Distribution and variability of the Balkan endemic Geum bulgaricum (Rosaceae) - a species of European concern

As a European endemic restricted to a few European countries, Geum bulgaricum is here treated as a “target species” or “species of European concern”. Although of great international significance, its distribution is insufficiently known. Based on several years of field studies and analyses of herbarium and literature data, we have determined that G. bulgaricum is a Balkan endemic plant distributed in Albania, Bosnia and Herzegovina, Bulgaria, Montenegro, and Serbia. Although the range of its distribution is divided into two main parts - “eastern” (the Rila Mountains in the Rhodope-Rila mountain system) and “western” (several mountains in the Dinaric system and one isolated population in the northeastern part of the Scardo-Pindic system) - in fact all populations are grouped into four disjunctions. Based on our studies of extensive chorological data and estimation of the number of individuals and condition of the populations, we have now defined G. bulgaricum as IUCN NT in Albania and Montenegro, and VU D2 E in Serbia. Also, we have confirmed its status as NT in Bulgaria, and changed its status from LR to VU D2 E in Bosnia and Herzegovina. The species is most often found in alpine and subalpine acidophilous (Juncetea trifidi) and calcicolous (Elyno-Seslerietea) grasslands and swards, as well as in the vegetation of scree habitats (Thlaspietea rotundifolii), rocky crevices (Asplenietea trichomanis), subalpine belts of krummholz pine (Roso pendulinae-Pinetea mugo), and very localised serpentine outcrops. Its ecological optimum is in the subalpine and alpine vegetation belt. Furthermore, we here provide the first insight into the differentiation of its populations. We found that the Rhodope-Rila and Dinaric populations are slightly differentiated on the morphological level and well differentiated with respect to genome size. The name Geum bulgaricum is lectotypified