scholarly journals Niche tradeoffs, neutrality, and community structure: A stochastic theory of resource competition, invasion, and community assembly

2004 ◽  
Vol 101 (30) ◽  
pp. 10854-10861 ◽  
Author(s):  
D. Tilman
Keyword(s):  
Community Structure ◽  
Community Assembly ◽  
Resource Competition ◽  
Stochastic Theory

scholarly journals The capacity of wastewater treatment plants drives bacterial community structure and its assembly

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Young Kyung Kim ◽  
Keunje Yoo ◽  
Min Sung Kim ◽  
Il Han ◽  
Minjoo Lee ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Community Structure ◽  
Bacterial Community ◽  
Activated Sludge ◽  
Community Assembly ◽  
Bacterial Communities ◽  
Wastewater Treatment Plants ◽  
High Capacity ◽  
Operating Conditions ◽  
Rrna Gene

Abstract Bacterial communities in wastewater treatment plants (WWTPs) affect plant functionality through their role in the removal of pollutants from wastewater. Bacterial communities vary extensively based on plant operating conditions and influent characteristics. The capacity of WWTPs can also affect the bacterial community via variations in the organic or nutrient composition of the influent. Despite the importance considering capacity, the characteristics that control bacterial community assembly are largely unknown. In this study, we discovered that bacterial communities in WWTPs in Korea and Vietnam, which differ remarkably in capacity, exhibit unique structures and interactions that are governed mainly by the capacity of WWTPs. Bacterial communities were analysed using 16S rRNA gene sequencing and exhibited clear differences between the two regions, with these differences being most pronounced in activated sludge. We found that capacity contributed the most to bacterial interactions and community structure, whereas other factors had less impact. Co-occurrence network analysis showed that microorganisms from high-capacity WWTPs are more interrelated than those from low-capacity WWTPs, which corresponds to the tighter clustering of bacterial communities in Korea. These results will contribute to the understanding of bacterial community assembly in activated sludge processing.

scholarly journals Stochastic Assembly Leads to Alternative Communities with Distinct Functions in a Bioreactor Microbial Community

mBio ◽  
2013 ◽  
Vol 4 (2) ◽  
Author(s):  
Jizhong Zhou ◽  
Wenzong Liu ◽  
Ye Deng ◽  
Yi-Huei Jiang ◽  
Kai Xue ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Diversity ◽  
Microbial Community Structure ◽  
Community Assembly ◽  
Ecosystem Functioning ◽  
Dominant Role ◽  
Microbial Biodiversity ◽  
Stochastic Assembly

ABSTRACTThe processes and mechanisms of community assembly and its relationships to community functioning are central issues in ecology. Both deterministic and stochastic factors play important roles in shaping community composition and structure, but the connection between community assembly and ecosystem functioning remains elusive, especially in microbial communities. Here, we used microbial electrolysis cell reactors as a model system to examine the roles of stochastic assembly in determining microbial community structure and functions. Under identical environmental conditions with the same source community, ecological drift (i.e., initial stochastic colonization) and subsequent biotic interactions created dramatically different communities with little overlap among 14 identical reactors, indicating that stochastic assembly played dominant roles in determining microbial community structure. Neutral community modeling analysis revealed that deterministic factors also played significant roles in shaping microbial community structure in these reactors. Most importantly, the newly formed communities differed substantially in community functions (e.g., H2production), which showed strong linkages to community structure. This study is the first to demonstrate that stochastic assembly plays a dominant role in determining not only community structure but also ecosystem functions. Elucidating the links among community assembly, biodiversity, and ecosystem functioning is critical to understanding ecosystem functioning, biodiversity preservation, and ecosystem management.IMPORTANCEMicroorganisms are the most diverse group of life known on earth. Although it is well documented that microbial natural biodiversity is extremely high, it is not clear why such high diversity is generated and maintained. Numerous studies have established the roles of niche-based deterministic factors (e.g., pH, temperature, and salt) in shaping microbial biodiversity, the importance of stochastic processes in generating microbial biodiversity is rarely appreciated. Moreover, while microorganisms mediate many ecosystem processes, the relationship between microbial diversity and ecosystem functioning remains largely elusive. Using a well-controlled laboratory system, this study provides empirical support for the dominant role of stochastic assembly in creating variations of microbial diversity and the first explicit evidence for the critical role of community assembly in influencing ecosystem functioning. The results presented in this study represent important contributions to the understanding of the mechanisms, especially stochastic processes, involved in shaping microbial biodiversity.

scholarly journals Emergent Simplicity in Microbial Community Assembly

2017 ◽  
Author(s):  
Joshua E. Goldford ◽  
Nanxi Lu ◽  
Djordje Bajic ◽  
Sylvie Estrela ◽  
Mikhail Tikhonov ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Community Assembly ◽  
Competitive Exclusion ◽  
Ex Situ ◽  
Coarse Grained ◽  
Natural Environments ◽  
Complex Dynamic ◽  
Microbial Community Assembly ◽  
Consumer Resource

AbstractMicrobes assemble into complex, dynamic, and species-rich communities that play critical roles in human health and in the environment. The complexity of natural environments and the large number of niches present in most habitats are often invoked to explain the maintenance of microbial diversity in the presence of competitive exclusion. Here we show that soil and plant-associated microbiota, cultivated ex situ in minimal synthetic environments with a single supplied source of carbon, universally re-assemble into large and dynamically stable communities with strikingly predictable coarse-grained taxonomic and functional compositions. We find that generic, non-specific metabolic cross-feeding leads to the assembly of dense facilitation networks that enable the coexistence of multiple competitors for the supplied carbon source. The inclusion of universal and non-specific cross-feeding in ecological consumer-resource models is sufficient to explain our observations, and predicts a simple determinism in community structure, a property reflected in our experiments.

scholarly journals Aboveground and belowground arthropod communities experience different relative influences of stochastic and deterministic assembly processes following disturbance

2016 ◽  
Author(s):  
Scott Ferrenberg ◽  
Alexander S. Martinez ◽  
Akasha M. Faist
Keyword(s):  
Community Structure ◽  
Stochastic Processes ◽  
Community Assembly ◽  
Tree Mortality ◽  
Species Turnover ◽  
Mineral Soil ◽  
Relative Influence ◽  
Subalpine Forest ◽  
Arthropod Community ◽  
Arthropod Communities

Background. Understanding patterns of biodiversity is a longstanding challenge in ecology. Similar to other biotic groups, arthropod community structure can be shaped by deterministic and stochastic processes, with limited understanding of what moderates the relative influence of these processes. Disturbances have been noted to alter the relative influence of deterministic and stochastic processes on community assembly in various study systems, implicating ecological disturbances as a potential moderator of these forces. Methods. Using a disturbance gradient along a 5-year chronosequence of insect-induced tree mortality in a subalpine forest of the southern Rocky Mountains, Colorado, USA, we examined changes in community structure and relative influences of deterministic and stochastic processes in the assembly of aboveground (surface and litter-active species) and belowground (species active in organic and mineral soil layers) arthropod communities. Arthropods were sampled for all years of the chronosequence via pitfall traps (aboveground community) and modified Winkler funnels (belowground community) and sorted to morphospecies. Community structure of both communities were assessed via comparisons of morphospecies diversity and assemblages. Assembly processes were inferred from a mixture of linear models and matrix correlations testing for community associations with environmental properties, and from null-deviation models calculated from observed vs. expected levels of species turnover (Beta diversity) among samples. Results. Tree mortality altered community structure in both aboveground and belowground arthropod communities, but null models suggested that aboveground communities experienced greater relative influences of deterministic processes, while the relative influence of stochastic processes increased for belowground communities. Additionally, Mantel tests and linear regression models revealed significant associations between the aboveground arthropod communities and vegetation and soil properties, but no significant association among belowground arthropod communities and environmental factors. Discussion. Our results suggest context-dependent influences of stochastic and deterministic community assembly processes across different fractions of a ground-dwelling arthropod community following a disturbance. This variation in assembly may be linked to contrasting ecological strategies and dispersal rates within above- and below-ground communities. Our findings add to a growing body of evidence indicating concurrent influences of different processes in community assembly, and highlight the need to consider potential variation across different fractions of biotic communities when testing community ecology theory.

scholarly journals Plant Community Assembly in Invaded Recipient Californian Grasslands and Putative Donor Grasslands in Spain

Diversity ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 193
Author(s):  
Javier Galán Díaz ◽  
Enrique de la Riva ◽  
Ingrid Parker ◽  
María Leiva ◽  
Rubén Bernardo-Madrid ◽  
...  
Keyword(s):  
Community Structure ◽  
Exotic Species ◽  
Community Assembly ◽  
Model System ◽  
Context Dependency ◽  
Novel Ecosystems ◽  
Pest Species ◽  
Mediterranean Regions ◽  
Global And Local ◽  
Plant Community Assembly

The introduction of exotic species to new regions offers opportunities to test fundamental questions in ecology, such as the context-dependency of community structure and assembly. Annual grasslands provide a model system of a major unidirectional introduction of plant species from Europe to North America. We compared the community structure of grasslands in two Mediterranean regions by surveying plots in Spain and in California with similar environmental and management conditions. All species found in Spanish grasslands were native to Spain, and over half of them (74 of 139 species) are known to have colonized California. In contrast, in California, over half of the species (52 of 95 species) were exotic species, all of them native to Spain. Nineteen species were found in multiple plots in both regions (i.e., shared species). The abundance of shared species in California was either similar to (13 species) or greater than (6 species) in Spain. In California, plants considered pests were more likely than non-pest species to have higher abundance. Co-occurring shared species tended to maintain their relative abundance in native and introduced communities, which indicates that pools of exotic species might assemble similarly at home and away. These findings provide interesting insights into community assembly in novel ecosystems. They also highlight an example of startling global and local floristic homogenization.

scholarly journals Comparative phylogeography of oceanic archipelagos: Hotspots for inferences of evolutionary process

2016 ◽  
Vol 113 (29) ◽  
pp. 7986-7993 ◽  
Author(s):  
Kerry L. Shaw ◽  
Rosemary G. Gillespie
Keyword(s):  
Community Structure ◽  
Community Assembly ◽  
Community Dynamics ◽  
Evolutionary Process ◽  
Comparative Phylogeography ◽  
Origin And Evolution ◽  
Species Radiation ◽  
Remote Island ◽  
Oceanic Archipelagos ◽  
Shed Light

Remote island archipelagos offer superb opportunities to study the evolution of community assembly because of their relatively young and simple communities where speciation contributes to the origin and evolution of community structure. There is great potential for common phylogeographic patterns among remote archipelagos that originate through hotspot volcanism, particularly when the islands formed are spatially isolated and linearly arranged. The progression rule is characterized by a phylogeographic concordance between island age and lineage age in a species radiation. Progression is most likely to arise when a species radiation begins on an older island before the emergence of younger islands of a hotspot archipelago. In the simplest form of progression, colonization of younger islands as they emerge and offer appropriate habitat, is coincident with cladogenesis. In this paper, we review recent discoveries of the progression rule on seven hotspot archipelagos. We then discuss advantages that progression offers to the study of community assembly, and insights that community dynamics may offer toward understanding the evolution of progression. We describe results from two compelling cases of progression where the mosaic genome may offer insights into contrasting demographic histories that shed light on mechanisms of speciation and progression on remote archipelagos.

Community structure of acorn weevils (Curculio): inferences from multispecies occupancy models

2015 ◽  
Vol 93 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Byju N. Govindan ◽  
Robert K. Swihart
Keyword(s):  
Community Structure ◽  
Tree Species ◽  
Resource Competition ◽  
Host Tree ◽  
Parameter Estimates ◽  
Storage Effect ◽  
Primary Host ◽  
Host Trees ◽  
Host Tree Species ◽  
Mast Production

We tested whether community structure of insect seed predators is influenced by spatiotemporal variation in mast availability on host-tree species. Specifically, mast production and acorn weevil (Curculio L., 1758) occupancy were estimated annually from 2006 to 2008 for individual host trees in a sample of 74 northern red oaks (Quercus rubra L.), 100 white oaks (Quercus alba L.), and 81 shagbark hickories (Carya ovata (Mill.) K. Koch) in west-central Indiana, USA. Occupancy and vital rates of nine Curculio species on their primary host-tree species were derived using multispecies, multiseason (MSMS) models within a Bayesian framework, accounting for imperfect detection. Mast production of host trees had a strong positive effect on community-level occupancy and survival of Curculio. Mast production varied considerably between years and generally was spatially autocorrelated only at distances <2 km, which likely reduced interspecific resource competition. Derived estimates of mean weevil species richness per tree and community similarity were highest in 2007 when mast production on all host-tree species was in phase. Generalist species compensated for lower survival rate on secondary hosts with higher colonization rates on these hosts during a year of mast failure in the primary host. We hypothesize that differential suitability of hosts as resources for Curculio created a spatial storage effect that, when coupled with a temporal storage effect induced by prolonged diapause common among Curculio, facilitated species coexistence. Methodologically, increased precision of parameter estimates from MSMS models makes it generally more useful than single-species models in studies of community dynamics.

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