TY - GEN
T1 - Regime shifts in spatially extended ecosystems: fairy circles as a case model
AU - Zelnik, Yuval
AU - Bel, Golan
AU - Hagberg, Aric
AU - Meron, Ehud
PY - 2014/5/1
Y1 - 2014/5/1
N2 - Ecosystem regime shifts are regarded as abrupt global transitions from
one stable state to an alternative stable state, induced by slow
environmental changes or by global disturbances. Spatially extended
ecosystems, however, can also respond to local disturbances by forming
small domains of the alternative state. Such a response can lead to
gradual regime shifts, involving the expansion of alternative-state
domains by front propagation and domain coalescence [1]. When one of the
states is spatially patterned, a multitude of stable hybrid states can
appear [1,2]. Hybrid states involve stable confined domains of one state
in a system otherwise occupied by the other state. Their appearance can
be attributed to the pinning of the fronts that separate the two
alternative states in a range of the control parameter. This behavior,
often referred to as "homoclinic snaking", is unlike the case of two
stable uniform states, where isolated fronts generally propagate, and
are stationary only at a single parameter value - the so-called Maxwell
point. The presence of hybrid states can lead to incipient shifts, i.e.
shifts that terminate at hybrid states, or, in the presence of
environmental fluctuations (e.g. a series of droughts) to a
unidirectional cascade of small shifts from one hybrid state to another
that culminates in a global transition to the alternative state. In this
presentation I will review a few relevant results of pattern formation
theory related to front dynamics, discuss applications of these results
to gradual regime shifts in dryland vegetation [3], focusing on
bistability of uniform vegetation and periodic gap patterns, and
conclude by comparing theoretical predictions with empirical
observations of Fairy-Circles dynamics in Namibia. References 1. Bel G.,
Hagberg A., Meron E., Gradual regime shifts in spatially extended
ecosystems (2012) Theoretical Ecology 5, 591-604. 2. Meron E.,
Pattern-formation approach to modelling spatially extended ecosystems
(2012) Ecological Modelling 234, 70-82. 3. Zelnik Y., Kinast S., Yizhaq
H., Bel G. and Meron E. , Regime shifts in models of dryland vegetation
(2013) Phil. Trans. R. Soc. A 371, 20120358.
AB - Ecosystem regime shifts are regarded as abrupt global transitions from
one stable state to an alternative stable state, induced by slow
environmental changes or by global disturbances. Spatially extended
ecosystems, however, can also respond to local disturbances by forming
small domains of the alternative state. Such a response can lead to
gradual regime shifts, involving the expansion of alternative-state
domains by front propagation and domain coalescence [1]. When one of the
states is spatially patterned, a multitude of stable hybrid states can
appear [1,2]. Hybrid states involve stable confined domains of one state
in a system otherwise occupied by the other state. Their appearance can
be attributed to the pinning of the fronts that separate the two
alternative states in a range of the control parameter. This behavior,
often referred to as "homoclinic snaking", is unlike the case of two
stable uniform states, where isolated fronts generally propagate, and
are stationary only at a single parameter value - the so-called Maxwell
point. The presence of hybrid states can lead to incipient shifts, i.e.
shifts that terminate at hybrid states, or, in the presence of
environmental fluctuations (e.g. a series of droughts) to a
unidirectional cascade of small shifts from one hybrid state to another
that culminates in a global transition to the alternative state. In this
presentation I will review a few relevant results of pattern formation
theory related to front dynamics, discuss applications of these results
to gradual regime shifts in dryland vegetation [3], focusing on
bistability of uniform vegetation and periodic gap patterns, and
conclude by comparing theoretical predictions with empirical
observations of Fairy-Circles dynamics in Namibia. References 1. Bel G.,
Hagberg A., Meron E., Gradual regime shifts in spatially extended
ecosystems (2012) Theoretical Ecology 5, 591-604. 2. Meron E.,
Pattern-formation approach to modelling spatially extended ecosystems
(2012) Ecological Modelling 234, 70-82. 3. Zelnik Y., Kinast S., Yizhaq
H., Bel G. and Meron E. , Regime shifts in models of dryland vegetation
(2013) Phil. Trans. R. Soc. A 371, 20120358.
M3 - Conference contribution
VL - 16
BT - EGU General Assembly 2014
ER -