SPATIO-TEMPORAL CHAOS IN AN ECOLOGICAL COMMUNITY AS A RESPONSE TO UNFAVOURABLE ENVIRONMENTAL CHANGES

2001 ◽  
Vol 04 (02n03) ◽  
pp. 227-249 ◽  
Author(s):  
SERGEI V. PETROVSKII ◽  
HORST MALCHOW
Keyword(s):  
Population Dynamics ◽  
Chaotic Dynamics ◽  
Environmental Changes ◽  
Temporal Dynamics ◽  
Ecological Community ◽  
Species Extinction ◽  
Population Extinction ◽  
Small Domain ◽  
Spatio Temporal ◽  
The Impact

The impact of ecological chaos on population dynamics has been an issue of intense discussion over the last decade. While many authors consider chaotic dynamics as a favourable factor facilitating species biodiversity, there is also a strong opinion that chaos may enhance population extinction. In this paper we show that chaotic spatio-temporal dynamics in an ecological community can arise as a response of the community to unfavourable environmental changes. Appearing in that way, chaos can prevent species extinction in a situation when it would be inevitable otherwise. We also show that an essential consequence of chaotic dynamics is that the issue of species extinction is subject to the size of the domain inhabited by the population, the extinction more likely happens in a small domain than in a large one.

scholarly journals SPATIO-TEMPORAL DYNAMICS ALONG THE TERRAIN GRADIENT OF DIVERSE LANDSCAPE

2014 ◽  
Vol 22 (1) ◽  
pp. 50-63 ◽  
Author(s):  
T. V. Ramachandra ◽  
Settur Bharath ◽  
Aithal Bharath
Keyword(s):  
Land Cover ◽  
Environmental Changes ◽  
Temporal Dynamics ◽  
Demographic Data ◽  
Coastal Region ◽  
Data Sets ◽  
Lulc Change ◽  
Multi Temporal ◽  
Spatio Temporal ◽  
The Impact

Land use (LU) land cover (LC) information at a temporal scale illustrates the physical coverage of the Earth’s terrestrial surface according to its use and provides the intricate information for effective planning and management activities. LULC changes are stated as local and location specifc, collectively they act as drivers of global environmental changes. Understanding and predicting the impact of LULC change processes requires long term historical restorations and projecting into the future of land cover changes at regional to global scales. The present study aims at quantifying spatio temporal landscape dynamics along the gradient of varying terrains presented in the landscape by multi-data approach (MDA). MDA incorporates multi temporal satellite imagery with demographic data and other additional relevant data sets. The gradient covers three different types of topographic features, planes; hilly terrain and coastal region to account the signifcant role of elevation in land cover change. The seasonality is another aspect to be considered in the vegetation dominated landscapes; variations are accounted using multi seasonal data. Spatial patterns of the various patches are identifed and analysed using landscape metrics to understand the forest fragmentation. The prediction of likely changes in 2020 through scenario analysis has been done to account for the changes, considering the present growth rates and due to the proposed developmental projects. This work summarizes recent estimates on changes in cropland, agricultural intensifcation, deforestation, pasture expansion, and urbanization as the causal factors for LULC change.

scholarly journals Increasing frequency of low summer precipitation synchronizes dynamics and compromises metapopulation stability in the Glanville fritillary butterfly

2015 ◽  
Vol 282 (1806) ◽  
pp. 20150173 ◽  
Author(s):  
Ayco J. M. Tack ◽  
Tommi Mononen ◽  
Ilkka Hanski
Keyword(s):  
Population Dynamics ◽  
Population Change ◽  
Temporal Dynamics ◽  
Summer Precipitation ◽  
Life History Stage ◽  
General Effect ◽  
Spatial Synchrony ◽  
Glanville Fritillary Butterfly ◽  
Spatio Temporal

Climate change is known to shift species' geographical ranges, phenologies and abundances, but less is known about other population dynamic consequences. Here, we analyse spatio-temporal dynamics of the Glanville fritillary butterfly ( Melitaea cinxia ) in a network of 4000 dry meadows during 21 years. The results demonstrate two strong, related patterns: the amplitude of year-to-year fluctuations in the size of the metapopulation as a whole has increased, though there is no long-term trend in average abundance; and there is a highly significant increase in the level of spatial synchrony in population dynamics. The increased synchrony cannot be explained by increasing within-year spatial correlation in precipitation, the key environmental driver of population change, or in per capita growth rate. On the other hand, the frequency of drought during a critical life-history stage (early larval instars) has increased over the years, which is sufficient to explain the increasing amplitude and the expanding spatial synchrony in metapopulation dynamics. Increased spatial synchrony has the general effect of reducing long-term metapopulation viability even if there is no change in average metapopulation size. This study demonstrates how temporal changes in weather conditions can lead to striking changes in spatio-temporal population dynamics.

scholarly journals Spatio-temporal dynamics of schistosomiasis in Rwanda between 2001 and 2012: impact of the national Neglected Tropical Disease control programme

2017 ◽  
Vol 12 (1) ◽  
Author(s):  
Elias Nyandwi ◽  
Tom Veldkamp ◽  
Frank Badu Osei ◽  
Sherif Amer
Keyword(s):  
Temporal Dynamics ◽  
Public Health Problem ◽  
Incidence Rates ◽  
Control Programme ◽  
Scan Statistics ◽  
Major Public Health Problem ◽  
Implementation Phase ◽  
Incidence Data ◽  
Spatio Temporal ◽  
The Impact

Schistosomiasis is recognised as a major public health problem in Rwanda. We aimed to identify the spatio-temporal dynamics of its distribution at a fine-scale spatial resolution and to explore the impact of control programme interventions. Incidence data of Schistosoma mansoni infection at 367 health facilities were obtained for the period 2001-2012. Disease cluster analyses were conducted using spatial scan statistics and geographic information systems. The impact of control interventions was assessed for three distinct sub-periods. Findings demonstrated persisting, emerging and re-emerging clusters of schistosomiasis infection across space and time. The control programme initially caused an abrupt increase in incidence rates during its implementation phase. However, this was followed by declining and disappearing clusters when the programme was fully in place. The findings presented should contribute to a better understanding of the dynamics of schistosomiasis distribution to be used when implementing future control activities, including prevention and elimination efforts.

Predicting change in biogeochemical potential of subsurface systems with changing hydrogeological conditions

2021 ◽  
Author(s):  
Swamini Khurana ◽  
Falk Heße ◽  
Martin Thullner
Keyword(s):  
Water Quality ◽  
Preferential Flow ◽  
Nutrient Loading ◽  
Temporal Dynamics ◽  
Reaction Network ◽  
Climate Scenario ◽  
Ecosystem Functions ◽  
External Forcing ◽  
Spatio Temporal ◽  
The Impact

<p>In a changing climate scenario, we expect weather event patterns to change, both in frequency and in intensity. The subsequent impacts of these changing patterns on ecosystem functions are of great interest. Water quality particularly is critical due to public health concerns. Already, seasonal variation of water quality has been attributed to varying microbial community assemblages and nutrient loading in the corresponding water body but the contribution of the variations in the quantity of groundwater recharge is a missing link. It is thus beneficial to establish links between external forcing such as changing infiltration rate or recharge on nutrient cycling in the subsurface. We undertake this study to investigate the impact of temporal variation in external forcing on the biogeochemical potential of spatially heterogeneous subsurface systems using a numerical modeling approach. We used geostatistical tools to generate spatial random fields by considering difference combinations of the variance in the log conductivity field and the anisotropy of the domain. Tuning these two parameters assists in effective representation of a wide variety of geologic materials with varying intensity of preferential flow paths in the heterogeneous domain. We ran simulations using OGS#BRNS that enables us to combine a flexibly defined microbial mediated reaction network with the mentioned spatially heterogeneous domains in transient conditions. We propose that a combination of estimated field indicators of Damköhler number, Peclet number (transformed Damköhler number: Da<sub>t</sub>), and projected temporal dynamics in surface conditions can assist us in predicting the change in biogeochemical potential of the subsurface system. Preliminary results indicate that we miss potentially critical variations in reactive species concentration if we neglect spatio-temporal heterogeneities for regimes where 1<Da<sub>t</sub><40. For regimes characterized by values outside this range, we propose that spatio-temporal heterogeneities due to subsurface structure and changing hydrological forcing may not be relevant.</p>

scholarly journals Spatio-Temporal Dynamics of Landuse/Land Cover Around NTPC Using High Resolution Satellite Imagery

2020 ◽  
pp. 101-109
Keyword(s):  
Rapid Growth ◽  
Agricultural Land ◽  
Environmental Changes ◽  
Temporal Dynamics ◽  
Geographical Area ◽  
Considerable Change ◽  
Central Component ◽  
Land Resource ◽  
Spatio Temporal ◽  
Level I

Land is becoming scarce resource due to population growth and industrialization. Rapid growth of human activities can also be attributed as one of the reasons. Thus, it becomes an important task to regulate land resource for sustainable development and environmental protection. LULC change studies have become a central component in current strategies for managing and planning land resources and monitoring environmental changes. In this paper an attempt has been made to bring out spatio-temporal dynamics of LULC patterns of NTPCRamagundam and its surrounding environment by using multi-temporal satellite data of Landsat-4, IRS P6 LISS-III and IRS 2 LISS-IV and GIS techniques for the years 1984, 2005, 2011, 2015, 2018. The methodology includes base map preparation having features like Road (SH), Rail, Canal, River, Stream, Tanks, Forest boundary and other administrative boundaries from SOI topo sheet and the features digitized are updated on satellite images. Interpretation of study area for LULC feature extraction on satellite imageries of respective years is carried with Nrsc’s standard LULC classification system. Change detection statistics can be generated out of 5 LULC thematic layers obtained and analysed specially with respect to NTPC environs. Results from this study shows the percentage of geographical area occupied by built-up land, agricultural land, forests, wasteland and waterbodies of level-I LULC features were 10.27%, 60.68%, 6.61%, 11.81%, 10.63% respectively in 1984 and were changed into 21.41%, 48.51%, 5.97%, 12.77%, 11.34% respectively in 2018. This analysis shows a rapid growth in built-up land and fall in agricultural land between 1984 and 2018. There is a considerable change in the remaining features from 1984 and 2018.

scholarly journals Regional Public Stock Reductions in Spain: Estimations from a Multiregional Spatial Vector Autorregressive Model

REGION ◽  
2017 ◽  
Vol 4 (1) ◽  
pp. 129 ◽  
Author(s):  
Miguel A Márquez ◽  
Julian Ramajo ◽  
Geoffrey Hewings
Keyword(s):  
Economic Growth ◽  
Temporal Dynamics ◽  
Public Investment ◽  
Public Capital ◽  
Regional Economic Growth ◽  
State Variables ◽  
Regional System ◽  
Negative Effect ◽  
Spatio Temporal ◽  
The Impact

The estimation of the impact of public investment on regional economic growth requires consideration of the spatio-temporal dynamics among the state variables of each region.  Recent austerity policies in Spain that feature temporary decreases in the accumulation of regional public capital should thus be evaluated in terms of their impact on the economy as a whole, on specific regions together with the spillovers effects from one region to the rest of the regional system.  Applying a multiregional integrated specification to model interdependencies across regions, our results indicate that, while global decreases in public investment have a homogenously negative effect on the output of all the regions, the Spanish regions portray heterogeneous responses from localized public capital stock reductions over the simulation period considered.

Spatio-Temporal Dynamics of Sociology in Post-1990 Turkey

2019 ◽  
Vol 24 (4) ◽  
pp. 598-616
Author(s):  
Canan Neşe Kınıkoğlu
Keyword(s):  
Temporal Dynamics ◽  
Sociological Research ◽  
Sociological Knowledge ◽  
Social Foundations ◽  
Methodological Nationalism ◽  
Turkish Nationalism ◽  
Spatial Differences ◽  
Phd Theses ◽  
Spatio Temporal ◽  
The Impact

This study explores the spatio-temporal conditions of producing sociological knowledge at universities at a time of transformation in post-1990 (1990–2017) Turkey. Through a content analysis of the sociology PhD theses submitted in this period, it investigates the questions of where, when, and how sociological knowledge is institutionalized in Turkey. The study has two main findings. First, spatial distribution of sociology PhD theses highlights the ensuing centre–periphery relationships inside Turkey, a country itself located in the periphery. Endowed with better resources, the centre (mainly Ankara and Istanbul) focuses on macro solutions to the problems faced by Turkey and other countries, whereas the rest of the country produces knowledge about their immediate surroundings, that is, particular regions/cities/towns of Turkey. This difference illustrates the degrees to which sociological research in post-1990 Turkey is territorially limited by (Turkish) national borders. Second, temporally speaking, the sociological interest in domestic issues revolves mainly around ‘politics’ and ‘economy’, insofar as they relate to the economic crises, neoliberalism, globalization, and democratization attempts Turkey experienced in the post-1990 period. A closer reading of this spatio-temporality may suggest that Turkish sociology is susceptible to methodological nationalism that downplays the impact of nationalism, conforms to the nation-state and nations, and territorially limits the unit of analysis. Despite the transformations brought about by the period and the spatial differences in knowledge production between the centre and the periphery, sociology in Turkey is bound by the national territorial and ideational boundaries, reproducing the ethnic, political, cultural, and social foundations of Turkish nationalism. This study argues that although Turkish sociology stands on the periphery within the non-Western context, it is nonetheless formalized around its own centre–periphery relationship within the country itself, and that its spatio-temporal institutionalization in the post-1990 period has reproduced an implicit methodological nationalism that relies on Turkish nationalism.

scholarly journals THE IMPACT OF ENVIRONMENTAL CHANGES ON BLACK MARLIN, Makaira indica (Cuvier, 1832) ABUNDANCES IN THE EASTERN INDIAN OCEAN

2020 ◽  
Vol 26 (1) ◽  
pp. 41
Author(s):  
Bram Setyadji ◽  
Zulkarnaen Fahmi
Keyword(s):  
Indian Ocean ◽  
Fishery Management ◽  
Environmental Changes ◽  
Stock Assessment ◽  
Sea Surface ◽  
Main Driver ◽  
Spatio Temporal ◽  
Standardized Index ◽  
By Catch ◽  
The Impact

Black marlin (Makaira indica) is commonly caught as frozen by-catch from Indonesian tuna longline fleets. Its contribution estimated 18% (~2,500 tons) from total catch in Indian Ocean. Relative abundance indices as calculated based on commercial catches are the input data for several to run stock assessment analyses that provide models to gather information useful information for decision making and fishery management, however, little are known about the influence of environmental factors to its abundance. In this paper, the abundance was represented as standardized index in order to eliminate any bias on other factors which might influence it. Data were collected from August 2005 to December 2017 through scientific observer program (2005-2017) and national observer program (2016-2017). Most of the vessels monitored were based in Benoa Port, Bali. Overall, time trends of abundance was fluctuated, although, there was increasing trend since 2010 then dropped significantly into relatively similar figure in 2005. Even though, Sea Surface Temperature (SST) and Sea Surface Height (SSH) were statistically significant when incorporating into the models, but it allegedly wasn’t the main driver in determining the abundance of black marlin. Instead, it was more likely driven by spatio-temporal factors (year and area) effect rather than environmental changes.

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