Distribution and phenology of Fritillaria dagana Turcz. ex Trautv. (Liliaceae Juss.) in the north-eastern part of Tuva

УДК 582.572.226:581.95+581.543+502.75(235.223)(571.52)

Abstract

The State Nature Reserve Azas protects 11 species of vascular plants included in the Red Book of the Russian Federation (2008). One of its priority tasks is to monitor the state of populations of rare species of flora in the Reserve and in the adjacent territory. Fritillaria dagana Turcz. ex Trautv., a rare endemic of the mountains of South Siberia, was chosen as an object of research; the state of its cenopopulations in Tuva has not been studied. The paper analyzes the distribution of F. dagana in north-eastern Tuva based on herbarium collections and other materials, and compiles a map of its locations. As a result of studies organized by the Reserve in 1987-2023, 7 localities of F. dagana were identified on its territory and adjacent area, of which 3 are indicated for the first time. The data suggest a wider distribution of the endemic in the western part of its geographic range. The phenological monitoring was carried out in the cenopopulation of F. dagana, located near the village of Toora-Khem at an altitude of 920 m above sea level. During 25 years of observations (1999-2023), generative shoots were recorded in the cenopopulation every year except 2003. In 80 % of cases (years) the generative phase ended with flowering. Entry into the fruiting phase occurred with a break of 5-6 years. The number of generative shoots is subject to year-to-year dynamics with alternation of peaks and declines. The average dates of onset of the main phenophases of seasonal development of F. dagana were determined in the conditions of lowland landscape of the north-eastern part of Tuva. The materials supplement the data on geography, ecology and biology of the species in Tuva.