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Thresholds Database > Eutrophication, lake Erhai, China

Certainty of shift:
Location: Yunnan Province, China
System Type: Ecological
Regime Shift Category: 4a
Ecosystem Type
Lake
Spatial Scale
Landscape/Local
Type of Resource Use
Fisheries
Number of Possible Regimes
2
Ecosystem Service
Tourism, water, food, recreation
Time Scale of Change
Months
Resource Users
Fishers, farmers 
Reversibility of Shift
Reversible with hysteresis

Background

Large lake-catchment system (~2500 km2) in tectonically active mountains with millenial-long history of agricultural land use (rice paddy, wheat, vegetables) supporting local population.

Alternate Regimes

mesotrophic aquatic system
eutrophic aquatic system with algal blooms

Fast or Dependent Variable(s)
water level
Slow or Independent Variable(s)
nutrient loading
Disturbance or Threshold Trigger(s)
agricultural intensification
External / Internal Trigger
External

Mechanism

low seasonal water level interacts with high nutrient loadings to drive positive feedback in the form of anoxia of bottom waters and recycling of phosphorus.

Management Decisions in Each Regime

Contact
John Dearing

Email
j.dearing@soton.ac.uk

Geography and Environment
University of Southampton
Southampton SO17 1BJ, UK

Keywords
China, lake erhai, eutrophication, flickering, early warning signals, fold bifurcation

References

Wang, R., Dearing, J.A., Langdon, P.G., Zhang, E., Yang, X., Dakos, V., Scheffer, M. 2012. Flickering gives early warning signals of a critical transition to a eutrophic lake state. Nature 492, 419-422.
 

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