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

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.

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

Applied and Environmental Microbiology ◽

10.1128/aem.04042-14 ◽

2015 ◽

Vol 81 (9) ◽

pp. 3104-3114 ◽

Cited By ~ 40

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.

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Community Assembly Mechanisms Underlying the Core and Random Bacterioplankton and Microeukaryotes in a River–Reservoir System

Water ◽

10.3390/w11061127 ◽

2019 ◽

Vol 11 (6) ◽

pp. 1127 ◽

Cited By ~ 9

Author(s):

Alain Isabwe ◽

Kexin Ren ◽

Yongming Wang ◽

Feng Peng ◽

Huihuang Chen ◽

...

Keyword(s):

Community Assembly ◽

Anthropogenic Impacts ◽

Null Model ◽

Distribution Patterns ◽

Ecological Processes ◽

The Core ◽

Reservoir System ◽

Environmental Selection ◽

River Reservoir ◽

Plankton Communities

Whether bacterioplankton are assembled in the same way as microeukaryotes is a key question that has been answered only partially in microbial ecology. In particular, relating distribution patterns to the underlying ecological processes for plankton communities in highly dynamic ecosystems, such as river–reservoirs subjected to anthropogenic impacts, remains largely unstudied. Here, we analyzed taxonomic distribution patterns, and unraveled community assembly processes underlying the core and random bacterioplankton and microeukaryotes from a subtropical river–reservoir system. These plankton domains were modelled using the spatial abundance distributions (SpADs) of the operational taxonomic units (OTUs) as a proxy for abundant and rare taxa delineation. Both bacterioplankton and microeukaryote plankton communities exhibited significant distance–decay relationships, and samples were grouped depending on reservoir or river habitats. The neutral community model showed that 35–45% of the plankton community variation could be explained by neutral processes. The phylogenetic null model revealed that dispersal limitation accounted for the largest percentage of pairwise comparisons (42–68%), followed by environmental selection (18–25%). We concluded that similar prevalence of ecological processes acting on particular subsets of the bacterioplankton and microeukaryotes might have resulted from similar responses to environmental change, potentially induced by human activities in the watershed.

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Distinct assembly mechanisms underlie similar biogeographical patterns of rare and abundant bacteria in Tibetan Plateau grassland soils

10.21203/rs.2.19893/v1 ◽

2020 ◽

Author(s):

Mukan Ji ◽

Weidong Kong ◽

James Stegen ◽

Linyan Yue ◽

Fei Wang ◽

...

Keyword(s):

Tibetan Plateau ◽

Community Assembly ◽

Climatic Factors ◽

Variation Partitioning ◽

Terrestrial Ecosystems ◽

The Tibetan Plateau ◽

Grassland Soils ◽

Ecological Processes ◽

Local Factors ◽

Grassland Types

Abstract Background: Bacteria in low abundance represent the majority of Earth’s biodiversity and perform vital ecological functions, but little is known about their biogeography nor the ecological processes that drive their community assembly in terrestrial ecosystems. Here, we investigated the community compositions and phylogenies of rare (relative abundance < 0.1%) and abundant (> 1%) soil bacteria along a transect containing three alpine grassland types (meadow, steppe, and desert) on the Tibetan Plateau. Results: Our results revealed similar biogeographical patterns of rare and abundant bacteria, with their community compositions and phylogenies shifting gradually along the transect. The similar patterns, however, were driven by contrasting community assembly processes, with rare subcommunity being more heavily influenced by stochasticity (72%) than abundant (57%). The composition of abundant subcommunity (80%) was better explained by local (including soil and vegetation factors), geospatial and climatic factors than that of rare subcommunity (41%), while the phylogeny of the rare one (36%) was better explained than that of the abundant one (29%). Variation partitioning analysis indicated that pure local factors consistently explained a higher proportion of the community composition than geospatial factors in both rare (12.3% and 8.7%, respectively) and abundant bacteria (18.3% and 14.1%, respectively). In contrast, the phylogeny of rare subcommunity was explained by local and geospatial factors equally (11.5% and 11.9%, respectively), while that of abundant subcommunity was more explained by geospatial (22.1%) than local factors (11.3%). Furthermore, our results revealed a tighter connection between the community phylogeny and composition in rare than in abundant bacteria. Conclusions: Our results revealed consistent biogeographical patterns of rare and abundant bacteria in grassland soils, but their assembly processes were distinct. We further demonstrated that rare subcommunity was less predictable than the abundant subcommunity by environmental and geospatial factors. Rare and abundant bacteria responded differentially to factors, which was attributed to the distinct life strategies. Our study provides novel insights into the assembly processes and biographical patterns of rare and abundant bacteria in terrestrial ecosystems.

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

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2011.0056 ◽

2011 ◽

Vol 366 (1576) ◽

pp. 2403-2413 ◽

Cited By ~ 334

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.

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Key Community Assembly Processes Switch between Scales in Shaping Beta Diversity in Two Primary Forests, Southwest China

Forests ◽

10.3390/f11101106 ◽

2020 ◽

Vol 11 (10) ◽

pp. 1106

Author(s):

Mengesha Asefa ◽

Han-Dong Wen ◽

Min Cao ◽

Yue-Hua Hu

Keyword(s):

Community Assembly ◽

Beta Diversity ◽

Spatial Scales ◽

Process Models ◽

Small Scale ◽

Life Stages ◽

Relative Importance ◽

Vegetation Types ◽

Ecological Processes ◽

Environmental Selection

Environmental and dispersal-based processes have been widely investigated for the understanding of community assembly. However, the relative importance of these ecological processes across spatial scales, life history stages and forest types needs to be largely studied. We test the variability of ecological processes in shaping tree community composition across life stages and spatial scales, and in particular, the hypothesis that dispersal limitation dominates at smaller scales and early life stages, but environmental filtering at larger scales and later life stages. We used spatially explicit point process models to estimate the relative importance of environmental and dispersal processes and their combined effect on beta diversity across spatial scales and life stages in tropical and subtropical forests. These models fit the observed species distribution pattern and generated realizations of the fitted models for each species. We found that the importance of environmental and dispersal processes did not shift with life stages or vegetation types, but did with spatial scales. Dispersal provided the best explanation of large-scale patterns, but dispersal combined with environmental selection was superior for small-scale patterns. In conclusion, we confirm the importance of spatial scale for the effects and identification of community assembly mechanisms. Our results also suggest that the importance of both dispersal and environmental processes for community assembly could be pervasive across life stages and vegetation types. The generality of these findings should be tested further in different vegetation types and life stages to assess whether specific ecological processes have consistent effects on community structure across life stages and vegetation types.

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

Biogeosciences ◽

10.5194/bg-13-2901-2016 ◽

2016 ◽

Vol 13 (10) ◽

pp. 2901-2911 ◽

Cited By ~ 9

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.

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The Exploitation of Animals in Roman Britain

10.1093/oxfordhb/9780199697731.013.045 ◽

2014 ◽

Author(s):

Mark Maltby

Keyword(s):

Species Abundance ◽

Cultural Factors ◽

Relative Importance ◽

Roman Britain ◽

Human Animal ◽

Regional Settlement ◽

Domestic Stock

Concentrating mainly on the zooarchaeological data, this chapter reviews the evidence for the exploitation of animals in Roman Britain. The review focuses initially on domestic mammals and their exploitation, with particular attention being paid to the species that contributed the most to the diet—cattle, pig, and sheep. This discussion is followed by a shorter summary of the evidence for the exploitation of other mammals, birds, and fish. The relative importance of the different species for their meat and other commodities is outlined, and reasons for variations in species abundance, mortality patterns, butchery methods, and the stature of domestic stock are discussed. Chronological, regional, settlement, and cultural factors all need to be taken into account when considering the complexities of human–animal relationships in Roman Britain.

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