Red Data Book vascular plants in the Mordovia State Nature Reserve, a protected area in European Russia

Protected areas are widely considered as tool for biodiversity conservation on a global scale. Current lack of data on biodiversity and threats in federal Russian protected areas is recognised. It especially concerns patterns of spatial plant distribution in natural ecosystems in both Russia and the whole world. Hence, research of plant diversity in protected areas is very important to obtain comprehensive knowledge on the functioning and management of plant diversity refugia. We aimed to study the most threatened component of plant diversity (i.e. Red Data Book species) in the Mordovia State Nature Reserve located in European Russia. We used personal (2010 –2018) and literary (1936 –2009) data to obtain information on habitat preferences, IUCN status, year of the first record, spatial plant distribution in protected area and taxon’s representativeness index (RI) for 47 protected vascular plant species currently known in the Mordovia State Nature Reserve. We demonstrate the higher species richness in the vicinity of some research stations and its decrease when moving away from them. These results highlight the significance of biodiversity research. It also outlines the need to inverstigate less-studied areas (white gaps) in the Mordovia State Nature Reserve. During the preparation of the flora list for the Mordovia State Nature Reserve, we recognised an increase of the number of Red Data Book species. We thus indicate two major peaks (ending in 1960 and the other in 1987) and one insignificant peak (2013 –2016) of species number increasing within the protected area. 63.9% of the total number of protected plant taxa are confirmed by only 1– 4 records: 14 Critically Endangered, nine Endangered, four Vulnerable and two Data Deficient species. This underlines the need for additional investigations. Seven plant species growing in the Republic of Mordovia occurr only in the protected area, which highlights the uniqueness of the Mordovia State Nature Reserve for conservation of plant diversity. We suggest further studies of plant diversity in the Mordovia State Nature Reserve and a comprehensive analysis of patterns of spatial plant distribution in the protected area