Preface / Vorwort

Ecological systems are dynamic. Take succession as an example; following a change in habitat conditions or the creation of a new habitat, a sequence of species replacements occurs which leads eventually to a relatively stable state, usually called the climax. However, even a 'stable' community is highly dynamic; the plants and animals which make up an ecosystem grow and die, and most natural vegetation consists of a mosaic of patches at different stages of regeneration. The first person to describe the basic features of succession was an American ecologist called Clements who published detailed studies of change in several plant communities in 1916. Clements' conclusions, and those of most later ecologists, come from observing different patches of the same type of vegetation which were assumed to be of different ages. However, here we come to some important methodological problems. Firstly, how can we be certain about the age of different patches?, and secondly, even if we do know the age accurately, how can we be sure that, apart from their age, the different areas are truly comparable?

The basic problem is that, from a human perspective, many ecological processes are very slow. For example, it may take several hundred years for a stable community to develop in Alpine regions following the retreat of a glacier. The best kind of evidence for change or stability would come from long-term observations of the same site, but this is clearly not possible in such cases. Furthermore, our universities and research institutions do not easily accommodate work that involves collecting data over a long time span. Time constraints are imposed by such factors as the duration of research grants and PhD studies (usually three years), and the changing priorities of the research community. In a paper entitled ´How unusual are unusual events?, Weatherhead (1986) reviewed 308 ecological studies and found that the mean duration was 2.5 years. This is an extremely short period in which to draw conclusions about dynamic processes which may unfold over hundreds of years. Similarly, Tilman (1989) analysed some 749 empirical studies in the journal Ecologyand found that only 13 of them (1.7%) were field studies that lasted five years or more.

Some of the longest sequences of ecological records anywhere in the world were produced in the Swiss National Park, which ranges in altitude from 1500 to 3170 m a.s.l. and encompasses an area of 170 sqkm. Not only was it one of the first major national parks to be established (in 1914), but the systematic recording of ecological conditions began almost immediately after its foundation. In 1917, Josias Braun-Blanquet, a pioneer of plant ecology and the dominant figure in European vegetation science for much of the 20th century, set out a number of permanent plots within the National Park to record how the vegetation would change following the giving up of agricultural activity. From 1939 until 1988, Balthasar Stüssi continued and expanded the work of Braun-Blanquet to a total of more than 160 permanent plots, monitoring the development of the vegetation at intervals of 5 to 10 years. Fortunately, these early records have been preserved and we know the exact location of most of the plots, so that they can still be monitored. Zoologists have also been active in the National Park. Since 1918 yearly records exist of the maximum number of wild ungulates (red deer, chamois, ibex, roe deer) present in the Park during the summer months. These data show that between 1918 and today the number of wild ungulates has tripled, primarily due to a steady increase in the number of red deer from almost none in 1918 to around 2000 over the past 30 years. As various papers in this volume will show, the excellent opportunities provided by the National Park for long-term observational studies, and the unique sets of ecological data which have resulted, are very valuable in understanding how the vegetation of the Park has responded to changing environmental conditions over the past eighty years or so. In particular, the bringing together of the long-term records on ungulate numbers and plant species composition has provided remarkable insights into the impact of grazing on the structure and function of Alpine ecosystems.

This volume also describes several other long-term monitoring projects currently in progress in the Swiss National Park. These projects are particularly significant, precisely because they are carried out in a national park. Few would doubt that in the future we shall be increasingly affected by the effects of environmental change caused by human activities. Possible changes in climate is just one example. However, without long-term records it is extremely difficult to know whether and how conditions are changing. Moreover, in the human-dominated landscape it is often impossible to identify the causes of a particular effect because so many factors are changing at the same time. In most places it would be difficult if not impossible to detect the effects of recent climatic change on biodiversity because land-use, management and levels of pollution have also changed over the same period. In addressing questions of environmental change, records from the Swiss National Park will be of the greatest importance because they come from an area where many of these anthropogenic effects can be ignored. This is because the traditional human activities such as logging, hunting and grazing of livestock ceased in 1914. The land use during the past 80 years is exactly known, and the Park offers excellent guarantees that the area will remain untouched by humans in the future.

For these reason then Swiss National Park represents an almost unique ecological reference area located in the heart of the Alps. This mountainous region is of crucial importance for Europe, both with regard to its hydrology and biodiversity. Furthermore, the unique cultural landscape of the Alps offers an increasingly popular environment for recreation. However, the Alps face major economic problems. It is uncertain how much longer it will be possible to finance the currently applied traditional systems of agriculture and forestry. In order to preserve the valuable resources of the Alps for future generations it is urgent to develop novel concepts for land use. This in turn requires a sound understanding of the long-term development of alpine ecosystems in space and time, and their responses to changes in the biotic and abiotic environment.

It is in the nature of long-term monitoring exercises that we cannot be certain in advance for what purposes the data presented in this volume will be used. What is certain is that they will be used, and sometimes for quite unexpected purposes! It is no exaggeration to say that these data will provide an essential basis for interpreting how our environment is changing and how human beings are affecting it.

Many people, too numerous to list, have assisted in different ways in producing this volume. However, we should not close without acknowledging the extremely helpful comments of the following reviewers: Irene Bisang, Stockholm; Roland Bobbink, Nijmegen; Reiner Cornelius, Berlin; Walter Dietl, Zurich; Georg Grabherr, Vienna; Walter Keller, Birmensdorf; Johannes Kollmann, Copenhagen; Nino Kuhn, Birmensdorf; Elias Landolt, Zurich; Wolfgang Schröder, Munich; Josef Senn, Birmensdorf; Andreas Stampfli, Berne; Edi Urmi, Zurich.

NATIONALPARK-FORSCHUNG IN DER SCHWEIZ 89 (2000)

Schütz, M.; Krüsi, B.O.; Edwards, .PJ. (eds): Natl.park-Forsch. Schweiz 89, 5 - 8