Home – Home – Jornals – Contemporary Problems of Ecology 2024 number 6

Fluctuation dynamics (studied for 9-27 years) of the abundance, density, age and spatial structure of Dactylorhiza maculata (L.) Soó population on Lake Dolgoe of the Volga-Kama Reserve reflects the mechanisms of maintaining the population at the southern border of the range. The data were stored into the database. Abiotic and biotic factors of transitional shrub-sedge sphagnum bogs are the most suitable for the conservation of a rare species, where boreal and arcto-boreal species are preserved, and favourable microsites are open and moist areas of the mire, with pH 4.1-4.5. The biodiversity of sphagnum mosses in the habitats of Dactylorhiza maculata is represented by 9 species, where the carpet species is Sphagnum angustifolium, and Sphagnum divinum appears in open and wet micro-areas, Sphagnum centrale appears in areas overgrown with open forest. A significant relationship of the species abundance with climatic factors revealed: positive relationship with precipitation, negative relationship with average temperatures of the growing season. The number of reproductive D. maculata does not depend on precipitation in moist microsites. Ontogenetic stages were reliably identified using the morphometric parameters of vegetative and reproductive plants: juvenile (j); immature (im); virginal (v); young reproductive (g1); mature reproductive (g2). The ontogenetic spectrum is 11.5: 17: 29: 42.5 (j: im: v: g), proportion of pre-reproductive individuals fluctuated between 57-66 % in the period of 9-27 years of study, due to a high percentage of fruit formation (up to 60 %). Spatial distribution of individuals predominantly is clustered, consisting of aggregations with a radius of 0.5-1.2 m, distributed randomly. The dynamics of spatial mosaics, accompanied by the migration of seeds and individuals of D. maculata to favourable microsites, is a natural compensatory resistance mechanism that ensures the dynamic balance of the population.