Confirmed occurrence of the native plant species Eleocharis ovata (Cypera­ceae) in Lithuania

Abstract

Information on the occurrence of Eleocharis ovata (Cyperaceae) in Lithuania for a long time had been based on misidentified specimens only. During the studies on the flora of South Lithuania in 2020, we discovered this species in Varėna district on the shores of Lake Pabezninkai. We performed field investigations on the distribution, size of population and habitats of E. ovata from August to October 2020 on the shores of Lake Pabezninkai and, searching for this species, surveyed potential habitats on the shores of eight other lakes in South Lithuania. A total of 63 individuals of E. ovata were found on the shores of Lake Pabezninkai, and they were widely dispersed on the northern and south-western shores of the lake. Most of the registered individuals of E. ovata were found growing on wet sand and mud in the communities of the Isoëto-Nanojuncetea class. Solitary individuals were also found in communities of the Phragmito-Magnocaricetea class. Assessment of E. ovata according to the IUCN criteria revealed that this species, currently occurring at a single locality in Lithuania, should be classified as critically endangered (CR). Conservation of E. ovata and other rare plant species recorded on the shores of Lake Pabezninkai should be organised by maintaining favourable habitat conditions.

Study on the Rare Semiaquatic Plant Elatine hydropiper (Elatinaceae) in Lithuania: Population Density, Seed Bank and Conservation Challenges

“…Such communities are mostly found in fish-ponds, and Elatine hydropiper is sometimes referred to as a specific species of fishpond [56]. It should be added that Eleocharis ovata, a characteristic species of the Polygono-Eleocharitetum ovatae association, was also found in Lake Pabezninkai for the first time in Lithuania [35,36]. As the water level in Lake Pabezninkai has receded by about 1.5-1.6 m over the last four years, Elatine hydropiper was found in communities of different developmental stages.…”

“…There are no clear signs of pollution of Lake Pabezninkai at the present time, but until 1990 the lake was affected by pollution from nearby livestock farms. Despite the former pollution, the lake bottom sediments are not rich in nutrients, as the tall helophytes (Phragmites australis, Typha latifolia) grow fragmentary on the shores and the nitrophilous plants (Bidens, Persicaria) are scarce on the wet exposed shores [35,36].…”

“…During investigations in southern Lithuania in 2020, we found a large and abundant population of Elatine hydropiper on the exposed shores of Lake Pabezninkai (Varėna district), where Scirpus radicans and Eleocharis ovata, previously unreported in the country, and several other protected plant species were found [35,36]. The discovery of the Elatine hydropiper population in Lake Pabezninkai and its shores prompted us to perform detailed studies with the aim of determining the status of the population and assessing its potential for long-term survival.…”