scholarly journals Immigration from the metacommunity affects bdelloid rotifer community dynamics most

2018 ◽  
Author(s):  
Nicolas Debortoli ◽  
Frederik De Laender ◽  
Karine Van Doninck
Keyword(s):  
Environmental Conditions ◽  
Species Interactions ◽  
Community Dynamics ◽  
Local Community ◽  
Bdelloid Rotifer ◽  
Rotifer Community ◽  
Dominant Process ◽  
Spatio Temporal ◽  
Community Variability ◽  
Different Levels

AbstractDispersal is an important driver of local community dynamics. It has been proposed that, for communities composed of microscopic organisms, dispersal could well be the dominant process, outpacing local processes driven by environmental conditions and species interactions. This is because microscopic organisms often reproduce asexually, fostering rapid colonization, and are easily dispersed by water or air current. We studied the case of bdelloid rotifers belonging to the genus Adineta, microscopic asexual animals with dried stages that are easily dispersed by wind to investigate the relative effects of dispersal and local processes on their community dynamics. To this end, we constructed a classic competition model to theoretically examine how spatial and local biodiversity dynamics varied with fitness and dispersal characteristics of bdelloid Adineta species. Next, we compared our predictions with an experimental dataset containing spatio-temporal Adineta community dynamics from the wild. This comparison suggested that immigration from the local meta-community was the most critical parameter under the conditions tested. One Adineta vaga species, abundant in the surrounding area, rapidly colonized our experimental habitats and dominated most of the communities. We also ran the model under different levels of environmental conditions (permissive, intermediate and harsh) to simulate seasonal community variability and found that communities experience important bottlenecks yearly in winter but that the same community re-established. The dissimilarities observed between roof communities suggest differences in adaptation or immigration capacities. Besides their asexual reproduction and extreme desiccation tolerance, a key characteristic of bdelloid ecology identified here, is the spatio-temporal dynamic of abundant bdelloid clones present in the meta-community that rapidly colonize empty patches to establish new populations.

Distribution, abundance, and diversity of stream fishes under variable environmental conditions

2006 ◽  
Vol 63 (1) ◽  
pp. 43-54 ◽  
Author(s):  
Christopher M Taylor ◽  
Thomas L Holder ◽  
Riccardo A Fiorillo ◽  
Lance R Williams ◽  
R Brent Thomas ◽  
...  
Keyword(s):  
Species Richness ◽  
Environmental Conditions ◽  
Community Dynamics ◽  
Local Community ◽  
Fish Assemblages ◽  
Fish Distribution ◽  
Stream Fish ◽  
Spatial And Temporal Variability ◽  
Regional Patterns ◽  
Abundance And Diversity

The effects of stream size and flow regime on spatial and temporal variability of stream fish distribution, abundance, and diversity patterns were investigated. Assemblage variability and species richness were each significantly associated with a complex environmental gradient contrasting smaller, hydrologically variable stream localities with larger localities characterized by more stable flow regimes. Assemblages showing the least variability were the most species-rich and occurred in relatively large, stable environments. Theory suggests that species richness can be an important determinant of assemblage variability. Although this appears to be true in our system, we suggest that spatial and temporal heterogeneity in the environment largely determines both assemblage richness and variability, providing a more parsimonious explanation for the diversity–variability correlation. Changes in species richness of local assemblages across time were coordinated across the landscape, and assemblages formed spatially and temporally nested subset patterns. These results suggest an important link between local community dynamics and community-wide occurrence. At the species level, mean local persistence was significantly associated with regional occurrence. Thus, the more widespread a species was, the greater its local persistence. Our results illustrate how the integrity of local stream fish assemblages is dependent on local environmental conditions, regional patterns of species distribution, and landscape continuity.

Statistical modelling for exploring diel vertical movements and spatial correlations of marine fish species: a supplementary tool to assess species interactions

2019 ◽  
Vol 76 (6) ◽  
pp. 1776-1783 ◽  
Author(s):  
Lisha Guan ◽  
Xianshi Jin ◽  
Qiang Wu ◽  
Xiujuan Shan
Keyword(s):  
Fish Species ◽  
Species Interactions ◽  
Community Dynamics ◽  
The Yellow Sea ◽  
Trawl Survey ◽  
Diel Variation ◽  
Spatial Correlations ◽  
Vertical Movements ◽  
Temporal Models ◽  
Spatio Temporal

Abstract Species interactions are important for explaining community dynamics and population trends, but very time- and effort-consuming to assess. Although diel vertical movements (DVM) and spatial correlations for various fish species have been explored to assess species interactions in aquatic communities, there is lack of cost-efficient approaches to studying both aspects concurrently. In this study, we proposed a single-species spatio-temporal model to quantify diel variations in the probabilities of a non-empty catch (p) and catch rates given that the catch is non-empty (λ). The model is applied to investigate patterns in DVM of nine dominant fish and shrimp species in the Yellow Sea (YS) using bottom trawl survey data. Subsequently, we utilized the spatio-temporal models built for the nine species to hindcast the spatial distributions of p and λ by year and species, which were further used to calculate between-species spatial correlation coefficients (corspatial). Results showed the nine species exhibited three different patterns of diel variation in p or λ, indicating they utilize the water column swept by the bottom trawls at different times of a day. Moreover, for the nine species in the YS those with limited interactions generally have negative corspatial or positive corspatial < 0.2 in λ, and others linked by strong predator–prey relationships or major food overlaps have corspatial ≥ 0.46 in λ. The strength of the positive spatial correlations in λ of different fishes shows some correspondence with the intensity of predation and competition between species and may be a supplementary tool to assess species interactions.

scholarly journals The importance of species interactions in eco-evolutionary community dynamics under climate change

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Anna Åkesson ◽  
Alva Curtsdotter ◽  
Anna Eklöf ◽  
Bo Ebenman ◽  
Jon Norberg ◽  
...  
Keyword(s):  
Climate Change ◽  
Species Interactions ◽  
Community Dynamics ◽  
Evolutionary Dynamics ◽  
Negative Impact ◽  
Trophic Levels ◽  
Temperature Dependent ◽  
Modeling Framework ◽  
Impact Of Climate Change ◽  
The Impact

AbstractEco-evolutionary dynamics are essential in shaping the biological response of communities to ongoing climate change. Here we develop a spatially explicit eco-evolutionary framework which features more detailed species interactions, integrating evolution and dispersal. We include species interactions within and between trophic levels, and additionally, we incorporate the feature that species’ interspecific competition might change due to increasing temperatures and affect the impact of climate change on ecological communities. Our modeling framework captures previously reported ecological responses to climate change, and also reveals two key results. First, interactions between trophic levels as well as temperature-dependent competition within a trophic level mitigate the negative impact of climate change on biodiversity, emphasizing the importance of understanding biotic interactions in shaping climate change impact. Second, our trait-based perspective reveals a strong positive relationship between the within-community variation in preferred temperatures and the capacity to respond to climate change. Temperature-dependent competition consistently results both in higher trait variation and more responsive communities to altered climatic conditions. Our study demonstrates the importance of species interactions in an eco-evolutionary setting, further expanding our knowledge of the interplay between ecological and evolutionary processes.

Proximate Composition and Spatio-temporal Heterogeneity of Phytochemicals in Agave sisalana (sisal) adapted in different agro-ecological zones of Punjab, Pakistan

2021 ◽  
Author(s):  
Sobia Shahzad ◽  
Mumtaz Hussain ◽  
Hassan Munir ◽  
Muhammad Arfan
Keyword(s):  
Environmental Conditions ◽  
Proximate Composition ◽  
Block Design ◽  
Temporal Variations ◽  
Proximate Analysis ◽  
Ecological Zones ◽  
Autumn Season ◽  
Spatial Differences ◽  
Different Seasons ◽  
Spatio Temporal

Abstract Exploring extractable phytochemicals from locally adapted sisal plant vegetation vary seasonally at different locations. This study elaborated proximate composition and phytochemical heterogeneity in sisal due to varying environmental conditions analyzed from five districts, i.e., Chakwal, Khushab, Rawalpindi, Faisalabad, and Layyah in Punjab, Pakistan. Extensive surveying and plant sampling across two years 2017-18 and 2018-19, during mid-spring, summer, autumn, and winter seasons were carried out for understanding the seasonal impact on sisal. The present study was designed in a randomized complete block design (RCBD) and analyzed considering seasonal, yearly, and locational impact. The spatial differences in phytochemicals concentration were strongly associated with environmental conditions prevailing in different seasons. Autumn season reflected saponins, tannins, and flavonoids in higher concentrations during 2018-19 while steroids and terpenoids were higher during spring 2018-19. While Spatio-temporal variations in the proximate analysis were more apparent in different samples collected from different districts. Data recorded for the Khushab district and autumn season reflected the higher composition of a proximate analysis and phytochemical contents as compared to other seasons. Overall, the spatial differences in phytochemicals concentration were strongly associated with soils and environmental conditions prevailing in different seasons in selected districts.

scholarly journals The effect of seasonality on the structure of rotifers in a black-water shallow lake in Central Amazonia

2014 ◽  
Vol 86 (3) ◽  
pp. 1359-1372 ◽  
Author(s):  
CLARICE C. NOVA ◽  
VANESSA G. LOPES ◽  
LEONARDO COIMBRA E SOUZA ◽  
BETINA KOZLOWSKY-SUZUKI ◽  
TALITA A.A. PEREIRA ◽  
...  
Keyword(s):  
Species Composition ◽  
Driving Force ◽  
Community Dynamics ◽  
Flood Pulse ◽  
Small Lakes ◽  
Black Water ◽  
Negro River ◽  
Rotifer Community ◽  
Central Amazonia ◽  
Physical And Chemical

Rotifers have often been used as indicators of sudden changes in physical and chemical features of the aquatic environment. Such features vary greatly during flood pulse events in small lakes connected to major floodplains. However, few are the studies that investigate the consequences of the flood pulse in rotifer species composition, abundance, richness and diversity, especially in Amazonian lakes. We analyzed samples from a small blackwater lake of an “igarapé” connected permanently to the Negro river, in Central Amazonia. Samples were taken twice a year for two years, comprising flooding and receding periods of the flood pulse. Rotifer abundance increased significantly after draught events, and electrical conductivity and turbidity were intrinsically related to such variation. Species composition also changed from flooding to receding periods. Some taxa, such as Brachionus zahniseri reductus and Lecane remanei were restricted to receding periods, while Brachionus zahniseri, Brachionus gillardi and Lecane proiecta were only present during flooding. A shift in the composition of rotifer families was observed from one period to another, showing the effect of renewing waters of the flood pulse. These results suggest that the flood pulse acts as a driving force and stressing condition, considerably altering rotifer community dynamics, either changing species composition or decreasing abundance.

scholarly journals Introduction: Special issue on species interactions, ecological networks and community dynamics – Untangling the entangled bank using molecular techniques

2019 ◽  
Vol 28 (2) ◽  
pp. 157-164 ◽  
Author(s):  
Tomas Roslin ◽  
Michael Traugott ◽  
Mattias Jonsson ◽  
Graham N. Stone ◽  
Simon Creer ◽  
...  
Keyword(s):  
Species Interactions ◽  
Community Dynamics ◽  
Ecological Networks ◽  
Molecular Techniques ◽  
Special Issue

Community dynamics in Fijian coral reef fish communities vary with conservation and shark-based tourism

2019 ◽  
Vol 25 (4) ◽  
pp. 363
Author(s):  
Mallory G. McKeon ◽  
Joshua A. Drew
Keyword(s):  
Community Dynamics ◽  
Local Community ◽  
Census Data ◽  
Fish Abundance ◽  
Full Potential ◽  
Community Members ◽  
Composition And Structure ◽  
Feeding Methods ◽  
Abundance And Diversity ◽  
Unprotected Area

Marine protected areas (MPAs) effectively improve the biomass and diversity in heavily exploited marine systems, but often fail to reach their full potential because they require more space, time, and consistency of regulation. Recently, shark-based tourism, which utilises some of the remaining shark strongholds as tourism hotspots, has brought about increased awareness to exploited reef systems. In Fiji, specifically, shark diving companies include local community members in their operations to promote better understanding of their reefs. We seek to investigate whether seemingly denser shark populations during feeding times influence community composition and structure. Visual census data were collected from 50-m belt transects at four different reefs in Fiji: two MPAs with shark-based ecotourism with food provisioning, one MPA without shark-based ecotourism, and one unprotected area without shark-based tourism. Paradoxically, indices of evenness and diversity were highest in the non-protected site. However, there was significantly higher fish abundance and species diversity within reserves than outside of reserves. Within reserves, sites with shark feeding had lower fish abundance and higher richness, diversity, and evenness. Mean trophic level was highest at sites with shark feeding. Use of chum increased average fish abundance and diversity within shark-dive sites. These results indicate that there are evident differences between MPAs that do and do not offer trophic supplementation for shark-based ecotourism. Thus, tourism may be facilitating a shift of ecosystem composition in such areas. Furthermore, the results suggest that feeding methods may augment the impacts of shark-based tourism on the reef at large.

scholarly journals Facilitation costs and benefits function simultaneously on stress gradients for animals

2018 ◽  
Vol 285 (1885) ◽  
pp. 20180983 ◽  
Author(s):  
Olivier Dangles ◽  
Mario Herrera ◽  
Carlos Carpio ◽  
Christopher J. Lortie
Keyword(s):  
Conceptual Framework ◽  
Environmental Conditions ◽  
Species Interactions ◽  
Stress Gradient ◽  
Species Interaction ◽  
Positive Interactions ◽  
Costs And Benefits ◽  
Strong Basis ◽  
Stress Gradients ◽  
High Resource

Understanding the variation in species interactions along environmental stress gradients is crucial for making robust ecological predictions about community responses to changing environmental conditions. The facilitation–competition framework has provided a strong basis for predictions (e.g. the stress-gradient hypothesis, SGH), yet the mechanisms behind patterns in animal interactions on stress gradients are poorly explored in particular for mobile animals. Here, we proposed a conceptual framework modelling changes in facilitation costs and benefits along stress gradients and experimentally tested this framework by measuring fitness outcomes of benefactor–beneficiary interactions across resource quality levels. Three arthropod consumer models from a broad array of environmental conditions were used including aquatic detritivores, potato moths and rainforest carrion beetles. We detected a shift to more positive interactions at increasing levels of stress thereby supporting the application of the SGH to mobile animals. While most benefactors paid no significant cost of facilitation, an increase in potato moth beneficiary's growth at high resource stress triggered costs for benefactors. This study is the first to experimentally show that both costs and benefits function simultaneously on stress gradients for animals. The proposed conceptual framework could guide future studies examining species interaction outcomes for both animals and plants in an increasingly stressed world.

scholarly journals Measuring the modal parameters of a cultural heritage tower by using strong-motion signals

ACTA IMEKO ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 86 ◽  
Author(s):  
Mariella Diaferio ◽  
Dora Foti ◽  
Nicola Ivan Giannoccaro ◽  
Salvador Ivorra Ivorra
Keyword(s):  
Phase Shift ◽  
Environmental Conditions ◽  
Excitation Frequency ◽  
Strong Motion ◽  
Forced Vibrations ◽  
Mode Shapes ◽  
Modal Parameters ◽  
Vibration Modes ◽  
Experimental Campaign ◽  
Different Levels

This paper presents the dynamic experimental campaign carried out on a stocky masonry clock tower situated in the Swabian Castle of Trani (Italy). The main objective of this paper is, after estimating the main frequencies and vibration modes of the considered structure, defining the transmission of vibrations along the height of the tower by varying the forced frequency at the base. At this aim, short acceleration records have been acquired simultaneously in 20 points of the tower at different levels, due to a series of sinusoidal forced vibrations applied at the base by using a pneumatic shaker device specify designed for the tests. The proposed procedure permit to extract for each monitored point the amplitude of the sinusoidal component related to the excitation frequency and the phase shift due to the structure damping. The results of the proposed procedure are compared with the results of a classical operational modal analysis in environmental conditions in order to demonstrate that the short forced tests permit to classify the typology of the structure mode shapes.

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