Fusarium circinatum, the causal agent of pine pitch canker (PPC), is currently one of the most important threats of Pinus spp. globally. This pathogen is known in many pine-growing regions, including natural and planted forests, and can affect all life stages of trees, from emerging seedlings to mature trees. Despite the importance of PPC, the global distribution of F. circinatum is poorly documented, and this problem is also true of the hosts within countries that are affected. The aim of this study was to review the global distribution of F. circinatum, with a particular focus on Europe. We considered (1) the current and historical pathogen records, both positive and negative, based on confirmed reports from Europe and globally; (2) the genetic diversity and population structure of the pathogen; (3) the current distribution of PPC in Europe, comparing published models of predicted disease distribution; and (4) host susceptibility by reviewing literature and generating a comprehensive list of known hosts for the fungus. These data were collated from 41 countries and used to compile a specially constructed geo-database. A review of 6297 observation records showed that F. circinatum and the symptoms it causes on conifers occurred in 14 countries, including four in Europe, and is absent in 28 countries. Field observations and experimental data from 138 host species revealed 106 susceptible host species including 85 Pinus species, 6 non-pine tree species and 15 grass and herb species. Our data confirm that susceptibility to F. circinatum varies between different host species, tree ages and environmental characteristics. Knowledge on the geographic distribution, host range and the relative susceptibility of different hosts is essential for disease management, mitigation and containment strategies. The findings reported in this review will support countries that are currently free of F. circinatum in implementing effective procedures and restrictions and prevent further spread of the pathogen.
12 August 2020 in Rendiconti Lincei. Scienze Fisiche e Naturali
Dragonflies are important bioindicators of aquatic ecosystem health. We discuss the distribution and richness of the 22 dragon- and damselfly species known from the Socotra Archipelago UNESCO World Heritage Site (Yemen) in the western Indian Ocean. We compiled 841 records from literature, field data and museum collections, covering a surveying period of 123 years (1896–2019). Distribution of the only endemic, the Socotra BluetAzuragrion granti(McLachlan, 1903), an indicator of pristine lotic waters, is updated. Relatively higher dragonfly species richness occurs in eastern Socotra where suitable aquatic habitats are present all year. We observed a significant drop of the number of taxa over several decades in areas in the Hadiboh Plain where human development impacts are strongest. We discuss the indigenous people’s perception of dragonflies to assess the potential of these invertebrates as local flagships for aquatic biodiversity conservation. Our knowledge of the Socotran Odonata remains incomplete, yet they are now among the best studied animal groups in the archipelago. A new record of an OrientalAnaxindicates that the island’s dragonfly fauna may yet harbour surprises. Our compilation of odonate records is the first for Socotra and serves as a baseline for future monitoring of the archipelago’s vital aquatic habitats. We converted all records into a geodatabase which we uploaded to an online, freely available web mapping server and mobile application to facilitate research and conservation of the Socotran dragonflies (www.dragonfliesofsocotra.com).Graphic
This article is a broad review focused on dragon trees—one of the most famous groups of trees in the world, well known from ancient times. These tertiary relicts are severely endangered in most of the area where they grow. The characteristic features of the dragon tree group are described and the species belonging to this group are listed. This review gathers together current knowledge regarding the taxonomy, evolution, anatomy and morphology, physiology, and ontogeny of arborescent dragon tree species. Attention is also paid to the composition, harvesting, medicinal, and ethnobotanical use of the resin (dragons’ blood). An evaluation of population structure, distribution, ecology, threats, and nature conservation forms the final part of the review. In the conclusions we recommend further avenues of research that will be needed to effectively protect all dragon tree species.
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. Community forestry controlled by a local certification system is suggested as a sustainable land management approach providing traditional and new benefits and enabling the reforestation of endemic tree species on Socotra Island.
• Lecanosticta spp.now recorded in 44 countries, mostly in the northern hemisphere. • L. acicola has increased its range, now found in 24 out of 26 European countries. • Climate change means L. acicola could affect 74% of Pinus forested area by 2100. • Lecanosticta species were recorded on 70 hosts, including Pinus, Cedrus and Picea. • We explore global BSNB management strategies using European Case studies.