Effectiveness of reducing external nutrient load entering a eutrophicated shallow lake ecosystem in the Naardermeer nature reserve, The Netherlands

• Published in: Biological conservation 1999-10, Vol.90 (3), p.193-201
• Main Authors: Bootsma, M.C., Barendregt, A., van Alphen, J.C.A
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Characeae; Conservation of biodiversity; Conservation, protection and management of environment and wildlife; Environmental degradation: ecosystems survey and restoration; Eutrophication abatement; Fundamental and applied biological sciences. Psychology; Naardermeer nature reserve; Najas marina; nature reserves; Netherlands; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; Shallow lake restoration; Species response model; The Netherlands
• ISSN: 0006-3207; 1873-2917
• DOI: 10.1016/S0006-3207(99)00027-0

This paper describes successes and complications in eutrophication abatement in the Naardermeer nature reserve, The Netherlands. Restoration of this lake started in 1985. The main measure was the reduction of external nutrient load by the supply of phosphate-free water. Water quality and aquatic vegetation were monitored and the usefulness of a modelling approach in designation of management programs was investigated. The monitoring showed that for the first 4 years, recovery was retarded, possibly because of phosphorus release from the lake-bed sediments. After 10 years, turbidity was reduced and characteristic vegetation with Najas marina and Characeae species had re-established in large parts of the lake. Due to spatial heterogeneity it appeared necessary to dredge the lake-bed sediments locally. The model predicted most changes in aquatic vegetation correctly, indicating its predictive value. However, to predict restoration perspectives for rare species, expert judgement still remains necessary. Suggestions are made for selection of successful management measures depending on the conditions of lake ecosystems.