Phoretic relationships between Plagionotus detritus (Coleoptera: Cerambycidae) and Trichouropoda sociata (Acari: Mesostigmata)

The aim of the study was to explore phoretic relationships between Plagionotus detritus and mites from the order Mesostigmata. In total, 635 individuals of P. detritus were caught, and mites were found on 86 of them. The dominant species among 8,154 individuals of mites was Trichouropoda sociata (8,152 individuals), and the sporadically found species were Lasioseius thermophilus (1 ind.) and Typhlodromus sp. (1 ind.). Generally, the difference in the total abundance of females and males of P. detritus was not statistically significant (311 females vs 324 males). The proportional abundance of P. detritus with T. sociata differed between samplings, and in the pooled data, the proportional abundance of P. detritus females with T. sociata (39.5%) was less than that for P. detritus males (60.5%)

Impacts of soil conditions and light availability on natural regeneration of Norway spruce Picea abies (L.) H. Karst. in low-elevation mountain forests

& Key message Natural regeneration of P. abies (L.) H. Karst. may reach high densities in lower mountain elevations. The highest densities were found in sites with moderate light availability, with low pH, and not near the riverbank. However, age-height classes differed in the predicted magnitude of response, but were consistent in response directions. Mosses and understory species typical of coniferous forests were positively correlated with regeneration density. & Context Norway spruce Picea abies (L.) H. Karst. in Central Europe is at risk under climate change scenarios, particularly in mountain regions. Little is known about the impact of environmental factors on the natural regeneration of P. abies in lowelevation mountain forests. & Aims We aimed to assess impacts of distance from the riverbank, soil pH, and light availability on natural P. abies regeneration. We hypothesized that (1) natural P. abiesregeneration would depend on light availability and soil pH and (2) there are understory plant species which may indicate the microsites suitable for natural regeneration of P. abies. & Methods The study was conducted in the Stołowe Mountains National Park (SW Poland, 600–800 m a.s.l.). We established 160 study plots (25 m2 ) for natural regeneration, light availability, soil pH, and understory vegetation assessment

Consequences of the Reproductive Effort of Dioecious Taxus baccata L. Females in a Generative Bud Removal Experiment—Important Role of Nitrogen in Female Reproduction

Dioecious species differ in the pattern and intensity of male and female reproductive investments. We aimed to determine whether female shoots deprived of generative buds show biochemical features, indicating their less-pronounced reproductive effort. For this purpose, the same branches of mature Taxus baccata females were deprived of generative organs. In the second and third years of the experiment, measurements were made in every season from the control and bud-removed shoots of females and control males. Bud removal caused an increase in nitrogen concentration almost to the level detected in the needles of male specimens, but only in current-year needles. Moreover, differences between male and control female shoots were present in the C:N ratio and increment biomass, but they disappeared when bud removal was applied to females. Additionally, between-sex differences were observed for content of phenolic compounds, carbon and starch, and SLA, independent of the female shoot reproductive effort. The study revealed that nitrogen uptake in seeds and arils may explain the lower nitrogen level and consequently the lower growth rate of females compared to males. At the same time, reproduction did not disturb carbon level in adjacent tissues, and two hypotheses explaining this phenomenon have been put forward

Plant communities of the Czerwona Woda River Valley (Stołowe Mountains National Park)

The Czerwona Woda River is the main watercourse in the Stołowe Mountains National Park and drains the major part of the Stołowe Mts. It was regulated in the past, but its channel has been spontaneously naturalized. Now, managed spruce forests grow along almost the entire length of this small mountain stream. The aims of the present study were to investigate diversity of plant communities connected with the Czerwona Woda stream and to prepare detailed vegetation maps. The results obtained can potentially be a reference for future restoration projects implemented in the Stołowe Mountains National Park. As a result of vegetation mapping, there were distinguished 20 plant communities representative of the current vegetation and 3 communities representative of the potential vegetation. Phytosociological data on the vegetation was documented by making 62 phytosociological relevés. Based on these, 9 forest communities were distinguished, of which 3 were classified into associations, 1 – into alliance, 5 – into secondary forest communities. Furthermore, there were distinguished 14 non-forest communities, of which 10 were classified into associations. Several of the phytosociological classes distinguished have been reported for the first time in the Stołowe Mountains National Park