Connectivity of Niches of Adaptation Affects Vegetation Structure and Density in Self-Organized (Dis-Connected) Vegetation Patterns

2018 ◽  
Vol 29 (8) ◽  
pp. 2589-2594 ◽  
Author(s):  
Chiara Callegaro ◽  
Nadia Ursino
Keyword(s):  
Vegetation Structure ◽  
Vegetation Patterns ◽  
Self Organized

scholarly journals A mechanistic description of the formation and evolution of vegetation patterns

2013 ◽  
Vol 17 (1) ◽  
pp. 63-84 ◽  
Author(s):  
R. Foti ◽  
J. A. Ramírez
Keyword(s):  
Soil Moisture ◽  
Pattern Formation ◽  
Vegetation Pattern ◽  
Climatic Conditions ◽  
Vegetation Patterns ◽  
Self Organized ◽  
Physically Based ◽  
Density Surface ◽  
Formation And Evolution ◽  
Hillslope Scale

Abstract. Vegetation patterns are a common and well-defined characteristic of many landscapes. In this paper we explore some of the physical mechanisms responsible for the establishment of self-organized, non-random vegetation patterns that arise at the hillslope scale in many areas of the world, especially in arid and semi-arid regions. In doing so, we provide a fundamental mechanistic understanding of the dynamics of vegetation pattern formation and development. Reciprocal effects of vegetation on the hillslope thermodynamics, runoff production and run-on infiltration, root density, surface albedo and soil moisture content are analyzed. In particular, we: (1) present a physically based mechanistic description of processes leading to vegetation pattern formation; (2) quantify the relative impact of each process on pattern formation; and (3) describe the relationships between vegetation patterns and the climatic, hydraulic and topographic characteristics of the system. We validate the model by comparing simulations with observed natural patterns in the areas of Niger near Niamey and Somalia near Garoowe. Our analyses suggest that the phenomenon of pattern formation is primarily driven by run-on infiltration and mechanisms of facilitation/inhibition among adjacent vegetation groups, mediated by vegetation effects on soil properties and controls on soil moisture and albedo. Nonetheless, even in presence of those mechanisms, patterns arise only when the climatic conditions, particularly annual precipitation and net radiation, are favorable.

scholarly journals Termite mounds can increase the robustness of dryland ecosystems to climatic change

Science ◽  
2015 ◽  
Vol 347 (6222) ◽  
pp. 651-655 ◽  
Author(s):  
Juan A. Bonachela ◽  
Robert M. Pringle ◽  
Efrat Sheffer ◽  
Tyler C. Coverdale ◽  
Jennifer A. Guyton ◽  
...  
Keyword(s):  
Arid Ecosystems ◽  
Coarse Grained ◽  
Vegetation Patterns ◽  
Characteristic Sequence ◽  
Termite Mounds ◽  
Sparse Vegetation ◽  
Self Organized ◽  
Dryland Ecosystems ◽  
Substrate Heterogeneity ◽  
Catastrophic Shifts

Self-organized spatial vegetation patterning is widespread and has been described using models of scale-dependent feedback between plants and water on homogeneous substrates. As rainfall decreases, these models yield a characteristic sequence of patterns with increasingly sparse vegetation, followed by sudden collapse to desert. Thus, the final, spot-like pattern may provide early warning for such catastrophic shifts. In many arid ecosystems, however, termite nests impart substrate heterogeneity by altering soil properties, thereby enhancing plant growth. We show that termite-induced heterogeneity interacts with scale-dependent feedbacks to produce vegetation patterns at different spatial grains. Although the coarse-grained patterning resembles that created by scale-dependent feedback alone, it does not indicate imminent desertification. Rather, mound-field landscapes are more robust to aridity, suggesting that termites may help stabilize ecosystems under global change.

scholarly journals Microtopography alters self-organized vegetation patterns in water-limited ecosystems

2012 ◽  
Vol 117 (G3) ◽  
pp. n/a-n/a ◽  
Author(s):  
Gavan S. McGrath ◽  
Kyungrock Paik ◽  
Christoph Hinz
Keyword(s):  
Vegetation Patterns ◽  
Self Organized

Environmental modulation of self-organized periodic vegetation patterns in Sudan

Ecography ◽  
2011 ◽  
Vol 34 (6) ◽  
pp. 990-1001 ◽  
Author(s):  
Vincent Deblauwe ◽  
Pierre Couteron ◽  
Olivier Lejeune ◽  
Jan Bogaert ◽  
Nicolas Barbier
Keyword(s):  
Vegetation Patterns ◽  
Self Organized

scholarly journals Maximum entropy production allows a simple representation of heterogeneity in semiarid ecosystems

2010 ◽  
Vol 365 (1545) ◽  
pp. 1449-1455 ◽  
Author(s):  
Stanislaus J. Schymanski ◽  
Axel Kleidon ◽  
Marc Stieglitz ◽  
Jatin Narula
Keyword(s):  
Entropy Production ◽  
Maximum Entropy ◽  
Bare Soil ◽  
Vegetation Patterns ◽  
Subgrid Scale ◽  
Infiltration Capacity ◽  
Semiarid Ecosystems ◽  
Maximum Entropy Production ◽  
Self Organized ◽  
Scale Heterogeneity

Feedbacks between water use, biomass and infiltration capacity in semiarid ecosystems have been shown to lead to the spontaneous formation of vegetation patterns in a simple model. The formation of patterns permits the maintenance of larger overall biomass at low rainfall rates compared with homogeneous vegetation. This results in a bias of models run at larger scales neglecting subgrid-scale variability. In the present study, we investigate the question whether subgrid-scale heterogeneity can be parameterized as the outcome of optimal partitioning between bare soil and vegetated area. We find that a two-box model reproduces the time-averaged biomass of the patterns emerging in a 100 × 100 grid model if the vegetated fraction is optimized for maximum entropy production (MEP). This suggests that the proposed optimality-based representation of subgrid-scale heterogeneity may be generally applicable to different systems and at different scales. The implications for our understanding of self-organized behaviour and its modelling are discussed.

scholarly journals Existence of Periodic Traveling Waves in the Klausmeier Model of Desertification and its Modification: A Comparative Study

2019 ◽  
Vol 38 ◽  
pp. 27-46
Author(s):  
Md AS Howlader ◽  
Md Ariful Islam Arif ◽  
LS Andallah ◽  
M Osman Gani
Keyword(s):  
Traveling Waves ◽  
Arid Ecosystems ◽  
Vegetation Patterns ◽  
Transport Parameter ◽  
Variable Model ◽  
Periodic Traveling Waves ◽  
Self Organized ◽  
Spatially Periodic ◽  
Semi Arid ◽  
Banded Vegetation

Self-organized and spatially periodic banded vegetation patterns have been observed in many semi-arid ecosystems. In order to understand the mechanism of these patterns, we consider a system of reaction-advection-diffusion equations in a two-variable model of desertification. This work deals with the investigation of the existence of periodic traveling waves in a one-parameter family of solutions. In addition, we investigate the existence of periodic traveling waves as a function of water transport parameter in the model. GANIT J. Bangladesh Math. Soc.Vol. 38 (2018) 27-46

scholarly journals A mechanistic description of the formation and evolution of vegetation patterns

2012 ◽  
Vol 9 (7) ◽  
pp. 8737-8798
Author(s):  
R. Foti ◽  
J. A. Ramírez
Keyword(s):  
Soil Moisture ◽  
Pattern Formation ◽  
Vegetation Pattern ◽  
Climatic Conditions ◽  
Vegetation Patterns ◽  
Self Organized ◽  
Physically Based ◽  
Density Surface ◽  
Formation And Evolution ◽  
Hillslope Scale

Abstract. Vegetation patterns are a common and well-defined characteristic of many landscapes. In this paper we explore some of the physical mechanisms responsible for the establishment of self-organized, non-random vegetation patterns that arise at the hillslope scale in many areas of the world, especially in arid and semi-arid regions. In doing so, we provide a fundamental mechanistic understanding of the dynamics of vegetation pattern formation and development. Reciprocal effects of vegetation on the hillslope thermodynamics, runoff production and run-on infiltration, root density, surface albedo and soil moisture content are analyzed. In particular, we: (1) present a physically based mechanistic description of processes leading to vegetation pattern formation; (2) quantify the relative impact of each process on pattern formation; and (3) describe the relationships between vegetation patterns and the climatic, hydraulic and topographic characteristics of the system. We validate the model by comparing simulations with observed natural patterns in the areas of Niger near Niamey and Somalia near Garoowe. Our analyses suggest that the phenomenon of pattern formation is primarily driven by run-on infiltration and mechanisms of facilitation/inhibition among adjacent vegetation groups mediated by vegetation effects on soil properties and controls on soil moisture and albedo. Nonetheless, even in presence of those mechanisms, patterns arise only when the climatic conditions, particularly annual precipitation and net radiation, are favorable.

Problem behavior in autism spectrum disorders: A paradigmatic self-organized perspective of network structures

2019 ◽  
Vol 42 ◽  
Author(s):  
Lucio Tonello ◽  
Luca Giacobbi ◽  
Alberto Pettenon ◽  
Alessandro Scuotto ◽  
Massimo Cocchi ◽  
...  
Keyword(s):  
Autism Spectrum Disorder ◽  
Problem Behaviors ◽  
Autism Spectrum ◽  
The Self ◽  
Network Structures ◽  
Self Organized ◽  
Critical Equilibrium ◽  
Self Organized Criticality ◽  
Acute Agitation ◽  
Spectrum Disorders

AbstractAutism spectrum disorder (ASD) subjects can present temporary behaviors of acute agitation and aggressiveness, named problem behaviors. They have been shown to be consistent with the self-organized criticality (SOC), a model wherein occasionally occurring “catastrophic events” are necessary in order to maintain a self-organized “critical equilibrium.” The SOC can represent the psychopathology network structures and additionally suggests that they can be considered as self-organized systems.

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