Recovery of the herbaceous layer in the young silver birch and black alder stands that developed spontaneously after a forest fire

The studies, which were conducted in southern Poland, focused on the recovery of the herb layer in 17-year-old post-fire silver birch and black alder forests. Although both types of stands, which are of the same age, developed spontaneously, the alder stands occupied damper sites (with thicker A horizons that survived the fire) than those in the birch forests. We surveyed the migration rates of 44 woodland species, primarily ancient woodland indicators, into both forests and the potential differences in these rates depending on their moisture regime and the community type represented by unburned forests, which were treated as the source of the woodland species pool. Additionally, the role of local depressions with high humidity that were covered by post-fire alder woods in the colonization process, as well as species survivorship and recolonisation, were estimated. Woodland species showed diverse migration paces among the sites; most of them migrated faster on more fertile sites with a higher humidity. Small patches of post-fire alder woods contributed to the recolonisation process since many woodland species in the herb layer survived the fire due to its high humidity, which inhibited the intensity of the forest fire. The recovery of woodland species in post-fire woods is the combined effect of regeneration, which relies on autochthonic propagules, and secondary succession, which is based on allochthonic propagules. Local depressions, which provide refuges for fire-sensitive, dispersal-limited species, contribute to their survivorship and thus to the successive recovery of herbaceous layers after a fire

Diversity, variability and habitat characteristics of the communities dominated by <i>Sesleria</i> species (Poaceae) in the Western Carpathians

<p>This study provides a view of vegetation types dominated by <i>Sesleria</i> species in the Western Carpathians (<i>Sesleria caerulea</i>, <i>S. heufleriana</i>, <i>S. tatrae</i>, and <i>S. uliginosa</i>). We also took into account characteristics/traits such as plant life forms, autochthonous status, endemism, and ploidy level occurring within each relevé in our data set. Altitude and Ellenberg indicator values derived for each relevé were considered as well. Eight vegetation types/formations/habitats were recognized in a data set of 942 phytosociological relevés: (1) synanthropic vegetation, (2) rock fissures and screes, (3) alpine grasslands and heaths, (4) mesic grasslands and pastures, (5) springs and fens, (6) forests, (7) xerophilous shrubland, and (8) high-mountain scrubs (krummholz). Results corroborated and clearly emphasized that <i>Sesleria caerulea</i> has the widest ecological amplitude of all studied species because the species occurred among all studied vegetation types. <i>Sesleria tatrae</i> was present only in several vegetation types occurring from montane to alpine vegetation belts in the highest mountains. <i>Sesleria heufleriana</i> and <i>S. uliginosa</i> were recorded only in low-altitude areas. The difference between them lies mainly in the dampness of each locality. <i>Sesleria heufleriana</i> was frequently found in xerophilous communities, whereas <i>S. uliginosa</i> preferred humid habitats of springs and fens.</p