Non-linear analysis indicates chaotic dynamics and reduced resilience in model-based Daphnia populations exposed to environmental stress

• Published in: PloS one Vol. 9; no. 5; p. e96270
• Main Authors: Ottermanns, Richard, Szonn, Kerstin, Preuβ, Thomas G, Roβ-Nickoll, Martina
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 08-05-2014; Public Library of Science (PLoS)
• Subjects: Age; Analysis; Animals; Anthropogenic factors; Biology and Life Sciences; Chaos theory; Climate change; Computer and Information Sciences; Computer Simulation; Crustaceans; Daphnia - physiology; Daphnia magna; Disturbance; Dynamic tests; Earth Sciences; Ecology and Environmental Sciences; Ecosystem; Ecosystems; Environmental stress; Extinction; Fractals; Linear analysis; Models, Theoretical; Nature; Newborn babies; Noise; Nonlinear analysis; Nonlinear Dynamics; Physical Sciences; Population; Population (statistical); Population biology; Population Dynamics; Resilience; Species extinction; Statistical analysis; Stress, Physiological - physiology; Test procedures; Time series; Aachen Germany; Germany
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0096270

In this study we present evidence that anthropogenic stressors can reduce the resilience of age-structured populations. Enhancement of disturbance in a model-based Daphnia population lead to a repression of chaotic population dynamics at the same time increasing the degree of synchrony between the population's age classes. Based on the theory of chaos-mediated survival an increased risk of extinction was revealed for this population exposed to high concentrations of a chemical stressor. The Lyapunov coefficient was supposed to be a useful indicator to detect disturbance thresholds leading to alterations in population dynamics. One possible explanation could be a discrete change in attractor orientation due to external disturbance. The statistical analysis of Lyapunov coefficient distribution is proposed as a methodology to test for significant non-linear effects of general disturbance on populations. Although many new questions arose, this study forms a theoretical basis for a dynamical definition of population recovery.