scholarly journals Effect of ecological factors on the zonation of wetland vegetation

2011 ◽  
Vol 74 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Richard Hrivnák
Keyword(s):  
Water Table ◽  
Aquatic Macrophytes ◽  
Temporal Dynamics ◽  
Typha Latifolia ◽  
Ground Surface ◽  
Ecological Factors ◽  
Marsh Vegetation ◽  
Spatial And Temporal Dynamics ◽  
Belt Transect

The influence of some ecological factors to aquatic and marsh vegetation was studied during 1998-2000. Three basic vegetation units (<em>Caricetum buekii</em>, <em>Typhetum latifoliae</em> and <em>Ceratophylletum submersi</em>) and three transitional communities were defined in the belt transect, which was established along the moisture gradient. The content of available soil nutrients in individual vegetation types differed only in case of the <em>Ceratophyllum submersum</em> community, where a higher magnesium and nitrogen content accumulated due to specific environmental conditions. Water and marsh vegetation is usually characterised by a pronounced spatial and temporal dynamics. In the studied area, its zonation was dependent from the terrain morphology, and both depth and duration of floods. The fluctuation of ground and surface water table during a three-year period caused changes in the occurrence and cover of several species (e.g. <em>Carex buekii</em>, <em>Typha latifolia</em>, aquatic macrophytes). Pronounced changes in the cover of some species occurred even within a single vegetation season due to the long-term sink of water table below the ground surface.

scholarly journals Modelling and  assessing driving factors of the spatial and temporal dynamics of the sand  dunes in the district of Errachidia, Morocco

2021 ◽  
Author(s):  
Tudal SINSIN ◽  
Fouad MOUNIR ◽  
Ahmed El ABOUDI
Keyword(s):  
Sand Dune ◽  
Temporal Dynamics ◽  
Moving Average ◽  
Sand Dunes ◽  
Ecological Factors ◽  
Temperature And Precipitation ◽  
Spatial And Temporal Dynamics ◽  
Combined Action ◽  
Landsat Satellite ◽  
Dune Dynamics

The desertification affects more than 250,000 ha in the district of Errachidia and results in the expansion of desert landscapes such as the Regs, Hamadas and the Dunes. The latter is a big concern in the district since it is the source of siltation, which threatens dwellings, cultivated lands and water bodies. It is of paramount importance to understand the causes and consequences of silting to develop strategies to combat it. Thus, first, we analysed the spatial and temporal dynamics of sand dunes until 2069 by applying the Seasonal Autoregressive Integrated Moving-Average (SARIMA) model on a time series of sand dune areas. These areas were calculated annually from 1987 to 2019 by computing the sand cover index (SCI) on Landsat satellite images. Furthermore, we evaluated the influence of different natural and human factors such as temperature, precipitation, wind, vegetation, and population growth, on sand dune dynamics using Spearman’s correlation test. The results indicated that the area of sand dunes will increase by 1.7% per year between 2019 and 2069 in the district of Errachidia. This increase would be mainly caused by the combined action of ecological factors, which vary from year to year. In general, temperature and precipitation act indirectly on wind and vegetation to influence the dynamics of sand dunes in hyper-arid areas where the soil is bare or poorly covered with vegetation, where precipitation is low and where temperature is high.

Surface-groundwater interactions in karst: overview, concept and mapping

2021 ◽  
Author(s):  
Natasa Ravbar ◽  
Cyril Mayaud ◽  
Matej Blatnik ◽  
Metka Petrič
Keyword(s):  
Environmental Changes ◽  
Temporal Dynamics ◽  
Field Measurements ◽  
Spatial Dimension ◽  
Karst Aquifers ◽  
Wetland Ecosystems ◽  
Spatial And Temporal Dynamics ◽  
Ecohydrological Processes

&lt;p&gt;Under special meteorological and hydrological circumstances, shallow karst areas and karst poljes may experience surface water overflow. As a result, surface- groundwater interaction occurs usually creating intermittent lakes. Although human settlements and activities have traditionally adapted to these natural conditions, extensive temporary floods are classified among the most common natural disasters in karst. On the other hand, intermittent lakes are considered as natural reservoirs of excess recharge and good flood regulators in the lower parts of river basins. Due to specific ecohydrological processes and environmental conditions, these areas host unique wetland ecosystems with high levels of biodiversity and provide various ecosystem services, such as ecological productivity, photosynthesis and carbon storage. Given the dynamic nature of hydrological processes in karst aquifers, a distinctive feature of the phenomena described is its high variability of occurrence and duration. Therefore, the identification, characterization as well as the determination of the spatial dimension of flood levels is a challenging task. Focusing on the Slovenian karst, a literature review and analysis of topographical and hydrological data of the selected study areas was conducted. The hydrological analyses were based on long-term monitoring data from Slovenian Environmental Agency and partly on the authors' own database of field measurements and knowledge of the areas concerned. Consequently, the conceptual framework and the key criterion for the determination and recording of areas subject to temporary flooding were developed. A systematic survey reveals the significance of the extent, duration and frequency of flooding. Evaluation results are useful to designers of various water policies and management mechanisms for flood mitigation and protection of special habitats. Observing trends in the spatial and temporal dynamics of flood levels is also valuable for understanding how and to what extent karst aquifers are vulnerable to environmental changes. Finally, the analyses also enable prediction of the effects of these changes on other parts of the environment (e.g., hydrophilic habitats).&lt;/p&gt;

scholarly journals Spatial and Temporal Dynamics of Electrical and Photosynthetic Activity and the Content of Phytohormones Induced by Local Stimulation of Pea Plants

Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1364
Author(s):  
Maria Ladeynova ◽  
Maxim Mudrilov ◽  
Ekaterina Berezina ◽  
Dmitry Kior ◽  
Marina Grinberg ◽  
...  
Keyword(s):  
Photosynthetic Activity ◽  
Temporal Dynamics ◽  
Response Analysis ◽  
Vascular Bundles ◽  
Variation Potential ◽  
Spatial And Temporal Dynamics ◽  
Two Phases ◽  
Local Stimulation ◽  
Transpiration Suppression

A local leaf burning causes variation potential (VP) propagation, a decrease in photosynthesis activity, and changes in the content of phytohormones in unstimulated leaves in pea plants. The VP-induced photosynthesis response develops in two phases: fast inactivation and long-term inactivation. Along with a decrease in photosynthetic activity, there is a transpiration suppression in unstimulated pea leaves, which corresponds to the long-term phase of photosynthesis response. Phytohormone level analysis showed an increase in the concentration of jasmonic acid (JA) preceding a transpiration suppression and a long-term phase of the photosynthesis response. Analysis of the spatial and temporal dynamics of electrical signals, phytohormone levels, photosynthesis, and transpiration activity showed the most pronounced changes in the more distant leaf from the area of local stimulation. The established features are related to the architecture of the vascular bundles in the pea stem.

scholarly journals Dinámica espacio-temporal del esfuerzo en una pesquería de buceo artesanal multiespecífica y sus efectos en la variabilidad de las capturas: Implicaciones para el manejo sostenible

2014 ◽  
Vol 62 (4) ◽  
pp. 1565 ◽  
Author(s):  
Helven Naranjo Madrigal ◽  
Silvia Salas Márquez
Keyword(s):  
Fisheries Management ◽  
Pacific Coast ◽  
Temporal Dynamics ◽  
Fishing Effort ◽  
The North ◽  
Fishing Strategies ◽  
Personal Consumption ◽  
Spatial And Temporal Dynamics ◽  
The North Pacific

Artisanal diving fisheries are a source of income, employment and food security of coastal areas in many countries. Understanding the dynamics of these fisheries, including the spatial and temporal dynamics of fishing effort, gears and species can help to address the challenges involved in fisheries management. We aimed to analyze the differences in fishing strategies undertaken by fishers that use two different diving methods (hookah and free diving), and the conditions and their potential impacts on catches when adjustments to those strategies are applied over time. For this, detailed information of fishing operations from artisanal boats in the North Pacific coast of Costa Rica was analyzed in two fishing seasons (2007-2008 and 2011-2012). Data were collected by onboard observers (fishing site, fishing time, species composition, depth and visibility). Additionally, interviews with divers were applied to obtain information of price per species, species volume and fishing operations. From the total number of trips during both seasons, hookah diving was represented by a sample size of 70.5%, while free diving, with a sample of 69.5%. More than 15 species were identified in each fishing season. Nevertheless, three categories had substantial contributions in both seasons with differences in the proportions for each case: green lobster (<em>Panulirus gracilis</em>), octopus (<em>Octopus</em> sp.) and parrotfish (<em>Scarus perrico</em> and <em>S. ghobban</em>). It is worth noting that an important proportion of catch was retained by fishers for personal consumption purposes, including species of high commercial value. Additional night diving activity, increased the number of dives from one season to another. Besides, cooperation processes in free diving fishing operations, and changes in fishing effort between seasons, defined important changes in fishing strategies. Potential causes of changes in fishing strategies and the implications for management to ensure the sustainability of these fisheries in the long term are discussed.

scholarly journals Rebound in functional distinctiveness following warming and reduced fishing in the North Sea

2021 ◽  
Vol 288 (1942) ◽  
pp. 20201600
Author(s):  
Juliette Murgier ◽  
Matthew McLean ◽  
Anthony Maire ◽  
David Mouillot ◽  
Nicolas Loiseau ◽  
...  
Keyword(s):  
North Sea ◽  
Temporal Dynamics ◽  
Distinct Species ◽  
Common Species ◽  
Fishing Pressure ◽  
The North ◽  
Spatial And Temporal Dynamics ◽  
Recent Climate ◽  
The North Sea

Functionally distinct species (i.e. species with unique trait combinations in the community) can support important ecological roles and contribute disproportionately to ecosystem functioning. Yet, how functionally distinct species have responded to recent climate change and human exploitation has been widely overlooked. Here, using ecological traits and long-term fish data in the North Sea, we identified functionally distinct and functionally common species, and evaluated their spatial and temporal dynamics in relation to environmental variables and fishing pressure. Functionally distinct species were characterized by late sexual maturity, few, large offspring, and high parental care, many being sharks and skates that play critical roles in structuring food webs. Both functionally distinct and functionally common species increased in abundance as ocean temperatures warmed and fishing pressure decreased over the last three decades; however, functionally distinct species increased throughout the North Sea, but primarily in southern North Sea where fishing was historically most intense, indicating a rebound following fleet decommissioning and reduced harvesting. Yet, some of the most functionally distinct species are currently listed as threatened by the IUCN and considered highly vulnerable to fishing pressure. Alarmingly these species have not rebounded. This work highlights the relevance and potential of integrating functional distinctiveness into ecosystem management and conservation prioritization.

Early Medieval Great Hall Complexes in England: Temporality and Site Biographies

2020 ◽  
Vol 22 ◽  
pp. 50-67
Author(s):  
Christopher Scull ◽  
Gabor Thomas
Keyword(s):  
Social Action ◽  
Temporal Dynamics ◽  
Eighth Century ◽  
Short Term ◽  
The Past ◽  
Spatial And Temporal Dynamics ◽  
The Social ◽  
Elite Identity ◽  
Site History

This paper offers a critical reconsideration of the social, spatial and temporal dynamics of sixth- to eighth-century great hall complexes in England. The major interpretative issues and constraints imposed by the data are considered, and the sites are then subject to comparative analysis across long-term and short-term temporal scales. The former highlights persistence of antecedent activity and centrality, the latter the ways in which the built environment was perceived in the past, structured social action, and was a medium for the construction and consolidation of elite identity and authority. Within the broad similarity that defines the site-type there is evidence for considerable diversity and complexity of site history and afterlife.

scholarly journals Developing by borrowing? Inter-jurisdictional competition, land finance and local debt accumulation in China

Urban Studies ◽  
2016 ◽  
Vol 54 (4) ◽  
pp. 897-916 ◽  
Author(s):  
Fenghua Pan ◽  
Fengmei Zhang ◽  
Shengjun Zhu ◽  
Dariusz Wójcik
Keyword(s):  
Local Government ◽  
Local Governments ◽  
Financial Stability ◽  
Temporal Dynamics ◽  
Government Debt ◽  
Debt Accumulation ◽  
Spatial And Temporal Dynamics ◽  
National Economic ◽  
Jurisdictional Competition

Although the investment-oriented development model for economic growth adopted by Chinese governments has generated spectacular results, the risks of debt-financed urbanisation and economic development have recently become evident in mounting local debts that are undermining the financial system, triggering concerns with respect to local governments’ indebtedness, financial stability and sovereign risk in China. In this paper, we portray the uneven spatial and temporal dynamics of local government debt in China, and examine the ways in which it is intertwined with institutional, political and economic factors. Our analysis shows that while global and national economic conditions have resulted in a dramatic increase in local government debt, particularly in the late 2000s and the early 2010s, the spatial variation of local debt accumulation in China could be partly explained by two institutional factors: land finance and inter-jurisdictional competition. We argue that the behaviour of local governments may harm the long-term future of Chinese cities.

scholarly journals Possible ecology and epidemiology of medically important mosquito-borne arboviruses in Great Britain

2006 ◽  
Vol 135 (3) ◽  
pp. 466-482 ◽  
Author(s):  
J. M. MEDLOCK ◽  
K. R. SNOW ◽  
S. LEACH
Keyword(s):  
Great Britain ◽  
Disease Ecology ◽  
Temporal Dynamics ◽  
Ecological Factors ◽  
Human Infection ◽  
Mosquito Vectors ◽  
West Nile ◽  
Spatial And Temporal Dynamics ◽  
Reservoir Hosts ◽  
Ecological Differences

Nine different arboviruses are known to be transmitted by, or associated with, mosquitoes in Europe, and several (West Nile, Sindbis and Tahyna viruses) are reported to cause outbreaks of human disease. Although there have been no reported human cases in Great Britain (GB), there have been no published in-depth serological surveys for evidence of human infection. This paper investigates the ecological and entomological factors that could influence or restrict transmission of these viruses in GB, suggesting that in addition to West Nile virus, Sindbis and Tahyna viruses could exist in enzootic cycles, and that certain ecological factors could facilitate transmission to humans. However, the level of transmission is likely to be lower than in endemic foci elsewhere in Europe due to key ecological differences related to spatial and temporal dynamics of putative mosquito vectors and presence of key reservoir hosts. Knowledge of the potential GB-specific disease ecology can aid assessments of risk from mosquito-borne arboviruses.

scholarly journals Spatial and Temporal Dynamics of Invasive Freshwater Shrimp (Mysis diluviana): Long-Term Effects on Ecosystem Properties in a Large Oligotrophic Lake

Ecosystems ◽  
2016 ◽  
Vol 20 (1) ◽  
pp. 183-197 ◽  
Author(s):  
Shawn P. Devlin ◽  
Samantha K. Tappenbeck ◽  
James A. Craft ◽  
Tyler H. Tappenbeck ◽  
Dale W. Chess ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Oligotrophic Lake ◽  
Long Term Effects ◽  
Freshwater Shrimp ◽  
Ecosystem Properties ◽  
Mysis Diluviana ◽  
Spatial And Temporal Dynamics

scholarly journals Spatial and Temporal Dynamics in the Ionic Driving Force for GABAAReceptors

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
R. Wright ◽  
J. V. Raimondo ◽  
C. J. Akerman
Keyword(s):  
Driving Force ◽  
Neural Circuit ◽  
Temporal Dynamics ◽  
Spatial And Temporal Dynamics ◽  
Mature Brain ◽  
Gabaergic Synapses ◽  
Circuit Development ◽  
And Function ◽  
Activity Dependent

It is becoming increasingly apparent that the strength of GABAergic synaptic transmission is dynamic. One parameter that can establish differences in the actions of GABAergic synapses is the ionic driving force for the chloride-permeable GABAAreceptor (GABAAR). Here we review some of the sophisticated ways in which this ionic driving force can vary within neuronal circuits. This driving force for GABAARs is subject to tight spatial control, with the distribution of Cl−transporter proteins and channels generating regional variation in the strength of GABAAR signalling across a single neuron. GABAAR dynamics can result from short-term changes in their driving force, which involve the temporary accumulation or depletion of intracellular Cl−. In addition, activity-dependent changes in the expression and function of Cl−regulating proteins can result in long-term shifts in the driving force for GABAARs. The multifaceted regulation of the ionic driving force for GABAARs has wide ranging implications for mature brain function, neural circuit development, and disease.

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