scholarly journals Effect of cold fronts on the benthic macrofauna of exposed sandy beaches with contrasting morphodynamics

2009 ◽  
Vol 57 (2) ◽  
pp. 73-94 ◽  
Author(s):  
Eliana dos Santos Alves ◽  
Paulo Ricardo Pezzuto
Keyword(s):  
Environmental Changes ◽  
Temporal Dynamics ◽  
High Energy ◽  
Sandy Beaches ◽  
Benthic Macrofauna ◽  
Swash Zone ◽  
Short Term ◽  
Cold Fronts ◽  
Rapid Restoration ◽  
Abundance And Distribution

The aim of this study was to determine the short-term environmental changes caused by the simultaneous passage of a high energy event on two sandy beaches with different morphodynamic states and their influence on the richness, abundance and distribution of the benthic macrofauna. Two microtidal exposed sandy beaches with contrasting morphodynamics were simultaneously sampled before, during and after the passage of two cold fronts in Santa Catarina. The reflective beach showed a higher susceptibility to the increase in wave energy produced by the passage of cold fronts and was characterized by rapid and intense erosive processes in addition to a capacity for rapid restoration of the beach profile. As regards the dissipative beach, erosive processes operated more slowly and progressively, and it was characterized further by a reduced capacity for the recovery of its sub-aerial profile. Although the intensity of the environmental changes was distinct as between the morphodynamic extremes, changes in the composition, richness and abundance of macrobenthos induced by cold fronts were not evident for either of the beaches studied. On the other hand, alterations in the distribution pattern of the macrofauna were observed on the two beaches and were related to variations in sea level, position of the swash zone and moisture gradient, suggesting that short-term accommodations in the spatial structure of the macrobenthos occur in response to changes in environmental conditions in accordance with the temporal dynamics characteristic of each morphodynamic state.

scholarly journals A new comprehensive trait database of European and Maghreb butterflies, Papilionoidea

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Joseph Middleton-Welling ◽  
Leonardo Dapporto ◽  
Enrique García-Barros ◽  
Martin Wiemers ◽  
Piotr Nowicki ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Species Traits ◽  
Vegetation Changes ◽  
Short Term ◽  
Multinomial Data ◽  
Northwest Africa ◽  
Indicator Group ◽  
Information Sets ◽  
Ecological Conservation ◽  
Abundance And Distribution

Abstract Trait-based analyses explaining the different responses of species and communities to environmental changes are increasing in frequency. European butterflies are an indicator group that responds rapidly to environmental changes with extensive citizen science contributions to documenting changes of abundance and distribution. Species traits have been used to explain long- and short-term responses to climate, land-use and vegetation changes. Studies are often characterised by limited trait sets being used, with risks that the relative roles of different traits are not fully explored. Butterfly trait information is dispersed amongst various sources and descriptions sometimes differ between sources. We have therefore drawn together multiple information sets to provide a comprehensive trait database covering 542 taxa and 25 traits described by 217 variables and sub-states of the butterflies of Europe and Maghreb (northwest Africa) which should serve for improved trait-based ecological, conservation-related, phylogeographic and evolutionary studies of this group of insects. We provide this data in two forms; the basic data and as processed continuous and multinomial data, to enhance its potential usage.

scholarly journals Spatial distribution of macrobenthic fauna on three sandy beaches from northern Rio Grande do Sul, southern Brazil

2006 ◽  
Vol 54 (2-3) ◽  
pp. 135-145 ◽  
Author(s):  
Frederico Monteiro Neves ◽  
Carlos Emílio Bemvenuti
Keyword(s):  
Spatial Distribution ◽  
Environmental Parameters ◽  
Abundant Species ◽  
Sandy Beaches ◽  
Average Density ◽  
Benthic Macrofauna ◽  
Swash Zone ◽  
Sediment Grain Size ◽  
Horizontal Variation ◽  
Three Samples

The spatial distribution of benthic macrofauna on the beaches of Tramandaí, Jardim do Éden and Harmonia, was investigated over five consecutive days in April, 2003. The distribution pattern was also analyzed along with environmental parameters. Three transects were set on each beach, 50 m apart, with four sample stations set along each transect. On every station, three samples of benthic macrofauna were taken daily, with a core sampler with 20 cm diameter. In the midlittoral zone, the polychaete Euzonus furciferus and the isopod Excirolana armata dominated. In the swash zone, tidal migrators, Emerita brasiliensis,Donax hanlevanus and Mesodesma mactroides, were the most abundant species and, on some days, the polychaete Scolelepis gaucha. In the lower zones of the beaches, D. hanleyanus,M. mactroides and the amphipod Puelche orensani dominated. This zonation pattern was found for all three studied beaches, based on the average density of each species, over the five days period. Horizontal variation in the fauna was not found, either inter or intra the studied beaches, possibly due to little variability in slope and homogeneity of sediment grain size presented in the three beaches.

scholarly journals Vertical distribution of meiofauna on reflective sandy beaches

2015 ◽  
Vol 63 (4) ◽  
pp. 469-480 ◽  
Author(s):  
Mariana de Oliveira Martins ◽  
Tito Cesar Marques de Almeida ◽  
Maikon Di Domenico
Keyword(s):  
Organic Matter ◽  
Vertical Distribution ◽  
High Energy ◽  
Sandy Beaches ◽  
Swash Zone ◽  
Physical Conditions ◽  
Physical Chemical ◽  
Average Grain Size ◽  
Sediment Sorting ◽  
The Vertical Distribution

Abstract Extreme physical conditions usually limit the meiofauna occurrence and distribution in highly hydrodynamic environments such as reflective beaches. Despite sediment grains of the upper layers being constantly resuspended and deposited, the high energy of the swash zone besides depositing coarse sediments allows an ample vertical distribution of meiofaunal organisms. The effect of physical, chemical and sediment variables on the vertical distribution of meiofaunal organims and nematodes was analysed on two reflective exposed beaches. Sampling was conducted at three sampling points on each beach in the swash zone. The sediment collected was divided into four 10-cm strata (0-10 cm, 10-20 cm, 20-30 cm, 30-40 cm). The statistical differences between strata due to factors previously established (i.e. meiofaunal composition, density of most abundant taxa) were tested using a hierarchical PERMANOVA applied under similarity and euclidian distances. An inverse relation among average grain size, content of organic matter and sediment sorting was evident. Coarser sediment characterized the upper layers, while at deeper layers the sediment was very poorly sorted and presented a higher content of organic matter. A similar pattern in the vertical distribution of meiofaunal and nematofaunal composition and density was detected. The lowest densities were associated with the first stratum (0-10 cm), highly affected by hydrodynamics. The vertical distribution of organisms was statistically different only when the interaction among factors was considered. This result suggests that zonation and vertical distribution of meiofaunal organisms are determined by the within-beach variability.

Economic conditions and perceptions of immigrants as an economic threat in Europe: Temporal dynamics and mediating processes

2021 ◽  
pp. 002071522199352
Author(s):  
Boris Heizmann ◽  
Nora Huth
Keyword(s):  
Temporal Dynamics ◽  
European Social Survey ◽  
Primary Objective ◽  
Conflict Theory ◽  
Economic Conditions ◽  
Political Climate ◽  
Short Term ◽  
Economic Threat ◽  
Party Positions

This article addresses the extent to which economic downturns influence the perception of immigrants as an economic threat and through which channels this occurs. Our primary objective is an investigation of the specific mechanisms that connect economic conditions to the perception of immigrants as a threat. We therefore also contribute to theoretical discussions based on group threat and realistic group conflict theory by exposing the dominant source of competition relevant to these relationships. Furthermore, we investigate whether people react more sensitive to short-term economic dynamics within countries than to the long-term economic circumstances. Our database comprises all waves of the European Social Survey from 2002 to 2017. The macro-economic indicators we use include GDP per capita, unemployment, and national debt levels, covering the most salient economic dimensions. We furthermore control for the country’s migration situation and aggregate party positions toward cultural diversity. Our results show that the dynamic short-term developments of the economy and migration within countries are of greater relevance for perceived immigrant threat than the long-term situation. In contrast, the long-term political climate appears to be more important than short-term changes in the aggregate party positions. Further mediation analyses show that objective economic conditions influence anti-immigrant attitudes primarily through individual perceptions of the country’s economic performance and that unemployment rates are of primary importance.

Dynamic Subspecies Population Structure of Vibrio Cholerae in Dhaka, Bangladesh

2021 ◽  
Author(s):  
Mohammad Islam ◽  
Tania Nasreen ◽  
Kevin Y. H. Liang ◽  
Fatema-Tuz Johura ◽  
Paul C. Kirchberger ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Temporal Dynamics ◽  
Sampling Period ◽  
Amplicon Sequencing ◽  
Rapid Expansion ◽  
Capital City ◽  
Dhaka City ◽  
Physiochemical Parameters ◽  
Subspecies Level ◽  
Abundance And Distribution

Abstract Cholera has been endemic to the Ganges delta for centuries. Although the causative agent, Vibrio cholerae, is autochthonous to coastal and brackish water, cholera occurs continually in Dhaka, the inland capital city of Bangladesh which is surrounded by fresh water. Despite the persistence of this problem, little is known about the environmental abundance and distribution of lineages of V. cholerae, the most important being the pandemic generating lineage (PG) consisting mostly of serogroup O1 strains. To understand spatial and temporal dynamics of PG and other lineages belonging to the V. cholerae species in surface water in and around Dhaka city, we used qPCR and high throughput amplicon sequencing. Seven different freshwater sites across Dhaka were investigated for six consecutive months and physiochemical parameters were measured in situ. Total abundance of V. cholerae was found to be relatively stable throughout the six months sampling period, with 2×105 to 4×105 genome copies/L at six sites and around 5 ×105 genome copies/L at the site located in the most densely populated part of Dhaka city. PG O1 V. cholerae was present in high abundance during the entire sampling period and composed between 24-92% of the total V. cholerae population, only showing occasional but sudden reductions in abundance. In instances where PG O1 lost its dominance, other lineages underwent a rapid expansion while the size of the total V. cholerae population remained almost unchanged. Intraspecies richness of V. cholerae was positively correlated to salinity, conductivity and total dissolved solids (TDS), while it was negatively correlated to dissolved oxygen (DO) concentration in water. Interestingly, negative correlation was observed specifically between PG O1 and salinity, even though the changes in this variable were minor (0-0.8 ppt). Observations in this study suggest that at the subspecies level, population composition of naturally occurring V. cholerae can be influenced by fluctuations in environmental factors, which can lead to altered competition dynamics among the lineages.

Exploring RPAS potentiality using a RGB camera to understand short term variation on sandy beaches

CATENA ◽  
2022 ◽  
Vol 210 ◽  
pp. 105949
Author(s):  
R.M. Gonçalves ◽  
T.F. Holanda ◽  
H.A.A. Queiroz ◽  
P.H.G.O. Sousa ◽  
P.S. Pereira
Keyword(s):  
Sandy Beaches ◽  
Short Term ◽  
Term Variation

Ecological succession as an aspect of structure in fossil communities

Paleobiology ◽  
1975 ◽  
Vol 1 (3) ◽  
pp. 238-257 ◽  
Author(s):  
Kenneth R. Walker ◽  
Leonard P. Alberstadt
Keyword(s):  
Environmental Changes ◽  
Food Chains ◽  
Short Term ◽  
Niche Specialization ◽  
Pattern Diversity ◽  
Physical Environments ◽  
Autogenic Succession ◽  
Succession Stage ◽  
Stratigraphic Sequences

Succession involves changes in a community through time, whether internally or externally controlled. As succession progresses, niche specialization, species diversity (variety and equitability), complexity of food chains, and pattern diversity increase; net production and species growth rate decrease. We apply the succession concept to three types of ancient community sequences: 1) fossil reefs (Ordovician—Cretaceous in age), 2) short-term successions occurring through thin stratigraphic intervals, and 3) long-term successions occurring through thicker stratigraphic intervals. Ancient reefs show four vertical zones: (1) a basal stabilization zone (autogenic), 2) the overlying colonization zone (autogenic, pioneer stage), 3) the diversification zone, the bulk of most reefs (diversification culminating in climax), and 4) the uppermost domination zone. The first three zones represent autogenic succession but the final stage may involve allogenic succession. Short-term succession usually occurs where periodic allogenic catastrophes wipe out the community which is rebuilt through autogenic succession. Opportunistic pioneer species are important and in our examples (Ordovician, Silurian, and Cretaceous) are species which pave soft substrata. Paleozoic strophomenid brachiopods filled this role, and inoceramid pelecypods served the function in the Mesozoic. The succession which begins with opportunists progresses to a climax community of equilibrists. Repetition of catastrophe-succession couplets produces a cyclic stratigraphic record. Long-term successions are recorded in thicker stratigraphic sequences, and are of two types: 1) autogenic succession in unchanging physical environments and 2) allogenic succession in changing physical environments. Our examples of these are from the Devonian Haragan-Bois D'Arc formations of Oklahoma and the Lime Creek Formation of Iowa. This type of succession represents a temporal-spatial mosaic. The Haragan data (unchanging environments) indicate characteristic, intergrading, and ubiquitous species in the brachiopod communities. Most ubiquitous species in the pioneer community were eurytopic opportunists. The Lime Creek data allows testing of the prediction that environmental changes cause regression to an earlier succession stage. The brachiopod communities after environmental changes have more ubiquitous and intergrading eurytopic species. These represent an earlier stage in the succession.

scholarly journals Holocene sea level and climate interactions on wet dune slack evolution in SW Portugal: A model for future scenarios?

The Holocene ◽  
2018 ◽  
Vol 29 (1) ◽  
pp. 26-44 ◽  
Author(s):  
Manel Leira ◽  
Maria C Freitas ◽  
Tania Ferreira ◽  
Anabela Cruces ◽  
Simon Connor ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Environmental Changes ◽  
Sediment Accumulation ◽  
High Energy ◽  
Sediment Supply ◽  
Dune Slack ◽  
Ecological Stability ◽  
The Holocene ◽  
Climate Interactions

We examine the Holocene environmental changes in a wet dune slack of the Portuguese coast, Poço do Barbarroxa de Baixo. Lithology, organic matter, biological proxies and high-resolution chronology provide estimations of sediment accumulation rates and changes in environmental conditions in relation to sea-level change and climate variability during the Holocene. Results show that the wet dune slack was formed 7.5 cal. ka BP, contemporaneous with the last stages of the rapid sea-level rise. This depositional environment formed under frequent freshwater flooding and water ponding that allowed the development and post-mortem accumulation of abundant plant remains. The wetland evolved into mostly palustrine conditions over the next 2000 years, until a phase of stabilization in relative sea-level rise, when sedimentation rates slowed down to 0.04 mm yr−1, between 5.3 and 2.5 cal. ka BP. Later, about 0.8 cal. ka BP, high-energy events, likely due to enhanced storminess and more frequent onshore winds, caused the collapse of the foredune above the wetlands’ seaward margin. The delicate balance between hydrology (controlled by sea-level rise and climate change), sediment supply and storminess modulates the habitat’s resilience and ecological stability. This underpins the relevance of integrating past records in coastal wet dune slacks management in a scenario of constant adaptation processes.

The role of short-term weather conditions in temporal dynamics of fire regime features in mainland Spain

2019 ◽  
Vol 241 ◽  
pp. 575-586 ◽  
Author(s):  
Adrián Jiménez-Ruano ◽  
Marcos Rodrigues Mimbrero ◽  
W. Matt Jolly ◽  
Juan de la Riva Fernández
Keyword(s):  
Temporal Dynamics ◽  
Fire Regime ◽  
Weather Conditions ◽  
Short Term

scholarly journals A three-dimensional view on biodiversity changes: spatial, temporal, and functional perspectives on fish communities in the Baltic Sea

2018 ◽  
Vol 75 (7) ◽  
pp. 2463-2475 ◽  
Author(s):  
Romain Frelat ◽  
Alessandro Orio ◽  
Michele Casini ◽  
Andreas Lehmann ◽  
Bastien Mérigot ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Environmental Conditions ◽  
Environmental Changes ◽  
Temporal Dynamics ◽  
Marine Ecosystem ◽  
Fish Communities ◽  
The Baltic Sea ◽  
Functional Richness ◽  
Holistic Understanding ◽  
The Baltic

Abstract Fisheries and marine ecosystem-based management requires a holistic understanding of the dynamics of fish communities and their responses to changes in environmental conditions. Environmental conditions can simultaneously shape the spatial distribution and the temporal dynamics of a population, which together can trigger changes in the functional structure of communities. Here, we developed a comprehensive framework based on complementary multivariate statistical methodologies to simultaneously investigate the effects of environmental conditions on the spatial, temporal and functional dynamics of species assemblages. The framework is tested using survey data collected during more than 4000 fisheries hauls over the Baltic Sea between 2001 and 2016. The approach revealed the Baltic fish community to be structured into three sub-assemblages along a strong and temporally stable salinity gradient decreasing from West to the East. Additionally, we highlight a mismatch between species and functional richness associated with a lower functional redundancy in the Baltic Proper compared with other sub-areas, suggesting an ecosystem more susceptible to external pressures. Based on a large dataset of community data analysed in an innovative and comprehensive way, we could disentangle the effects of environmental changes on the structure of biotic communities—key information for the management and conservation of ecosystems.

Sign in / Sign up

Export Citation Format

Share Document