Arenaria rigida
Arenaria rigida M. Bieb.
Caryophyllaceae – Pink family
Conservation status. Critically Endangered [CR B1ab(ii,iv,v)+2ab(ii,v)]. IUCN(R), BDA.
Morphology and biology. Caespitose perennial herb. Stems with very short internodes at base. Leaves setaceous, erect, stiff, silvery grey pruinose, up to 12 cm long. Inflorescences 15–30(40) cm, straight, compact, flowers 6–25. Flowers white, 5–8 mm. Fruit a capsule. Fl. VI, fr. VIII. Insect pollination. Reproduction by seeds, the recruitment is very poor.
Habitats and populations. Tertiary sands in the nature phenomenon Pobiti Kamani (standing stones), where it grows in stony places. The vegetation cover is open, consisting of psammophytes and chasmophytes. The population of A. rigida in Bulgaria numbers about 1000 plants in 3 subpopulations. The mature individuals prevail in the subpopulations.
Distribution in Bulgaria. Black Sea Coast (Northern – Pobiti Kamani nature monument – groups: central, Beloslav Zapad and Slanchevo Yugoiztok).
General distribution. SE Europe (Bulgaria, Romania, Ukraine).
Threats. In the past – afforestation in the area. The subpopulation near Beloslav town, which includes more than 90% of the whole population and is within a protected area, suffers from illegal grazing, sand-pitting and strong trampling by the stock. Natural invasion of Pinus nigra from the neighbouring plantation and of the alien Opuntia vulgaris Mill. also have negative effects.
Conservation measures taken. The species is protected by the Biodiversity Act. Included in 1997 IUCN Red List of Threatened Plants with a category “rare”. All known localities are included in protected areas (Pobiti Kamani Protected Sites) and sites of the European ecological network Natura 2000 in Bulgaria.
Conservation measures needed. Preparation and implementation of a management plan for Pobiti Kamani Protected Sites; elimination of the threatening factors in Beloslav Zapad group and trampling by tourists in the Central group.
Note. Reports for Dobrich district (Kozhuharov & Kuzmanov 1966; Delipavlov 1984) were incorrect due to misinterpretation of the old Turkish name of Povelyanovo village. Report for Toundzha Hilly Country (Dimitrov & Tzonev 2001) is based on erroneous identification.
References. Kozhuharov & Kuzmanov 1966; Delipavlov 1984; Petrova 1997; Walter && Gillet 1998; Dimitrov & Tzonev 2001; Filipova-Marinova & Petrova 2003.
Author: Antoaneta Petrova
