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<jats:title>Abstract</jats:title><jats:sec> <jats:title>Background and aims</jats:title> <jats:p>Two local threatened endemics from Valencian salt marshes were analysed from a multidisciplinary perspective combining field studies with experiments performed under greenhouse-controlled conditions. The work aimed to investigate the habitat of the two species but also to explore their limits of tolerance to severe drought and salinity and the mechanisms behind their stress responses.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>The number of individuals in several populations, climatic conditions, soil characteristics and accompanying vegetation in the natural habitats were analysed in the field study. Plants obtained by seed germination were grown in the greenhouse and subjected to one month of water and salt stress treatments. Growth and biochemical parameters were analysed after the treatments were finalised.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>No correlation between climatic parameters and the number of individuals censed of the two <jats:italic>Limonium</jats:italic> species could be established. Although <jats:italic>L. dufourii</jats:italic> was found in more saline soils in the natural habitats, under controlled greenhouse conditions, this species was more severely affected by salt treatment than <jats:italic>L. albuferae</jats:italic>, which is more susceptible to water stress. A common biochemical response was the increase of proline under all stress treatments, but mostly in water-stressed plants. Oxidative stress markers, MDA and H<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub>, did not indicate significant differences between the treatments. The differences in the two species' responses to the two kinds of stress were correlated with the activation of the antioxidant enzymes, more pronounced in conditions of salt stress in <jats:italic>L. albuferae</jats:italic> and of water stress in <jats:italic>L. dufourii</jats:italic>.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Although <jats:italic>L. albuferae</jats:italic> is found in sites with lower salinity in the natural habitats, the greenhouse experiment indicated that it tolerates higher concentrations of salt than <jats:italic>L. dufouri</jats:italic>, which is more resistant to drought. The two species efficiently mitigate oxidative stress by activation of antioxidant enzymes. The results obtained may be helpful for the conservation management of the two species: whereas salinity is not problematic, as the two species tolerated under controlled conditions salinities far beyond those in their natural environments, water scarcity may be a problem for <jats:italic>L. albuferae</jats:italic>, which proved to be more susceptible to water deficit.</jats:p> </jats:sec>

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Aim</jats:title> <jats:p>Overstorey tree species influence both soil properties and microclimate conditions in the forest floor, which in turn can induce changes in ground bryophyte communities. The aim of the study was to investigate the effect of tree species identity and the most important habitat factors influencing understorey bryophytes.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>We assessed the effect of 14 tree species and related habitat parameters, including soil parameters, vascular plant presence and light intensity on bryophytes in monospecific plots covered by nearly fifty-year-old trees in the Siemianice Experimental Forest (Poland).</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>The canopy tree species determined bryophyte species richness and cover. The strongest differences were observed between plots with deciduous and coniferous trees. Soils with a more acidic pH and lower content of macronutrients supported larger bryophyte coverage. We also found a positive correlations between vascular plants and availability of light as well as bryophyte species richness.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusion</jats:title> <jats:p>Tree species identity and differences in habitat conditions in the forest floor lead to changes of ground bryophyte richness, cover and species composition. Consequently, the changes in the dominant tree species in the stand may result in significant repercussions on ground bryophyte communities. We indicated that the introduction of alien tree species, i.e. <jats:italic>Quercus rubra</jats:italic>, has an adverse effect on bryophyte communities and suggested that the selection of tree species that contribute to the community consistent with the potential natural vegetation is highly beneficial for maintaining ground bryophyte biodiversity.</jats:p> </jats:sec>