Reproductive strategy, sexual structure and productivity of fertile plants of the epigeic moss Atrichum undulatum (Hedw.) P. Beauv. depending on the microclimatic locality conditions

The influence of microclimatic conditions on the reproductive traits of the heteroicous moss Atrichum undulatum (Hedw.) P. Beauv was studied. Moss samples from research areas in the forest ecosystems of the Roztochchya Nature Reserve (ancient beech forest) and Yavoriv National Park (recreation and felling areas) were analyzed, which differed in water and temperature regimes and light intensity. Moss sampling was carried out in spring, summer and autumn by the envelope method, in general not less than 150 plants for each territory. The results of determining the height and weight of female plants with sporogones indicate a relationship between their vegetative growth and the frequency of sporophytes. In all research areas, female plants were larger and with more weight, probably through the need to accumulate significant reserves of biomass and energy resources for the formation of gametangia and support the development of sporophytes, while male individuals are characterized by relatively lower growth rates, probably due to higher reproductive investments in the formation of gametes. It was found that in spring, plants that are functionally dioecious prevailed in moss turfs. In April, phenotypically unisexual male and female plants were found in the reserve areas, while in the felling and recreation areas, only plants with male gametangia were detected. In summer, both male and female unisexual plants were found in all plots, but in anthropogenically disturbed areas, female individuals prevailed. In addition, 20% of plants with close proximity of bisexual gametangia and the highest productivity of antheridia were established in the felling area. In autumn, 2–3 male branches with antheridia were revealed at the base of bisexual plants. The smallest number of A. undulatum plants with sporophytes was determined in the recreation area. In summer, unisexual female plants prevailed there, while in autumn – male plants, no bisexual plants were found. During the year, the productivity of female and male gametangia in this area was low and increased insignificantly in autumn. It was established that, depending on the adaptive possibilities of sexual individuals of A. undulatum, the environmental conditions of the forest ecosystems caused a change in the sex ratio, their reproductive productivity and the frequency of sporophytes.