Consulta: subjectFacets:"Thresholds"
Registros recuperados: 22
Data/hora: 11/06/2024 10:14:51

Introduction to Special Feature on Catastrophic Thresholds, Perspectives, Definitions, and Applications
Provedor de dados: 7
Autores: Washington-Allen, Robert A; Department of Ecosystem Science and Management, Texas A&amp;M University; washington-allen@tamu.edu; Briske, David D.; Department of Ecosystem Science and Management, Texas A&amp;M University; dbriske@tamu.edu; Shugart, Herman H.; W.W. Corcoran Professor of Environmental Sciences &amp; Director, Center for Regional Environmental Studies, Department of Environmental Sciences, University of Virginia; hhs@virginia.edu; Salo, Lucinda F.; Sage Ecosystem Science; csalo11@hotmail.com.
The contributions to this special feature focus on several conceptual and operational applications for understanding non-linear behavior of complex systems with various ecological criteria at unique levels of organization. The organizing theme of the feature emphasizes alternative stable states or regimes and intervening thresholds that possess great relevance to ecology and natural resource management. The authors within this special feature address the conceptual models of catastrophe theory, self-organization, cross-scale interactions and time-scale calculus; develop operational definitions and procedures for understanding the occurrence of dynamic regimes or multiple stable states and thresholds; suggest diagnostics tools for detection of states and...
Tipo: Peer-Reviewed article
Palavras-chave: Catastrophe theory; Complex systems science; Dynamical systems analysis; Ecological resilience; Non-equilibrium ecology; Self-organization; Thresholds; Time-scale calculus.
Ano: 2010

Navigating the adaptive cycle: an approach to managing the resilience of social systems
Provedor de dados: 7
Autores: Fath, Brian D; Advanced Systems Analysis, International Institute for Applied Systems Analysis; Department of Biological Sciences, Towson University; bfath@towson.edu; Dean, Carly A; Advanced Systems Analysis, International Institute for Applied Systems Analysis; carly.ann.dean@gmail.com; Katzmair, Harald; FAS.research; harald.katzmair@fas.at.
The concept of resilience continues to crescendo since the 1990s, touching on multiple fields with multiple interpretations and uses. Here, we start from its origins in systems ecology, framing the resilience concept explicitly in the adaptive cycle with the observation that resilient systems are ones that successfully navigate all stages of growth, development, collapse, and reorientation of this cycle. The model is explored in terms of the traps and pathologies that hinder this successful navigation, particularly when applied to socioeconomic organizations and decision-management situations. For example, for continuous function over the adaptive life cycle, a system needs activation energy or resources to grow, followed by adequate structure and...
Tipo: Peer-Reviewed Insight
Palavras-chave: Adaptive cycle; Collapse; Development; Growth; Re-orientation; Resilience; Succession; Thresholds.
Ano: 2015

Are We Entering an Era of Concatenated Global Crises?
Provedor de dados: 7
Autores: Biggs, Duan; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville Australia; ancientantwren@gmail.com; Biggs, Reinette (Oonsie); Stockholm Resilience Centre, Stockholm University, Sweden; oonsie.biggs@stockholmresilience.su.se; Dakos, Vasilis; Department of Aquatic Ecology &amp; Water Quality Management, Wageningen University; vasileios.dakos@wur.nl; Scholes, Robert J; CSIR Natural Resources and the Environment, Pretoria, South Africa; BScholes@csir.co.za; Schoon, Michael; School of Human Evolution and Social Change, Arizona State University; Michael.Schoon@asu.edu.
An increase in the frequency and intensity of environmental crises associated with accelerating human-induced global change is of substantial concern to policy makers. The potential impacts, especially on the poor, are exacerbated in an increasingly connected world that enables the emergence of crises that are coupled in time and space. We discuss two factors that can interact to contribute to such an increased concatenation of crises: (1) the increasing strength of global vs. local drivers of change, so that changes become increasingly synchronized; and (2) unprecedented potential for the propagation of crises, and an enhanced risk of management interventions in one region becoming drivers elsewhere, because of increased connectivity. We discuss the...
Tipo: Peer-Reviewed Insight
Palavras-chave: Concatenation; Connectivity; Crisis; Disaster; Food price crisis; Governance; Learning; Thresholds.
Ano: 2011

Variance as a Leading Indicator of Regime Shift in Ecosystem Services
Provedor de dados: 7
Autores: Brock, William A; University of Wisconsin-Madison; WBrock@ssc.wisc.edu; Carpenter, Stephen R; University of Wisconsin-Madison; srcarpen@wisc.edu.
Many environmental conflicts involve pollutants such as greenhouse gas emissions that are dispersed through space and cause losses of ecosystem services.  As pollutant emissions rise in one place, a spatial cascade of declining ecosystem services can spread across a larger landscape because of the dispersion of the pollutant.  This paper considers the problem of anticipating such spatial regime shifts by monitoring time series of the pollutant or associated ecosystem services.  Using such data, it is possible to construct indicators that rise sharply in advance of regime shifts. Specifically, the maximum eigenvalue of the variance-covariance matrix of the multivariate time series of pollutants and ecosystem services rises prior to the regime shift. No...
Tipo: Peer-Reviewed Reports
Palavras-chave: Ecological economics; Ecosystem service; Indicators; Markets; Pollution; Regime shifts; Thresholds; Variance.
Ano: 2006

Resilience and Regime Shifts: Assessing Cascading Effects
Provedor de dados: 7
Autores: Kinzig, Ann P; Arizona State University; Ann.Kinzig@asu.edu; Ryan, Paul; CSIRO; paul.ryan@csiro.au; Etienne, Michel; INRA; etienne@avignon.inra.fr; Allison, Helen; Murdoch University; helenallison@ozemail.com.au; Elmqvist, Thomas; University of Stockholm; thomase@ecology.su.se; Walker, Brian H.; CSIRO; Brian.Walker@csiro.au.
Most accounts of thresholds between alternate regimes involve a single, dominant shift defined by one, often slowly changing variable in an ecosystem. This paper expands the focus to include similar dynamics in social and economic systems, in which multiple variables may act together in ways that produce interacting regime shifts in social-ecological systems. We use four different regions in the world, each of which contains multiple thresholds, to develop a proposed &amp;#8220;general model&amp;#8221; of threshold interactions in social-ecological systems. The model identifies patch-scale ecological thresholds, farm- or landscape-scale economic thresholds, and regional-scale sociocultural thresholds. &amp;#8220;Cascading thresholds,&amp;#8221; i.e., the...
Tipo: Peer-Reviewed Synthesis
Palavras-chave: Thresholds; Regime shifts; Social-ecological systems; System interactions; Cascading effects.
Ano: 2006

The Interplay of Well-being and Resilience in Applying a Social-Ecological Perspective
Provedor de dados: 7
Autores: Armitage, Derek; University of Waterloo; derek.armitage@uwaterloo.ca; Charles, Anthony T; Saint Mary's University; Tony.Charles@SMU.CA; Johnson, Derek; University of Manitoba; derek_johnson@umanitoba.ca; Allison, Edward H; The WorldFish Center and the University of East Anglia; e.allison@cgiar.org.
Innovative combinations of social and ecological theory are required to deal with complexity and change in human-ecological systems. We examined the interplay and complementarities that emerge by linking resilience and social well-being approaches. First, we reflected on the limitations of applying ecological resilience concepts to social systems from the perspective of social theory, and particularly, the concept of well-being. Second, we examined the interplay of resilience and well-being concepts in fostering a social-ecological perspective that promises more appropriate management and policy actions. We examined five key points of interplay: (1) the limits of optimization thinking (e.g., maximum sustainable yield), (2) the role of human agency and...
Tipo: Peer-Reviewed Synthesis
Palavras-chave: Adaptation; Agency; Governance; Integration; Interdisciplinarity; Policy; Sustainability; Thresholds; Transdisciplinarity; Uncertainty.
Ano: 2012

Collective action and the risk of ecosystem regime shifts: insights from a laboratory experiment
Provedor de dados: 7
Autores: Schill, Caroline; The Beijer Institute of Ecological Economics, The Royal Swedish Academy of Sciences; Stockholm Resilience Centre, Stockholm University; caroline.schill@beijer.kva.se; Lindahl, Therese; The Beijer Institute of Ecological Economics, The Royal Swedish Academy of Sciences; Stockholm Resilience Centre, Stockholm University; therese.lindahl@beijer.kva.se.
Ecosystems can undergo regime shifts that potentially lead to a substantial decrease in the availability of provisioning ecosystem services. Recent research suggests that the frequency and intensity of regime shifts increase with growing anthropogenic pressure, so understanding the underlying social-ecological dynamics is crucial, particularly in contexts where livelihoods depend heavily on local ecosystem services. In such settings, ecosystem services are often derived from common-pool resources. The limited capacity to predict regime shifts is a major challenge for common-pool resource management, as well as for systematic empirical analysis of individual and group behavior, because of the need for extensive preshift and postshift data. Unsurprisingly,...
Tipo: Peer-Reviewed Reports
Palavras-chave: Common-pool resources; Cooperation; Ecological dynamics; Laboratory experiments; Regime shifts; Risk; Social-ecological systems; Thresholds; Uncertainty.
Ano: 2015

Sediments and herbivory as sensitive indicators of coral reef degradation
Provedor de dados: 7
Autores: Goatley, Christopher H. R.; College of Marine and Environmental Sciences, James Cook University; Australian Research Council Centre of Excellence for Coral Reef Studies; christopher.goatley@jcu.edu.au; Fox, Rebecca J.; College of Marine and Environmental Sciences, James Cook University; Australian Research Council Centre of Excellence for Coral Reef Studies;  Division of Evolution, Ecology and Genetics, Australian National University; School of Life Sciences, University of Technology Sydney; rebecca.fox-1@uts.edu.au; Bellwood, David R.; College of Marine and Environmental Sciences, James Cook University; Australian Research Council Centre of Excellence for Coral Reef Studies; david.bellwood@jcu.edu.au.
Around the world, the decreasing health of coral reef ecosystems has highlighted the need to better understand the processes of reef degradation. The development of more sensitive tools, which complement traditional methods of monitoring coral reefs, may reveal earlier signs of degradation and provide an opportunity for pre-emptive responses. We identify new, sensitive metrics of ecosystem processes and benthic composition that allow us to quantify subtle, yet destabilizing, changes in the ecosystem state of an inshore coral reef on the Great Barrier Reef. Following severe climatic disturbances over the period 2011-2012, the herbivorous reef fish community of the reef did not change in terms of biomass or functional groups present. However, fish-based...
Tipo: Peer-Reviewed Reports
Palavras-chave: Disturbances; Ecosystem state; Herbivory; Management; Monitoring; Processes; Resilience; Sediment; Thresholds.
Ano: 2016

Social Thresholds and their Translation into Social-ecological Management Practices
Provedor de dados: 7
Autores: Christensen, Lisa; Yukon College; lc.yukon@gmail.com; Krogman, Naomi; University of Alberta; naomi.krogman@ualberta.ca.
The objective of this paper is to provide a preliminary discussion of how to improve our conceptualization of social thresholds using (1) a more sociological analysis of social resilience, and (2) results from research carried out in collaboration with the Champagne and Aishihik First Nations of the Yukon Territory, Canada. Our sociological analysis of the concept of resilience begins with a review of the literature followed by placement of the concept in the domain of sociological theory to gain insight into its strengths and limitations. A new notion of social thresholds is proposed and case study research discussed to support the proposition. Our findings suggest that rather than view social thresholds as breakpoints between two regimes, as thresholds...
Tipo: Peer-Reviewed Reports
Palavras-chave: Functionalism; Social-ecological resilience; Thresholds; Yukon Territory.
Ano: 2012

Évaluation du descripteur 5 « Eutrophisation » en France métropolitaine. Rapport scientifique pour l’évaluation 2018 au titre de la DCSMM
Provedor de dados: 5
Autores: Devreker, David; Lefebvre, Alain.
This report is the second assessment of French marine water eutrophication status (descriptor 5) done in the framework of the MSFD. The goal of this report is to determine if French marine water reach the Good Ecological State as defined by the MSFD. It stands next to the initial evaluation made in 2012, from which it is an update. It introduces the second cycle of the Marine Environment Action Program. It shows that French marine waters, behind the 12 nm line, reach the GES as defined by the MSFD. Problems link to eutrophication occurs in marine waters above the 12 nm, where 6.5% of the area do not reach the GES.
Tipo: Text
Palavras-chave: DCSMM; Eutrophisation; Évaluation; Bon Etat Ecologique; Seuils; Indicateurs; Nutriments; Chlorophylle-a; Oxygène; Turbidité; Macroalgues; Pressions écologiques; MSFD; Eutrophication; Assessment; Good Environmental Status; Thresholds; Indicators; Nutrients; Chlorophyll-a; Oxygen; Turbidity; Macroalgae; Ecological pressures.
Ano: 2018
URL: http://archimer.ifremer.fr/doc/00437/54868/56361.pdf

Protection protocol for marine fauna and seismic campaigns
Provedor de dados: 5
Autores: Ducatel, Cecile; Le Gall, Yves; Lurton, Xavier.
This document explains measures taken by Ifremer to protect marine fauna when using class 1 seismic sources (&gt; 500 in3). Before presenting the protocol to be applied during marine geoscience campaigns, the acoustic risk assessment principles are recapped.
Tipo: Text
Palavras-chave: Seismic; Marine mammals; Turtles; Thresholds; PTS; TTS; Exclusion zone; MMOs; PAM; Pre-shot research; Ramp-up; Stopping shots.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00623/73519/73003.pdf

An ecosystem-based approach and management framework for the integrated evaluation of bivalve aquaculture impacts
Provedor de dados: 5
Autores: Cranford, Peter J.; Kamermans, Pauline; Krause, Gesche; Mazurie, Joseph; Buck, Bela H.; Dolmer, Per; Fraser, David; Van Nieuwenhove, Kris; O'Beirn, Francis X.; Sanchez-mata, Adoracion; Thorarinsdottir, Gudrun G.; Strand, Oivind.
An ecosystem-based approach to bivalve aquaculture management is a strategy for the integration of aquaculture within the wider ecosystem, including human aspects, in such a way that it promotes sustainable development, equity, and resilience of ecosystems. Given the linkage between social and ecological systems, marine regulators require an ecosystem-based decision framework that structures and integrates the relationships between these systems and facilitates communication of aquaculture-environment interactions and policy-related developments and decisions. The Drivers-Pressures-State Change-Impact-Response (DPSIR) management framework incorporates the connectivity between human and ecological issues and would permit available performance indicators to...
Tipo: Text
Palavras-chave: Bivalve aquaculture management; Ecosystem-based approach; DPSIR framework; Indicators; Thresholds; Benthic effects; Pelagic effects; Social-ecological systems.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00099/20997/18624.pdf

Détermination de Valeurs Guides Environnementales (VGE) mollusques alternatives aux Normes de Qualité Environnementale (NQE) définies dans la DCE
Provedor de dados: 5
Autores: Sire, Alizee; Amouroux, Isabelle.
The Water Framework Directive (DCE 2000/60/CE), aims to achieve the good conditions (chemical and ecological) of different waters in Europe. The Environmental Quality Standards (EQS) are the tools used to evaluate the chemical condition waters. Initially, the EQS are defined for the water matrix, but with the analytical difficulties and low spatial and temporal representativity of water samples, the monitoring of contaminants must be carried out on alternative matrices, as mollusks and particularly the mussels.  Among the 45 priority and dangerous priority substances establishes by the WFD 2013/39/UE, 25 substances are hydrophobic and bioaccumulable. The main goal of this study is to determine thresholds applicable in the mussels at least as protective as...
Tipo: Text
Palavras-chave: Norme de Qualité Environnementale; Valeur Guide Environnementale; Mollusques; Moules; Facteur de bioconcentration (BCF); Facteur de bioaccumulation (BAF); Modèles QSAR; Directive Cadre sur l’Eau.; Environmental Quality Standards; Thresholds; Mollusks; Mussels; Bioconcentration factor (BCF); Bioaccumulation factor (BAF); QSAR models; Water Framework Directive.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00333/44378/43991.pdf

Modelling Trends in Food Market Integration: Method and an Application to Tanzanian Maize Markets
Provedor de dados: 31
Autores: van Campenhout,   Bjorn.
Pushed by increasing availability of price data and extensive market liberalisation efforts in many developing countries, research on food market integration has evolved rapidly over the last two decades. Empirical methods to measure market integration diverged in two directions: on the one hand, there is the Parity Bounds Model (PBM), while on the other hand the use of Threshold Autoregressive (TAR) Models has been proposed. This article provides a discussion of the two methods and argues that TAR models are more able to capture the dynamics of the arbitrage process underlying interconnected markets. Furthermore, we extend the standard TAR model to include a time trend in both the threshold and the adjustment parameter. Using weekly maize price data on...
Tipo: Conference Paper or Presentation
Palavras-chave: Market integration; Transaction costs; Thresholds; Maize; Tanzania; Agribusiness; F15; O18.
Ano: 2005
URL: http://purl.umn.edu/24718

Harvest-Time Protein Shocks and Price Adjustment in U.S. Wheat Markets
Provedor de dados: 31
Autores: Goodwin,   Barry K.; Smith,   Vincent H.
Dynamic relationships among three classes of wheat are investigated using threshold VAR models that incorporate the effects of protein availability. Changes in the stock of protein are found to generate significant responses in the prices of hard red spring wheat and hard red winter wheat, but not soft red wheat. The responses to identical changes in protein stocks are larger when the magnitudes of deviations of protein stocks from normal levels are large. Shocks to the prices of individual classes of wheat result in complex responses in the prices of the other wheat classes. Notably, however, a shock to the price of hard red winter wheat appears to result in little or no response in the price of hard spring wheat, though importantly, the opposite is not...
Tipo: Report
Palavras-chave: Protein; Thresholds; Vector autoregressions; Wheat prices; Crop Production/Industries.
Ano: 2009
URL: http://purl.umn.edu/54544

Price Volatility, Nonlinearity, and Asymmetric Adjustments in Corn, Soybean, and Cattle Markets: Implications of Ethanol-Driven (Market) Shocks
Provedor de dados: 31
Autores: Tejeda,   Hernan A.; Goodwin,   Barry K.
Grain prices have risen sharply since 2005 and 2006 affecting livestock markets by increasing feed prices and leading to significant volatility shocks. The high price levels and magnitude of sustained high volatilities has raised concerns for many sectors of the economy, in particular those with direct relation to these markets. Policy makers are analyzing the interrelationships among these markets, and the effects of energy market shocks on agricultural markets. This study considers a threshold structure in a multivariate time-series model that evaluates these market linkages, capturing asymmetric correlations between grain and livestock prices, including volatility spillovers. We empirically study the impact of corn usage for ethanol production in the...
Tipo: Conference Paper or Presentation
Palavras-chave: Price volatility; Market linkages; Thresholds; Ethanol-driven shocks; Asymmetric correlations; Spillovers; Agribusiness; Agricultural and Food Policy; Agricultural Finance; Demand and Price Analysis; Farm Management; Financial Economics; Public Economics; Research Methods/ Statistical Methods.
Ano: 2009
URL: http://purl.umn.edu/53039

A State Dependent Regime Switching Model of Dynamic Correlations
Provedor de dados: 31
Autores: Tejeda,   Hernan A.; Goodwin,   Barry K.; Pelletier,   Denis.
Replaced with revised version of paper 07/29/09.
Tipo: Conference Paper or Presentation
Palavras-chave: Dynamic correlations; Regime switching; State dependent probabilities; Thresholds; Spillovers; Research Methods/ Statistical Methods.
Ano: 2009
URL: http://purl.umn.edu/49370

Horizontal Price Transmission of the Finnish Meat Sector with Major EU Players
Provedor de dados: 31
Autores: Liu,   Xing.
The integration of the Finnish meat market in the EU has important implications for domestic agricultural policy. Our aim is to estimate the characteristics of the Finnish pork and beef markets in relation to those of Germany and Denmark. Our analysis uses symmetric and asymmetric threshold error correction models. Both pork and beef prices in Finland are found to have slowly cointegrated with German prices, but the cointegration relationship of the two counties is only found to be symmetric for pork prices, while it is asymmetric for beef prices. The producer price for pork in Finland is symmetrically cointegrated with the Danish price, but the Finnish and Danish beef prices show a random walk. This implies that the price transmission to the Finnish pork...
Tipo: Conference Paper or Presentation
Palavras-chave: Cointegration; Asymmetric; Error correction; Thresholds; Pork and beef prices; Demand and Price Analysis; Livestock Production/Industries.
Ano: 2011
URL: http://purl.umn.edu/114380

Horizontal price transmission of the Finnish meat sector with major EU players
Provedor de dados: 31
Autores: Liu,   Xing.
The integration of the Finnish meat market in the EU has important implications for domestic agricultural policy. Our aim is to estimate the characteristics of the Finnish pork and beef markets in relation to those of Germany and Denmark. Our analysis uses symmetric and asymmetric threshold error correction models. Both pork and beef prices in Finland are found to have slowly cointegrated with German prices, but the cointegration relationship of the two counties is only found to be symmetric for pork prices, while it is asymmetric for beef prices. The producer price for pork in Finland is symmetrically cointegrated with the Danish price, but the Finnish and Danish beef prices show a random walk. This implies that the price transmission to the Finnish pork...
Tipo: Working or Discussion Paper
Palavras-chave: Cointegration; Asymmetric; Error correction; Thresholds; Pork and beef prices; Agribusiness; Demand and Price Analysis; Food Consumption/Nutrition/Food Safety; International Relations/Trade.
Ano: 2011
URL: http://purl.umn.edu/100215

Nonlinear Models of Exchange Rate Pass-Through in International Forest Product Markets
Provedor de dados: 31
Autores: Onel,   Gulcan; Prestemon,   Jeffrey P.; Holt,   Matthew T.; Goodwin,   Barry K.
Tipo: Conference Paper or Presentation
Palavras-chave: Forest Products; International Price Linkages; Exchange Rate Pass-Through; Vector Error Correction Models (VECM); Thresholds; International Relations/Trade; Research Methods/ Statistical Methods.
Ano: 2010
URL: http://purl.umn.edu/61620

PRICE TRANSMISSION, THRESHOLD BEHAVIOR, AND ASYMMETRIC ADJUSTMENT IN THE U.S. PORK SECTOR
Provedor de dados: 31
Autores: Goodwin,   Barry K.; Harper,   Daniel C.
The US pork sector has experienced many significant structural changes in recent years.  Such changes may have influenced price dynamics and transmission of shocks through marketing channels.  We investigate linkages among farm, wholesale, and retail markets using weekly price data for the period covering 1987 through 1998.  Our analysis uses a threshold cointegration model that permits asymmetric adjustment to positive and negative price shocks.  Our results reveal important asymmetries.  Our results are consistent with existing literature which has determined that price adjustment patterns are unidirectional and that information tends to flow from farm, to wholesale, to retail markets.
Tipo: Journal Article
Palavras-chave: Asymmetric price transmission; Vertical price transmission; Error correction; Thresholds; Pork markets; Demand and Price Analysis; Livestock Production/Industries.
Ano: 2000
URL: http://purl.umn.edu/15308

Modeling Nonlinearities in Farmland Values: A Dynamic Panel Threshold Error-Correction Model
Provedor de dados: 31
Autores: Onel,   Gulcan.
Earlier studies usually indicate that farmland prices and cash rents are not cointegrated, a finding that seems at odds with the implications of the present value model. The main objective of this study is to explore whether this absence of empirical support for the present value model can be attributed to the restrictiveness of conventional time series methods. I suggest a panel unit root model with two regimes in which the adjustment process may be characterized by the presence of thresholds and discontinuities reflecting the presence of transactions costs and other barriers to adjustment. Using farmland value and cash rents data for 10 agricultural states of the U.S. between 1960 and 2008, empirical findings give modest improvement over the linear unit...
Tipo: Conference Paper or Presentation
Palavras-chave: Present Value Model; Transactions costs; Thresholds; Panel unit root; Land Economics/Use; Research Methods/ Statistical Methods.
Ano: 2009
URL: http://purl.umn.edu/49445