Prostorska razporeditev in ohranitveno stanje vrst iz rodu bosvelija (Boswellia spp.) na otoku Sokotra

This study investigates the endangered status of Frankincense trees (Boswellia spp.) on Socotra Island through four comprehensive chapters. Chapter one assesses the population decline of the endangered endemic Boswellia elongata over a period of seven decades, using digitized images from various sources in the period 1956–2017 and combined this with direct field measurements of the population between 2011 and 2017. The study of this chapter reveals a continuous decline in the Homhil Nature Sanctuary population, with a significant acceleration caused by cyclones in 2015. Chapter two focuses on seed germination rates of nine endemic Boswellia taxa on Socotra Island. Controlled experiments (trials of 21 days) conducted over two years show variations in germination rates among species, localities, and years, indicating the influence of external ecological factors. Chapter three focuses on exclosure experiments to assess the natural regeneration of Boswellia spp. Five exclosure sites were established, comparing fenced and control plots. The study found significantly higher seedling mortality and lower height increments in the control plots. Chapter four provides an overview of the current distribution and IUCN Red List, re-assessment based on thorough field and remote sensing (by UAV) survey for all eleven endemic Boswellia taxa in the Socotra Archipelago. Urgent protection strategies are recommended to mitigate these threats and the conservation status of Boswellia spp on Socotra Archipelago.