Plant diversity of Hyrcanian relict forests: An annotated checklist, chorology and threat categories of endemic and near endemic vascular plant species

Abstract

In this paper a critical annotated checklist of 256 endemic and near endemic species belonging to 152 genera and 50 families of flowering plants known from Hyrcanian relict forests is presented. Distribution maps of taxa, elevational range, number of known records, chorotypes, life forms, IUCN threat categories and habitat types are also provided. The chorotypes are categorized into eight main patterns: 1) the Omni-Hyrcanian pattern (OH), 2) West Hyrcanian pattern (WH), 3) Manjil-Rudbar pattern (MR), 4) Central Hyrcanian pattern (CH), 5) Central and East Hyrcanian pattern (CEH), 6) East Hyrcanian pattern (EH), 7) Alborz-Hyrcanian pattern (AH), and 8) Euxino-Hyrcanian pattern (XH). The richness and distribution maps were generated based on 5408 records gained from herbarium specimens and literature records. The life form spectra show that the majority of taxa (54.7%) belong to hemicryptophytes, followed by the tuberous, bulbous and parasitic geophytes with 45 species (17.6%) and phanerophytes with 28 taxa (10.9%). The conservation status of species according to IUCN criteria indicates that 30 taxa are Critically Endangered, 52 taxa Endangered, 30 taxa Vulnerable, 25 taxa Near Threatened and 81 taxa are of Least Concern. Our present data were not sufficient to evaluate 38 taxa that are categorized here as Data Deficient. The new combination of Leutea translucens (=Peucedanum translucens) is validated with inclusion of Peucedanum hyrcanicum as its synonym. The disjunct occurrence of the Caucasian species Gentiana grossheimii is reported from the eastern parts of the Hyrcanian forests in Iran for the first time. We conclude that (i) the Hyrcanian forests and associated habitats in the northern slopes of the Alborz Mountains harbour tremendous floristic diversity of high conservation priority, and (ii) the Hyrcanian forest zone is an important and unique center of endemism within the Euro-Siberian region that should be considered a floristic province with a large number of relict species.