scholarly journals At what spatial scales are alternative stable states relevant in highly interconnected ecosystems?

2019 ◽  
Author(s):  
Vadim A. Karatayev ◽  
Marissa L. Baskett
Keyword(s):  
Spatial Scales ◽  
Alternative Stable States ◽  
Stable State ◽  
Environmental Stochasticity ◽  
Rocky Reef ◽  
Alternative States ◽  
Stable States ◽  
Long Distance ◽  
Rocky Reefs ◽  
Model Predictions

AbstractWhether ecosystems recover from disturbance depends on the presence of alternative stable states, which are theoretically possible in simple models of many systems. However, definitive empirical evidence for this phenomenon remains limited to demographically closed ecosystems such as lakes. In more interconnected systems such as temperate rocky reefs, the local relevance of alternative stable states might erode as immigration overwhelms local feedbacks and produces a single stable state. At larger spatial scales, dispersal might counter localized disturbance and feedbacks to synchronize states throughout a region. Here, we quantify how interconnectedness affects the relevance of alternative stable states using dynamical models of California rocky reef communities that incorporate observed environmental stochasticity and feedback loops in kelp-urchin-predator interactions. Our models demonstrate the potential for localized alternative states despite high interconnectedness likely due to feedbacks affecting dispersers as they settle into local communities. Regionally, such feedbacks affecting settlement can produce a mosaic of alternative stable states that span local (10-20km) scales despite the synchronizing effect of long-distance dispersal. The specific spatial scale and duration of each state predominantly depend on the scales of environmental variation and on local dynamics (here, fishing). Model predictions reflect observed scales of community states in California rocky reefs and suggest how alternative states co-occur in the wide array of marine and terrestrial systems with settlement feedbacks.

scholarly journals Path-dependent institutions drive alternative stable states in conservation

2018 ◽  
Vol 116 (2) ◽  
pp. 689-694 ◽  
Author(s):  
Edward W. Tekwa ◽  
Eli P. Fenichel ◽  
Simon A. Levin ◽  
Malin L. Pinsky
Keyword(s):  
Renewable Resources ◽  
Path Dependence ◽  
Alternative Stable States ◽  
Stable State ◽  
Empirical Support ◽  
Stable States ◽  
Alternative Stable State ◽  
Important Challenge ◽  
Quantitative Analyses ◽  
Path Dependent

Understanding why some renewable resources are overharvested while others are conserved remains an important challenge. Most explanations focus on institutional or ecological differences among resources. Here, we provide theoretical and empirical evidence that conservation and overharvest can be alternative stable states within the same exclusive-resource management system because of path-dependent processes, including slow institutional adaptation. Surprisingly, this theory predicts that the alternative states of strong conservation or overharvest are most likely for resources that were previously thought to be easily conserved under optimal management or even open access. Quantitative analyses of harvest rates from 217 intensely managed fisheries supports the predictions. Fisheries’ harvest rates also showed transient dynamics characteristic of path dependence, as well as convergence to the alternative stable state after unexpected transitions. This statistical evidence for path dependence differs from previous empirical support that was based largely on case studies, experiments, and distributional analyses. Alternative stable states in conservation appear likely outcomes for many cooperatively managed renewable resources, which implies that achieving conservation outcomes hinges on harnessing existing policy tools to navigate transitions.

scholarly journals Catastrophic Hydraulic Failure and Tipping Points in Plants

2021 ◽  
Author(s):  
Daniel Johnson ◽  
Gabriel G Katul ◽  
Jean-Christophe Domec
Keyword(s):  
Water Potential ◽  
Plant Biomass ◽  
Spatial Scales ◽  
Alternative Stable States ◽  
Soil Water Potential ◽  
Tipping Points ◽  
Stable States ◽  
Xylem Embolism ◽  
Plant Hydraulics ◽  
Hydraulic Failure

Water inside plants forms a continuous chain from water in soils to the water evaporating from leaf surfaces. Failures in this chain result in reduced transpiration and photosynthesis and these failures are caused by soil drying and/or cavitation-induced xylem embolism. Xylem embolism and plant hydraulic failure share a number of analogies to “catastrophe theory” in dynamical systems. These catastrophes are often represented in the physiological and ecological literature as tipping points or alternative stable states when control variables exogenous (e.g. soil water potential) or endogenous (e.g. leaf water potential) to the plant are allowed to slowly vary. Here, plant hydraulics viewed from the perspective of catastrophes at multiple spatial scales is considered with attention to bubble expansion (i.e. cavitation), organ-scale vulnerability to embolism, and whole-plant biomass as a proxy for transpiration and hydraulic function. The hydraulic safety-efficiency tradeoff, hydraulic segmentation and maximum plant transpiration are examined using this framework. Underlying mechanisms for hydraulic failure at very fine scales such as pit membranes, intermediate scales such as xylem network properties and at larger scales such as soil-tree hydraulic pathways are discussed. Lacunarity areas in plant hydraulics are also flagged where progress is urgently needed.

scholarly journals Spatial, temporal and ontogenetic variation in the association of fishes (family Labridae) with rocky-reef habitats

2011 ◽  
Vol 62 (7) ◽  
pp. 870 ◽  
Author(s):  
Jason K. Morton ◽  
William Gladstone
Keyword(s):  
Fish Assemblages ◽  
Spatial Scales ◽  
Abundant Species ◽  
Habitat Associations ◽  
Rocky Reef ◽  
Habitat Variability ◽  
Life History Stages ◽  
Multiple Spatial Scales ◽  
Habitat Specialisation ◽  
Rocky Reefs

Habitat variability is an important factor structuring fish assemblages of rocky reefs in temperate Australia. Accepting the generality of this model requires that habitat-related variation is consistent through time, across multiple spatial scales, and applies to all life-history stages. We used repeated underwater visual surveys at multiple spatial scales over a 22-month period to test whether three distinct rocky-reef habitats had different wrasse assemblages and whether these assemblages were subject to spatial, temporal and ontogenetic variability. Overall, the strongest and most consistent habitat association was with sponge gardens, which had the most distinct assemblage, and the greatest species richness and density of individuals. Habitat associations in fringe and barrens were less consistent. A substantial increase in the abundance of small individuals, coinciding with warmer sea temperatures, contributed to temporal fluctuations in the density of wrasses. Overall, habitats were not strongly partitioned among larger individuals of the most abundant species, suggesting that adults are largely habitat generalists whereas small, recruiting individuals showed greater habitat specialisation. The present study emphasises the importance of incorporating spatial, temporal and ontogenetic variability into surveys of fish assemblages to understand more fully the dynamics of temperate rocky-reef systems.

Mental disorders, network models, and dynamical systems

2017 ◽  
Author(s):  
Denny Borsboom
Keyword(s):  
Mental Disorders ◽  
Alternative Stable States ◽  
Stable State ◽  
Network Models ◽  
External Shocks ◽  
Stable States ◽  
Adverse Life Events ◽  
Healthy State ◽  
Strongly Connected ◽  
Network Approaches

Network approaches have been proposed as an alternative way of thinking about relations between symptoms of mental disorders. Unlike traditional psychometric approaches, network models view these associations as the result of direct interactions between symptoms. Disorders are defined as alternative stable states of a network due to increased connectivity between symptoms. This increased connectivity creates a pattern of reinforcement, so the system can get stuck in a state of prolonged activation. Mental health is defined as the stable state of a weakly connected network. Although symptomatology may be temporarily increased in a healthy network (e.g., due to adverse life events), as the influence of a shock wanes the network will spontaneously return to its healthy state. Strongly connected networks, however, may transition into disordered states upon similar external shocks, and may not naturally recover. Thus, the proposed definitions yield plausible conceptualizations of resilience and vulnerability.

Movements and distribution of dugongs (Dugong dugon) in a macro-tidal environment in northern Australia

2008 ◽  
Vol 56 (4) ◽  
pp. 215 ◽  
Author(s):  
Scott D. Whiting
Keyword(s):  
Spatial Scales ◽  
Close Association ◽  
Information Source ◽  
Satellite Tracking ◽  
Rocky Reef ◽  
Rocky Reefs ◽  
Aerial Surveys ◽  
Satellite Transmitters ◽  
Spatial Use ◽  
Four Blocks

A combination of aerial surveys, community sightings and satellite tracking revealed distribution, habitat, relative densities and spatial use of individual dugongs in the Darwin region of the Northern Territory. Aerial surveys in both the wet and dry seasons estimated relatively low densities of dugongs. Most group sightings (73% of all sightings) and densities up to 0.54 dugongs km−2 occurred in one of the four blocks surveyed. This block contained the Vernon Islands and large macro-tidal algal rocky reefs. Two dugongs tracked using satellite transmitters were captured above these reefs and kept a close association with similar reef types during most of their tracking periods of 53 and 154 days. Tracking revealed that dugongs used multiple and distinct areas for periods of several days to over 80 days and utilised coastal sections of up to 300 km in length. This indicates that dugong management in the Darwin region requires the consideration of large spatial scales, multiple habitat types and rocky reef habitat. Community sightings were an important information source and revealed locations of dugongs not identified with either the aerial surveys or satellite tracking.

scholarly journals Shifting States, Altered Fates: Divergent Fuel Moisture Responses after High Frequency Wildfire in an Obligate Seeder Eucalypt Forest

Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 436 ◽  
Author(s):  
Jamie Burton ◽  
Jane Cawson ◽  
Philip Noske ◽  
Gary Sheridan
Keyword(s):  
High Frequency ◽  
Alternative Stable States ◽  
Stable State ◽  
Fuel Moisture ◽  
Stable States ◽  
Alternative Stable State ◽  
Obligate Seeder ◽  
Time Since Fire ◽  
Mountain Ash ◽  
Moisture Dynamics

High frequency wildfires can shift the structure and composition of obligate seeder forests and initiate replacement with alternative vegetation states. In some forests, the alternative stable state is drier and more easily burned by subsequent fires, driving a positive feedback that promotes further wildfire and perpetuates alternative stable states. Mountain Ash (Eucalyptus regnans (F.Muell.)) forests are highly valued for their biodiversity, water, timber and carbon. Fires are a natural part of the lifecycle of these forests, but too frequent fires can eliminate Mountain Ash and trigger a transition to lower stature, non-eucalypt forests which are dominated by understorey species. This study sought to better understand the fuel moisture dynamics of alternative stable states resulting from high frequency wildfires. A vegetation mosaic in the Central Highlands, Victoria created a unique opportunity to measure fuel moisture in adjacent forest stands that differed in overstorey species composition and time since fire. Specifically, we measured fuel moisture and microclimate at two eucalypt sites (9 and 79 years old) and three non-eucalypt sites (two 9 year old and one 79 year old). Fuel availability, defined here as the number of days surface fuels were below 16% and dry enough to ignite and sustain fire, was calculated to estimate flammability. Fuel availability differed between sites, particularly as a function of time since fire, with recently burnt sites available to burn more often (4–17 versus 0–3 days). There were differences in fuel availability between non-eucalypt sites of the same age, suggesting that high frequency fire does not always lead to the same vegetation condition or outcome for fuel availability. This indicates there is potential for both positive and negative flammability feedbacks following state transition depending on the composition of the non-eucalypt state. This is the first study to provide empirical insight into the fuel moisture dynamics of alternative stable states in Mountain Ash forests.

scholarly journals Transient invaders can induce shifts between alternative stable states of microbial communities

2020 ◽  
Vol 6 (8) ◽  
pp. eaay8676 ◽  
Author(s):  
Daniel R. Amor ◽  
Christoph Ratzke ◽  
Jeff Gore
Keyword(s):  
Environmental Changes ◽  
Alternative Stable States ◽  
Stable State ◽  
Natural Soil ◽  
Stable States ◽  
Alternative Stable State ◽  
Community Shift ◽  
Invader Species ◽  
Potential Impact ◽  
And Function

Microbial dispersal often leads to the arrival of outsider organisms into ecosystems. When their arrival gives rise to successful invasions, outsider species establish within the resident community, which can markedly alter the ecosystem. Seemingly less influential, the potential impact of unsuccessful invaders that interact only transiently with the community has remained largely ignored. Here, we experimentally demonstrate that these transient invasions can induce a lasting transition to an alternative stable state, even when the invader species itself does not survive the transition. First, we develop a mechanistic understanding of how environmental changes caused by these transient invaders can drive a community shift in a simple, bistable model system. Beyond this, we show that transient invaders can also induce switches between stable states in more complex communities isolated from natural soil samples. Our results demonstrate that short-term interactions with an invader species can induce lasting shifts in community composition and function.

scholarly journals Transient invaders can induce shifts between alternative stable states of microbial communities

2019 ◽  
Author(s):  
Daniel R. Amor ◽  
Christoph Ratzke ◽  
Jeff Gore
Keyword(s):  
Community Composition ◽  
Environmental Changes ◽  
Alternative Stable States ◽  
Stable State ◽  
Natural Soil ◽  
Stable States ◽  
Alternative Stable State ◽  
Community Shift ◽  
Invader Species ◽  
And Function

AbstractMicrobial dispersal often leads to the arrival of outsider organisms into ecosystems. When their arrival give rise to successful invasions, outsider species establish within the resident community, which can dramatically alter the ecosystem. Seemingly less influential, the potential impact of unsuccessful invaders that interact only transiently with the community has remained largely ignored. Here, we experimentally demonstrate that such transient invasions can perturb the stability of microbial ecosystems and induce a lasting transition to an alternative stable state, even when the invader species itself does not survive the transition. First, we develop a mechanistic understanding of how environmental changes caused by such transient invaders can drive a community shift in a simple, bistable model system. Beyond this, we show that transient invaders can also induce switches between stable states in more complex communities isolated from natural soil samples. Our results demonstrate that short-term interactions with an invader species can induce lasting shifts in community composition and function.One Sentence SummaryTransient invaders can cause lasting shifts in community composition and function.

scholarly journals Grazer behavior can regulate large-scale patterning of community states

2019 ◽  
Author(s):  
Vadim A. Karatayev ◽  
Marissa L. Baskett ◽  
David J. Kushner ◽  
Nicholas T. Shears ◽  
Jennifer E. Caselle ◽  
...  
Keyword(s):  
New Zealand ◽  
Predation Risk ◽  
Species Interactions ◽  
Large Scale ◽  
Environmental Heterogeneity ◽  
Alternative Stable States ◽  
Dynamical Models ◽  
Stable States ◽  
Rocky Reefs ◽  
Best Fitting

AbstractEcosystem patterning can arise from environmental heterogeneity, biological feedbacks that produce multiple persistent ecological states, or their interaction. One source of feedbacks is density-dependent changes in behavior that regulates species interactions. By fitting dynamical models to large-scale (~500km) surveys on temperate rocky reefs, we find that behavioral feedbacks best explain why kelp and urchin barrens form either reef-wide patches or local mosaics. Best-supported models in California include feedbacks where starvation intensifies grazing across entire reefs create reef-scale, alternatively stable kelp- and urchin-dominated states (39% of sites). Best-fitting models in New Zealand include the feedback of urchins avoiding dense kelp stands that can increase abrasion and predation risk, which drives a transition from shallower urchin-dominated to deeper kelp-dominated zones, with patchiness at 3-8m depths with intermediate wave stress. Connecting locally-studied processes with region-wide data, we highlight how behavior can explain community patterning and why some systems exhibit community-wide alternative stable states.

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