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Vegetation dynamics in a mountain pine stand burnt down in 1951
Patricia Geissler1, Josef Hartmann21 Conservatoire et jardin botaniques de la Ville de Genève, C.P. 60, CH-1292 Chambésy, Switzerland2 Amt für Natur und Landschaft, Rohanstrasse 5, CH-7000 Chur, Switzerland AbstractIn spring 1951, a fire destroyed 6 ha of mountain pine forest on a steep southern slope close to the timberline in the Swiss National Park. We studied the development of the vegetation after this fire on seven permanent plots established immediately after the fire in summer 1951. One additional plot was set up as a control in the adjacent pine forest. Time-series of up to 50 years originated from temporal replicates of relevés of vascular plants and bryophytes. In addition, the vegetation (vacular plants) was mapped, bryophyte inventories were carried out and fenced and non-fenced surfaces were compared to study the impact of grazing ungulates on the development of the vegetation.The fire destroyed most of the vegetation, e.g. bryophytes persisted only in a single wet hollow. During the first years following the fire, both species richness of bryophytes and constancy of pioneer mosses increased on the permanent plots. In the succeeding period, these pioneer species were replaced by a set of twelve species on four permanent plots. Eight of the twelve species were also recorded from pine forests. Three permanent plots remained moss-free after the death of the pioneer species. In contrast, both species richness and the constancy of vascular plants increased continuously during the whole successional process. The constancy of vascular forest species decreased during succession on those permanent plots where such species had survived the fire. The importance of grassland species, however, increased on all the permanent plots. Mountain pine seedlings where first recorded on the permanent plots in 1954. However, although seedlings of mountain pine are still recorded, they fail to establish as trees. The exclusion of ungulates by fencing has induced an increase in the constancy of abundant vascular plant species and a decrease in species richness; in contrast, species richness has increased in the unfenced control over the same period. Preface | abstract 1 | abstract 2 | abstract 3 | abstract 4 | abstract 5 | abstract 6 | abstract 7 | abstract 8 | abstract 9 | abstract 10 | abstract 11 |