sustainability Article Sustainable Land Use Management Needed to Conserve the Dragon’s Blood Tree of Socotra Island, a Vulnerable Endemic Umbrella Species Petr Madˇera 1,*, Daniel Volaˇrík 1, ZdenˇekPatoˇcka 2 , Hana Kalivodová 1, Josef Divín 2, Martin Rejžek 1 , Jan Vybíral 1,3, Samuel Lvonˇcík 1, David Jeník 4, Pavel Hanáˇcek 4, Abdullateef Saad Amer 5 and Petr Vahalík 2 1 Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemˇedˇelská 3, 613 00 Brno, Czech Republic 2 Department of Forest Management and Applied Geoinformatics, Mendel University in Brno, Zemˇedˇelská 3, 613 00 Brno, Czech Republic 3 Lower Morava Biosphere Reserve, Zámecké námˇestí 69, 691 44 Lednice, Czech Republic 4 Department of Plant Biology, Mendel University in Brno, Zemˇedˇelská 3, 613 00 Brno, Czech Republic 5 UNEP/GEF Project, Hadibo, Socotra, Republic of Yemen * Correspondence:
[email protected] Received: 13 May 2019; Accepted: 26 June 2019; Published: 28 June 2019 Abstract: Unsustainable overgrazing is one of the most important threats to the endemic and endangered population of dragon’s blood tree (Dracaena cinnabari) on Socotra Island (Republic of Yemen). However, there is a lack of information about the exact population size and its conservation status. We estimated the population size of D. cinnabari using remote sensing data. The age structure was inferred using a relationship between crown projection area and the number of branch sections. The conservation importance of each sub-population was assessed using a specially developed index. Finally, the future population development (extinction time) was predicted using population matrices. The total population size estimated consists of 80,134 individuals with sub-populations varying from 14 to 32,196 individuals, with an extinction time ranging from 31 to 564 years.