A three thousand year succession of plant communities on a valley bottom in the Vosges Mountains, NE France, reconstructed from fossil pollen, plant macrofossils, and modern phytosociological communities

Pollen and macrofossils were studied in a core from a fen at the foot of a slope in the Vosges Mountains, NE France. The present-day vegetation of little disturbed Abies, Fagus, and Picea forest and wetlands has been described in detail in terms of phytosociological communities using the Braun-Blanquet approach. Past ecological conditions are reconstructed in five steps: (1) The modern vegetation types are described as combinations of phytosociological species groups. (2) Micro- and macrofossils are assigned to these groups. (3) These in combination determine the past vegetation types at the site; there were simultaneously several such types in some biozones. (4) The sequence of past vegetation types is interpreted as successional pathways. (5) Past ecological conditions are inferred from these pathways. Results are: (1) The types of local forest and fen were the same around 1000 b.c. as today. (2) Rising groundwater around 650 b.c. caused a natural wet meadow to develop at the site. (3) Trees were felled near the site in the first century b.c. (Late Iron Age), facilitating the immigration of Picea. (4) Groundwater level rose during early Medieval times because of a wetter climate and alder carr replaced the dry-soil forest close to the site. (5) During High Medieval Times (10th-13th century) the nearby raised bog expanded over the site. (6) Forestry starting around a.d. 1750 caused nutrient-rich water to reach the site, resulting in abrupt vegetation change. (7) The creation of a forest road around a.d. 1855 (historical information) caused further nutrient enrichment of the site. The validity of the method used depends on the assumption that past and present vegetation types are virtually identical, which is true in our study area and study period, according to all the indications that we hav

The tourist's drives : GIS oriented methods for analysing tourist recreation complexes

See also theweb sitebased on this thesisTourism is a product of diverse composition. An increasing number of people pursue their own specific wishes and combine various products which may or may not be intended for tourists; they create their own individual holiday package. In order to determine how this trend of combining elements influences the use of (tourist) products in a region, it is necessary to gain insight into tourist time-space behaviour. Time, space and context are important domains for describing tourist time-space behaviour. People differ, situations constantly change and a particular interaction depends on the circumstances (personal and topological) in which it takes place. The analysis of tourist time-space behaviour might provide an explanation for this combinatory behaviour. This type of analysis requires specific personal data about time spent, places visited, routes chosen, information used, perception and motivation. Not only the visible tourist time-space pattern is important, but also the process involved.To date, most researchers have attempted to analyse spatially related tourism data using statistical methods. The data structure needed for such a statistical analysis requires data for each period considered and for each possible location and road in a region. However, a maximum of only 1% of these data is likely to be significantly related to one person. Furthermore, the enormous size of the data set makes it difficult to uncover spatial relations. Geographical Information Systems (GIS) are capable of handling spatial relationships. Four main data groups can be distinguished:(1) tourist related characteristics;(2) perception of space and of activities undertaken, and observed time-space behaviour;(3) spatial objects;(4) specific (tourism) codes added to these objects.The constructed tourist recreation complex can be understood as an interwoven structure of several different network s. None of these networks prevails or determines tourist behaviours exclusively. A methodology consisting of two steps is proposed for the analysis of tourist time-space behaviour:(1) Survey the use of the physical environment by tourists, using exploratory spatial data analysis techniques and dynamic visualisation. Determine clusters of product elements and a possible typology of tourist groups.(2) Deduce, describe and analyse tourist recreation complexes using graph and network analysis techniques, and statistical methods. The individual network is based on products and product-clusters and tourist time-space behaviour in relation to the use of the environment and the tourist's perception of it. Execute pattern analysis using graph techniques and accessibility studies for the links and nodes in the network.Data visualization is used to make patterns in scientific data visible. The application of dynamic cartography adds a new dimension to the visualization process: data can be interactively explored for errors and patterns. The Cartographic Data Visualizer for Time-Space data (CDV-TS) can be used to make a coherent analysis of the use of space, the time distribution and the context of time- space behaviour. GIS is an instrument which is particularly suited to the analysis of clearly limited physical elements. Current GIS software can be applied to obtain a static overview and to perform spatial analyses of the use of a region at a certain moment in a specific context. The storage of time-space data within the GIS data structure is more efficient than the data storage for a statistical application. However, the statistical uses of current GIS are limited to descriptive forms. A linkage between GIS and statistical software creates a powerful instrument. The current generation of commercial GIS software is not capable of dealing with time. Applications were developed to approximate this. A GIS has few network capabilities for supporting tourist time-space behaviour analyses. Network pattern recognition and comparison is not possible at all, and network indices cannot be calculated within a GIS. A newly developed morphologic pattern describer seems appropriate for comparing different constructed network patterns.Two data sets were used to illustrate how the applications and approaches developed can describe a tourist recreation complex in a tourist region. The applications otter a wealth of opportunities for the interactive examination of time- space oriented data, and to search for different tourist combinations of products supplied. A main drawback of the applications is the amount of data that has to be processed

Human impact on vegetation at the Alpine tree-line ecotone during the last millennium: lessons from high temporal and palynological resolution

Three mires and a small lake in the Swiss and Austrian Alps were studied palynologically at high resolution, covering the last 1,000, 400, 50 and 1,200years, respectively. Methodological lessons include: (1) Sub-decadal resolution in upper, little-decomposed peat layers reveals recurrent marked fluctuations in both percentages and influx of regional tree-pollen types, reflecting variations in pollen production rather than in plant-population sizes. (2) Intermittent, single-spectrum pollen maxima in samples of sub-decadal resolution indicate pollen transport in clumps. This type of pollen transport may remain unrecognized in sections with lower sampling resolution, which may then lead to inappropriate interpretation in terms of plant-population sizes. (3) The detection of short-lived phases of human impact in decomposed peat requires sampling intervals as close as 0.2cm. (4) PAR (pollen influx) may reflect vegetation dynamics more faithfully than percentages. Reliable PAR, however, is difficult to achieve in Alpine mires due to past human impact on peat growth, even when complex depth-age modelling techniques are used. Critical comparison of PAR with percentages is therefore essential. (5) Careful consideration of spatial scales in pollen signals (local-regional and subdivisions) is essential for a realistic palaeo-ecological interpretation. Results in terms of past human impact on vegetation are summarized as follows: (1) Trends in pollen types reflecting regional human action are in general agreement with earlier findings for the western Swiss Alps, allowing for regional differences. (2) All mires in the Alps investigated here and in an earlier study experienced human impact during the last millennium. The studied small lake, lying in sub-alpine pasture, records forest dynamics at a lower elevation since a.d. 80

Holocene vegetation, fire and land use dynamics at Lake Svityaz, an agriculturally marginal site in northwestern Ukraine

Observing natural vegetation dynamics over the entire Holocene is difficult in Central Europe, due to pervasive and increasing human disturbance since the Neolithic. One strategy to minimize this limitation is to select a study site in an area that is marginal for agricultural activity. Here, we present a new sediment record from Lake Svityaz in northwestern Ukraine. We have reconstructed regional and local vegetation and fire dynamics since the Late Glacial using pollen, spores, macrofossils and charcoal. Boreal forest composed of Pinus sylvestris and Betula with continental Larix decidua and Pinus cembra established in the region around 13,450 cal BP, replacing an open, steppic landscape. The first temperate tree to expand was Ulmus at 11,800 cal BP, followed by Quercus, Fraxinus excelsior, Tilia and Corylus ca. 1,000 years later. Fire activity was highest during the Early Holocene, when summer solar insolation reached its maximum. Carpinus betulus and Fagus sylvatica established at ca. 6,000 cal BP, coinciding with the first indicators of agricultural activity in the region and a transient climatic shift to cooler and moister conditions. Human impact on the vegetation remained initially very low, only increasing during the Bronze Age, at ca. 3,400 cal BP. Large-scale forest openings and the establishment of the present-day cultural landscape occurred only during the past 500 years. The persistence of highly diverse mixed forest under absent or low anthropogenic disturbance until the Early Middle Ages corroborates the role of human impact in the impoverishment of temperate forests elsewhere in Central Europe. The preservation or reestablishment of such diverse forests may mitigate future climate change impacts, specifically by lowering fire risk under warmer and drier conditions