Steppe grassland flora of Natura 2000 site in Northeast Croatia

Dry grasslands of the alliance Festucion valesiacae with rich and unique steppe flora are very rare in Croatia since the majority of these grasslands have been greatly modified and converted to productive agricultural land. This study was carried out at the grassland area situated at the local cemetery in Bilje (45˚36'N ; 18˚45'E), Baranja region. The area has a moderately warm, rainy climate without extremely dry months during the year. The air temperature fluctuates from -1.4 °C in winter to 40 °C in summer. The annual precipitation range is between 600 and 700 mm. Geomorphologically, the study area mostly belongs to the lowland area built of Quaternary sediments formed during the Holocene and Pleistocene. Investigated dry grassland in Bilje covers approximately 0.63 ha. In order to preserve this very rare grassland type in Croatia, the area is protected as Natura 2000 site (code HR200078) and it is proclaimed as monument of nature. The floristic survey was performed from the beginning of April to the end of November 2015. In total, 157 plant taxa classified into 47 families were found. Families Poaceae (21), Fabaceae (14), Asteraceae (10), Caryophyllaceae (10), Cichoriaceae (8), Lamiaceae (8) and Rosaceae (8), contained the greatest number of taxa. Life form analyses showed that hemicryptophytes were dominant (56.05% of total number of plant taxa) followed by therophytes (22.29%), geophytes (14.65%), chamaephytes (3.18%), and phanerophytes (3.82%). According to phytogeographical analysis, Eurasian (45 taxa), Pontic-Central-Asian (36 taxa), Central European (33 taxa) and Cosmopolite (26 taxa) geoelements predominated. Among the identified taxa, three of them are critically endangered, four are nearly threatened, one is vulnerable and four are classified as invasive species. Mowing and controlling of spreading of invasive and woody plant species should be important steps toward long-term persistence of this diverse grassland flora.