Sex‐based differences in vigor and site preferences of Juniperus communis subsp. nana

Abstract

Dioecious alpine juniper has been influenced by human impacts, management and climate changes; hence, its present populations are remnant fragments of its former distribution in central Europe. Complex environmental shifts have had fatal consequences for growth, reproduction and health of juniper and hence for its population structure. We asked the questions: 1) what was the population size structure, the sex ratio and the health status of individuals? 2) How were the population parameters linked with the environmental conditions and surrounding vegetation? The study area was close and above the upper forest limit in central Europe, the Hrubý Jeseník Mts. The parameters of each juniper individual and its environmental conditions were obtained, Ellenberg's indicator values and habitat categories were also determined. Proportions of sex categories, shrub size and environmental conditions were investigated to assess relationships between the population categories and environmental factors. We revealed linkage among the shrub size, health vigor, vegetation cover, a habitat and environmental factors. While there was equal ratio of females and males (1:1), small individuals of undetermined sex predominated that reducing the effective population size. Juniper health vigor was associated with surrounding vegetation cover. Individuals of undetermined sex were smaller than those of remaining sex categories and prefer specific habitats at higher elevation, underlining the effect of abiotic conditions on sex performance and ratio. The observed pattern, which was attributed to shift in land‐use practices in the middle of 20th century and climate changes, could be improved by management. We recommended experimental local grazing and mowing accompanying by profound and continuing assessment of interaction among environmental factors and juniper performance.

Ionomic Parameters of Populations of Common Juniper (Juniperus communis L.) Depending on the Habitat Type

“…For various plant species, including junipers, Ellenberg indicator values (EIV) of neighboring herbaceous plant species are widely used to evaluate environment in the sites without the need to perform physico-chemical measurements [ 73 , 74 , 75 , 76 , 77 ]. During evaluation of J. communis environments by EIV, the soil richness in nutrients (EIV-N) [ 35 ] showed low fertility for all habitats; it was lower than the middle value (5) and ranged in the interval of 2.7 to 4.4.…”

Artificial habitat – a chance for survival of a rare montane dragonfly (Odonata): case study on an alpine emerald (Somatochlora alpestris)

“…mostly on the preservation of its hydrological regime and leaving the surface of the peatland untouched. However, subalpine habitats are changing and becoming overgrown due to climate change, spread of woody plants, loss of grazing and tourism development (Kašák et al 2013(Kašák et al , 2015Zeidler et al 2020;Šenfeldr et al 2021), threatening populations of relict mountain insect species (Kašák et al 2015;Konvicka et al 2021). Therefore, alternative methods for dragonflies´ conservation are being sought in the form of active management -including the support of populations through the creation of artificial habitats.…”