Lake ecosystem health assessment: indicators and methods.

Area of Science:

• Environmental Science
• Ecology
• Limnology

Background:

• Lake ecosystems face chemical stresses like acidification, eutrophication, and contamination.
• Assessing lake ecosystem health requires comprehensive indicators covering structural, functional, and system-level aspects.

Purpose of the Study:

• To propose a set of ecological indicators for lake ecosystem health assessment.
• To develop and validate two methods: a direct measurement method (DMM) and an ecological modeling method (EMM).

Main Methods:

• Proposed structural indicators: phytoplankton/zooplankton size and biomass, species diversity, and various ratios.
• Proposed functional indicators: C assimilation, resource use efficiency, production, and energy flow ratios.
• Proposed system-level indicators: ecological buffer capacities and energy.
• Developed DMM involving indicator identification, measurement, and assessment.
• Developed EMM involving model design, parameterization, simulation, and indicator calculation.

Main Results:

• Both DMM and EMM provided comparable results for lake ecosystem health assessment.
• The assessment results from both methods aligned with the lake's actual trophic state.
• The proposed indicators effectively captured ecosystem responses to chemical stresses.

Conclusions:

• The developed DMM and EMM are effective tools for assessing lake ecosystem health.
• The proposed ecological indicators provide a robust framework for evaluating lake health.
• These methods can aid in understanding and managing lake ecosystems under environmental stress.