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 Advances, challenges and a developing synthesis of ecological community assembly theory

2011 ◽  
Vol 366 (1576) ◽  
pp. 2403-2413 ◽  
Author(s):  
Evan Weiher ◽  
Deborah Freund ◽  
Tyler Bunton ◽  
Artur Stefanski ◽  
Tali Lee ◽  
...  
Keyword(s):  
Community Assembly ◽  
Common Ground ◽  
Environmental Gradients ◽  
Environmental Filtering ◽  
Relative Importance ◽  
Species Sorting ◽  
Neutral Processes ◽  
Multiple Processes ◽  
Niche Assembly

Ecological approaches to community assembly have emphasized the interplay between neutral processes, niche-based environmental filtering and niche-based species sorting in an interactive milieu. Recently, progress has been made in terms of aligning our vocabulary with conceptual advances, assessing how trait-based community functional parameters differ from neutral expectation and assessing how traits vary along environmental gradients. Experiments have confirmed the influence of these processes on assembly and have addressed the role of dispersal in shaping local assemblages. Community phylogenetics has forged common ground between ecologists and biogeographers, but it is not a proxy for trait-based approaches. Community assembly theory is in need of a comparative synthesis that addresses how the relative importance of niche and neutral processes varies among taxa, along environmental gradients, and across scales. Towards that goal, we suggest a set of traits that probably confer increasing community neutrality and regionality and review the influences of stress, disturbance and scale on the importance of niche assembly. We advocate increasing the complexity of experiments in order to assess the relative importance of multiple processes. As an example, we provide evidence that dispersal, niche processes and trait interdependencies have about equal influence on trait-based assembly in an experimental grassland.

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 The Relative Importance of Niche Process and Neutral Process in the Community Assembly of Subtropical Karst Forest: A Perspective on the Changes of Species Distribution Patterns at Different Scales

2021 ◽  
Author(s):  
Yan He ◽  
Yong Jiang ◽  
Hongling Lin ◽  
Yuanfang Pan ◽  
Shichu Liang ◽  
...  
Keyword(s):  
Community Assembly ◽  
Variation Partitioning ◽  
Species Abundance ◽  
Distribution Patterns ◽  
Relative Importance ◽  
Ecological Processes ◽  
Abundance Pattern ◽  
Karst Forest ◽  
Neutral Processes ◽  
Neutral Process

Abstract Background and aimsThe importance of niche processes and neutral processes to community assembly has been affirmed by most studies, although their relative importance needs to be determined in many systems. Moreover, as the spatial scale changes, the ecological processes that determine the community pattern may differ. We tested these ideas in subtropical karst forest in southwestern China in order to aid efforts of community reconstruction.MethodsTo test the importance of niche-based and neutral mechanisms we compared the fit six models to the observed SAD of the plot at three different sampling scales (10 m × 10 m, 20 m × 20 m, 50 m × 50 m). We also used spatial autocorrelation and distance-based Moran's eigenvector maps (dbMEM) combined with variation partitioning to further determine the relative contribution of the niche process and the neutral process under different sampling scales.ResultsThe neutral theoretical and statistical models fit the observed species abundance distribution curve best at each sampling scale. And variation partitioning showed that although the contribution of spatial structure was lower at larger sampling scales, it was still important, suggesting that neutral processes drive community structure at all sampling scales. In contrast, habitat filtering and interspecies competition may lead to a net weakening of the contribution of the niche process to the species abundance pattern of the community because they act in opposite directions. ConclusionsIn the restoration and reconstruction of local karst forest communities, environmental heterogeneity, inter-species relationships, and geographic spatial differences should all be considered.

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 Trait convergence and trait divergence in lake phytoplankton reflect community assembly rules

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Gábor Borics ◽  
Viktória B-Béres ◽  
István Bácsi ◽  
Balázs A. Lukács ◽  
E. T-Krasznai ◽  
...  
Keyword(s):  
Environmental Stress ◽  
Community Assembly ◽  
Environmental Gradients ◽  
Environmental Filtering ◽  
Limiting Similarity ◽  
Relative Importance ◽  
Trait Divergence ◽  
Phytoplankton Communities ◽  
Trait Convergence ◽  
Phytoplankton Traits

Abstract Environmental filtering and limiting similarity are those locally acting processes that influence community structure. These mechanisms acting on the traits of species result in trait convergence or divergence within the communities. The role of these processes might change along environmental gradients, and it has been conceptualised in the stress-dominance hypothesis, which predicts that the relative importance of environmental filtering increases and competition decreases with increasing environmental stress. Analysing trait convergence and divergence in lake phytoplankton assemblages, we studied how the concepts of ‘limiting similarity’ versus ‘environmental filtering’ can be applied to these microscopic aquatic communities, and how they support or contradict the stress-dominance hypothesis. Using a null model approach, we investigated the divergence and convergence of phytoplankton traits along environmental gradients represented by canonical axes of an RDA. We used Rao’s quadratic entropy as a measure of functional diversity and calculated effect size (ES) values for each sample. Negative ES values refer to trait convergence, i.e., to the higher probability of the environmental filtering in community assembly, while positive values indicate trait divergence, stressing the importance of limiting similarity (niche partitioning), that is, the competition between the phytoplankters. Our results revealed that limiting similarity and environmental filtering may operate simultaneously in phytoplankton communities, but these assembly mechanisms influenced the distribution of phytoplankton traits differently, and the effects show considerable changes along with the studied scales. Studying the changes of ES values along with the various scales, our results partly supported the stress-dominance hypothesis, which predicts that the relative importance of environmental filtering increases and competition decreases with increasing environmental stress.

Environmental filtering and neutral processes shape octocoral community assembly in the deep sea

Oecologia ◽  
2016 ◽  
Vol 183 (1) ◽  
pp. 221-236 ◽  
Author(s):  
Andrea M. Quattrini ◽  
Carlos E. Gómez ◽  
Erik E. Cordes
Keyword(s):  
Community Assembly ◽  
Deep Sea ◽  
Environmental Filtering ◽  
Neutral Processes

scholarly journals Distinguishing the signatures of local environmental filtering and regional trait range limits in the study of trait-environment relationships

2019 ◽  
Author(s):  
Pierre Denelle ◽  
Cyrille Violle ◽  
François Munoz
Keyword(s):  
Community Assembly ◽  
Environmental Gradients ◽  
Boundary Effect ◽  
Extreme Environments ◽  
Environmental Filtering ◽  
Range Limits ◽  
Species Pool ◽  
Statistical Tool ◽  
Leaf Trait ◽  
Trait Convergence

AbstractUnderstanding the imprint of environmental filtering on community assembly along environmental gradients is a key objective of trait-gradient analyses. Depending on local constraints, this filtering generally entails that species departing from an optimum trait value have lower abundances in the community. The Community-Weighted Mean (CWM) and Variance (CWV) of trait values are then expected to depict the optimum and intensity of filtering, respectively. However, the trait distribution within the regional species pool and its limits can also affect local CWM and CWV values apart from the effect of environmental filtering. The regional trait range limits are more likely to be reached in communities at the extremes of environmental gradients. Analogous to the mid-domain effect in biogeography, decreasing CWV values in extreme environments can then represent the influence of regional trait range limits rather than stronger filtering in the local environment. We name this effect the “Trait-Gradient Boundary Effect” (TGBE). First, we use a community assembly framework to build simulated communities along a gradient from a species pool and environmental filtering with either constant or varying intensity while accounting for immigration processes. We demonstrate the significant influence of TGBE, in parallel to environmental filtering, on CWM and CWV at the extremes of the environmental gradient. We provide a statistical tool based on Approximate Bayesian Computation to decipher the respective influence of local environmental filtering and regional trait range limits. Second, as a case study, we reanalyze the functional composition of alpine plant communities distributed along a gradient of snow cover duration. We show that leaf trait convergence found in communities at the extremes of the gradient reflect an influence of trait range limits rather than stronger environmental filtering. These findings challenge correlative trait-environment relationships and call for more explicitly identifying the mechanisms responsible of trait convergence/divergence along environmental gradients.

scholarly journals Genome size mediates the effect of environmental filtering in determining plant β-diversity across temperate grasslands

2021 ◽  
Author(s):  
Hai-Yang Zhang ◽  
Xiaotao Lü ◽  
cunzheng wei ◽  
Jeff Powell ◽  
Xiaobo Wang ◽  
...  
Keyword(s):  
Genome Size ◽  
Community Assembly ◽  
Nuclear Dna ◽  
Environmental Filtering ◽  
Nuclear Dna Content ◽  
Mean Annual Precipitation ◽  
Mean Annual Temperature ◽  
Nitrogen And Phosphorus ◽  
Temperate Grasslands ◽  
Β Diversity

Elucidating mechanisms underlying community assembly and biodiversity patterns is central to ecology and evolution. Genome size (GS, i.e. nuclear DNA content) determines species’ capacity to tolerate environmental stress or to exploit new environments and therefore potentially drive community assembly. However, its role in driving β-diversity (i.e., the site-to-site variability in species composition) remains unclear. We measured GS for 169 plant species and investigated their occurrences within plant communities across 52 sites spanning a 3200-km transect in the temperate grasslands of China. We found environmental factors showed larger effects on β-diversity of large-GS than that of small-GS species. Community weighted mean GS increased with mean annual precipitation, soil total nitrogen and phosphorus concentrations, but decreased with mean annual temperature, suggesting a negative selection against species with large GS in resources-limited or warmer climates. These findings highlight the roles for GS in driving community assembly and predicting species responses to climate change.

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