Distribution and ecology of Carex secalina in the Czech Republic and Slovakia

Current and historical occurrence as well as coenotic affinity and ecology of Carex secalina in the Czech Republic and Slovakia are presented. The study is based on revision of herbarium specimens from 25 herbaria, literature data excerption and a field survey carried out during 2004-2010. Altogether, 168 sites were documented in the Czech Republic divided to two separate areas. Stabile occurrence trend was found in last decades, because 45 localities were documented in period 1975-1999 (27% of sites) and recent occurrence was confirmed at 42 localities (24% of sites). On the basis of our current knowledge the species was included into the IUCN threat category VU (vulnerable). In Slovakia, 19 localities of the species were recorded in total, but only 4 sites were confirmed recently (21% of sites recorded). However, only a small number of individuals was recorded there (less than 50 individuals in total) and half of this sites is acutely threatened by destruction (ploughing, secondary succession). Therefore, the C. secalina status in the Slovak Red List was changed to the IUCN category "critically endangered" (CR). Results of the study are summarised in the maps of historical and current species distribution. C. secalina usually occurred in halophytic grassland communities, especially in association Agrostio stoloniferae-Juncetum ranarii Vicherek 1962. However, it may occur in many other communities which suggest that the species had not well-defined coenotic relationships. On the basis of our knowledge, we consider C. secalina as an obligate halophyte.