Tamás Rédei

STATISTICAL AND BIOLOGICAL CONSEQUENCES OF PREFERENTIAL SAMPLING IN PHYTOSOCIOLOGY: THEORETICAL CONSIDERATIONS AND A CASE STUDY

Due to the long tradition of the Braun-Blanquet approach, many relevés using this approach have been made. Recent developments in vegetation-plot databases provide an opportunity to effectively use these relevés to study ecological problems as well. Opinions differ, however, concerning the applicability of these datasets, often with their use being restricted to exploration and hypothesis generation only.We assert that preferential sampling, which is characteristic of the Braun-Blanquet approach, means using a special definition of statistical population rather than non-random sampling. We present a case study, where consequences of using a preferential and non-preferential definition of statistical population are studied. Although the traits of stands that are preferred or avoided by the phytosociologist during preferential sampling can be identified, there are no general rules that could predict the difference between the preferential and non-preferential datasets obtained for the same object.

Regeneration of sandy old-fields in the forest steppe region of Hungary

Abstract Abandoned agricultural fields are potential sites for the regeneration of natural vegetation, and land abandonment is a widespread phenomenon in the developed world. We studied the vegetation of 161 old-fields in the Kiskunság, central Hungary. Old-fields were categorized into three age groups based on historical aerial photographs: fields abandoned 1–7, 8–20, and 21–57 years ago. Old-field vegetation was compared to potential target communities (open and closed grassland and forest) based on the richness and cover of predefined species groups (all species, neophytes, characteristic species of natural habitats). In general, the medium- and old-aged old-fields only slightly differed from each other, and were more similar to open natural grasslands than to closed ones, although they occupied environments that were intermediate between open and closed grasslands. Forest species establishment was limited in the old-fields; therefore, forest regeneration seems to be unlikely on old-fields at a decadal time scale. The dominance of alien species only slightly declined with old-field age and was much higher than in natural grasslands. The finding that open grassland communities recovered on these old-field sites, but were accompanied by stable alien components, suggests that these communities could be regarded as a new combination of species, or novel communities, with a considerably high conservation value.

On the possible role of local effects on the species richness of acidic and calcareous rock grasslands in northern Hungary

Ewald (Folia Geobot. 38: 357–366, 2003, this issue) stated that in Central Europe the number of calcifrequent species is higher than the number of acidofrequent species, while the range of acidofrequent communities is larger than that of the calcifrequent ones. All the explanations considered in his paper are based on an evolutionary spatial and temporal scale. In this paper we are trying to prove that local effects might also be important.Five open rock grassland communities on different bedrocks, viz. rhyolite (acidic), andesite (slightly acidic), calcareous sandstone (slightly calcareous), limestone (calcareous) and dolomite (calcareous) were chosen for the analysis. Two parameters of the species-area curve (i.e., local richness and the slope of log area-species richness line) were estimated based on all species and on rock specialist species separately. With this method we could simultaneously study three attributes of diversity: local species number, the slope of log area-species richness line, and species pool size.We found that the size of the regional species pool is determined by local effects through local richness (slopes do not differ significantly). Consequently, in this case weathering is a more important characteristic for bedrocks than the Ca2+ content. The extremely high number of rock species on dolomite is also determined by local effects; the fine, continuously changing pattern of microhabitats makes the role of competition weaker.The slope of log area-species richness line, calculated for the rock specialist species is unambiguously higher on the calcareous grasslands. The difference can be explained by the smaller species pool on acidic rocks caused by the lower speciation ability. This is supported by the fact that the endemic species of dry habitats are concerntrated on the calcareous ones. One possible explanation for the lower speciation ability could be that adaptation to acidic habitats is more difficult than to calcareous ones.The different behaviour of rock specialist species is the consequence of the limited permeability of the surrounding landscape. Hence, on calcareous habitats the arrival of all species from the larger species pool needs more time.

A higher‐level classification of the Pannonian and western Pontic steppe grasslands (Central and Eastern Europe)

Abstract Questions What are the main floristic patterns in the Pannonian and western Pontic steppe grasslands? What are the diagnostic species of the major subdivisions of the class Festuco‐Brometea (temperate Euro‐Siberian dry and semi‐dry grasslands)? Location Carpathian Basin (E Austria, SE Czech Republic, Slovakia, Hungary, Romania, Slovenia, N Croatia and N Serbia), Ukraine, S Poland and the Bryansk region of W Russia. Methods We applied a geographically stratified resampling to a large set of relevés containing at least one indicator species of steppe grasslands. The resulting data set of 17 993 relevés was classified using the TWINSPAN algorithm. We identified groups of clusters that corresponded to the class Festuco‐Brometea. After excluding relevés not belonging to our target class, we applied a consensus of three fidelity measures, also taking into account external knowledge, to establish the diagnostic species of the orders of the class. The original TWINSPAN divisions were revised on the basis of these diagnostic species. Results The TWINSPAN classification revealed soil moisture as the most important environmental factor. Eight out of 16 TWINSPAN groups corresponded to Festuco‐Brometea. A total of 80, 32 and 58 species were accepted as diagnostic for the orders Brometalia erecti, Festucetalia valesiacae and Stipo‐Festucetalia pallentis, respectively. In the further subdivision of the orders, soil conditions, geographic distribution and altitude could be identified as factors driving the major floristic patterns. Conclusions We propose the following classification of the Festuco‐Brometea in our study area: (1) Brometalia erecti (semi‐dry grasslands) with Scabioso ochroleucae‐Poion angustifoliae (steppe meadows of the forest zone of E Europe) and Cirsio‐Brachypodion pinnati (meadow steppes on deep soils in the forest‐steppe zone of E Central and E Europe); (2) Festucetalia valesiacae (grass steppes) with Festucion valesiacae (grass steppes on less developed soils in the forest‐steppe zone of E Central and E Europe) and Stipion lessingianae (grass steppes in the steppe zone); (3) Stipo‐Festucetalia pallentis (rocky steppes) with Asplenio septentrionalis‐Festucion pallentis (rocky steppes on siliceous and intermediate soils), Bromo‐Festucion pallentis (thermophilous rocky steppes on calcareous soils), Diantho‐Seslerion (dealpine Sesleria caerulea grasslands of the Western Carpathians) and Seslerion rigidae (dealpine Sesleria rigida grasslands of the Romanian Carpathians).

Apró közlemények=Short communications

1. Az Apium repens (Jacq.) Lagasca uj előfordulasa a Szigetkozben / New occurrence of Apium repens (Jacq.) Lagasca in Szigetkoz region (NW Hungary) | 2. A Limonium gmelinii (Willd.) Kuntze subsp. hungaricum (Klokov) Soo alkalmi megjelenesei utpadkakon / Casual occurrences of Limonium gmelinii (Willd.) Kuntze subsp. hungaricum (Klokov) Soo in roadside verges | 3. Az Asparagus verticillatus L. elvadulasanak első hazai adatarol / On the first sub-spontaneous occurrence of Asparagus verticillatus L. in Hungary | 4. A Digitalis lanata Ehrh. uj előfordulasa Kemencen (Borzsony) / New occurrence data of Digitalis lanata Ehrh. in Kemence (Borzsony Mts., N Hungary) | 5. Balkani csillagvirag (Prospero paratheticum Speta) első előfordulasi adata a Duna– Tisza-kozen / First report on the occurrence of Prospero paratheticum Speta from Danube–Tisza Interfluve (C Hungary) | 6. Nehany erdekesebb novenyfaj megjelenese a Duna 2013. evi nagy arvize utan a Szigetkoz hullamtereben / Some interesting floristic data from Szigetkoz (NW Hungary) after the great flooding of Danube in 2013 | 7. Az adventiv agas falgyom (Parietaria judaica L.) ujabb előfordulasi adata Debrecenből / Newly discovered locality of the pellitory-of-the-wall (Parietaria judaica L.) in the city of Debrecen (E Hungary) | 8. Kindbergia praelonga (Hedw.) Ochyra Sopron varos mohaflorajaban / Kindbergia praelonga (Hedw.) Ochyra in the urban bryoflora of the town of Sopron (W Hungary) | 9. Adatok a Plantago coronopus L. hazai elterjedesehez / Additional data to the distribution of Plantago coronopus L. in Hungary | 10. A csipkes gyongyvessző (Spiraea crenata L.) egykori kunpeszeri előfordulasarol / On the formerly occurrence of Spiraea crenata L. in Kunpeszer (C Hungary) | 11. A Spiraea crenata L. sas-hegyi (Budai-hegyseg) felfedezesenek tortenete / History of discovery of Spiraea crenata L. on Mt Sas (Buda Mts., Hungary)

Regional Vegetation Database of Kiskunság

The aim of the Regional Vegetation Database of Kiskunsag (GIVD ID EU-HU-001) was to study the effect of different land-use on plant biodiversity. The Kiskunsag region is a highly heterogeneous cultural landscape in central Hungary, with unique natural values, high diversity of land-use, its own well-defined environmental problems, and ongoing socio-economic changes, thus being an ideal setting for conducting integrative socio-ecological research and setting up an LTSER platform. In the past few years, we expanded the KISKUN LTER program into a broad-scale research framework or LTSER program by (1) covering all major landuse/habitat types occurring in the region; (2) reaching regional representativity by having multiple sites. Within the 7,500 km2 study region, using a pre-defined algorithm we selected a network of 16 sites (5 x 5 km) that covers the regional variability in land-use pattern, naturalness, and soil. We sampled three replicate stands (if available) of all major habitat types (arable land and vineyards, oldfields, natural grasslands and woodlands, forest plantations) in all 16 sites between 2006 and 2008. In a total of 604 plots (20 x 20 m) we detected the plant species present and estimated their cover.