scholarly journals Assembly processes of gastropod community change with horizontal and vertical zonation in ancient Lake Ohrid: a metacommunity speciation perspective

2016 ◽  
Vol 13 (10) ◽  
pp. 2901-2911 ◽  
Author(s):  
Torsten Hauffe ◽  
Christian Albrecht ◽  
Thomas Wilke
Keyword(s):  
Community Composition ◽  
Community Assembly ◽  
Environmental Filtering ◽  
Dispersal Limitation ◽  
Species Interaction ◽  
Relative Importance ◽  
Lake Depth ◽  
Ancient Lake ◽  
Lake Ohrid ◽  
Speciation Model

Abstract. The Balkan Lake Ohrid is the oldest and most diverse freshwater lacustrine system in Europe. However, it remains unclear whether species community composition, as well as the diversification of its endemic taxa, is mainly driven by dispersal limitation, environmental filtering, or species interaction. This calls for a holistic perspective involving both evolutionary processes and ecological dynamics, as provided by the unifying framework of the “metacommunity speciation model”.The current study used the species-rich model taxon Gastropoda to assess how extant communities in Lake Ohrid are structured by performing process-based metacommunity analyses. Specifically, the study aimed (1) to identifying the relative importance of the three community assembly processes and (2) to test whether the importance of these individual processes changes gradually with lake depth or discontinuously with eco-zone shifts.Based on automated eco-zone detection and process-specific simulation steps, we demonstrated that dispersal limitation had the strongest influence on gastropod community composition. However, it was not the exclusive assembly process, but acted together with the other two processes – environmental filtering and species interaction. The relative importance of the community assembly processes varied both with lake depth and eco-zones, though the processes were better predicted by the latter.This suggests that environmental characteristics have a pronounced effect on shaping gastropod communities via assembly processes. Moreover, the study corroborated the high importance of dispersal limitation for both maintaining species richness in Lake Ohrid (through its impact on community composition) and generating endemic biodiversity (via its influence on diversification processes). However, according to the metacommunity speciation model, the inferred importance of environmental filtering and biotic interaction also suggests a small but significant influence of ecological speciation. These findings contribute to the main goal of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) deep drilling initiative – inferring the drivers of biotic evolution – and might provide an integrative perspective on biological and limnological dynamics in ancient Lake Ohrid.

scholarly journals Gastropod diversification and community structuring processes in ancient Lake Ohrid: a metacommunity speciation perspective

2015 ◽  
Vol 12 (18) ◽  
pp. 16081-16103 ◽  
Author(s):  
T. Hauffe ◽  
C. Albrecht ◽  
T. Wilke
Keyword(s):  
Community Assembly ◽  
Species Interactions ◽  
Environmental Filtering ◽  
Dispersal Limitation ◽  
Species Interaction ◽  
Relative Importance ◽  
Lake Depth ◽  
Ancient Lake ◽  
Lake Ohrid ◽  
Speciation Model

Abstract. The Balkan Lake Ohrid is the oldest and most speciose freshwater lacustrine system in Europe. However, it remains unclear whether the diversification of its endemic taxa is mainly driven by neutral processes, environmental factors, or species interactions. This calls for a holistic perspective involving both evolutionary processes and ecological dynamics. Such a unifying framework – the metacommunity speciation model – considers how community assembly affects diversification and vice versa by assessing the relative contribution of the three main community assembly processes, dispersal limitation, environmental filtering, and species interaction. The current study therefore used the species-rich model taxon Gastropoda to assess how extant communities in Lake Ohrid are structured by performing process based metacommunity analyses. Specifically, the study aimed at (i) identifying the relative importance of the three community assembly processes and (ii) to test whether the importance of these individual processes changes gradually with lake depth or whether they are distinctively related to eco-zones. Based on specific simulation steps for each of the three processes, it could be demonstrated that dispersal limitation had the strongest influence on gastropod community structures in Lake Ohrid. However, it was not the exclusive assembly process but acted together with the other two processes – environmental filtering, and species interaction. In fact, the relative importance of the three community assembly processes varied both with lake depth and eco-zones, though the processes were better predicted by the latter. The study thus corroborated the high importance of dispersal limitation for both maintaining species richness in Lake Ohrid (through its impact on community structure) and generating endemic biodiversity (via its influence on diversification processes). However, according to the metacommunity speciation model, the inferred importance of environmental filtering and biotic interaction also suggests a small but significant influence of ecological speciation. These findings contribute to the main goal of the SCOPSCO initiative – inferring the drivers of biotic evolution – and might provide an integrative perspective on biological and limnological dynamics in ancient Lake Ohrid.

scholarly journals The role of environmental filtering, geographic distance and dispersal barriers in shaping the turnover of plant and animal species in Amazonia

2020 ◽  
Vol 29 (13) ◽  
pp. 3609-3634 ◽  
Author(s):  
Cristian Dambros ◽  
Gabriela Zuquim ◽  
Gabriel M. Moulatlet ◽  
Flávia R. C. Costa ◽  
Hanna Tuomisto ◽  
...  
Keyword(s):  
Community Composition ◽  
Environmental Conditions ◽  
Environmental Gradients ◽  
Isolation By Distance ◽  
Geographic Distance ◽  
Environmental Filtering ◽  
Dispersal Limitation ◽  
Multivariate Techniques ◽  
Time Period ◽  
Dispersal Barriers

Abstract To determine the effect of rivers, environmental conditions, and isolation by distance on the distribution of species in Amazonia. Location: Brazilian Amazonia. Time period: Current. Major taxa studied: Birds, fishes, bats, ants, termites, butterflies, ferns + lycophytes, gingers and palms. We compiled a unique dataset of biotic and abiotic information from 822 plots spread over the Brazilian Amazon. We evaluated the effects of environment, geographic distance and dispersal barriers (rivers) on assemblage composition of animal and plant taxa using multivariate techniques and distance- and raw-data-based regression approaches. Environmental variables (soil/water), geographic distance, and rivers were associated with the distribution of most taxa. The wide and relatively old Amazon River tended to determine differences in community composition for most biological groups. Despite this association, environment and geographic distance were generally more important than rivers in explaining the changes in species composition. The results from multi-taxa comparisons suggest that variation in community composition in Amazonia reflects both dispersal limitation (isolation by distance or by large rivers) and the adaptation of species to local environmental conditions. Larger and older river barriers influenced the distribution of species. However, in general this effect is weaker than the effects of environmental gradients or geographical distance at broad scales in Amazonia, but the relative importance of each of these processes varies among biological groups.

scholarly journals Vertical stratification of microbial communities in woody plants

2021 ◽  
Author(s):  
Mohammad Bahram ◽  
Kati Kings ◽  
Mari Pent ◽  
Sergei Polme ◽  
Daniyal Gohar ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Community Assembly ◽  
Boreal Forests ◽  
Fungal Endophytes ◽  
Environmental Filtering ◽  
Dispersal Limitation ◽  
Distribution Patterns ◽  
Fungal Communities ◽  
Spatial Distance ◽  
Related Factors

Bacterial and fungal endophytes form diverse communities and contribute to the performance and health of their host plants. Recent evidence suggests that both host related factors and environmental conditions determine the community structure of plant endophytes. Yet, we know little about their distribution patterns, and underlying community assembly mechanisms across plant compartments. Here we analysed the structure of bacterial and fungal communities associated with tree compartments as well as their underlying soils across 12 tree individuals in boreal forests. We found that the structure of bacterial and fungal communities depends more strongly on the vertical location of tree compartments rather than the locality, species, and individuals of host trees. Microbial communities showed much stronger host specificity in aboveground than belowground compartments. While having lower compartment community variability compared to fungi, bacterial communities were markedly more distinct between below- and aboveground components but not between hosts, reflecting the greater importance of environmental filtering rather than dispersal limitation and host identity in their community assembly. Our data suggest that spatial distance from soil as a major microbiome source contributes to the formation of microbiomes in plants, and that bacterial and fungal communities may follow contrasting assembly processes.

scholarly journals pH Influences the Importance of Niche-Related and Neutral Processes in Lacustrine Bacterioplankton Assembly

2015 ◽  
Vol 81 (9) ◽  
pp. 3104-3114 ◽  
Author(s):  
Lijuan Ren ◽  
Erik Jeppesen ◽  
Dan He ◽  
Jianjun Wang ◽  
Lone Liboriussen ◽  
...  
Keyword(s):  
Community Assembly ◽  
Environmental Filtering ◽  
Relative Importance ◽  
Limited Information ◽  
Freshwater Lakes ◽  
Ph Gradients ◽  
Bacterioplankton Community ◽  
Neutral Processes ◽  
Acidic Lakes ◽  
Bacterioplankton Communities

ABSTRACTpH is an important factor that shapes the structure of bacterial communities. However, we have very limited information about the patterns and processes by which overall bacterioplankton communities assemble across wide pH gradients in natural freshwater lakes. Here, we used pyrosequencing to analyze the bacterioplankton communities in 25 discrete freshwater lakes in Denmark with pH levels ranging from 3.8 to 8.8. We found that pH was the key factor impacting lacustrine bacterioplankton community assembly. More acidic lakes imposed stronger environmental filtering, which decreased the richness and evenness of bacterioplankton operational taxonomic units (OTUs) and largely shifted community composition. Although environmental filtering was determined to be the most important determinant of bacterioplankton community assembly, the importance of neutral assembly processes must also be considered, notably in acidic lakes, where the species (OTU) diversity was low. We observed that the strong effect of environmental filtering in more acidic lakes was weakened by the enhanced relative importance of neutral community assembly, and bacterioplankton communities tended to be less phylogenetically clustered in more acidic lakes. In summary, we propose that pH is a major environmental determinant in freshwater lakes, regulating the relative importance and interplay between niche-related and neutral processes and shaping the patterns of freshwater lake bacterioplankton biodiversity.

scholarly journals Spatial Variation in Soil Fungal Communities across Paddy Fields in Subtropical China

mSystems ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Pengfa Li ◽  
Weitao Li ◽  
Alex J. Dumbrell ◽  
Ming Liu ◽  
Guilong Li ◽  
...  
Keyword(s):  
Spatial Variation ◽  
Fungal Community ◽  
Community Assembly ◽  
Soil Depth ◽  
Environmental Filtering ◽  
Its Region ◽  
Dispersal Limitation ◽  
Fungal Communities ◽  
Subtropical China ◽  
Soil Layers

ABSTRACT Fungi underpin almost all terrestrial ecosystem functions, yet our understanding of their community ecology lags far behind that of other organisms. Here, red paddy soils in subtropical China were collected across a soil depth profile, comprising 0-to-10-cm- (0-10cm-), 10-20cm-, and 20-40cm-deep layers. Using Illumina MiSeq amplicon sequencing of the internal transcribed spacer (ITS) region, distance-decay relationships (DDRs), and ecological models, fungal assemblages and their spatial patterns were investigated from each soil depth. We observed significant spatial variation in fungal communities and found that environmental heterogeneity decreased with soil depth, while spatial variation in fungal communities showed the opposite trend. DDRs occurred only in 0-10cm- and 10-20cm-deep soil layers, not in the 20-40cm layer. Our analyses revealed that the fungal community assembly in the 0-10cm layer was primarily governed by environmental filtering and a high dispersal rate, while in the deeper layer (20-40cm), it was primarily governed by dispersal limitation with minimal environmental filtering. Both environmental filtering and dispersal limitation controlled fungal community assembly in the 10-20cm layer, with dispersal limitation playing the major role. Results demonstrate the decreasing importance of environmental filtering and an increase in the importance of dispersal limitation in structuring fungal communities from shallower to deeper soils. Effectively, “everything is everywhere, but the environment selects,” although only in shallower soils that are easily accessible to dispersive fungal propagules. This work highlights that perceived drivers of fungal community assembly are dependent on sampling depth, suggesting that caution is required when interpreting diversity patterns from samples that integrate across depths. IMPORTANCE In this work, Illumina MiSeq amplicon sequencing of the ITS region was used to investigate the spatial variation and assembly mechanisms of fungal communities from different soil layers across paddy fields in subtropical China, and the results demonstrate the decreasing importance of environmental filtering and an increase in the importance of dispersal limitation in structuring fungal communities from shallower to deeper soils. Therefore, the results of this study highlight that perceived drivers of fungal community assembly are dependent on sampling depth and suggest that caution is required when interpreting diversity patterns from samples that integrate across depths. This is the first study focusing on assemblages of fungal communities in different soil layers on a relatively large scale, and we thus believe that this study is of great importance to researchers and readers in microbial ecology, especially in microbial biogeography, because the results can provide sampling guidance in future studies of microbial biogeography.

Differences among regions in environmental predictors of primate community similarity affect conclusions about community assembly

2019 ◽  
Vol 35 (2) ◽  
pp. 83-90 ◽  
Author(s):  
Lydia Beaudrot ◽  
Andrew J. Marshall
Keyword(s):  
Community Assembly ◽  
Environmental Variables ◽  
Geographic Distance ◽  
Environmental Filtering ◽  
Dispersal Limitation ◽  
Community Similarity ◽  
Primate Communities ◽  
Assembly Mechanism ◽  
Primate Community ◽  
Environmental Distance

AbstractUnderstanding why ecological communities contain the species they do is a long-standing question in ecology. Two common mechanisms that affect the species found within communities are dispersal limitation and environmental filtering. Correctly identifying the relative influences of these mechanisms has important consequences for our understanding of community assembly. Here variable selection was used to identify the environmental variables that best predict tropical forest primate community similarity in four biogeographic regions: the Neotropics, Afrotropics, Madagascar and the island of Borneo in South-East Asia. The environmental variables included net primary productivity and altitude, as well as multiple temperature, precipitation and topsoil variables. Using the best environmental variables in each region, Mantel and partial Mantel tests were used to reanalyse data from a previously published study. The proportion of variance explained increased for each region. Despite increases, much of the variation remained unexplained for all regions (R2: Africa = 0.45, South America = 0.16, Madagascar = 0.28, Borneo = 0.10), likely due to different evolutionary and biogeographic histories within each region. Nonetheless, substantial variation among regions in the environmental variables that best predicted primate community similarity were documented. For example, none of the 14 environmental variables was included for all four regions, yet each variable was included for at least one region. Contrary to prior results, environmental filtering was an important assembly mechanism for primate communities in tropical forests worldwide. Geographic distance more strongly predicted African and South American communities whereas environmental distance more strongly predicted Malagasy and Bornean communities. These results suggest that dispersal limitation structures primate communities more strongly than environmental filtering in Africa and in South America whereas environmental filtering structures primate communities more strongly than dispersal limitation in Madagascar and Borneo. For communities defined by genera, environmental distance more strongly predicted primate communities than geographic distance in all four regions, which suggests that environmental filtering is a more influential assembly mechanism at the genus level. Therefore, a more nuanced consideration of environmental variables affects conclusions about the influences of environmental filtering and dispersal limitation on primate community structure.

scholarly journals Spatial gradients in soil-carbon character of a coastal forested floodplain are associated with abiotic features, but not microbial communities

2019 ◽  
Author(s):  
Aditi Sengupta ◽  
Julia Indivero ◽  
Cailene Gunn ◽  
Malak M. Tfaily ◽  
Rosalie K. Chu ◽  
...  
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Organic Compounds ◽  
Community Composition ◽  
Community Assembly ◽  
Dispersal Limitation ◽  
Water Soluble ◽  
Microbial Composition ◽  
Organic C ◽  
Shallow Soils

Abstract. Coastal terrestrial-aquatic interfaces (TAIs) are dynamic zones of biogeochemical cycling influenced by salinity gradients. However, there is significant heterogeneity in salinity influences on TAI soil biogeochemical function. This heterogeneity is perhaps related to unrecognized mechanisms associated with carbon (C) chemistry and microbial communities. To investigate this potential, we evaluated hypotheses associated with salinity-associated shifts in organic C thermodynamics, biochemical transformations, and heteroatom content in a first-order coastal watershed in the Olympic Peninsula of Washington state, USA. In contrast to our hypotheses, thermodynamic favorability of water soluble organic compounds in shallow soils decreased with increasing salinity, as did the number of inferred biochemical transformations and total heteroatom content. These patterns indicate lower microbial activity at higher salinity that is potentially constrained by accumulation of less favorable organic C. Furthermore, organic compounds appeared to be primarily marine/algal-derived in forested floodplain soils with more lipid-like and protein-like compounds, relative to upland soils that had more lignin-, tannin-, and carbohydrate-like compounds. Based on a recent simulation-based study, we further hypothesized a relationship between microbial community assembly processes and C chemistry. Null modelling revealed strong influences of dispersal limitation over microbial composition, which may be due to limited hydrologic connectivity within the clay-rich soils. Dispersal limitation indicated stochastically assembled communities, which was further reflected in the lack of an association between community assembly processes and C chemistry. This suggests a disconnect between microbial community composition and C biogeochemistry, thereby indicating that the salinity-associated gradient in C chemistry was driven by a combination of spatially-structured inputs and salinity-associated metabolic responses of microbial communities that were independent of community composition. We propose that impacts of salinity on coastal soil biogeochemistry need to be understood in the context of C chemistry, hydrologic/depositional dynamics, and microbial physiology, while microbial composition may have less influence.

scholarly journals The joint contributions of environmental filtering and spatial processes to macroinvertebrate metacommunity dynamics in the alpine stream environment of Baima Snow Mountain, Southwest China

2021 ◽  
Author(s):  
Muhammad Farooq ◽  
Xianfu Li ◽  
Zhengfei Li ◽  
Ronglong Yang ◽  
Zhen Tian ◽  
...  
Keyword(s):  
Community Ecology ◽  
Community Composition ◽  
Community Assembly ◽  
Environmental Filtering ◽  
Mountain Stream ◽  
High Mountain ◽  
Spatial Processes ◽  
Relative Significance ◽  
Alpine Stream ◽  
Over Time

As a rapidly growing field of community ecology, the study of meta-communities provides an effective framework to unravel community assembly mechanisms by focusing on the relative contributions of environmental screening and spatial processes. While macroinvertebrates have been extensively investigated in many river ecosystems, meta-community ecology perspectives in high mountain stream networks are very limited. In this study, we assessed the role of ecological determinants and temporal dynamics in the macroinvertebrate meta-community assembly of an alpine stream situated in a dry-hot valley of Baima Snow Mountain, Northwest Yunnan. Our results show significant differences in the macroinvertebrate community composition across time periods. Spatial structuring and environmental filtering jointly drive the configuration of macroinvertebrate meta-community, with relative contributions to the variance in community composition varying over time. Redundancy Analysis (RDA) and variation partitioning indicate that environmental variables are the most important predictors of community organization in most scenarios, whereas spatial determinants also play a significant role. Moreover, the explanatory power, identity, and the relative significance of ecological indicators change over time. Particularly, in the years 2018 and 2019, stronger environmental filtering was found shaping community assembly, suggesting that deterministic mechanisms predominated in driving community dynamics in such a specific environment of the stream. However, spatial factors had a stronger predictive power on meta-community structures in 2017, implying conspicuous dispersal mechanisms which may be owing to increased connectivity amongst locations. Thereby, we inferred that the stream macroinvertebrate metacommunity composition can be regulated by the interaction of both spatial processes and environmental filtering, with relative contributions varying over time. Based on these findings, we suggest that community ecology studies in aquatic systems should be designed beyond single snapshot investigations.

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