rss_2.0Folia Oecologica FeedSciendo RSS Feed for Folia Oecologica Oecologica 's Cover the invasive ambrosia beetle withstand an unusually cold winter in the West Carpathian forest in Central Europe?<abstract> <title style='display:none'>Abstract</title> <p>The capability of a non-native species to withstand adverse weather is indicative of its establishment in a novel area. An unusually cold winter of 2016/2017 that occurred in the West Carpathians of Slovakia and other regions within Europe provided an opportunity to indirectly assess survival of the invasive ambrosia beetle <italic>Xylosandrus germanus</italic> (Coleoptera: Curculionidae, Scolytinae). We compared trap captures of this species in the year preceding and succeeding the respective cold winter. Ethanol-baited traps were deployed in 24 oak dominated forest stands within the southern and central area from April to August 2016, and again from April to August 2017 to encompass the seasonal flight activity of <italic>X. germanus</italic> and to get acquainted with temporal changes in the abundance of this species in these two distant areas. Dispersing <italic>X. germanus</italic> were recorded in all surveyed stands before and after the aforementioned cold winter. Their total seasonal trap captures were lower in the southern area following low winter temperatures, but remained similar in the central area. Our results suggest that <italic>X. germanus</italic> can withstand adverse winter weather in oak dominated forests of the West Carpathians within altitudes of 171 and 450 m asl. It is likely that minimum winter temperatures will not reduce the establishment or further spread of this successful invader in forests in Central Europe.</p> </abstract>ARTICLE2021-12-30T00:00:00.000+00:00Endemic and invasive Coccinellidae associated with maize ( L.) fields, in Manabi province, Ecuador<abstract> <title style='display:none'>Abstract</title> <p>Maize (<italic>Zea mays</italic> L.), which is considered an important cereal everywhere, is widely cultivated in different agroecological conditions. Throughout their phenological stages, maize crops are attacked by pests and diseases, and in Ecuador these phytosanitary problems are usually counteracted with applications of pesticides. However, knowledge of beneficial entomofauna is fundamental to guide pest management programs. As part of this objective, the Coccinellidae species present in maize fields in localities (Santa Ana, Colon, and Danzarin) in Manabí province were identified. In each zone, maize plants were sampled from 2018–2019. A total of 2,654 specimens belonging to 14 taxa were collected in this study, of which <italic>Cheilomenes sexmaculata</italic>, <italic>Cycloneda sanguinea</italic>, <italic>Hippodamia convergens</italic>, <italic>Hyperaspis arida</italic>, and <italic>Psyllobora confluens</italic> were found in all the studied areas. <italic>Hyperaspis arida</italic> and <italic>Diomus apollonia</italic> are reported for the first time in Ecuador.</p> </abstract>ARTICLE2021-12-30T00:00:00.000+00:00The assessment of the current status of L. populations of the Ukrainian Carpathians: Ecological and genetic approaches<abstract> <title style='display:none'>Abstract</title> <p>Based on the analysis of the genetic polymorphisms (RGAP- and CDDP-PCR) among populations and comparison of these results with ecological characteristics (density, area, spatial and vitality structure, age, ability of renewal and self-maintenance), the status of five natural (Lemska, Gutyn Tomnatyk, Sheshul-Pavlyk, Krachuneska, Troyaska-Tataruka) and one man-made (Pozhyzhevska) populations of <italic>Gentiana lutea</italic> from the Ukrainian Carpathians was assessed. The results of the complex ecological and genetic analysis have revealed that three populations are unstable (Krachuneska, Troyaska-Tataruka, Gutyn Tomnatyk), two are relatively stable (Lemska, Pozhyzhevska) and only one is stable (Sheshul-Pavlyk). The research results can be used for stabilizing the number of violations and restoring the endangered natural populations. Based on these data, the recommendations for the conservation and protection of <italic>G. lutea</italic> populations have been developed.</p> </abstract>ARTICLE2021-12-30T00:00:00.000+00:00Temporal and spatial changes in small mammal communities in a disturbed mountain forest<abstract> <title style='display:none'>Abstract</title> <p>In 2005–2016, we investigated a secondary succession of small mammal communities in forest ecosystems in High Tatras (Slovakia) disturbed by windstorm and fire. This long-term ecological study confirmed the occurrence of significant temporal and spatial changes in species composition and number of dominant small mammal species. A comparison between disturbed and undisturbed plots indicated notable differences in species richness and abundance. The gradations of dominant small mammal species in disturbed habitats were asynchronous and showed a wider range of amplitude than in the undisturbed plots. An analysis of the temporal and spatial changes in the structure of small mammal communities in relation to selected environmental gradients confirmed the statistically significant effect of secondary succession on species composition, abundance, and exchange in forest ecosystems in the High Tatra Mountains following a disturbance.</p> </abstract>ARTICLE2021-12-30T00:00:00.000+00:00Ecogenesis and primary soil formation on the East European Plain. A review<abstract> <title style='display:none'>Abstract</title> <p>Numerous published studies have shown that soil formation, including primary pedogenesis, is closely connected functionally, energetically and operationally with ecogenesis as a key biogenic exploration mechanism of the Earth’s surface by living organisms. The ontogenetic stage of soil evolution, especially in the initial phases, is determined by geogenic conditions and the intensity and trends of biogenic-accumulative processes in the developing ecosystem. Primary soils are considered critical in the rapid development of the initial ancient biosphere, supporting multiple environmental possibilities for ecosystems in that stage of their formation. Currently, similar models of correlated soil formation and ecogenesis are actualised when new substrates appear suitable for biogenic-abiogenic interactions, which occur in both natural and anthropogenic landscapes. Biotic factors during primary pedogenesis have accumulative and transformative effects on the edaphic component complex. At this stage, the initial pedon is a key functional stage in the evolution of terrestrial ecosystems (biogeocenosis). When restoration of natural ecosystems occurs during the independent growth of exposed substrates, the natural regeneration mechanisms normally occur. These processes are based on the biogenic development of the substrate through the accumulation and transformation of organic matter.</p> </abstract>ARTICLE2021-12-30T00:00:00.000+00:00The cytogenetic parameters of L. under conditions of the Far North of Russia (Karelia)<abstract> <title style='display:none'>Abstract</title> <p>The cytogenetic analysis of the <italic>Pinus sylvestris</italic> L. seed progeny in the forests of the northern taiga in the Far North of Russia conditions was carried out. Two <italic>Pinus sylvestris</italic> populations growing in Ambarnskoy and Pyaozerskoy forest divisions of Loukhsky district of Karelia Republic were studied. The number of chromosomes, the frequency and types of mitosis disturbances at the metaphase, anaphase and telophase (as a percentage of the total number of dividing cells at the same stages), and the frequency of micronuclei occurrence, as well as the laboratory seed germination, were studied. As a result of the study, it was found that 50–56% of the studied sprouts were mixoploid. Analysis of mitosis showed that the root meristem of the studied samples contained cells with various pathologies; simultaneously, the frequency of mitosis pathologies in the Ambarnskoy population was significantly higher than in the Pyaozerskoy one. It amounted to 6.8 ± 0.4 and 4.9 ± 0.4%, respectively. Nine types of abnormalities were identified; chromosome overrun and bridges prevailed. Micronuclei were registered in 35–38% of the studied <italic>Pinus sylvestris</italic> sprouts. At the same time, the proportion of cells with micronuclei in the Ambarnskoy population was 2-fold higher than in the Pyaozerskoy one and averaged 0.12 ± 0.03% and 0.07 ± 0.02%, respectively.</p> </abstract>ARTICLE2021-12-30T00:00:00.000+00:00Evaluation of , , and plants following selection for drought tolerance at seedling stages<abstract> <title style='display:none'>Abstract</title> <p>The genetic potentials of eight species of Achillea (A. millefolium, A. fillipendulla, A. biebersteinii, A. nobilis, <italic>A. eriophora</italic>), <italic>Matricaria</italic> (<italic>M. ricotita</italic>), and <italic>Anthemis</italic> (<italic>An. haussknechtii</italic> and <italic>An. tinctoria</italic>) under drought conditions during the seedling stage were measured. Non-ionic water-soluble polymer polyethylene glycol (PEG, molecular weight 6000) was used to simulate water stress at five osmotic potential levels (0, –0.3, –0.6, –0.9, and –1.2 MPa). An acceptable threshold value for germination was osmotic potential –0.6 MPa, and the modest osmotic potential was –1.2 MPa for studied taxa. Seedlings of germinated at two control and osmotic potential –0.6 MPa (as an acceptable threshold value for germination) treatments were sowed in a field under rainfed conditions. Genetic differentiation of control plants (CP) versus early selected plants (ESP, germinated at osmotic potential –0.6 MPa) was studied using morphological, physiological, and molecular (ISSR) markers. No significant differences were observed between morphological traits of CP and ESP in all species, however, days to full flowering shortened in ESP. The physiological results demonstrate that under rainfed conditions, the ESP, in a quick response, collect osmolytes and amplify the activity of antioxidative enzymes to survive drought. The genetic relationship in the group of genotypes, that ISSR marker set it out, is affiliated to taxon even though AMOVA showed a partial differentiation between CP and ESP groups (21%). It was concluded that the selection of tolerating individuals at the seedling stage represents a likely positive strategy to have higher drought tolerance feature in plants under rainfed conditions.</p> </abstract>ARTICLE2021-12-30T00:00:00.000+00:00A comparative assessment between artificial neural network, neuro-fuzzy, and support vector machine models in splash erosion modelling under simulation circumstances<abstract> <title style='display:none'>Abstract</title> <p>Splash erosion, as the first step of soil erosion, causes the movement of the soil particles and lumps and is considered an important process in soil erosion. Given the complexity of this process in nature, one way of identifying and modeling the process is to use a rainfall simulator and to study it under laboratory circumstances. For this purpose, transported material was measured with various rainfall intensities and different amounts of poly-acryl-amide. In the next step, artificial neural network (ANN), adaptive neuro-fuzzy inference system (ANFIS), and support vector machine (SVM) were used to model the transported materials. The results showed that among the three methods, the best values of evaluation criteria were related to SVM, and ANFIS respectively. Among the three studied durations, the experiment with a duration of 30 minutes received the best results. The results based on available data showed by increasing the number of membership functions, over-fitting happens in the ANFIS method. To reduce the complexity of the model and the likelihood of over-fitting, some rules were eliminated. The results showed that the performance of the model improved by eliminating some rules.</p> </abstract>ARTICLE2021-12-30T00:00:00.000+00:00Spatial exploration, dendrometric characteristics and prediction models of wood production in a stand of in Durango, Mexico<abstract> <title style='display:none'>Abstract</title> <p>Degraded vegetation is the result of a process that affects structural and functional characteristics. Tree species from the <italic>Acacia</italic> genus are very important to the ecosystem in semi-arid lands due to their participation in the recovery of highly degraded areas. One of the most important species among this genus is <italic>A. schaffneri.</italic> The status of a forest stand is determined according to its structure, including height, stratum and density. Remote sensing is a valuable method for estimating volumetric stocks and associated changes in forest populations over established periods of time. The objective of this research was to estimate wood volume of <italic>A. schaffneri</italic> using remote sensing, and to complement that information with the results obtained from an estimation method based on forest measurements. The results obtained showed that the crown area was the dendrometric variable that can be used in a wood volume prediction model. In the exploratory analysis between dendrometric variables and remote sensing showed low and negative associations were observed in the four stations analyzed. There are conservation problems due to anthropogenic activities, among which stands out the intensive grazing that results in a decrease of the natural regeneration capacity of <italic>Acacia schaffneri.</italic></p> </abstract>ARTICLE2021-12-30T00:00:00.000+00:00The effect of long-term CO enrichment on carbon and nitrogen content of roots and soil of natural pastureland<abstract> <title style='display:none'>Abstract</title> <p>Increasing levels of atmospheric CO<sub>2</sub> may change C and N dynamics in pasture ecosystems. The present study was conducted to examine the impact of four years of CO<sub>2</sub> enrichment on soil and root composition and soil N transformation in natural pastureland. Plots of open-top growth chambers were continuously injected with ambient CO<sub>2</sub> (350 µL L<sup>–1</sup>) and elevated CO<sub>2</sub> (625 µL L<sup>–1</sup>). Soil cores exposed to ambient and elevated CO<sub>2</sub> treatment were incubated and collected each year. Net N-mineralization rates in soil (NH<sub>4</sub><sup>+</sup>-N plus NO<sub>3</sub>ˉ<sup>–</sup>-N), in addition to total C and N content (%) of soil and root tissues were measured. Results revealed that elevated CO<sub>2</sub> caused a significant reduction in soil NO<sub>3</sub> (P &lt; 0.05), however, no significant CO<sub>2</sub> effect was found on total soil C and N content (%). Roots of plants grown under elevated CO<sub>2</sub> treatment had higher C/N ratios. Changes in root C/N ratios were driven by changes in root N concentrations as total root N content (%) was significantly reduced by 30% (P &lt; 0.05). Overall, findings suggest that the effects of CO<sub>2</sub> enrichment was more noticeable on N content (%) than C content (%) of soil and roots; elevated CO<sub>2</sub> significantly affected soil N-mineralization and total N content (%) in roots, however, no substantial change was found in C inputs in CO<sub>2</sub>-enriched soil.</p> </abstract>ARTICLE2021-07-31T00:00:00.000+00:00Annual course of temperature and precipitation as proximal predictors of birds’ responses to climatic changes on the species and community level<abstract> <title style='display:none'>Abstract</title> <p>The study was conducted in the landscapes of south-eastern Ukraine during the nesting seasons 1988–2018. Within the landscape system associated with the Molochny Estuary, the ten most important ecosystem types were investigated, including the following: agricultural land, vegetated strips, meadows, islands and spits, reedbeds, urban areas, salt marshes, steppe, cliffs, artificial forests. Bird species responded to temperature and precipitation gradients. The patterns of responses were presented using Huisman, Olff and Fresco expanded by the Jansen-Oksanen hierarchical models. The nature of species response in the gradient of temperature or precipitation conditions depends on the type of particular ecosystem and is not uniform for all populations inhabiting the different landscape types. The bird communities were revealed to demonstrate an abrupt dynamic over time. The continuous changes in community structure initiated by the external environmental factors are combined with modifications of internal biotic interactions, which may lead to abrupt reorganization of the community.</p> </abstract>ARTICLE2021-07-31T00:00:00.000+00:00Plasticity in response to soil texture affects the relationships between a shoot and root trait and responses vary by population<abstract> <title style='display:none'>Abstract</title> <p>The relationships between shoot and root traits can inform plant selection for restoration, forestry, and agriculture and help to identify relationships that inform plant productivity and enhance their performance. But the strength of coordination between above- and belowground morphological and physiological traits varies due to differences in edaphic properties and population variation. More assessments are needed to determine what conditions influence these relationships. So, we tested whether plant population and soil texture affect the relationship between shoot and root traits which have important ecological ramifications for competition and resource capture: shoot height and root tip production. We grew seedlings of two populations of <italic>Bromus tectorum</italic> due to is fast growing nature in a growth chamber in loam soil, sand, and clay. We found variation in height by plant population and the substrate used (<italic>R<sup>2</sup></italic> = 0.44, <italic>p</italic> &lt; 0.0001), and variation in root tip production by the substrate used (<italic>R<sup>2</sup></italic> = 0.33, <italic>p</italic> &lt; 0.0001). Importantly, we found that relationships between shoot height and root tip production varied by soil texture and population (<italic>R<sup>2</sup></italic> = 0.54, <italic>p</italic> &lt; 0.0001), and growth in sand produced the strongest relationship and was the most water deficient substrate (<italic>R<sup>2</sup></italic> = 0.32). This shows that screening populations under several environments influences appropriate plant selection.</p> </abstract>ARTICLE2021-07-31T00:00:00.000+00:00Dispersion of the epigeic fauna groups in the agricultural landscape<abstract> <title style='display:none'>Abstract</title> <p>Changes in the structure of epigeic animal groups indicate ecological stability, which are influenced by urbanization, agriculture, and forestry. The aim of the paper was to assess the impact of agrarian land in the vicinity of urban and suburban landscape and non-fragmented forest in the vicinity of rural landscape on the occurrence of epigeic groups. We recorded the pitfall traps - 19, 676 individuals belonging to 20 taxonomic groups at 9 localities representing 7 types of habitat. Our results indicate a year-on-year increase in the number of individuals of epigeic groups in the city, with surrounding agrarian land. We found a correlation between eudominant epigeic groups of Aranea and Hymenoptera and rural landscape with the non-fragmented surrounding. Coleoptera has shown a link between the conditions of urban and suburban landscape with the surrounding developed agriculture. We confirmed a statistically significant effect for luminosity (p = 0.002), humidity (p = 0.025) and pH (p = 0.017).</p> </abstract>ARTICLE2021-07-31T00:00:00.000+00:00Effect of increased ambient temperature on seasonal generation number in (Diptera, Calliphoridae)<abstract> <title style='display:none'>Abstract</title> <p>Global climate change and, specifically, rising temperatures, may increase the number of generations of necrophagous insects. The common green bottle fly <italic>Lucilia sericata</italic> (Meigen, 1826) (Diptera, Calliphoridae) ranks among the most important cosmopolitan necrophagous insects that utilize corpses and cause myiasis in farm animals and humans. Based on the data simulations, the use of accumulated degree-hours enables to calculate the number of generations of this forensically important species of blowfly with a greater accuracy than before, considering short-term increases of temperature at the boundary of the cold and warm seasons. The number of generations of <italic>L. sericata</italic> has increased from 7.65 to 8.46 in the Ukrainian steppe zone over the last 15 years, while the active developmental period of this species has increased by 25 days due to earlier start in spring. The average temperature increase of 1 °C increased the number of generations of <italic>L. sericata</italic> by 0.85. With a global climate change following the Representative Concentration Pathway (RCP) 4.5 scenario (average temperature increase of 2.4 °C), adopted by the Intergovernmental Panel on Climate Change, by 2100 the number of generations of <italic>L. sericata</italic> in a simulated ecosystem will increase by 2.0 to 9.0 generations per year.</p> </abstract>ARTICLE2021-07-31T00:00:00.000+00:00Nickel in forests – a short review on its distribution and fluxes<abstract> <title style='display:none'>Abstract</title> <p>The distribution and cycling of nickel (Ni) in forests is greatly affected by their proximity to emission sources of the metal. The throughfall deposition is always richer in Ni than the bulk deposition. It can be inferred that some dry deposition enriches the throughfall. In remote forested areas, the hydrological fluxes of Ni do not differ a lot from those in litterfall. In addition, the current year needles in conifers have higher concentrations than the older needles, a sign of absorption and mobility of the metal. In contrast, near an industrial Ni source the older needles accumulate much more of the metal. The Ni content in bark tissue can be used to map the deposition distribution of the metal around an area (rural or urban). The concentrations of Ni in forest soils is also dependent on their distances from the Ni emission sources and the nature of the soil parent material. The Ni concentrations increase with soil depth due to the geogenic origin of the metal. Low pH greatly enhances the mobility of the metal in soils, much more than the leachability of organic matter.</p> </abstract>ARTICLE2021-07-31T00:00:00.000+00:00Distribution patterns and conservation status of species in Iran, one of the diversity centers of in the Middle East<abstract> <title style='display:none'>Abstract</title> <p>Assessing distribution patterns of valuable taxa plays an important role in the biodiversity conservation of these taxa. The genus <italic>Crocus</italic> L. (Iridaceae) comprises about 100 species that are distributed mainly in the Mediterranean region and western Asia. The present study purposed to assess the distribution patterns of Iranian <italic>Crocus</italic> species (including <italic>C. sativus</italic> L. and 8 wild species) and their conservation status in Iran as one of diversity centers of <italic>Crocus</italic> in the Middle East. A set of geographic distribution data was compiled through field studies, and reviews of herbarium specimens, iNaturalist, and various Flora. Localities were marked on geo-referenced maps (1/106) of Iran using ArcView version 3.2 (Esri, 2000). The distribution patterns of the taxa were mapped per 0.25° × 0.25° universal transverse Mercator grid cells (25 km<sup>2</sup> with the exception of boundary area). Based on the species distribution (SDI) (33%) and species specialization (SSI) (44%) indices, those Iranian <italic>Crocus</italic> species that are threatened are mainly distributed in Irano-Turanian region. The mountainous ecosystems of Almeh and Western Alborz are important distribution centers of these taxa. Iranian <italic>Crocus</italic> species with SSI &lt; 0.5 (<italic>C. almehensis</italic>, <italic>C. gilanicus</italic>, <italic>C. michelsonii</italic>, and <italic>C. caspius</italic>) have the highest conservation value.</p> </abstract>ARTICLE2021-07-31T00:00:00.000+00:00Constructing single-entry stem volume models for four economically important tree species of Greece<abstract> <title style='display:none'>Abstract</title> <p>Three different nonlinear regression models were tested for their ability to predict stem volume for economically important native tree species in Greece. Τhe models were evaluated using adjusted R square (A<sub>dj</sub> R<sub>sqr</sub>) root mean square error (RMSE) and Akaike information criterion (AICc), where necessary. In general, the quadratic polynomial and cubic polynomial models and the two-parameter power models fit the data well. Although the two-parameter power function fit best for fir, oak, and beech trees, the cubic polynomial model produced the best fit statistics for black pine. Making forest inventory estimates often involves predicting tree volumes from only the diameter at breast height (DBH) and merchantable height. This study covers important gaps in fast and cost-effective methods for calculating the volume of tree species at national level. However, the increasing need for reliable estimates of inventory components and volume changes requires more accurate volume estimation techniques. Especially when those estimates concern the national inventory, those models must be validated using an entire range of age/diameter and site classes of each species before their extended use across the country to promote the sustainable use of forest resources.</p> </abstract>ARTICLE2021-07-31T00:00:00.000+00:00Populations of and (Apiaceae) in Kyiv (Ukraine)<abstract> <title style='display:none'>Abstract</title> <p>In connection with the increasing negative impact of invasive alien species on biodiversity and the environment in general, their research, as well as throughout the world, is relevant. The distribution of the <italic>Heracleum sosnowskyi</italic> and <italic>H. mantegazzianum</italic> of the secondary range on the example of the Kyiv agglomeration is investigated in the work. In our study we aimed to evaluate the possibility of spontaneous spread of giant hogweeds in the secondary range, adaptation of the species to the new conditions of the environment that favor to control of these species’ expansion and reduce the threat to the urban ecosystems and citizens’ health. We hypothesise that in the secondary range <italic>H. sosnowskyi</italic> and <italic>H. mantegazzianum</italic> settle sites with relatively high temperature (Tr), lightening (Lc), and soil moisture conditions similar to that in their natural range. 17 populations and four localities (sites) of <italic>H. sosnowskyi</italic> and <italic>H. mantegazzianum</italic> were studied. They were found within forest, meadow, riverine and ruderal plant communities. It is indicated that the advent species fully adapted to the conditions of the environment. The difference by ecological indicators Lc2 and Tm1 is pointed out. According to the results of our research, for the area of Kyiv urban agglomeration the growth of <italic>H. sosnowskyi</italic> and <italic>H. mantegazzianum</italic> is indicated in the plants communities of six classes. They spread most in ruderal plant communities of the: Robinietea, Artemisietea, Epilobietea classes. The studied species belong to invasive plant species in Ukraine and are characterized by extremely high effect on the environment and high invasive potential.</p> </abstract>ARTICLE2021-07-31T00:00:00.000+00:00Impact of management measures on the European ground squirrel population development<abstract> <title style='display:none'>Abstract</title> <p>In the past, the European ground squirrel represented a common part of Slovakian fauna. During the 20th century, there was a substantial decrease in its number, mainly due to the intensification of agriculture. Currently, several programs focused on the recovery and preservation of ground squirrel colonies have been implemented. The aim in supporting the population of the European ground squirrel is to increase the number of birds of prey and to ensure a food base for them. In this paper, we focus on evaluating the success rate of European ground squirrel (<italic>Spermophilus citellus</italic>) management measures. The research was realized at two localities in the Protected Bird Area Slovenský kras (Hrhov and Gemerská Hôrka) in the years 2015–2018. Activities were focused on the management of grassland and supplemental feeding during the breeding period. As a result of the management measures and the supplemental feeding, we managed to maintain a positive trend in the populations’ development, as there was an increase observed in all the monitored seasons.</p> </abstract>ARTICLE2021-07-31T00:00:00.000+00:00Drought tolerance of three ethnomedicinal shrubs evaluated based on their seed germination rates at different drought levels induced by using polyethylene glycol (PEG)<abstract> <title style='display:none'>Abstract</title> <p><italic>Sideritis incana</italic>, <italic>Stachys ocymastrum</italic>, and <italic>Thymus fontanesii</italic> are medicinal plants belonging to the Lamiaceae family and occurring in semi-arid lands in northern Algeria and in many other countries along the Mediterranean coastline. Despite the ecological and economic interests and also the questionable future these species may meet in their natural habitats, various aspects of their seed biology have not been recognised to this date. This study was intended for <italic>in situ</italic> conservation of these plants. The problem investigated was the germination response of seeds to different water potential levels attained with using different amounts of polyethylene glycol (PEG<sub>6000</sub>) (0, –0.03, –0.07, –0.2, –0.5, –1 and –1.6 MPa). In this way, the appropriate conditions and the threshold tolerance of seed germination against water stress were assessed. Seeds of the three species lacked primary/innate dormancy and they germinated abundant and fast in distilled water (<italic>S. incana</italic> – 65%; <italic>S. ocymastrum</italic> – 60% and <italic>T. fontanseii</italic> – 90%). Small seeds of <italic>T. fontanesii</italic> tolerated more water stress and germinated under up to –1 MPa (–10 bars). Large seeds of <italic>S. incana</italic> and <italic>S. ocymastrum</italic>, however, were more sensitive to the drought stress and germinated only under –0.5 MPa (–5 bars). Moreover, more studied parameters were found developing negative reponse under rising drought stress, such as postponed triggering of seed germination, decreased germination velocity and prolonged germination duration, as well as the average time of germination. Therefore, these three plants appear to postpone their establishment until arrival of conditions promising for germination, including sufficient rainfall.</p> </abstract>ARTICLE2021-03-01T00:00:00.000+00:00en-us-1