scholarly journals Gradual regime shifts in fairy circles

2015 ◽  
Vol 112 (40) ◽  
pp. 12327-12331 ◽  
Author(s):  
Yuval R. Zelnik ◽  
Ehud Meron ◽  
Golan Bel
Keyword(s):  
Mathematical Modeling ◽  
Alternative Stable States ◽  
Regime Shifts ◽  
Self Organization ◽  
Stable States ◽  
Birth And Death Processes ◽  
Spatially Extended ◽  
Pattern Forming ◽  
Water Vegetation

Large responses of ecosystems to small changes in the conditions—regime shifts—are of great interest and importance. In spatially extended ecosystems, these shifts may be local or global. Using empirical data and mathematical modeling, we investigated the dynamics of the Namibian fairy circle ecosystem as a case study of regime shifts in a pattern-forming ecosystem. Our results provide new support, based on the dynamics of the ecosystem, for the view of fairy circles as a self-organization phenomenon driven by water–vegetation interactions. The study further suggests that fairy circle birth and death processes correspond to spatially confined transitions between alternative stable states. Cascades of such transitions, possible in various pattern-forming systems, result in gradual rather than abrupt regime shifts.

scholarly journals Resilience of Alternative Stable States during the Recovery of Shallow Lakes from Eutrophication: Lake Veluwe as a Case Study

Ecosystems ◽  
2007 ◽  
Vol 10 (1) ◽  
pp. 4-16 ◽  
Author(s):  
Bas W. Ibelings ◽  
Rob Portielje ◽  
Eddy H. R. R. Lammens ◽  
Ruurd Noordhuis ◽  
Marcel S. van den Berg ◽  
...  
Keyword(s):  
Shallow Lakes ◽  
Alternative Stable States ◽  
Stable States

scholarly journals Regime shifts in models of dryland vegetation

2013 ◽  
Vol 371 (2004) ◽  
pp. 20120358 ◽  
Author(s):  
Yuval R. Zelnik ◽  
Shai Kinast ◽  
Hezi Yizhaq ◽  
Golan Bel ◽  
Ehud Meron
Keyword(s):  
Alternative Stable States ◽  
Bare Soil ◽  
Periodic Pattern ◽  
Stable States ◽  
Open Problems ◽  
Self Organized ◽  
Pattern Dynamics ◽  
Vegetation Patchiness ◽  
Pattern Forming ◽  
Abrupt Shifts

Drylands are pattern-forming systems showing self-organized vegetation patchiness, multiplicity of stable states and fronts separating domains of alternative stable states. Pattern dynamics, induced by droughts or disturbances, can result in desertification shifts from patterned vegetation to bare soil. Pattern formation theory suggests various scenarios for such dynamics: an abrupt global shift involving a fast collapse to bare soil, a gradual global shift involving the expansion and coalescence of bare-soil domains and an incipient shift to a hybrid state consisting of stationary bare-soil domains in an otherwise periodic pattern. Using models of dryland vegetation, we address the question of which of these scenarios can be realized. We found that the models can be split into two groups: models that exhibit multiplicity of periodic-pattern and bare-soil states, and models that exhibit, in addition, multiplicity of hybrid states. Furthermore, in all models, we could not identify parameter regimes in which bare-soil domains expand into vegetated domains. The significance of these findings is that, while models belonging to the first group can only exhibit abrupt shifts, models belonging to the second group can also exhibit gradual and incipient shifts. A discussion of open problems concludes the paper.

scholarly journals Geometric Analysis of Regime Shifts in Coral Reef Communities

2020 ◽  
Author(s):  
Edward W. Tekwa ◽  
Lisa C. McManus ◽  
Ariel Greiner ◽  
Madhavi A. Colton ◽  
Michael S. Webster ◽  
...  
Keyword(s):  
Spatial Clustering ◽  
Alternative Stable States ◽  
Geometric Analysis ◽  
Three Dimensional ◽  
Single Species ◽  
Regime Shifts ◽  
State Transitions ◽  
Stable States ◽  
Species Dominance ◽  
Community Grazing

AbstractCoral reefs are among the many communities believed to exhibit regime shifts between alternative stable states, single-species dominance, and coexistence. Proposed drivers of regime shifts include changes in grazing, spatial clustering, and ocean temperature. Here we distill the dynamic regimes of coral-macroalgal interaction into a three-dimensional geometry, akin to thermodynamic phase diagrams of state transitions, to facilitate analysis. Specific regime-shifting forces can be understood as bifurcation vectors through the cubic regime geometry. This geometric perspective allows us to understand multiple forces simultaneously in terms of the stability and persistence of interacting species. For example, in a coral-macroalgae community, grazing on macroalgae can lead to alternative stable states when there is no spatial clustering (e.g., high habitat connectivity). However, with spatial clustering, grazing can lead to coexistence because of elevated local intraspecific competition. The geometrical analysis of regime shifts is applicable to any two-species communities and can help conservation efforts navigate complexity and abrupt changes.

scholarly journals Regime shifts in exploited marine food webs: detecting mechanisms underlying alternative stable states using size-structured community dynamics theory

2015 ◽  
Vol 370 (1659) ◽  
pp. 20130262 ◽  
Author(s):  
Anna Gårdmark ◽  
Michele Casini ◽  
Magnus Huss ◽  
Anieke van Leeuwen ◽  
Joakim Hjelm ◽  
...  
Keyword(s):  
Community Dynamics ◽  
Prey Availability ◽  
Alternative Stable States ◽  
Individual Performance ◽  
Regime Shifts ◽  
Trophic Levels ◽  
Stable States ◽  
Ecosystem Recovery ◽  
Piscivorous Fish ◽  
Combining Data

Many marine ecosystems have undergone ‘regime shifts’, i.e. abrupt reorganizations across trophic levels. Establishing whether these constitute shifts between alternative stable states is of key importance for the prospects of ecosystem recovery and for management. We show how mechanisms underlying alternative stable states caused by predator–prey interactions can be revealed in field data, using analyses guided by theory on size-structured community dynamics. This is done by combining data on individual performance (such as growth and fecundity) with information on population size and prey availability. We use Atlantic cod ( Gadus morhua ) and their prey in the Baltic Sea as an example to discuss and distinguish two types of mechanisms, ‘cultivation-depensation’ and ‘overcompensation’, that can cause alternative stable states preventing the recovery of overexploited piscivorous fish populations. Importantly, the type of mechanism can be inferred already from changes in the predators' body growth in different life stages. Our approach can thus be readily applied to monitored stocks of piscivorous fish species, for which this information often can be assembled. Using this tool can help resolve the causes of catastrophic collapses in marine predatory–prey systems and guide fisheries managers on how to successfully restore collapsed piscivorous fish stocks.

Evolutionary rescue can prevent rate-induced tipping in predator-prey systems

2021 ◽  
Author(s):  
Ulrike Feudel ◽  
Anna Vanselow ◽  
Lukas Halekotte
Keyword(s):  
Environmental Change ◽  
Time Scale ◽  
Alternative Stable States ◽  
Rapid Evolution ◽  
Regime Shifts ◽  
Rate Of Change ◽  
Stable States ◽  
Critical Rate ◽  
Predator Prey ◽  
Evolutionary Rescue

<p>Nowadays, populations are faced with unprecedented rates of global climate change, habitat fragmentation and destruction causing an accelerating conversion of their living conditions. Critical transitions in ecosystems, often called regime shifts, lead to sudden shifts in the dominance of species or even to species’ extinction and decline of biodiversity. Many regime shifts are explained as transitions between alternative stable states caused by (i) certain bifurcations when certain parameters or external forcing cross critical thresholds, (ii) fluctuations or (iii) extreme events. We address a fourth mechanism which does not require alternative states but instead, the system performs a large excursion away from its usual behaviour when environmental  conditions change too fast. During this excursion, the system can embrace dangerously, unexpected states. We demonstrate that predator-prey systems can exhibit a population collapse if the rate of environmental change crosses a certain critical rate. In reference to this critical rate of change which has to be surpassed, this transition is called rate-induced tipping (R-tipping). A further difference to the other three tipping mechanisms is that R-tipping mainly manifests during the transient dynamics – the dynamics before the long-term dynamics are reached.  Whether a system will track its usual state or will tip with the consequence of a possible extinction of a species depends crucially on the time scale relations between the ecological timescale and the time scale of environmental change as well as the initial condition. However, populations have the ability to respond to environmental change due to rapid evolution. Employing an eco-evolutionary model we show how such kind of adaptation can prevent rate-induced tipping in predator-prey systems. The corresponding mechanism, called evolutionary rescue, introduces a third timescale which needs to be taken into account. Only a large genetic variation within a population reflecting rapid evolution would be able to successfully counteract an overcritically fast environmental change.</p><p> </p>

scholarly journals Critical transitions in Chinese dunes during the past 12,000 years

2020 ◽  
Vol 6 (9) ◽  
pp. eaay8020 ◽  
Author(s):  
Zhiwei Xu ◽  
Joseph A. Mason ◽  
Chi Xu ◽  
Shuangwen Yi ◽  
Sebastian Bathiany ◽  
...  
Keyword(s):  
Alternative Stable States ◽  
Northern China ◽  
Hysteretic Behavior ◽  
Stable States ◽  
The Past ◽  
Critical Transitions ◽  
Smooth Change ◽  
Spatially Extended ◽  
Spatially Extended Systems ◽  
Dune Dynamics

Dune systems can have alternative stable states that coexist under certain environmental conditions: a vegetated, stabilized state and a bare active state. This behavior implies the possibility of abrupt transitions from one state to another in response to gradual environmental change. Here, we synthesize stratigraphic records covering 12,000 years of dynamics of this system at 144 localities across three dune fields in northern China. We find side-by-side coexistence of active and stabilized states, and occasional sharp shifts in time between those contrasting states. Those shifts occur asynchronously despite the fact that the entire landscape has been subject to the same gradual changes in monsoon rainfall and other conditions. At larger scale, the spatial heterogeneity in dune dynamics averages out to produce relatively smooth change. However, our results do show different paths of recovery and collapse of vegetation at system-wide scales, implying that hysteretic behavior occurs in spatially extended systems.

Fire Feedbacks with Vegetation and Alternative Stable States

2009 ◽  
Vol 18 (1) ◽  
pp. 159-173 ◽  
Author(s):  
Brian Beckage ◽  
Chris Ellingwood ◽  
Keyword(s):  
Alternative Stable States ◽  
Stable States ◽  
Fire Feedbacks

ICT-ENABLED BOTTOM-UP ARCHITECTURAL DESIGN

2016 ◽  
Vol 10 (1) ◽  
pp. 26 ◽  
Author(s):  
Burak Pak
Keyword(s):  
Information And Communication Technologies ◽  
Design Education ◽  
Architectural Design ◽  
Communication Technologies ◽  
Self Organization ◽  
Literature Study ◽  
Bottom Up ◽  
Information And Communication ◽  
Ict Tools

This paper aims at discussing the potentials of bottom-up design practices in relation to the latest developments in Information and Communication Technologies (ICT) by making an in-depth review of inaugural cases. The first part of the study involves a literature study and the elaboration of basic strategies from the case study. The second part reframes the existing ICT tools and strategies and elaborates on their potentials to support the modes of participation performed in these cases. As a result, by distilling the created knowledge, the study reveals the potentials of novel modes of ICT-enabled design participation which exploit a set of collective action tools to support sustainable ways of self-organization and bottom-up design. The final part explains the relevance of these with solid examples and presents a hypothetical case for future implementation. The paper concludes with a brief reflection on the implications of the findings for the future of architectural design education.

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