Ornamental plants constitute a major source of invasive species. Gaillardia aristata (great blanketflower) is planted worldwide and its escape has been reported in several European countries without ecological impact assessment on the invasive potential. As there is a markedly spreading population with invasive behaviour in Hungary, we aimed to reveal the distribution, impacts and traits of G. aristata. We gathered occurrence data outside the gardens in Hungary, based on literature, unpublished observations by experts and our own records. We investigated the impacts of an extended population, where the species invaded sandy old-fields within a 25 km2 area. Here, we compared the species richness, diversity, community composition and height of invaded and uninvaded vegetation. Furthermore, we evaluated the traits potentially associated with the invasiveness of G. aristata in comparison with other herbaceous invasive species in the region. We found that G. aristata occurred mostly by casual escapes, but naturalised and invasive populations were also detected in considerable numbers. G. aristata usually appeared close to gardens and ruderal habitats, but also in semi-natural and natural grasslands and tended to spread better in sandy soils. We found lower plant species richness and Shannon diversity in the invaded sites and the invasion of G. aristata significantly influenced the composition of the plant community. The trait analyses revealed that the invasive potential of G. aristata is backed by a wide germination niche breadth, extremely long flowering period, small shoot-root ratio (large absorption and gripping surface), large seeds (longer persistence) and dispersal by epizoochory of grazing livestock (mostly by sheep), probably helping the species’ survival and spreading in the disturbed, species-poor, sandy, open habitats. These functional traits, as well as the ornamental utilisation, may act together with the aridisation of the climate and the changing land-use practices (e.g. abandoned, disturbed sites) in the success of G. aristata. We raise awareness of the rapid transition of G. aristata from ornamental plant to casual alien and then to invasive species in certain environmental conditions (i.e. sandy soils, species-poor communities, human disturbances), although it seems to be not a strong ecosystem transformer so far. Nonetheless, banning it from seed mixtures, developing eradication strategy and long-term monitoring of this species would be important to halt its spreading in time.

Microclimate and vegetation architecture are interdependent. Little information is available, however, about the fine-scale spatio-temporal relationship between the microclimate and herb layer of forest-steppe mosaics. In 2018 a three-season-long vegetation sampling and measurements of air temperature and air humidity were performed along 4 transects (44 m long each) in the herb layer with 89 dataloggers in the sandy region of Central Hungary, in a poplar grove and the surrounding open grassland. In order to improve data analysis, we introduced the use of a duration curve widely used in hydrology and proved to be useful in the processing of intensive climatic data. We analysed the effect of the direction and altitude of the solar irradiation and the edge effect on the microclimatic pattern. We also surveyed, seasonally, the spatial pattern of the exceedance rate for the vapour pressure deficit (VPD) in relation to the transect direction and to the edge of the grove. The exceedance rate for the VPD indicated considerable seasonal differences. The VPD exceedance rate indicates the stress effect for the vegetation. The moderating effect of the grove was small at 1.2 kPa VPD, but at 3.0 kPa—stronger stress—it was considerable. On the warmer side of the transects, mostly exposed at the south-eastern edge, the exceedance rate rose abruptly with distance from the edge compared to the gradual increase on the colder side. The cardinal and intercardinal directions as well as the altitude of the Sun all had influences on the moderating and shading effects of the grove. The southern edge was not always consistently the warmest. The distribution of the VPD values above the 3.0 kPa threshold varied within a seemingly homogeneous grassland, which highlights the importance of fine-scale sampling and analysis. This knowledge is valuable for assessing the dynamics and spatio-temporal patterns of abiotic factors and physiognomy in this type of ecosystem.

Aims:The relative importance of species within an ecosystem shows spatio-temporal variability related to both the terrain features and numerous rapidly changing factors.Accordingly, functional and species patterns may show some level of persistence, or, due to various disturbances, fluctuations. Communities with high species richness were found to maintain a higher degree of stability than species-poor or perturbed vegetations; however, diversity and its stability may be spatio-temporally variable.Based on these considerations, our aim was to assess the responses of a sandy pasture, both species-wise and at the community level, to the relatively invariant habitat, and to the more rapidly changing environmental conditions. Location: Hungary. Methods:We surveyed the vegetation in an area of about 1 ha by means of highresolution spatio-temporal sampling: we recorded the surface aerial cover (%) of the plant species during 15 campaigns covering spring, summer and autumn aspects for seven years (2013)(2014)(2015)(2016)(2017)(2018)(2019) in 80 × 60 m grids. The biological activity of the ecosystem (above-ground biomass, soil respiration) was also followed up together with the environmental limiting factors.Results: During the study period, which was characterized by significant warming, the grassland showed a balanced physiological performance with year-to-year variability.Fluctuating differentiation of the plant species with different environmental optima along with the terrain attributes was assumed to be responsible for this balanced physiological performance. Although community-level diversity remained stable, some species favoring cooler, wetter positions disappeared. Conclusions:Terrain features of the study area within 1.5 m or less elevation differences created considerably heterogeneous conditions for a high number (114) of plant species with different ecological needs to co-occur. The stability of the diversity was found to show terrain relatedness, that is spatial as well as temporal patterns 2 of 15 |

<p>Spatial variability of ecosystem processes constitutes significant uncertainty source in greenhouse gas flux measurements and estimations. The major disadvantage of the chamber-based flux measurements is the poor spatial representativeness, but eddy-covariance measurements also have an uncertainty due to the unequal and not constant footprint area. One way to overcome these difficulties is the spatial sampling improving the field-scale data coverage.</p><p>The aim of this study was to describe the spatial variability of grassland soil CO<sub>2</sub> efflux under varying environmental conditions. For this reason, we conducted spatial measurements on a range of variables including soil respiration, above-ground biomass, greenness index of the vegetation, soil water content and soil temperature during a seven-year study in a dry grassland site in Hungary. Altitude and soil organic carbon (SOC) content of the measuring positions were also used as background factors. Measurements were repeated 19 times at 78 positions during the study, in the main phenological stages of the grassland vegetation: spring growth, summer drought, autumn regrowth. The sampling scheme was based on 80×60 m grid of 10 m resolution. SOC content was highly variable among the positions due to the exposure differences and their environmental constrains. We analyzed the effect of the drivers on soil respiration grouping the measuring positions by the SOC content of the soil.</p>