scholarly journals Flooding and hydrologic connectivity modulate community assembly in a dynamic river-floodplain ecosystem

2019 ◽  
Author(s):  
Stefano Larsen ◽  
Ute Karaus ◽  
Cecile Claret ◽  
Ferdinand Sporka ◽  
Ladislav Hamerlík ◽  
...  
Keyword(s):  
Community Assembly ◽  
Species Turnover ◽  
Compositional Variation ◽  
Hydrologic Connectivity ◽  
Aquatic Communities ◽  
Species Sorting ◽  
River Floodplains ◽  
Annual Dynamic ◽  
Variation Explained ◽  
Floodplain Habitats

SummaryBraided river floodplains are highly dynamic ecosystems, where aquatic communities are strongly regulated by the hydrologic regime. So far, however, understanding of how flow variation influences assembly mechanisms remains limited.We collected benthic chironomids and oligochaetes over a year across a lateral connectivity gradient in the semi-natural Tagliamento River (Italy). Four bankfull flood events occurred during the study, allowing the assessment of how flooding and hydrologic connectivity mediate the balance between stochastic and deterministic community assembly.While invertebrate density and richness were positively correlated with connectivity, diversity patterns showed no significant correlation. Species turnover through time increased with decreasing connectivity. Contrary to expectations, hydrologic connectivity did not influence the response of community metrics (e.g. diversity, density) to floods.Invertebrate composition was weakly related to connectivity, but changed predictably in response to floods. Multivariate ordinations showed that faunal composition diverged across the waterbodies during stable periods, reflecting differential species sorting across the lateral gradient, but converged again after floods. Stable hydrological periods allowed communities to assemble deterministically with prevalence of non-random beta-diversity and cooccurrence patterns and larger proportion of compositional variation explained by local abiotic features. These signals of deterministic processes clearly declined after flooding events. This occurred despite no apparent evidence of flood-induced homogenisation of habitat conditions.This study is among the first to examine the annual dynamic of aquatic assemblages across a hydrologic connectivity gradient in a natural floodplain. Results highlight how biodiversity can exhibit complex relations with hydrologic connectivity. However, appraisal of the assembly mechanisms through time indicated that flooding shifted the balance from deterministic species sorting across floodplain habitats, towards stochastic processes related to organisms redistribution and the likely resetting of assembly to earlier stages.

scholarly journals Phylogenetic turnover during subtropical forest succession across environmental and phylogenetic scales

2017 ◽  
Author(s):  
Oliver Purschke ◽  
Stefan G. Michalski ◽  
Helge Bruelheide ◽  
Walter Durka
Keyword(s):  
Community Structure ◽  
Community Assembly ◽  
Deterministic Model ◽  
Species Turnover ◽  
Subtropical Forest ◽  
List Type ◽  
Spatial And Temporal Patterns ◽  
Species Sorting ◽  
Phylogenetic Community Structure ◽  
Successional Stages

SummaryAlthough spatial and temporal patterns of phylogenetic community structure during succession are inherently interlinked and assembly processes vary with environmental and phylogenetic scale, successional studies of community assembly have yet to integrate spatial and temporal components of community structure, while accounting for scaling issues. To gain insight into the processes that generate biodiversity after disturbance, we combine analyses of spatial and temporal phylogenetic turnover across phylogenetic scales, accounting for covariation with environmental differences.We compared phylogenetic turnover, at the species-and individual-level, within and between five successional stages, representing woody plant communities in a subtropical forest chronosequence. We decomposed turnover at different phylogenetic depths and assessed its covariation with between-plot abiotic differences.Phylogenetic turnover between stages was low relative to species turnover and was not explained by abiotic differences. However, within the late successional stages, there was high presence/absence-based turnover (clustering) that occurred deep in the phylogeny and covaried with environmental differentiation.Our results support a deterministic model of community assembly where (i) phylogenetic composition is constrained through successional time, but (ii) towards late succession, species sorting into preferred habitats according to niche traits that are conserved deep in phylogeny, becomes increasingly important.

scholarly journals Water quality drives the regional patterns of an algal metacommunity in interconnected lakes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Min Sung Kim ◽  
Seok Hyun Ahn ◽  
In Jae Jeong ◽  
Tae Kwon Lee
Keyword(s):  
Water Quality ◽  
Community Assembly ◽  
River Flow ◽  
Geographical Area ◽  
Oxygen Demand ◽  
Algal Community ◽  
Regional Patterns ◽  
Algal Communities ◽  
Species Sorting ◽  
Metacommunity Structure

AbstractThe metacommunity approach provides insights into how the biological communities are assembled along the environmental variations. The current study presents the importance of water quality on the metacommunity structure of algal communities in six river-connected lakes using long-term (8 years) monitoring datasets. Elements of metacommunity structure were analyzed to evaluate whether water quality structured the metacommunity across biogeographic regions in the riverine ecosystem. The algal community in all lakes was found to exhibit Clementsian or quasi-Clementsian structure properties such as significant turnover, grouped and species sorting indicating that the communities responded to the environmental gradient. Reciprocal averaging clearly classified the lakes into three clusters according to the geographical region in river flow (upstream, midstream, and downstream). The dispersal patterns of algal genera, including Aulacoseira, Cyclotella, Stephanodiscus, and Chlamydomonas across the regions also supported the spatial-based classification results. Although conductivity, chemical oxygen demand, and biological oxygen demand were found to be important variables (loading > |0.5|) of the entire algal community assembly, water temperature was a critical factor in water quality associated with community assembly in each geographical area. These results support the notion that the structure of algal communities is strongly associated with water quality, but the relative importance of variables in structuring algal communities differed by geological regions.

scholarly journals Historical contingency impacts on community assembly and ecosystem function in chemosynthetic marine ecosystems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dimitri Kalenitchenko ◽  
Erwan Peru ◽  
Pierre E. Galand
Keyword(s):  
Community Assembly ◽  
Sea Water ◽  
Marine Ecosystem ◽  
Marine Ecosystems ◽  
Metagenomic Sequencing ◽  
Historical Contingency ◽  
Historical Events ◽  
Species Sorting ◽  
Environmental Selection ◽  
Microbial Community Assembly

AbstractPredicting ecosystem functioning requires an understanding of the mechanisms that drive microbial community assembly. Many studies have explored microbial diversity extensively and environmental factors are thought to be the principal drivers of community composition. Community assembly is, however, also influenced by past conditions that might affect present-day assemblages. Historical events, called legacy effects or historical contingencies, remain poorly studied in the sea and their impact on the functioning of the communities is not known. We tested the influence, if any, of historical contingencies on contemporary community assembly and functions in a marine ecosystem. To do so, we verified if different inoculum communities colonizing the same substrate led to communities with different compositions. We inoculated wood with sea water microbes from different marine environments that differ in ecological and evolutionary history. Using 16S rRNA and metagenomic sequencing, it was demonstrated that historical contingencies change the composition and potential metabolisms of contemporary communities. The effect of historical events was transient, dominated by environmental selection as, over time, species sorting was a more important driver of community assembly. Our study shows not only that historical contingencies affect marine ecosystems but takes the analysis a step further by characterizing this effect as strong but transient.

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.

Dormant propagule banks of aquatic invertebrates in ponds invaded by exotic pine species in southern Brazil

2017 ◽  
Vol 68 (5) ◽  
pp. 954 ◽  
Author(s):  
Cristina Stenert ◽  
Bruna Ehlert ◽  
Arthur Cardoso Ávila ◽  
Francisco Diogo Rocha Sousa ◽  
Fernanda Mara Esquinatti ◽  
...  
Keyword(s):  
Species Composition ◽  
Aquatic Invertebrates ◽  
Species Turnover ◽  
Survival Rates ◽  
Southern Brazil ◽  
Aquatic Communities ◽  
Β Diversity ◽  
Pine Invasion ◽  
Dry Sediments ◽  
Pine Species

Exotic pine invasion affects native wetland communities in the Southern Hemisphere by changing the hydrological regimen and physicochemical characteristics. Studies evaluating the emergence of aquatic invertebrates from dormant stages are vital to identify the resilience of aquatic communities in ponds invaded by exotic pine species. In the present study, we tested the hypotheses that: (1) pine invasion decreases the richness of drought-resistant aquatic invertebrates in ponds; (2) pine invasion modifies the invertebrate composition in ponds; and (3) these differences in species composition (β diversity) are associated primarily with species turnover. Dry sediment samples were collected from three natural ponds in native grassland and three ponds in a pine invasion matrix in southern Brazil. In all, 7205 invertebrates, primarily represented by cladocerans (18 species), were sampled after rewetting dry sediments. Pine invasion decreased the richness of aquatic invertebrates because the natural ponds had almost 60% more species and a higher number of estimated species than the pine ponds. The composition differed between natural and pine ponds, and this difference in species composition (β diversity) was associated primarily with the replacement of some species by others. The presence of pine appears to alter colonisation and survival rates of aquatic invertebrates that aestivate in dry sediments in southern Brazil wetlands.

scholarly journals Paddy fields located in water storage zones could take over the wetland plant community

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Takeshi Osawa ◽  
Takaaki Nishida ◽  
Takashi Oka
Keyword(s):  
Land Use ◽  
Plant Community ◽  
Community Assembly ◽  
Human Activities ◽  
Species Turnover ◽  
Paddy Fields ◽  
Species Loss ◽  
Habitat Conditions ◽  
Multi Temporal ◽  
Original Habitat

Abstract Land use change could affect not only local species richness but also community assemblies. Essentially, the possible patterns of plant community assemblies are nonrandom species loss (nestedness) and species turnover. Plant community assemblies in human-mediated land use have a combination of both nestedness and turnover. This is because of historical effects that cause nonrandom species loss due to previous and/or original habitat quality and because of direct effects of human activities that cause species turnover. We investigated the complexity of the process of plant community assemblage in a paddy field, which is a typical agricultural land use in the monsoon season in central Japan. Using multi-temporal plant monitoring records, we tested the relationship between the ratio of species nestedness/turnover through multi-temporal and both the original habitat conditions and the extent of human modification. The findings revealed that paddy fields that originated from wetland habitat had a high nestedness ratio, whereas paddy fields that were largely consolidated had a high turnover ratio. Thus, we could divide the community assembly processes in human-mediated land use based on original habitat conditions and human activities. This concept could help land managers establish conservation and/or restoration plans that take into account community assembly.

Any way the wind blows - frequent wind dispersal drives species sorting in ephemeral aquatic communities

Oikos ◽  
2007 ◽  
Vol 117 (1) ◽  
pp. 125-134 ◽  
Author(s):  
Bram Vanschoenwinkel ◽  
Saïdja Gielen ◽  
Maitland Seaman ◽  
Luc Brendonck
Keyword(s):  
Wind Dispersal ◽  
Aquatic Communities ◽  
Species Sorting

scholarly journals Habitat selection determines abundance, richness and species composition of beetles in aquatic communities

2005 ◽  
Vol 1 (3) ◽  
pp. 370-374 ◽  
Author(s):  
Christopher A Binckley ◽  
William J Resetarits
Keyword(s):  
Species Richness ◽  
Habitat Selection ◽  
Species Composition ◽  
Large Scale ◽  
Habitat Preferences ◽  
Differential Mortality ◽  
Aquatic Communities ◽  
Species Sorting ◽  
Random Dispersal ◽  
Random Site

Distribution and abundance patterns at the community and metacommunity scale can result from two distinct mechanisms. Random dispersal followed by non-random, site-specific mortality (species sorting) is the dominant paradigm in community ecology, while habitat selection provides an alternative, largely unexplored, mechanism with different demographic consequences. Rather than differential mortality, habitat selection involves redistribution of individuals among habitat patches based on perceived rather than realized fitness, with perceptions driven by past selection. In particular, habitat preferences based on species composition can create distinct patterns of positive and negative covariance among species, generating more complex linkages among communities than with random dispersal models. In our experiments, the mere presence of predatory fishes, in the absence of any mortality, reduced abundance and species richness of aquatic beetles by up to 80% in comparison with the results from fishless controls. Beetle species' shared habitat preferences generated distinct patterns of species richness, species composition and total abundance, matching large-scale field patterns previously ascribed to random dispersal and differential mortality. Our results indicate that landscape-level patterns of distribution and species diversity can be driven to a large extent by habitat selection behaviour, a critical, but largely overlooked, mechanism of community and metacommunity assembly.

scholarly journals Ecosystem size-induced environmental fluctuations affect the temporal dynamics of community assembly mechanisms

2022 ◽  
Author(s):  
Raven L Bier ◽  
Máté Vass ◽  
Anna J Székely ◽  
Silke Langenheder
Keyword(s):  
Community Assembly ◽  
Temporal Dynamics ◽  
Bacterial Community Composition ◽  
Dispersal Limitation ◽  
Priority Effects ◽  
Environmental Fluctuation ◽  
Species Sorting ◽  
Ecosystem Size ◽  
Environmental Fluctuations ◽  
Over Time

Understanding processes that determine community membership and abundance is important for many fields from theoretical community ecology to conservation. However, spatial community studies are often conducted only at a single timepoint despite the known influence of temporal variability on community assembly processes. Here we used a spatiotemporal study to determine how environmental fluctuation differences induced by mesocosm volumes (larger volumes were more stable) influence assembly processes of aquatic bacterial metacommunities along a press disturbance gradient. By combining path analysis and network approaches, we found mesocosm size categories had distinct relative influences of assembly process and environmental factors that determined spatiotemporal bacterial community composition, including dispersal and species sorting by conductivity. These processes depended on, but were not affected proportionately by, mesocosm size. Low fluctuation, large mesocosms primarily developed through the interplay of species sorting that became more important over time and transient priority effects as evidenced by more time-delayed associations. High fluctuation, small mesocosms had regular disruptions to species sorting and greater importance of ecological drift and dispersal limitation indicated by lower richness and higher taxa replacement. Together, these results emphasize that environmental fluctuations influence ecosystems over time and its impacts are modified by biotic properties intrinsic to ecosystem size.

Sign in / Sign up

Export Citation Format

Share Document