We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Which System Variables Carry Robust Early Signs of Upcoming Phase Transition? An Ecological Example.
- Authors
Negahbani, Ehsan; Steyn-Ross, D. Alistair; Steyn-Ross, Moira L.; Aguirre, Luis A.
- Abstract
Growth of critical fluctuations prior to catastrophic state transition is generally regarded as a universal phenomenon, providing a valuable early warning signal in dynamical systems. Using an ecological fisheries model of three populations (juvenile prey J, adult prey A and predator P), a recent study has reported silent early warning signals obtained from P and A populations prior to saddle-node (SN) bifurcation, and thus concluded that early warning signals are not universal. By performing a full eigenvalue analysis of the same system we demonstrate that while J and P populations undergo SN bifurcation, A does not jump to a new state, so it is not expected to carry early warning signs. In contrast with the previous study, we capture a significant increase in the noise-induced fluctuations in the P population, but only on close approach to the bifurcation point; it is not clear why the P variance initially shows a decaying trend. Here we resolve this puzzle using observability measures from control theory. By computing the observability coefficient for the system from the recordings of each population considered one at a time, we are able to quantify their ability to describe changing internal dynamics. We demonstrate that precursor fluctuations are best observed using only the J variable, and also P variable if close to transition. Using observability analysis we are able to describe why a poorly observable variable (P) has poor forecasting capabilities although a full eigenvalue analysis shows that this variable undergoes a bifurcation. We conclude that observability analysis provides complementary information to identify the variables carrying early-warning signs about impending state transition.
- Subjects
PHASE transitions; ECOLOGY; DYNAMICAL systems; BIFURCATION theory; OBSERVABILITY (Control theory); DEMOGRAPHY; DEATH rate; POPULATION biology
- Publication
PLoS ONE, 2016, Vol 11, Issue 9, p1
- ISSN
1932-6203
- Publication type
Article
- DOI
10.1371/journal.pone.0163003