Premium
Changing skewness: an early warning signal of regime shifts in ecosystems
Author(s) -
Guttal Vishwesha,
Jayaprakash Ciriyam
Publication year - 2008
Publication title -
ecology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.852
H-Index - 265
eISSN - 1461-0248
pISSN - 1461-023X
DOI - 10.1111/j.1461-0248.2008.01160.x
Subject(s) - skewness , warning system , regime shift , alternative stable state , environmental science , ecosystem , ecology , climate change , arid , vegetation (pathology) , psychological resilience , scale (ratio) , signal (programming language) , econometrics , computer science , geography , biology , mathematics , medicine , psychology , telecommunications , cartography , pathology , psychotherapist , programming language
Empirical evidence for large‐scale abrupt changes in ecosystems such as lakes and vegetation of semi‐arid regions is growing. Such changes, called regime shifts, can lead to degradation of ecological services. We study simple ecological models that show a catastrophic transition as a control parameter is varied and propose a novel early warning signal that exploits two ubiquitous features of ecological systems: nonlinearity and large external fluctuations. Either reduced resilience or increased external fluctuations can tip ecosystems to an alternative stable state. It is shown that changes in asymmetry in the distribution of time series data, quantified by changing skewness, is a model‐independent and reliable early warning signal for both routes to regime shifts. Furthermore, using model simulations that mimic field measurements and a simple analysis of real data from abrupt climate change in the Sahara, we study the feasibility of skewness calculations using data available from routine monitoring.