in turn to the alternation of cold fronts (producing fog events) and high pressure weather (pro- ducing nights with VPD up to 2 kPa). Moreover, in the hours following fog events without concurring rainfall, En was often higher as compared to fog-free nights with similar VPD across all species examined. Low-nutrient availability and high water content of the soils in the study area suggest a nutrient uptake benefit associated with the relatively high En rates observed.