Noise-driven cooperative dynamics between vegetation and topography in riparian zones

• Published in: Geophysical research letters Vol. 42; no. 19; pp. 8021 - 8030
• Main Authors: Vesipa, R., Camporeale, C., Ridolfi, L.
• Format: Journal Article
• Language: English
• Published: Washington Blackwell Publishing Ltd 16.10.2015; John Wiley & Sons, Inc
• Subjects: Dynamics; ecomorphodynamics; Economic models; ecosystem engineers; Ecosystems; Freshwater; Probability density function; Probability density functions; Probability theory; Randomness; Riparian land; Riparian vegetation; Rivers; Sediment; Sediments; Slope; state-dependent dichotomous noise; Stochastic models; Stochasticity; Survival; Topography; Topography (geology); Variation; Vegetation; Water levels
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/2015GL065688

Riparian ecosystems exhibit complex biotic and abiotic dynamics, where the triad vegetation‐sediments‐stream determines the ecogeomorphological features of the river landscape. Random fluctuations of the water stage are a key trait of this triad, and a number of behaviors of the fluvial environment can be understood only taking into consideration the role of noise. In order to elucidate how randomness shape riparian transects, a stochastic model that takes into account the main links between vegetation, sediments, and the stream is adopted, emphasizing the capability of vegetation to alter the plot topography. A minimalistic approach is pursued, and the probability density function of vegetation biomass is analytically evaluated in any transect plot. This probability density function strongly depends on the vegetation‐topography feedback. We demonstrate how the vegetation‐induced modifications of the bed topography create more suitable conditions for the survival of vegetation in a stochastically dominated environment. Key Points A stochastic model elucidates how random variations of water stage shape riparian transects A key feature of the model is to consider that vegetation alters the plot topography Vegetation modifies the topography for creating conditions more suitable to its survival