Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 410489
Title Abrupt regime shifts in space and time along rivers and connected lake systems
Author(s) Hilt, S.; Köhler, J.; Kozerski, H.P.; Nes, E.H. van; Scheffer, M.
Source Oikos 120 (2011)5. - ISSN 0030-1299 - p. 766 - 775.
DOI https://doi.org/10.1111/j.1600-0706.2010.18553.x
Department(s) Aquatic Ecology and Water Quality Management
WIMEK
Publication type Refereed Article in a scientific journal
Publication year 2011
Keyword(s) advection-dominated systems - alternative stable state - shallow lakes - submerged macrophytes - chlorophyll-a - water-quality - flow - ecosystems - streams - phytoplankton
Abstract Regime shifts between clear and turbid water states are commonly found in shallow lakes. These shifts are attributed to a positive feedback between water clarity and submerged macrophytes (underwater plants). Altering the retention time of the water may influence these interactions and thus potentially reduce the probability of alternative stable states. Here we assessed the effect of water retention time on the occurrence of alternative states in water quality of flushed lakes, chains of lakes and rivers using a spatially explicit simple model. Our results indicate that increased flushing of lakes rapidly decreases the range of parameters with alternative stable states up to their total disappearance at a flushing rate of about 50% the algal growth rate. Similarly, in a chain of lakes or in rivers with low flowing velocity, our model predicts that alternative stable states can only occur for systems with a high retention time. Despite the lack of hysteresis at lower water retention times, we predict that abrupt changes between clear and turbid states are still possible both in time and in space. Over a wide range of parameters, the equilibrium state of the chain of lakes shows a steep gradient of vegetation cover. Further, the transient dynamics of the model often include rapid shifts in time. For example, a local regime shift that occurs upstream may propagate through the whole lake chain or river due to a domino effect. All results of the simple model could qualitatively be reproduced with a more mechanistic model. The abrupt rather than gradual response of submerged macrophytes to reduced turbidity levels still makes river systems rather resilient to management measure. The importance of the initial turbidity and the observed domino effect suggest that restoration measures should start upstream and that these measures should eventually trigger regime shifts downstream
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