Instytut Botaniki im. W. Szafera Polskiej Akademii Nauk - W. Szafer Institute of Botany, Polish Academy of Sciences
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INTRODUCTION (fragm.)It is well known that many plant species are good indicators of habitat conditions. Detailed studies undertaken 50 years ago allowed us to calibrate many plant species with reference to habitat conditions; ecological indicator values for Central Europe (Ellenberg 1965, 1974, 1979; Ellenberg et al. 1992) have been used successfully by many authors (Dzwonko 2001; Dzwonko & Loster 2000 and literature therein).
The theoretical and methodological foundations for the evaluation of habitat conditions using indicator values were established by Ellenberg. On the basis of Polish geobotanical studies, the first list of indicator values for native and naturalized (fully domesticated) species in Poland was published in 1984 (Zarzycki 1984). The present work is a revised and supplemented version of it. It refers to similar lists by Ellenberg (I.e.), Landolt (1978) and Hill et al. (1999). In addition to indices of habitat conditions, the number of stations and present dynamic tendencies of species in Poland were estimated. Importantly, the ecological indicator values of Polish vascular plants are based on the results of taxonomic and geobotanical studies in Poland, so they describe Polish populations of plants versus local climatic and edaphic conditions.In most cases we used 5-grade scales where the intensity of particular factors increases from (0) 1 to 5 (6). Comparative analyses (Kozłowska 1991; Dzwonko & Loster 2000) have shown that similar results are obtained using both a 10-grade scale (Ellenberg 1979) and a 5-grade scale (Zarzycki 1984). In some cases (organic matter content in the soil) a 3-grade scale was needed.
The list comprises almost 2000 taxa, species and subspecies of wild and domesticated plants in Poland. With a few exceptions, the taxonomic units are in conformity with basic elaborations of Polish flora (Szafer et al. 1953, 1969; Flora polska 1919-1980) and nomenclature follows Mireket al. (1995). Of course, it was impossible to determine indicator values of species that died out in recent decades. Tiny species from the genera Alchemilla, Hieracium, Potentilia, Rosa and Rubus, which are difficult to identify, were omitted.
Phytosociological nomenclature in principle follows Matuszkiewicz (2001), but in some cases we kept to the larger units used in "Vegetation of Poland" (Szafer & Zarzycki 1972). Information is limited to the alliances, orders and classes of associations in which a species most often grows; names of phytosociological units to which it sometimes occurs are given in parentheses.The indicator values describe the most typical habitat conditions of a species, that is, the conditions in which it most often grows in Poland; they do not reflect its full, usually wide ecological amplitude. They are based on the results of field studies and knowledge of habitat conditions of particular groups of species. Much of the information on the numbers of stations of taxa came from Zając & Zając (2001).
The use of indicator values to characterize habitat requirements has its advantages and disadvantages. Brief, consistent, standardized descriptions, made using the same method for many taxa, are easily comparable; they can be entered into a data base and used for computation, listing and grouping. The main disadvantage is that they suggest precision where it is often lacking, and refer to limited sets of habitat factors. Moreover, these indicator values cannot be measured.
We divided the work as follows: K. Zarzycki coordinated the whole of the work and determined the indicator values for meadow plants. H. Trzcińska-Tacik determined the indices for synanthropic plants, Z. Szeląg for xerothermic and alpine plants. W. Różański for forest plants, J. Wołek for water plants, and J. Zieliński for Crataegus, Rosa and Rubus species. The present degree of threat was assessed by K. Zarzycki. Z. Szeląg and H. Trzcińska-Tacik (msk).The aim of this work is to provide information about ecological indicator values. Their usefulness is unlimited, and the relevant literature, based principally on Ellenberg's classic work (1979), is abundant (Ertsen et al. 1998; Diekmann & Lawesson 1999; Roy et al. 2000; Schaffers & Sykora 2000; Dzwonko 2001: Dzwonko & Loster 2001). For example, by comparing the flora of a given area over time, one may obtain a detailed picture of changes in edaphic conditions in that area. We welcome correspondence from reseachers who apply these data in their studies.