scholarly journals Simulating Destructive and Constructive Morphodynamic Processes in Steep Beaches

2021 ◽  
Vol 9 (1) ◽  
pp. 86
Author(s):  
Katerina Kombiadou ◽  
Susana Costas ◽  
Dano Roelvink
Keyword(s):  
Beach Profile ◽  
Short Term ◽  
Temporal Scales ◽  
Event Scale ◽  
Significant Recovery ◽  
Beach Morphodynamics ◽  
Wave Forcing ◽  
Runup Height ◽  
Calibration Parameters

Short-term beach morphodynamics are typically modelled solely through storm-induced erosion, disregarding post-storm recovery. Yet, the full cycle of beach profile response is critical to simulating and understanding morphodynamics over longer temporal scales. The XBeach model is calibrated using topographic profiles from a reflective beach (Faro Beach, in S. Portugal) during and after the incidence of a fierce storm (Emma) that impacted the area in early 2018. Recovery in all three profiles showed rapid steepening of the beachface and significant recovery of eroded volumes (68–92%) within 45 days after the storm, while berm heights reached 4.5–5 m. Two calibration parameters were used (facua and bermslope), considering two sets of values, one for erosive (Hm0 ≥ 3 m) and one for accretive (Hm0 < 3 m) conditions. A correction of the runup height underestimation by the model in surfbeat mode was necessary to reproduce the measured berm elevation and morphology during recovery. Simulated profiles effectively capture storm erosion, but also berm growth and gradual recovery of the profiles, showing good skill in all three profiles and recovery phases. These experiments will be the basis to formulate event-scale simulations using schematized wave forcing that will allow to calibrate the model for longer-term changes.

scholarly journals Information Analysis of Catchment Hydrologic Patterns across Temporal Scales

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Baoxiang Pan ◽  
Zhentao Cong
Keyword(s):  
Epistemic Uncertainty ◽  
Temporal Scale ◽  
Information Analysis ◽  
Energy Correlation ◽  
Temporal Scales ◽  
Correlation Pattern ◽  
Event Scale ◽  
Information Contents ◽  
Input Variables ◽  
Annual Water

Catchment hydrologic cycle takes on different patterns across temporal scales. The interim between event-scale hydrologic process and mean annual water-energy correlation pattern requires further examination to justify self-consistent understanding. In this paper, the temporal scale transition revealed by observation and simulation was evaluated in an information theoretical framework namedAleatory Epistemic Uncertainty Estimation. The Aleatory Uncertainty refers to posterior uncertainty of runoff given the input variables’ observations. The Epistemic Uncertainty refers to the posterior uncertainty increase due to the imperfect observationdecodingin models. Daily hydrometeorological observations in 24 catchments were aggregated from 10 days to 1 year before implementing the information analysis. Estimations of information contents and flows of hydrologic terms across temporal scales were related with the catchments’ seasonality type. It also showed that information distilled by the monthly and annual water balance models applied here did not correspond to that provided by observations around temporal scale from two months to half a year. This calls for a better understanding of seasonal hydrologic mechanism.

scholarly journals Individual-level specialisation and interspecific resource partitioning in bees revealed by pollen DNA metabarcoding

2021 ◽  
Author(s):  
Jan Klečka ◽  
Michael Mikát ◽  
Pavla Koloušková ◽  
Jiří Hadrava ◽  
Jakub Straka
Keyword(s):  
Resource Partitioning ◽  
Foraging Behaviour ◽  
Plant Reproduction ◽  
Short Term ◽  
Temporal Scales ◽  
Individual Level ◽  
Multi Scale ◽  
Foraging Preferences ◽  
Dna Metabarcoding ◽  
Flower Visiting

It is increasingly recognised that intraspecific variation in traits, such as morphology, behaviour, or diet is both ubiquitous and ecologically important. While many species of predators and herbivores are known to display high levels of between-individual diet variation, there is a lack of studies on pollinators. It is important to fill in this gap because individual-level specialisation of flower-visiting insects is expected to affect their efficiency as pollinators with consequences for plant reproduction. Accordingly, the aim of our study was to quantify the level of individual-level specialisation and foraging preferences, as well as interspecific resource partitioning, across different temporal scales in three co-occurring species of bees of the genus Ceratina (Hymenoptera: Apidae: Xylocopinae), C. chalybea, C. nigrolabiata, and C. cucurbitina. We conducted a field experiment where we provided artificial nesting opportunities for the bees and combined a short-term mark-recapture study with the dissection of the bees' nests to obtain repeated samples from individual foraging females and complete pollen provisions from their nests. Hence, we could study variation of the composition of pollen collected by the bees at different temporal scales. We used DNA metabarcoding based on the ITS2 locus to identify the composition of the pollen samples. We found that the composition of pollen carried on the bodies of female bees and stored in the brood provisions in their nests significantly differed among the three co-occurring species. At the intraspecific level, individual females consistently differed in their level of specialisation and in the composition of pollen carried on their bodies and stored in their nests. Our study thus provides evidence of consistent individual-level specialisation in pollinators across multiple temporal scales. We also demonstrate that higher generalisation at the species level stemmed from larger among-individual variation in diets as observed in other types of consumers, such as predators. Our study thus reveals how specialisation and foraging preferences of bees change from the scale of individual foraging bouts to complete pollen provisions accumulated in their nests over their lifetime. Such multi-scale view of foraging behaviour is necessary to improve our understanding of the functioning of plant-flower visitor communities.

The effects of Velpar L (hexazinone) on seedling growth and ectomycorrhizal symbiosis of Pinusresinosa

1988 ◽  
Vol 18 (7) ◽  
pp. 917-921 ◽  
Author(s):  
P. Chakravarty ◽  
L. Chatarpaul
Keyword(s):  
Seedling Growth ◽  
Field Studies ◽  
Indigenous Species ◽  
Mycorrhizal Infection ◽  
Infection Rates ◽  
Seedling Mortality ◽  
Short Term ◽  
Ectomycorrhizal Symbiosis ◽  
Significant Recovery ◽  
Application Rates

We investigated the effects of Velpar L (hexazinone) on ectomycorrhizal (Laccarialaccata) and nonmycorrhizal Pinusresinosa seedlings in the greenhouse and in the field. In both greenhouse and field studies, seedling growth was reduced by Velpar L at 1, 2, and 4 kg/ha application rates in the short term (2 months' exposure) with significant recovery occurring afterwards. Seedling mortality occurred only with herbicide treatments and was higher in the greenhouse than in the field. The 4 kg/ha Velpar L treatment caused the highest mortality and toxicity was most pronounced in the mycorrhizal (Laccarialaccata inoculated) seedlings. In both experiments mycorrhizal infection was significantly reduced by 2 and 4 kg/ha Velpar L treatments during the 0- to 2-month and 2- to 6-month exposure periods, with significant recovery occurring in the latter. Although seedlings not infected with Laccarialaccata became mycorrhizal through unidentified indigenous species, their infection rates were also affected by Velpar L at all levels during the 0- to 2-month period and at the 2 and 4 kg/ha levels after 2–6 months of exposure to the herbicide.

scholarly journals Multiple Temporal Scales Assessment in the Hydrological Response of Small Mediterranean Catchments

2019 ◽  
Author(s):  
Josep Fortesa ◽  
Julian García-Comendador ◽  
Aleix Calsamiglia ◽  
Miquel Tomàs-Burguera ◽  
Jérôme Latron ◽  
...  
Keyword(s):  
Agricultural Land ◽  
Biotic Factors ◽  
Hydrological Response ◽  
Rainfall Runoff ◽  
Runoff Generation ◽  
Temporal Scales ◽  
Event Scale ◽  
Hydrological Variability ◽  
Abiotic And Biotic Factors ◽  
Annual Scale

Mediterranean catchments are characterized by significant spatial and temporal hydrological variability caused by the interaction of natural as well human-induced abiotic and biotic factors. This study investigates the (non-)linearity rainfall-runoff relationship at multiple temporal scales in representative small Mediterranean catchments (i.e., &lt; 10 km2) to achieve a better understanding of the hydrological response. Rainfall-runoff relationship was evaluated in 44 catchments at annual and event &ndash;203 events in 12 of these 44 catchments&ndash; scales. A linear rainfall-runoff relation was observed at annual scale with higher scatter in pervious than impervious catchments. Larger scattering was observed at event scale, although pervious lithology and agricultural land use promoted significant rainfall-runoff linear relations in winter and spring. These relationships were particularly analysed during five hydrological years in Es Fangar catchment (3.35 km2; Mallorca, Spain) as a temporal downscaling to assess intra-annual variability in which antecedent wetness conditions played a significant role in runoff generation.

scholarly journals Hillslope characteristics as controls of subsurface flow variability

2012 ◽  
Vol 9 (6) ◽  
pp. 6889-6934 ◽  
Author(s):  
S. Bachmair ◽  
M. Weiler
Keyword(s):  
Soil Properties ◽  
Shallow Water ◽  
Water Table ◽  
Explanatory Power ◽  
Measurement Techniques ◽  
Subsurface Flow ◽  
Shallow Water Table ◽  
Temporal Scales ◽  
Event Scale ◽  
Flow Variability

Abstract. Hillslope hydrological dynamics, particularly subsurface flow (SSF), are highly variable and complex. A profound understanding of factors controlling this variability is needed. Therefore we investigated the relationship between variability of shallow water table dynamics and various hillslope characteristics. We ask whether measurable hillslope properties explain patterns of subsurface flow variability. To approach this question shallow water table dynamics of three adjacent large-scale hillslopes were monitored with high spatial and temporal resolution over 18 months. The hillslopes are similar in terms of topography and parent material, but different in vegetation cover (grassland, coniferous forest, and mixed forest). We expect vegetation to be an important driver of water table dynamics at our study site, especially given the minor differences in topography. Various hillslope properties were determined in the field and via GIS analysis: common topography descriptors, well depth, soil properties via slug tests, and several vegetation parameters. Response variables characterizing the water table response per well were calculated for different temporal scales (entire time series, seasonal scale, event scale). Partial correlation analysis and a Random Forest machine learning approach were carried out to assess the explainability of SSF variability by measurable hillslope characteristics. We found a complex interplay of predictors, yet soil properties and topography showed the highest single explanatory power. Surprisingly, vegetation characteristics played a minor role. Solely throughfall and canopy cover exerted a slightly stronger control, especially in summer. Most importantly, the examined hillslope characteristics explained only a small proportion of the observed SSF variability. Consequently there must be additional important drivers not represented by current measurement techniques of the hillslope configuration (e.g. bedrock properties, preferential pathways). We also found interesting differences in explainability of SSF variability among temporal scales and between both forested hillslopes and the grassland hillslope.

Behavioral, plastic, and evolutionary responses to a changing world

2018 ◽  
Author(s):  
Wolf U. Blanckenhorn
Keyword(s):  
Climate Change ◽  
Life History ◽  
Environmental Change ◽  
Physiological Responses ◽  
Short Term ◽  
Temporal Scales ◽  
Evolutionary Response ◽  
Physiological Adjustments ◽  
Changing World

Organisms can respond to environmental change by modifying their behavior to obtain an instant response, through short-term phenotypically plastic, often physiological, adjustments, and/or by adapting their life history through a more long-term evolutionary response. Behavioural and physiological responses, in fact, can occur at all these three temporal scales. Examples of behaviors so affected include congregation, dispersal, foraging, migration, or mating. Such responses have consequences at the population and community levels, and ultimately for the evolution of species. This chapter discusses insect examples of these kinds, with an emphasis on human-induced factors, such as (primarily) climate change, pollution, fragmentation, and urbanization.

The Phenological Community

2019 ◽  
pp. 94-106
Author(s):  
Eric Post
Keyword(s):  
Annual Cycle ◽  
Community Dynamics ◽  
Local Community ◽  
Dynamic Nature ◽  
Short Term ◽  
Temporal Scales ◽  
Individual Organism ◽  
Use Of Time ◽  
Allocation Of Time ◽  
The Individual

This chapter studies how the concept of phenological community relates to the utilization of time by species that co-occur in the local assemblage. It also examines the consequences for phenological community dynamics of differential use of time by co-occurring species. Indeed, a main point of emphasis in this chapter is the dynamic nature of the community in a phenological context. The allocation of time by the individual organism to phenophases within its annual cycle of growth, maintenance, and reproduction determines patterns of interactions in time among species co-occurring in the local assemblage. In the context of phenology, the local community is characterized by a capacity for pronounced variability on both short-term temporal scales (over days) and on longer-term temporal scales (from year to year).

scholarly journals Ramp forecasting performance from improved short-term wind power forecasting over multiple spatial and temporal scales

Energy ◽  
2017 ◽  
Vol 122 ◽  
pp. 528-541 ◽  
Author(s):  
Jie Zhang ◽  
Mingjian Cui ◽  
Bri-Mathias Hodge ◽  
Anthony Florita ◽  
Jeffrey Freedman
Keyword(s):  
Wind Power ◽  
Short Term ◽  
Temporal Scales ◽  
Wind Power Forecasting ◽  
Spatial And Temporal Scales ◽  
Forecasting Performance ◽  
Power Forecasting

scholarly journals EXPERIMENTAL STUDY ON ON-OFFSHORE SEDIMENT TRANSPORT OF ACCRETIVE BEACH

1986 ◽  
Vol 1 (20) ◽  
pp. 96
Author(s):  
Ching-Ton Kuo ◽  
Ching-Her Hwang ◽  
I-Chou Tseng
Keyword(s):  
Sediment Transport ◽  
Vital Role ◽  
Beach Profile ◽  
Short Term ◽  
Temporal And Spatial Distribution ◽  
Storm Wave ◽  
Deformation Processes ◽  
Profile Changes ◽  
Temporal And Spatial ◽  
Amount Of Knowledge

In treating coastal proceses, sediment transport is usually divided into along-shore and on-offshore components. It is believed that the on-offshore component has a prominant connection with short-term profile changes, observed during storm wave climates. Obviously its shift of sand plays a very vital role in shoreline migration. In other words, the beach profile has great bearing on coastal phenomena related to on-offshore sediment transport. As we know, there have been many studies on this kind of sediment transport rate, and considerable amount of knowledge on this problem has been accumulated so far. Yet it seems that we are still far from a reliable formulus to estimate the beach profile changes. The reason why is due to the complexity of mechanics of sediment transport. Therefore, the aim of this study is to examine experimentally the mechanism between onoffshore sediment transport and the deformation processes of twodimensional beach profile. Then , a predictive model of the temporal and spatial distribution of net on-offshore sediment transport based on two-dimensional beach profiles and an equation of continuity of sediment transport is proposed. Various parameters of net on-offshore sediment transport in this model are discussed also.

Prediction of Cross-Shore Beach Profile Evolution in the Vicinity of Seawalls

2011 ◽  
Author(s):  
Seyed Ahmad Lashteh-Neshaei ◽  
Mohammad Ali Lotfollahi-Yaghin ◽  
Morteza Biklaryan
Keyword(s):  
Present Model ◽  
Theoretical Models ◽  
Measured Data ◽  
Probability Density Functions ◽  
Density Functions ◽  
Beach Profile ◽  
Short Term ◽  
New Approach ◽  
Proposed Model ◽  
Measured Probability

Although there exist advanced models which predict to beach profile for natural beaches, the behavior of the beaches in front of seawalls still suffers from the lack of appropriate theoretical models and sufficient measured data. Following the results obtained from the measurements, a beach profile evolution model is developed, using the measured probability distribution of the near-bed horizontal velocities as input, to predict the short-term bed level changes in the vicinity of e partially reflective seawall. The present model introduces a new approach in which based on integrating the probability density functions of the near-bed horizontal velocities, the sediment displacements and consequently bed level changes are calculated in front of a partially reflective structure. The results obtained from the model and comparison with the experiments are promising and encouraging for further developments of the proposed model.

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