Special Issue

Nature Conservation 2009 — 1. 9. 2009 — Special Issue

Scenario of vegetation zone changes in the Czech Republic: ten years after

na území České republiky: deset let poté

authors: Antonín Buček, Veronika Vlčková

The regional scenario of climate change on the territory of the Czech Republic (Kal­vová & Brázdil 1993) was the starting point for considerations on the effect of global climate change on the vegetation in the Czech Republic.

This scenario is based on projections of doubling of the greenhouse gas level compared to the pre-indu­strial period by about 2030. Maps of isolines of the average annual temperatures and average annual total atmospheric precipitation in 1960–1990 and projection maps of the Czech Republics territory for 2030 were used as a basis for predictions of trends in vegetation zone changes.

Vegetation zones

Altitudal vegetation zones are a useful spatial framework for evaluating the possible climate change impacts on nature. The vegetation zone expresses the relationship between biocenoses at the altitude and exposure climate, primarily on air temperatures and the atmospheric precipitation amount. Current opinions suggest that the present-day vegetation zones stabilized in the early Subaltantic period (800–500 years B.C.). The distribution of the individual vege­tation zones in the landscape thus reflects orographically caused differences in climatic conditions and their fluctuations in a substantially longer period than that for which the results of basic climatic characteristic measurements are available.

The vegetation zones in the Czech Republic were delimited using bioindications based on the occurrence of characteristic plant species and plant communities. Current differen­ces in natural conditions, the natural and contemporary vegetation composition and anthropogenic effects within the vegetation zones are described in chara­cteristic supplementary units of the forest and landscape geobiocenological typolo­gy in the Czech Republic (Buček & Lacina 1999). Vegetation zones are also important frameworks for the possibility of growing agricultural crops (e.g.Grape Vines Vitis vini­feraexperience the best conditions in the 1^stvege­tation zone) and forest tree species (e.g., the Norway Spruce Picea abies has the best conditions in zones 5–7). Vegetation zones are named according to the main tree species of potential natural forest geobiocenoses (in brackets are given the percentage proportion in the territory of the Czech Republic and proportion of the current forest area):

1. Oak (3.46 , 1.47 %)
2. Beech-oak (12.06 %, 4.78 %)
3. Oak-beech (18.21 %, 14.27 %)
4. Beech, including beech-coniferous variants (43.07%, 41.96 %)
5. Fir-beech (19.52 %, 29.14 %)
6. Spruce-fir-beech (2.53 %, 5.55 %)
7. Spruce (1.0 %, 1.5 %)
8. Dwarf Pine (0.1 %, 0.1 %).
9. Scenario of changes

A model based on the spatial ana­logy projection method was developed for develo­ping scenarios of vegetation zone changes (Kopecká & Buček 1999). According to the classification of projection models on the global change effect on terrestrial ecosystems, this is a non-dynamic correlation model, as it is based on the relationship between the current climate and vegetation types (top-down model, Walker 1994). This is a static model that does not allow prediction of the rate of vegetation changes if a change occurs in climatic conditions. The model is based both on the relationship of the present vegetation zones and climatic conditions and also on the assumption that the above relationship will be maintained in the future. Therefore, expected climatic changes are expressed in a shift of current vegetation zones.

The computer model of the vegetation zone shift as a consequence of possible climatic changes was developed as a set of special programs (FORTRAN programming language) and applications in GIS ARC/INFO (Kopecká & Buček l.c.). Definition points were assigned to the characteristics of the current climate based on digitalization of maps of the mean annual temperatures and mean annual precipitation isolines in the Czech Republic in 1961–1990. Definition points were classified to the current vegetation zones according to the available vegetation zone maps. In the next step, the definition points were assigned to climatic characteristics predicted for 2030 and the correspon­ding vegetation zones. The Lang’s rain factor, which is the ratio of the sum of precipitation in mm to the average annual temperature in ^oC was used as a relationship indicator.

2030

According to the regional scenario of the trend in vegetation zones, the area with the conditions of the 1^stvegetation zone will be most widespread in the Czech Republic in 2030, and will cover almost a third of the countrys territory (29.44 %). The area with the conditions of zone 2 will increase to 17.11 % and the area with the conditions of zone 3 will increase to 27.40 %. The area with of vege­tation zone 4, the most extensive vegation zone nowadays, will decrease from the present 43.07 % to 20.07 % in 2030. The area with the conditions of zone 5 will decrease very substantially to 4.77 %. The area of vegetation zone 6 spruce-fir-beech, ve­getation zone 7 spruce and vegetation zone 8 dwarf pine will decrease from the present--day 3.68 % to only 1.22 %.

In the Czech Republic, the projected trends in vegetation zone changes will be expressed in a substantial improvement in conditions for xerothermophilous Ponto-Pannonian biota. The area with the climatic conditions of present-day vegetation zones 1 and 2 will increase from the present-day value of 15.51 % to 46.55 % in 2030. There will be a reduction in the area with conditions for the existence of Central European broad-leaved deciduous forest species. The area of the territory with the climatic cha­racteristics of vegetation zones 3–5 will decrease from the present 80.80 % to 52.24 % of the countrys total area. There will be a substantial reduction in the size of the territory with conditions for the occurrence of boreal forest mountain species, related to a cooler and wetter climate, as the area with the conditions of vegetation zones 6–8 will decrease to a third of the present-day values.

The consequences of the projected trends in vegetation zone changes for current biocenosis in the cultural landscape can be documented on the change in conditions for planting the Norway Spruce, which is currently the most widespread tree species in Czech Republic’s forests. The proportion of spruce growths in fo­rests reached 53.1 % in 2006, compared to 11.2 % for the natural tree species composition (Ministry of Agriculture of the Czech Republic 2006). According to the regional scenario, the forest land proportion with climatic conditions that are completely unsuitable for planting the Norway Spruce will increase from the present 6.25 % to 31.65 % in 2030. The forest land proportion with unfavourable conditions for planting the Norway Spruce will increase from the present 14.27 % to 28.32 %. The forest land proportion with favourable conditions for planting the Norway spruce will decrease from the present 41.95 % to 26.85 % and the forest land proportion with very favourable climatic conditions will decrease from the present 37.17 % to 13.17 % of the fo­rest land in 2030. Thus, good and very good climatic conditions for the Norway Spruce will be preserved only in the areas of its original natural occurrence at mountain altitudes. According to the regional scenario for 2030, the climatic conditions for the occurrence of vegetation zone 5 and higher alpine zones will be preserved only in the higher border mountain ranges, in Bohemia in the Krušné hory/Ore Mts., Slavkovský les/Slavkov Forest Mts., Český les Mts., Šumava/Bohemian Forest Mts., Novohradské hory/Nové Hrady Mts., Krkonoše/Giant Mts., Jizera Mts., Orlické hory/Eagle Mts. and in the Králický Sněžník Mts. and, in Moravia, only in the Hrubý Jeseník Mts. and in the Moravskoslezské Beskydy/Moravian--Silesian Beskids Mts.

Testing the hypothesis

If the species of lower vegetation zones begin to appear in some regions at the sites that currently belong to higher vegetation zones, this will imply that the climate change effects have been actually occurring. When assessing the possible climate change effects on ecosystems and the landscape, it is important to consider the hierarchy of proce­sses in the ecosystem in relation to the spatial and temporal scales. While the course of and changes in physiological processes in individuals can be determined in a very short time scale (in hours, days, weeks or months) and material cycles can be assessed on the annual basis, changes in processes and their consequences at the ecosystem and landscape level are manifested in the periods ranging from decades to centuries (Puhe & Ulrich 2001). Analysis of the potential global climatic change impacts in boreal forests in the 21^stcentury have led to the conclusion that, when the limit of resilience (the ability of an ecosystem to rapidly return to the origi­nal condition following a change caused by a disturbance: in other words, the ability of an ecosystem to recover after a disturbance. Measured as the rate at which an ecosystem returns to a single steady or cyclic state following a disturbance) of current ecosystems is exceeded, the changes in vegetation can be very rapid and unexpected, often result­i­ng in the establishment of very different ecosystems (Chapin et al. 2004).

The hypothesis on possible global climate changes effects on biocenoses and the landscape can be tested only by long--term monitoring of the natural biocenosis dynamics in protected areas. The network of permanent research/monitoring plots established in the 1930s by Professor A. Zlatník in the current Transcarpathian Ukraine is of the extraordinary importance in this respect. Repeated studies on the No. 11 plot in the Father Ivan of Maramures mountain range led to the conclusion that a change is being manifested in the altitude extent of tree species, particularly the European or Common Beech (Fagus sylvatica) and European Silver Fir (Abies alba)to higher altitudes (Buček et al.2008). These first preliminary results cannot, however, be considered to be the completely objective evidence of the climate warming effects resulted from possible climate changes. In any case, it is necessary to continue repeated studies and to carefully evaluate the results of all the studies that can assist in clarifying the consequences of the climate factors effects and their possible changes on organisms, ecosystems and the landscape.

Conclusions

Based on the results obtained during more than a decade of developing models on changes in the vegetation zones in the Czech Republic, we can suggest that, if the projected climate change scenario actually occurs, the ecological manifestations of these changes in the Czech Republic will most probably correspond to the regional scenario of trends in vegetation zone changes. We should not underestimate the results of the scenarios. At the present time, it is already useful to carefully and reaso­nably respect the precautionary principle and adapt the land use so that possible climate changes will not have catastrophic consequences for either nature or human beings. The up-to-date experience in warning ecological forecasts assessments indicates that, in contrast to economic forecasts, they usually prove true (Buček 2005).

A. Buček is Associate Professor at the Institute of Forest Botany, Dendrology and Geobiocoenology at the Faculty of Forestry and Wood Technology, Mendel University of Forestry and Agriculture in Brno.

V. Vlčková is at the Institute of Informatics and Telecommunications, Faculty of Transportation Sciences of the Czech Technical University Prague.