Shallow Lakes 95

Shallow lakes differ from deep ones in many aspects of nutrient dynamics, biotic structure and interactions of various trophic levels. Though very common in European lowlands, shallow lakes attract inadequate attention from research teams. This book aims at filling gaps in our knowledge of the processes which take place in non-stratified lakes. It contains proceedings from the international conference `Shallow Lakes *95' held in Mikolajki, Poland, on 20-26 August 1995. In more than 50 original papers up-to-date views on eutrophication, degradation and recovery of shallow lakes are presented. The first four sections of the book (Nutrient fluxes, Biotic structure, Trophic interactions and Whole lake studies) deal with theoretical aspects of lake functioning while the fifth (Biomanipulation, restoration and management) is devoted to practical measures undertaken to improve water quality in shallow lakes. The book is therefore addressed to university biologists and ecologists and PhD students, as well as to managers involved in restoration of shallow lakes.

This volume comprises the proceedings of the 5th International Symposium on Shallow Lakes, held at Dalfsen, The Netherlands, in June 2005. The theme of the symposium was Shallow Lakes in a Changing World, and it dealt with water-quality issues, such as changes in lake limnology, especially those driven by eutrophication and pollution, increased nutrient loading and productivity, perennial blooms of cyanobacteria and loss of biodiversity.

This work presents the state of the art of aquatic and semi-aquatic ecological restoration projects in The Netherlands. Starting from the conceptual basis of restoration ecology, the successes and failures of hundreds of restoration projects are described. Numerous successful projects are mentioned. In general ecological restoration endeavours greatly benefit from the progressive experience achieved in the course of the years. Failures mainly occur through insufficient application of physical, chemical or ecological principles. Spontaneous colonization by plants and animals, following habitat reconstruction, is preferred. However, sometimes the re-introduction of keystone species (e.g. eelgrass, salmon, beaver) is necessary in case the potential habitats are isolated or fragmented, or if a seed bank is lacking, thus not allowing viable populations to develop. Re-introducing traditional management techniques (e.g. mowing without fertilization, low intensity grazing) is important to rehabilitate the semi-natural and cultural landscapes that are so characteristic for The Netherlands.

Using a combination of empirical studies, experimental work and mathematical formulations, Scheffer presents a theoretical framework for understanding the dynamics of shallow lake communities.

The nutrient dynamics and biological structure of shallow non-stratified lakes differ markedly from that of deep and stratified lakes: for example, the return of nutrients lost through sedimentation is faster and the potential importance of fish and submerged macrophytes as food-web regulators is greater. In addition shallow lakes are more easily influenced by fluctuations in the physical environment caused by wind disturbance, temperature change, etc. Although shallow lakes are often the most common lake type in lowland countries, less attention has been paid to them than to deep stratified lakes and few comparisons have been made between shallow freshwater and brackish lakes. The volume is divided into five main themes, each introduced by an invited speaker: Nutrient dynamics with special emphasis on sediment water interactions and changes in loading (Professor Lambertus Lyklema); Biological structure and trophic interaction (Professor Stephen T. Threlkeld); Submerged macrophytes: dynamics and role in the lake ecosystems (Ass. Professor Kaj Sand Jensen); Comparison of freshwater and brackish lake ecosystems (Professor Brian Moss); Modelling the impact of nutrients, the biological structure and the recovery process (Dr Marten Scheffer).

Proceedings of a Conference held in Amsterdam, The Netherlands, 18-19 April, 1991

This volume combines articles on shallow lakes from leading European scientists in limnology. It covers aspects of the dynamics of macrophytes, phytoplankton, zooplankton and benthos, nutrient loading, littoral-pelagic interactions, and sediment-water interactions, as well as lake management. The object was not to separate theory (e.g. modelling) and management in order to generate new theories for the understanding of shallow lake ecosystems. The volume provides a comprehensive overview of the ecology of shallow lakes, a lake type which differs in prominent ways from deeper lakes. The broad spectrum of issues may also reflect the spectrum of interested readers such as limnologists, water engineers, hydrobiologists, who will be informed on a high level about new developments.