A large number of nationwide research programmes in the field of acidification have been carried out in the last decade. Especially in Western Europe, extensive programmes have resulted in a good overview of all the effects - mostly negative - caused by acidifying substances. There is now consensus that types of acidification damage relate to the unique geography of an area: air pollution affects vegetation; acid aerosol the ozone layer. New in this volume, is the relation between scientific results of integrated research programmes and policy actions to prevent, reduce and limit the widespread damage caused by acidification. The results of many different national research programmes are evaluated and compared to present a unique compilation for the research scientist and policy maker. In this volume thematic reviews on specific topics of acidification research are presented, followed by overviews of acidification policy plans and actual abatement plans. The result is the best review of acidification research carried out worldwide during the last decade and presentation of the critical relation between research results and policy actions.

The book begins with an overview of the research topics which were addressed in the three different phases of the Dutch Priority Program on Acidification (DPPA), executed between 1985 and 1994. This chapter is followed by a chapter which deals with the emissions of acidifying substances, the concentrations and the deposition to forest and nature conservation areas. Prognoses are given for the acid deposition in 2000 and 2010; the deposition in the countries surrounding the Netherlands is also mentioned. The differences in the results of the DPPA-II are analysed. The third chapter deals with the effects of exposure and load on forests. The chapter moves from small-scale to large-scale: first the effects in laboratory-scale studies are described, then the effects in the field, both at stand level and on a regional scale. In addition, the critical thresholds (critical level of concentration and critical load of deposition) are discussed. The fourth chapter covers terrestrial ecosystems (or parts thereof) as well as weakly buffered surface waters, springs and other streams. Critical levels and loads are also discussed. The most important results are given in chapter 5. In the appendices of the book, so-called umbrella theme reports on deposition, stand modelling and effects on forests are presented which describe in more detail the scientific work performed in the third phase of the DPPA. This book will be of interest to anyone involved in research related to acidification and eutrophication; i.e., not only those who perform the research in the causal chain from emissions to effects, but also policy-makers and students.

The First International Nitrogen Conference provided an opportunity for researchers and decision-makers to exchange information on environmental pollution by nitrogen compounds on three scales: global, continental/regional and local. The main topics were air, ground water and surface water pollution; emission sources, atmospheric chemistry, deposition processes and effects; disturbance of nitrogen cycles, critical loads and levels; assessments, policy development and evaluation; target groups and abatement techniques; and new approaches leading to an integrated abatement strategy.The peer-reviewed papers from the Conference presented in this volume will provide readers with a comprehensive review of the transport, deposition and impact on ecosystems of nitrogen.

Increased atmospheric nitrogen deposition and changes in the management of heathlands have caused a significant change in the species composition of the NW-European heathlands. This change from ericaceous towards gramineous dominance is analysed in detail in Heathlands: Patterns and Processes in a Changing Environment. Special emphasis is put on the effects of increased atmospheric nutrient input on nutrient cycling, competition between plant species and plant--herbivore interactions. The possibilities for the long-term conservation of heathlands are discussed by considering regeneration from seed and the usefulness of mathematical management models. The book provides a synthesis of pure and applied plant ecology. It is vital reading for plant ecologists, biological conservationists, heathland managers and government decision makers.