Prolonged instability prior to a regime shift

• Published in: PloS one Vol. 9; no. 10; p. e108936
• Main Authors: Spanbauer, Trisha L, Allen, Craig R, Angeler, David G, Eason, Tarsha, Fritz, Sherilyn C, Garmestani, Ahjond S, Nash, Kirsty L, Stone, Jeffery R
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 2014; Public Library of Science (PLoS)
• Subjects: Atmospheric sciences; Biology and Life Sciences; Climate Change; Earth Sciences; Ecology and Environmental Sciences; Ecosystem; Ecosystems; Environmental changes; Environmental protection; Environmental Sciences; Fisher information; Instability; Laboratories; Lakes; Miljövetenskap; Paleoecology; R&D; Regional climates; Research & development; Stability; Statistical analysis; Statistical methods; Statistics; Sustainability; Time series; Variables; Rocky Mountains; Montana; Ohio; Indiana; United States > US; Nebraska
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0108936

Regime shifts are generally defined as the point of 'abrupt' change in the state of a system. However, a seemingly abrupt transition can be the product of a system reorganization that has been ongoing much longer than is evident in statistical analysis of a single component of the system. Using both univariate and multivariate statistical methods, we tested a long-term high-resolution paleoecological dataset with a known change in species assemblage for a regime shift. Analysis of this dataset with Fisher Information and multivariate time series modeling showed that there was a∼2000 year period of instability prior to the regime shift. This period of instability and the subsequent regime shift coincide with regional climate change, indicating that the system is undergoing extrinsic forcing. Paleoecological records offer a unique opportunity to test tools for the detection of thresholds and stable-states, and thus to examine the long-term stability of ecosystems over periods of multiple millennia.