Razširjenost in združbe vrst Crypsis aculeata in Heleochloa schoenoides na Slovaškem

The distribution and communities of two annual grasses Crypsis aculeata and Heleochloa schoenoides were studied in Slovakia during 2003–2007. Herbarium and field data were used to reconstruct the occurrence of both taxa. A strong decline in C. aculeata localities was observed. This was mainly due to the destruction of periodically flooded saline habitats. By contrast, the occurrence of H. schenoides was changed only slightly. This species survives in secondary habitats (rural roads, field margins, field depressions). Point maps of historical and recent distribution are presented. Halophile vegetation of Crypsis aculeata and Heleochloa schoenoides has been sampled with the adapted Braun-Blanquet method. All collected relevés have been classified using the JUICE software. The results showed that the Crypsidetum aculeate Wenzl 1934 community is missing now in Slovakia, but Heleochloetum schoenoidis (Soó 1933) Ţopa 1939 was still recorded at a few sites. However, the community contained many ruderal plant species.Raziskave razširjenosti dveh enoletnih trav Crypsis aculeata in Heleochloa schoenoides smo raziskovali na Slovaškem med letoma 2003 in 2007. Za rekonstrukcijo pojavljanja obeh vrst smo uporabili herbarijske in terenske podatke. Opazili smo močno upadanje števila nahajališč, kjer se pojavlja C. aculeata. Razlog je predvsem uničenje periodično poplavljenih slanih rastišč. Nasprotno pa se je pojavljanje vrste H. schenoides le malo spremenilo. Vrsta lahko uspeva tudi na sekundarnih rastiščih (kolovozi, robovi njiv, uleknine na njivah). Historično in recentno razširjenost smo prikazali na točkovnih kartah. Halofilno vegetacijo vrst Crypsis aculeata in Heleochloa schoenoides smo vzorčili s prilagojeno Braun-Blanquetovo metodo. Vse popisno gradivo smo klasificirali s programom JUICE. Rezultati so pokazali, da asociacije Crypsidetum aculeate Wenzl 1934 na Slovaškem ne najdemo več, medtem ko je bila asociacija Heleochloetum schoenoidis (Soó 1933) Ţopa 1939 najdena na nekaj rastiščih, vendar se v njej pojavljajo številne ruderalne rastlinske vrste