Matthias Bürgi

Factors and Processes Shaping Land Cover and Land Cover Changes Along the Wisconsin River

Land use can exert a powerful influence on ecological systems, yet our understanding of the natural and social factors that influence land use and land-cover change is incomplete. We studied land-cover change in an area of about 8800 km2 along the lower part of the Wisconsin River, a landscape largely dominated by agriculture. Our goals were (a) to quantify changes in land cover between 1938 and 1992, (b) to evaluate the influence of abiotic and socioeconomic variables on land cover in 1938 and 1992, and (c) to characterize the major processes of land-cover change between these two points in time. The results showed a general shift from agricultural land to forest. Cropland declined from covering 44% to 32% of the study area, while forests and grassland both increased (from 32% to 38% and from 10% to 14% respectively). Multiple linear regressions using three abiotic and two socioeconomic variables captured 6% to 36% of the variation in land-cover categories in 1938 and 9% to 46% of the variation in 1992. Including socioeconomic variables always increased model performance. Agricultural abandonment and a general decline in farming intensity were the most important processes of land-cover change among the processes considered. Areas characterized by the different processes of land-cover change differed in the abiotic and socioeconomic variables that had explanatory power and can be distinguished spatially. Understanding the dynamics of landscapes dominated by human impacts requires methods to incorporate socioeconomic variables and anthropogenic processes in the analyses. Our method of hypothesizing and testing major anthropogenic processes may be a useful tool for studying the dynamics of cultural landscapes.

Reconstructing Anthropogenic Disturbance Regimes in Forest Ecosystems : A Case Study from the Swiss Rhone Valley

Anthropogenic disturbances of forest ecosystems are increasingly recognized as fundamental ecological processes with important long-term implications for biogeochemical cycles and vegetation patterns. This article aims at reconstructing the extent and intensity of the two most common types of traditional forest uses—forest litter collecting and wood pasture—in the Swiss Rhone valley (Valais) by (i) identifying the spatiotemporal patterns, and (ii) modeling the biomass removal through these practices. Detailed information on agricultural practices and socio-economic context were essential to develop reliable estimates of anthropogenic disturbance regimes. In the Valais, predominately goats and sheep grazed in the forests. The intensity of grazing was a function of the number of grazing animals and the available grazing area. Forest litter was used as bedding for farm animals during the winter. Key factors determining the intensity of litter collecting were the number of animal units, the amount of available substitute products (straw), and the area where litter raking could be practiced. The results show that wood pasture and forest litter collecting were practiced on a significant proportion of the forested landscape in the Valais up to the second half of the 20th century. Until the implementation of forest management plans in the 1930s, almost half of the forests in the study area were affected by wood pasture and/or forest litter collecting. The regulations in the management plans led to an essential reduction of the area available for these traditional practices but likewise to an increased pressure on the remaining areas. The results suggest that the notion of a slow but steady disappearance of traditional non-timber forest uses and the associated effects on forest ecosystems is oversimplified. Quantitative reconstructions of biomass output resulting from these practices confirm the importance of traditional non-timber forest uses for ecosystem development in this region. Furthermore, it is very likely that similar effects have been widespread throughout regions with similar natural and socio-economic context, for example, throughout a significant proportion of the European Alps. This study underlines the importance of environmental history for ecological sciences as well as for forest management and conservation planning.

Land-use and climate change effects in forest compositional trajectories in a dry Central-Alpine valley

Abstract• Increased mortality of Scots pine (Pinus sylvestris L.) and spreading of deciduous trees are observed in the Swiss Rhone valley. Previous research identified climate change effects as main drivers of this trend. On the local scale, we hypothesize that legacies from past anthropogenic disturbances are superimposed on climate effects.• We reconstructed land-use history and quantified changes in tree species composition from 1930 to 1994 on 9468 ha of forested land. The aim was to analyze the contribution of anthropogenic disturbances to the observed changes and to disentangle human impact from climate change effects.• At altitudes below 1 200 m a.s.l. we found a shift from pine (−11.4%) to deciduous trees (+11%) with significantly lower increase of deciduous trees in stands formerly used for grazing and/or litter collecting. Conversely, pine decrease was not correlated with former anthropogenic disturbances. We interpret pine mortality as an effect of increased drought stress due to climate change while spread of deciduous trees is driven by land-use change. Grazing and litter collecting hindered deciduous tree regeneration and it was not until their abandonment a few decades ago that forest composition started to change. At higher elevations the shift from Norway spruce (Picea abies; −8.5%) to European larch (Larix decidua; +8.2%) corresponds to silvicultural management schemes, aimed at promoting larch recruitment.• Our study illustrates the importance of disentangling climate from land-use change effects for understanding shifts in forest composition. The findings are relevant for other regions in the European Alps where forests undergo comparable environmental changes.

Reconstructing the collapse of wetland networks in the Swiss lowlands 1850–2000

In Central Europe vast wetland areas have been converted into agricultural land over the past few centuries. Long-term spatially explicit reconstructions of wetland cover changes at regional scale are rare but such information is vital for setting appropriate wetland conservation and restoration goals. In this study wetland cover change over the past 150xa0years was analyzed for the Canton Zurich (Switzerland) using information from historical and current topographical maps. Mapping instructions changed significantly over time, i.e., wetlands were mapped more conservatively on older maps. Therefore a technique was developed to account for changes in mapping instructions and to reconstruct a series of comparable maps spanning 1850–2000. Wetland cover dramatically decreased from 13,759xa0ha in 1850 (more than 8% of the total study area) to 1,233xa0ha in 2000 (less than 1%). Largest loss is observed for the first half of the twentieth century when more than 50% of the total wetland loss occurred. In 1850, almost all wetland patches were connected in two large networks defined by a 500xa0m buffer around all wetland patches to account for typical dispersal distances of wetland animals. Despite extensive wetland loss, this networks remained largely intact until 1950, but then collapsed into many medium and small networks consisting of only few wetland patches. In addition to the direct loss of wetland habitats increased habitat fragmentation is limiting metapopulation dynamics and hindering genetic exchange between populations. Amphibians and other wetland animals are particularly prone to habitat fragmentation because of their limited migration abilities. This may lead to time-delayed extinction in the future because current species occurrence might rather reflect historical than current wetland cover and habitat configuration. Future restoration efforts should focus on reestablishing connectivity between remaining smaller wetland networks.

The recent landscape history of Limpach valley, Switzerland: considering three empirical hypotheses on driving forces of landscape change

Understanding global landscape dynamics is a core challenge for the newly emerged field of land change science. Such an understanding requires insights into general pattern of landscape changes and the related driving forces. Many case studies of landscape change exist, but only few attempts have been made, to synthesize the results and to search for general pattern. We suggest that applying hypotheses on driving forces of landscape change derived from one case study in another region as a promising way to advance towards a more integrative view on landscape dynamics. Based on the conclusions drawn in a case study conducted in Godmanchester (Quebec, Canada; Domon and Bouchard 2007), we formulated three hypotheses and discussed them in a case study on landscape change in the Limpach valley, Switzerland. We confirm the importance of geomorphological characteristics for landscape development (hypothesis 1) and our analysis also supports the second hypothesis, which states that changes in demand for certain resources result in landscape change. However, we suggest replacing the term resources by the more encompassing concept of goods and services. The third hypothesis, which states that technological transformations stand at the beginning of landscape change, also was confirmed. Technologies have to be affordable, socially accepted, and corresponding to a demand, to be implemented on a large scale. This will cause a technological transformation, which then—depending on the specifics of the technology applied—becomes relevant for landscape development. We conclude with three reworded hypotheses on driving forces of landscape change and we hope that they will be tested and further developed in other case studies.

Legacy Effects of Human Land Use: Ecosystems as Time-Lagged Systems

A bstractToday, most ecosystems show some degree of human modification, ranging from subtle influences to complete remodeling and reshaping into anthropogenic ecosystems. In the first issue of the journal Ecosystems, the field of historical ecology, which focuses on the historical development of ecosystems, was prominently positioned with the papers of Foster and others (Ecosystems 1:96–119, 1998) and Fuller and others (Ecosystems 1:76–95, 1998). Starting from these two contributions, we (1) discuss how anthropogenic activities affect ecosystems and their development, (2) outline how land use can be assessed in ecosystem research, and we (3) discuss what the consequences of a historical perspective for our understanding of ecosystems are. We conclude by stating that whereas land-use intensity over time is an ecologically highly relevant parameter to grasp, the availability, quality, and characteristics of historical sources often restrict the analyses. In order to make optimal use of the sources and methods available and to strengthen this field of research and also increase its societal relevance, we suggest building interdisciplinary teams from a very early project phase on. Core task for these teams will be to jointly define research questions considering source availability, and including and merging modeling and experimental approaches in the study design. We propose that adopting a landscape perspective in historical ecology would provide a helpful framework and valuable background for such novel integrated analyses.

What, How, and Why? Collecting Traditional Knowledge on Forest Uses in Switzerland

During the nineteenth and twentieth centuries, forest use and management in Switzerland underwent radical changes (Burgi 1999). Before this period, traditional forest uses, such as woodland pasturing, wood hay and litter collection and even crop production on temporary fields in the forest were a common practice throughout the country. In the late nineteenth and early twentieth century, these non-timber forest uses have been increasingly abandoned and/or banned from the forests. This development has been paralleled by an increasing interest in wood as an industrial good and the introduction of the science of forestry together with the implementation of forest laws. Furthermore, agricultural modernization and a rapidly growing infrastructure after the Second World War facilitated importing resources from abroad and consequently took pressure from the forests to supply resources for the local demand. Lately, uses, such as woodland pasturing and litter collection, have gained attention from various scientific disciplines due to their importance for cultural history, ecosystem development and carbon sequestration in forests (Perruchoud et al. 1999; Gimmi et al. 2008).

Die Zürcher Wälder um 1823 – Betriebsformen und Baumarten

Die Zurcher Walder um 1823 – Betriebsformen und Baumarten Aus den Visitationsberichten von 1823 sollen Bewirtschaftung und Baumartenzusammensetzung der offentlichen Walder im Kanton Zurich im fruhen 19. Jahrhundert rekonstruiert werden. Dazu werden die Verteilung der Betriebsformen im ganzen Kanton und die Baumartenzusammensetzung in 31 ausgewahlten Gemeinden im Zurcher Unterland analysiert. Ausserdem wird fur diese Gemeinden ein Vergleich mit der heutigen Baumartenzusammensetzung durchgefuhrt. Die Auswertungen zeigen, dass der Mittelwald im fruhen 19. Jahrhundert die wichtigste Betriebsform im Kanton Zurich war. Die Betriebsformen unterscheiden sich sehr stark in ihrer Baumartenzusammensetzung, wobei die grosste Vielfalt an Baumarten in Nieder- und Mittelwaldern zu finden ist. Die Resultate legen die Vermutung nahe, dass kein klarer Zusammenhang zwischen der Baumartenzusammensetzung und naturlichen Faktoren wie Klima, Topografie und Boden besteht. Daraus kann geschlossen werden, dass die Bewirtschaftung ...