scholarly journals Uncovering the relative influences of space and environment in shaping the biogeographic patterns of mangrove mollusk diversity

2019 ◽  
Vol 77 (1) ◽  
pp. 30-39
Author(s):  
Guogui Chen ◽  
Wenqing Wang ◽  
Yi Liu ◽  
Yamian Zhang ◽  
Wei Ma ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Stochastic Processes ◽  
Marine Ecology ◽  
Global Changes ◽  
Diversity Pattern ◽  
Diversity Patterns ◽  
Biogeographic Patterns ◽  
Β Diversity ◽  
Α Diversity ◽  
Deterministic Processes

Abstract Determining the relative importance of ecological processes regulating the biogeographic patterns of marine species, especially with respect to α- and β-diversity in multi-habitat communities, is a central goal in marine ecology. We explored the relative contribution of spatial (stochastic processes) and environmental factors (deterministic processes) to the biogeographic patterns of the α- and β-diversity of mangrove mollusks. A total of 16 mangrove areas were sampled in southeast coast China from 18°N to 28°N latitude. The highest mean α-diversity was found at 20°N and that of β-diversity was at 21°N. Both spatial and environmental factors had significant effects on the α- and β-diversity patterns. The environments had greater effects than the spaces on shaping the α-diversity pattern, while the spaces were relatively more important in governing the β-diversity patterns than the environments. Our results suggest that the α-diversity pattern was mainly controlled by deterministic processes (environmental filtering), while β-diversity was primarily shaped by stochastic processes (dispersal-related), although both processes had significant impacts on α- and β-diversity patterns. Identifying the ecological variables and mechanisms that drive variations in α- and β-diversity may help guide the conservation for biodiversity in endangered mangrove ecosystems under anthropogenic and global changes.

scholarly journals Microbiome assembly predictably shapes diversity across a range of disturbance frequencies

2021 ◽  
Author(s):  
Ezequiel Santillan ◽  
Stefan Wuertz
Keyword(s):  
Temporal Dynamics ◽  
Ecological Communities ◽  
Β Diversity ◽  
Α Diversity ◽  
Deterministic Processes ◽  
Specialized Function ◽  
Successional Stages ◽  
And Function ◽  
Microbiome Assembly

Diversity is frequently linked to the functional stability of ecological communities. However, its association with assembly mechanisms remains largely unknown, particularly under fluctuating disturbances. Here, we subjected complex bacterial communities in bioreactor microcosms to different frequencies of organic loading shocks, tracking temporal dynamics in their assembly, structure and function. Null modelling revealed a stronger role of stochasticity at intermediate disturbance frequencies, preceding the formation of a peak in α-diversity. Communities at extreme ends of the disturbance range had the lowest α-diversity and highest within-treatment similarity in terms of β-diversity, with stronger deterministic assembly. Stochasticity prevailed during the initial successional stages, coinciding with better specialized function (nitrogen removal). In contrast, general functions (carbon removal and microbial aggregate settleability) benefited from stronger deterministic processes. We showed that changes in assembly processes predictably precede changes in diversity under a gradient of disturbance frequencies, advancing our understanding of the mechanisms behind disturbance-diversity-function relationships.

scholarly journals α- and β-Diversity Patterns of Macrophytes and Freshwater Fishes are Driven by Different Factors and Processes in Lakes of the Unexplored Southern Balkan Biodiversity Hotspot

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1984
Author(s):  
Anthi Oikonomou ◽  
Konstantinos Stefanidis
Keyword(s):  
Species Richness ◽  
Species Turnover ◽  
Biodiversity Hotspot ◽  
Environmental Drivers ◽  
Conservation Strategies ◽  
Compositional Variation ◽  
Related Factors ◽  
Diversity Patterns ◽  
Β Diversity ◽  
Α Diversity

Disentangling the main drivers of species richness and community composition is a central theme in ecology. Freshwater biodiversity patterns have been poorly explored; yet, it has been shown that different freshwater biota have different, often contrasting responses to environmental gradients. In this study, we investigated the relative contribution of geographical and environmental (habitat-, climate- and water quality-related) factors/gradients in shaping the α- and β-diversity patterns of macrophytes and fish in sixteen natural freshwater lakes of an unexplored Balkan biodiversity hotspot, the Southern Balkan Peninsula. We employed generalized linear modeling to identify drivers of α-diversity, and generalized dissimilarity modeling to explore commonalities and dissimilarities of among-biota β-diversity. Species richness of both biota was significantly associated with lake surface area, whereas macrophytes had an inverse response to altitude, compared to fish. Both species turnover and nestedness significantly contributed to the total β-diversity of macrophytes. In contrast, species turnover was the most significant contributor to the total fish β-diversity. We found that the compositional variation of macrophytes is primarily limited by dispersal and ultimately shaped by environmental drivers, resulting in spatially structured assemblages. Fish communities were primarily shaped by altitude, highlighting the role of species sorting. We conclude that among-biota diversity patterns are shaped by different/contrasting factors, and, thus, effective/sustainable conservation strategies should encompass multiple aquatic biota.

scholarly journals Elevational Diversity Patterns of Green Lacewings (Neuroptera: Chrysopidae) Uncovered With DNA Barcoding in a Biodiversity Hotspot of Southwest China

2021 ◽  
Vol 9 ◽  
Author(s):  
Yan Lai ◽  
Yunhui Liu ◽  
Xingyue Liu
Keyword(s):  
Species Diversity ◽  
Dna Barcoding ◽  
Diversity Index ◽  
Global Climate ◽  
Diversity Pattern ◽  
Diversity Patterns ◽  
Green Lacewings ◽  
Wiener Diversity Index ◽  
Α Diversity ◽  
Main Component

Elevational diversity patterns can reflect the responses of biodiversity to climate change spatially. We investigate the species diversity patterns of green lacewings (an important predatory group of insects) along the gradient of elevation from the Shaluli Mountains (Mts. Shaluli), which belong to the Hengduan Mountains in southwestern China, one of the important hotspots of global biodiversity. We combined multiple approaches, including Automatic Barcode Gap Discovery (ABGD), Assemble Species by Automatic Partitioning analysis (ASAP), General Mixed Yule Coalescent (GMYC), Poisson tree processes (bPTP), multi-rate Poisson tree processes (mPTP), to delimit the green lacewings species based on the standard barcoding region of cytochrome c oxidase subunit I (COI). The α-diversity and β-diversity patterns of green lacewings from the Mts. Shaluli along the gradient of elevation were analyzed, with further exploration on how the temperature effect elevational-diversity pattern on broad-scale (county scale) elevational gradients. The DNA barcoding reference library consisted of 40 green lacewing species from the Mts. Shaluli. The α-diversity of green lacewings decreased with the increasing elevation. The temperature was found to have a significant effect on the abundance and Shannon-Wiener diversity index but not on the species richness. Nestedness replaced turnover as the main component of Sørensen’s dissimilarity with the increasing elevation, and greater nestedness occurred at low temperature areas. The combination of a reliable DNA barcoding database could improve the accuracy and efficiency to investigate the species diversity patterns of green lacewings. Temperature, resource, and resultant interspecific competitions may have important roles in explaining the species diversity patterns of green lacewings from the Mts. Shaluli. Priority of conservation should be given to the species at low elevation, middle elevation, and relatively high temperature regions under the background of global climate warming.

SPECIES DIVERSITY AND COMMUNITY PATTERNS ALONG THE DISTURBANCE GRADIENT IN DRY TROPICAL FORESTS OF CHITRAKOOT, BANDA (U.P.) INDIA

2018 ◽  
Vol 24 (2) ◽  
Author(s):  
MILAN YADAV ◽  
RAVINDRA SINGH
Keyword(s):  
Importance Value Index ◽  
Importance Value ◽  
Community Patterns ◽  
Diversity Pattern ◽  
The Core ◽  
Β Diversity ◽  
Disturbance Gradient ◽  
Α Diversity ◽  
Forest Division ◽  
The Impact

The magnitude and recurrence of disturbance is the main factor to affect the structure of the forest communities in a variety of ways. A forty KM long disturbance gradient was identified across the forest of Chitrakoot in Banda Forest Division and the impact of different degrees of disturbance on the community attributes and diversity pattern of the forests along this gradient, was observed. The sum of frequency for species components of different stands increased along the gradient with marked fluctuations. The sum of density, however, increased only upto a few peripheral stands and stabilized further. The trend of the two indices and fluctuations in these values indicated highly patchy and heterogeneous communities along the disturbance gradient. Several potential under trees like Mallotus and Clerodendron dominated the shrub layer with greater abundance under high disturbance while other non-leguminous species of shrubby habit dominated the stands facing intermediate disturbance. The relative density of leguminous shrubs decreased along the gradient. The efficiently sprouting trees like Holarrhena and Terminalia have maximum importance value index (IVI) at moderate disturbance while Scleichera oleosa did so toward the core. A maximum Shannon’s Index of Diversity H of 3.53 was observed for the last but one stand towards the core. The trends of dominance and β-diversity were reverse to that of α-diversity along the gradient. From these observations, it may be inferred that the disturbance should be contained at the level suited for maximum diversity beside sparing a few ‘disturbancefriendly’ species in highly disturbed stands from complete destruction in order to provide bare minimum herbage cover, required for ecosystem attributes for the forests of the region.

scholarly journals Microbes and macro-invertebrates show parallel β-diversity but contrasting α-diversity patterns in a marine natural experiment

2019 ◽  
Vol 286 (1912) ◽  
pp. 20190999 ◽  
Author(s):  
Giovanni Rapacciuolo ◽  
J. Michael Beman ◽  
Lauren M. Schiebelhut ◽  
Michael N. Dawson
Keyword(s):  
Natural Experiment ◽  
Similar Degree ◽  
Ecological Communities ◽  
Diversity Patterns ◽  
Β Diversity ◽  
Α Diversity ◽  
Marine Lakes ◽  
Regional Species Pool ◽  
Marine Realm ◽  
Spatio Temporal

Documenting ecological patterns across spatially, temporally and taxonomically diverse ecological communities is necessary for a general understanding of the processes shaping biodiversity. A major gap in our understanding remains the comparison of diversity patterns across a broad spectrum of evolutionarily and functionally diverse organisms, particularly in the marine realm. Here, we aim to narrow this gap by comparing the diversity patterns of free-living microbes and macro-invertebrates across a natural experiment provided by the marine lakes of Palau: geographically discrete and environmentally heterogeneous bodies of seawater with comparable geological and climatic history, and a similar regional species pool. We find contrasting patterns of α-diversity but remarkably similar patterns of β-diversity between microbial and macro-invertebrate communities among lakes. Pairwise dissimilarities in community composition among lakes are positively correlated between microbes and macro-invertebrates, and influenced to a similar degree by marked gradients in oxygen concentration and salinity. Our findings indicate that a shared spatio-temporal and environmental context may result in parallel patterns of β-diversity in microbes and macro-invertebrates, in spite of key trait differences between these organisms. This raises the possibility that parallel processes also influence transitions among regional biota across the tree of life, at least in the marine realm.

scholarly journals Diversity Patterns of Different Life Forms of Plants along an Elevational Gradient in Crete, Greece

Diversity ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 200 ◽  
Author(s):  
Maria Lazarina ◽  
Athanasios Charalampopoulos ◽  
Maria Psaralexi ◽  
Nikos Krigas ◽  
Danai-Eleni Michailidou ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Large Scale ◽  
Regional Scale ◽  
Elevational Gradient ◽  
Life Forms ◽  
Species Pool ◽  
Diversity Patterns ◽  
Β Diversity ◽  
Α Diversity

Elevational gradients provide a unique opportunity to explore species responses to changing environmental conditions. Here, we focus on an elevational gradient in Crete, a climate-vulnerable Mediterranean plant biodiversity hotspot and explore the diversity patterns and underlying mechanisms of different plant life forms. We found that the significant differences in life forms’ elevational and environmental ranges are reflected in α- diversity (species richness at local scale), γ-diversity (species richness at regional scale) and β-diversity (variation in species composition). The α- and γ-diversity decreased with elevation, while β-diversity followed a hump-shaped relationship, with the peak varying between life forms. However, β-deviation (deviation from null expectations) varied significantly with elevation but was life formindependent. This suggests that species composition is shaped by the size of the available species pool which depends on life form, but also by other deterministic or stochastic processes that act in a similar way for different life forms. The strength of these processes varies with elevation, with hotter–drier conditions and increased human activities filtering species composition at lowlands and large-scale processes determining the species pool size overriding local ecological processes at higher elevations.

scholarly journals Dietary Fiber Influences Bacterial Community Assembly Processes in the Gut Microbiota of Durco × Bamei Crossbred Pig

2021 ◽  
Vol 12 ◽  
Author(s):  
Xianjiang Tang ◽  
Liangzhi Zhang ◽  
Chao Fan ◽  
Lei Wang ◽  
Haibo Fu ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Dietary Fiber ◽  
Community Assembly ◽  
Cecal Content ◽  
High Fiber ◽  
Β Diversity ◽  
Composition And Structure ◽  
Α Diversity ◽  
Deterministic Processes ◽  
Crossbred Pigs

Several studies have shown that dietary fiber can significantly alter the composition and structure of the gut bacterial community in humans and mammals. However, few researches have been conducted on the dynamics of the bacterial community assembly across different graded levels of dietary fiber in different gut regions. To address this, 24 Durco × Bamei crossbred pigs were randomly assigned to four experimental chows comprising graded levels of dietary fiber. Results showed that the α-and β-diversity of the bacterial community was significantly different between the cecum and the jejunum. Adding fiber to the chow significantly increased the α-diversity of the bacterial community in the jejunum and cecum, while the β-diversity decreased. The complexity of the bacterial network increased with the increase of dietary fiber in jejunal content samples, while it decreased in cecal content samples. Furthermore, we found that stochastic processes governed the bacterial community assembly of low and medium dietary fiber groups of jejunal content samples, while deterministic processes dominated the high fiber group. In addition, deterministic processes dominated all cecal content samples. Taken together, the variation of gut community composition and structure in response to dietary fiber was distinct in different gut regions, and the dynamics of bacterial community assembly across the graded levels of dietary fiber in different gut regions was also distinct. These findings enhanced our knowledge on the bacterial community assembly processes in gut ecosystems of livestock.

scholarly journals Beta diversity patterns of Bromeliaceae growing on rocky cliffs within the Atlantic Forest in southern Brazil

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Edilaine Andrade Melo ◽  
Jorge Luiz Waechter
Keyword(s):  
Environmental Factors ◽  
Species Composition ◽  
Atlantic Forest ◽  
Beta Diversity ◽  
Variation Partitioning ◽  
Floristic Composition ◽  
Spatial Effects ◽  
Environmental Predictors ◽  
Diversity Patterns ◽  
Β Diversity

Abstract: In recent years there has been increasing attention in patterns of β-diversity and mechanisms related to variations in species composition. In this study, we evaluated beta diversity patterns of bromeliads growing on cliffs immersed in Atlantic Forest. We hypothesized that the species composition varies according to the spatial scale, inferring that there is a replacement of species influenced mainly by environmental factors. The study was carried out on sandstone cliffs included in contiguous but distinct vegetation formations: Evergreen and Seasonal forests. Twenty-four vertical rocky outcrops were sampled. The spatial variation in species composition was evaluated by two β-diversity components, turnover and nestedness. Multivariate analysis and variation partitioning were performed to distinguish niche and stochastic processes. We recorded 26 bromeliad species and a significantly higher contribution of turnover explaining beta diversity. Environmental factors affect β-diversity patterns of Bromeliaceae. However, individually, the environmental predictors do not explain the data variation. Environmental variations spatially structured, and spatial variables determinate the dissimilarity in the composition of bromeliads on cliffs. Thus, our results revealed that both environmental and spatial effects can act together to define the floristic composition of rock-dwelling bromeliad communities.

scholarly journals Relative Importance of Deterministic and Stochastic Processes on Soil Microbial Community Assembly in Temperate Grasslands

2021 ◽  
Vol 9 (9) ◽  
pp. 1929
Author(s):  
Nana Liu ◽  
Huifeng Hu ◽  
Wenhong Ma ◽  
Ye Deng ◽  
Qinggang Wang ◽  
...  
Keyword(s):  
Stochastic Processes ◽  
Soil Microbes ◽  
Explanatory Power ◽  
Soil Microbial Communities ◽  
Northern China ◽  
Temperate Grasslands ◽  
Soil Layers ◽  
Soil Microbial ◽  
Β Diversity ◽  
Deterministic Processes

Changes in species composition across communities, i.e., β-diversity, is a central focus of ecology. Compared to macroorganisms, the β-diversity of soil microbes and its drivers are less studied. Whether the determinants of soil microbial β-diversity are consistent between soil depths and between abundant and rare microorganisms remains controversial. Here, using the 16S-rRNA of soil bacteria and archaea sampled at different soil depths (0–10 and 30–50 cm) from 32 sites along an aridity gradient of 1500 km in the temperate grasslands in northern China, we compared the effects of deterministic and stochastic processes on the taxonomic and phylogenetic β-diversity of soil microbes. Using variation partitioning and null models, we found that the taxonomic β-diversity of the overall bacterial communities was more strongly determined by deterministic processes in both soil layers (the explanatory power of environmental distance in topsoil: 25.4%; subsoil: 47.4%), while their phylogenetic counterpart was more strongly determined by stochastic processes (the explanatory power of spatial distance in topsoil: 42.1; subsoil 24.7%). However, in terms of abundance, both the taxonomic and phylogenetic β-diversity of the abundant bacteria in both soil layers was more strongly determined by deterministic processes, while those of rare bacteria were more strongly determined by stochastic processes. In comparison with bacteria, both the taxonomic and phylogenetic β-diversity of the overall abundant and rare archaea were strongly determined by deterministic processes. Among the variables representing deterministic processes, contemporary and historical climate and aboveground vegetation dominated the microbial β-diversity of the overall and abundant microbes of both domains in topsoils, but soil geochemistry dominated in subsoils. This study presents a comprehensive understanding on the β-diversity of soil microbial communities in the temperate grasslands in northern China. Our findings highlight the importance of soil depth, phylogenetic turnover, and species abundance in the assembly processes of soil microbial communities.

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