@misc{9226040,
  abstract     = {{This study investigates the occurrence and distribution of 18 lichen species associated with Nordic alvar and Precambrian limestone habitats on Gotland and Öland, which represent globally unique environments with a generally high biodiversity. During field surveys in the spring of 2025, historically known sites of the chosen lichen species were revisited, where species presence, frequency, and environmental variables related to vegetation, succession, grazing, and conservation were recorded. Data were analyzed both descriptively to assess current occurrence and distribution patterns, and by using Canonical Correspondence Analyses (CCA) to examine relationships between species distributions and environmental factors. Results indicate the presence of a few generalist species exhibiting widespread and stable occurrence, while the majority of specialist species were rarer and highly sensitive to habitat changes. Many of the rare species, including Flavocetraria nivalis, Heppia adglutinata, Megaspora verrucosa and Physconia muscigena, were negatively affected by both dense vegetation and overly open, homogenous environments, emphasizing the importance of specific microhabitats. Differences between the islands were also observed, with Gotland supporting more localized, rare species, and Öland a higher proportion of widespread species, reflecting landscape structure and dispersal potential. The CCA identified soil and grass cover and grazing as key drivers influencing species distributions, while conservation status showed a limited effect due to coarse resolution in the analyses. Furthermore, historical comparisons indicate that the new data records largely reflect an improved survey coverage, while several of the specialized species show local declines. The results thereby underscore that maintaining structural heterogeneity through continuous, moderate grazing and targeted management is essential for conserving both the specialist and generalist lichen species, whereas formal protection alone is insufficient to prevent encroachment and habitat loss.}},
  author       = {{Guldåker, Linn}},
  language     = {{swe}},
  note         = {{Student Paper}},
  title        = {{Lavar knutna till nordiskt alvar och kalkhällmarker på Gotland och Öland: förekomst och igenväxningsstatus}},
  year         = {{2026}},
}