Oribatid mite (Acari: Oribatida) communities reveal the negative impact of the red oak (Quercus rubra L.) on soil fauna in Polish commercial forests

The red oak (Quercus rubra L.) is a woody plant brought to Europe from North America for its decorative value and high tolerance to frost and pollution. The species has been planted for the reclamation of brownfield sites, and introduced to commercial forests to enrich local biodiversity. Although in Poland its presence was associated with depauperation of local flora, its invasive status is still under discussion. The aim of this study was to determine the impact of red oak stands on Acari communities (Oribatida, Mesostigmata, Astigmata, Prostigmata). In the detailed analyses we focused on the Oribatida species, one of the best bioindicators of soil condition. The presence of the red oak was compared to the pedunculate (native) oak, also planted on poor acid soils. The research design included oak stands introduced in commercial forests, divided into two groups: young and old. A total number of 240 soil samples were collected, and 173 species of oribatid mites were identified. A low proportion of the Oribatida species typical for the Palearctic region, specific to deciduous forests, with sexual reproduction and belonging to the trophic level of secondary decomposers, significantly distinguished the old alien oaks from old native oaks. The results presented in this work are one of the few which concern the reaction of soil oribatid mite community to plant invasions, and provide evidence of the harmful impact of these alien tree species, which can be overlooked in short-term studies

Communities of mites (Acari) in litter and soil under the invasive red oak (Quercus rubra L.) and native pedunculate oak (Q. robur L.)

Because of thoughtless decisions or unintentional introduction, alien species disturb native ecosystems. R ed oak (Quercus rubra), among other alien woody plants, is still used to rehabilitate degraded land because of its better resistance to pollution and faster growth, as compared to native tree species. Soil mites, especially O ribatida, are good bioindicators of ecosystem disturbance, so the main goal of this study was to explore the influence of invasive and native oaks on mite communities. F orest stands dominated by 40-year-old Q. rubra or 35-year-old Q. robur were compared. O ver 2300 soil mites were extracted from 20 soil and 20 litter samples. M ite densities in the communities were higher in red oak litter, which is probably a result of the thicker layer of shed leaves. C hanges in species composition of oribatid communities were observed in litter, in contrast to a lack of differences in soil. These observations are consistent with other researches on invasive woody plants. W e expect that over time these changes will also be noticeable in the soil and will increase in litter

Activity pattern and fat accumulation strategy of the Natterer’s bat (Vespertilionidae, Chiroptera) swarming population indicate the exact time of male mating effort

Studies concerning bat autumn swarming behavior suggest that the main purpose of this phenomenon is mating. However, the process of fat accumulation is crucial for surviving winter, and it seems to be in clear conflict with a need to strive for the opportunity to mate prior to hibernation. Investment in one activity limits the other one creating a trade-off between them. The aim of our study was to describe the activity pattern of each sex-age group (adult males, adult females, subadults) of the Natterer’s bat during swarming period and to investigate the fat accumulation process of adult males in the context of their reproductive strategy. Bats were captured by mist nets at the swarming site fortnightly from the early August until the late November. The age, sex, reproductive status, and body condition index (mass to forearm ratio, BCI) were recorded. The activity peak of both sexes, adults, and subadults was observed in the late September. That time in season, BCI of adult males was the lowest, and there was no correlation between the hour of an adult male capture and its BCI value within one night (rs = 0.23; p = 0.157). Such correlation was observed later in the season (early October: rs = 0.44; p = 0.020; late October: rs = 0.48; p = 0.002). A negative correlation between adult males’ BCI and proportion of adult females was found (r = 0.44; p = 0.000). We conclude that the activity peak of females is likely to be responsible for the effort of the mating behavior of the males, which is reflected by their low condition index. We suggest that the gleaning foraging strategy of Natterer’s bat allows the males to postpone their fat accumulation until just before hibernation

Seasonal activity of urban bats populations in temperate climate zone – a case study from Southern Poland

Municipal greenery can mitigate the negative impact of urbanization on biodiversity, including bats, by providing a migration corridor, food base and roosts. Our study aimed to evaluate the species composition and diversity, test the differences in activity between seasons, and identify the atmospheric conditions influencing the bats’ activity in the Planty Park (Cracow). Fieldworks were conducted in 2016 and 2017. We recorded 10 species, two new for this part of Poland: the Kuhl’s pipistrelle (Pipistrellus kuhlii) and the Savi’s pipistrelle (Hypsugo savii). Taxa were divided into three ecological guilds. Myotis group’s activity was insufficient to perform statistical analyses. The activity of Nyctalus, Eptesicus and Vespertilio group peaked in late summer. A similar insignificant trend was observed for Pipistrellus and Hypsugo. Temperature enhanced the activity of Nyctalus, Eptesicus and Vespertilio group in spring and early summer, while cloud cover suppressed their activity in autumn. Temperature also enhanced Pipistrellus and Hypsugo group activity in spring and autumn, but it suppressed their summer activity. Our study is one of the first to investigate temperate urban bats’ phenology and may serve as a preface for further research to introduce detailed urban landscape planning recommendations

Resting Frequency of Echolocation Calls within a Lesser Horseshoe Bat Population (Southern Poland) and its Relation to Body Size, Condition and Mass

The echolocation calls emitted by stationary bats are characterised by their resting frequency (RF). The ecological role of RF has been widely discussed across the literature concerning the Rhinolophidae family, where it has been found that the RF may vary depending on many factors, although its role in shaping the variability of different populations remains unclear, and the data for many species – including Rhinolophus hipposideros – is scarce. In this study, we aimed to determine how sex, age and biometric parameters (body mass, forearm length and the body condition index) affected the RF in a R. hipposideros population and to investigate the individual variability in this parameter. Bats were captured in front of two Carpathian caves in Southern Poland during the mating season. The echolocation calls of the hand-held bats were recorded, and later their peak frequency was measured with computer software. The analyses showed higher RF values for females than for males, but (in contrast to previous reports) no differences between the age classes were identified. RF did not correlate with any biometric parameters in the studied population, which rules out the possibility of quality characteristic signalling through this parameter. However, we observed significant individual differences in RF within the sex-age groups, which might reflect some communication potential. The discrepancies among the research results available for this topic indicate the need for further studies aimed at investigating the variability of RF and its role across species distribution ranges and their phenology

Effects of γ-polyglutamic acid on grassland sandy soil properties and plant functional traits exposed to drought stress

Abstract The current study provides field experimental data that support the use of γ-polyglutamic acid (γ-PGA) in drought stress and proposes its application in grassland management. We hypothesized that water treatment combined with PGA application to sandy soil would reduce drought stress in grasslands more effectively than watering alone. A randomized block design was used, with three replicate watering blocks (no watering, weekly watering, and monthly watering) and PGA treatments at four different concentrations (0%, 0.3%, 1%, and 2% PGA). The results showed that PGA acts as a biostimulant, alleviating the effects of stress in plants by: (1) increasing the availability of ions, especially K+, Zn2+, Mn2+, Fe2+/3+, Ca2+, and Mg2+, as well as N-NH4 +, and N-NO3 −, (2) elongating plant roots, (3) increasing the aboveground biomass, (4) improving the resprouting capacity of the dominant grass Nardus stricta, and (5) improving the regeneration of dicotyledons. In the case of meadows on sandy soils, the use of low PGA concentrations (0.3% or 1%) was the most beneficial for the availability of macro- and microelements and improving the functional traits of plants. Irrigation had a greater effect than using PGA only for the dicotyledon to monocotyledon ratio