Hyrcanian forests


The Hyrcanian forests are a zone of lush lowland and montane forests covering about near the shores of the Caspian Sea in Iran and Azerbaijan. The forest is named after the ancient region of Hyrcania. The World Wide Fund for Nature refers to the ecoregion as the Caspian Hyrcanian mixed forests. Since 5 July 2019, the Hyrcanian Forests have been designated a UNESCO World Heritage Site. In September 2023, the heritage site expanded to incorporate portions of the forest located in Azerbaijan.

Geography

In Iran, the Hyrcanian ecoregion comprises a long strip along the southern coast of the Caspian Sea and the northern slopes of the Alborz mountains. It covers parts of five provinces, from east to west: North Khorasan, Golestan, Mazandaran, Gilan and Ardabil.
The Golestan National Park spans the boundary of Golestan and Mazandaran provinces. In the Mazandaran province, where the Hyrcanian forest is estimated at, are used commercially, are protected and the rest are regarded as forest lands or over-used forests. The total of the forest woods used in this province is estimated at. The Kojoor, Dohezar and Sehezar forest watersheds are in Mazandaran province, Gilan province and Ardabil Province. At higher elevations to the south, the ecoregion grades into the Elburz Range forest steppe.
In southeastern Azerbaijan the ecoregion spans through the Lankaran Lowland and the Talysh Mountains.
The ecoregion's climate is humid subtropical at lower altitudes; at mid-altitudes it has oceanic features, while in the mountains it is humid continental. Summer is a humid but low-precipitation season. Alborz is the highest mountain range in the Middle East and it captures, by relief precipitation and dew point mists, much of the evaporation of the southern Caspian Sea. Annual rainfall ranges from in the east to in the west, making the forests much lusher than the desert, semi-desert, and steppe regions which it borders.

Flora

The natural forest vegetation is temperate deciduous broadleaved forest. 32.7 percent of volume of Hyrcanian forest is of oriental beech. A main feature of the region is the lack of conifers; only relics of coniferous species are present, which include European yew, junipers, Mediterranean cypress and Chinese arborvitae.
The Caspian Sea coastal plains were once covered by chestnut-leaved oak, European box, black alder, Caucasian alder, Caspian poplar and Caucasian wingnut, but these forests have been almost entirely converted to urban and agricultural land.
The lower slopes of Talysh and Alborz Mountains below harbor diverse humid forests containing chestnut-leaved oak, European hornbeam, Persian ironwood, Caucasian zelkova, Persian silk tree, and date-plum along with shrubs holly, Ruscus hyrcanus, Danae racemosa and Atropa pallidiflora, and lianas Smilax excelsa and Hedera pastuchovii. Persian Ironwood is endemic to the Talysh Mountains and northern Iran and nearly pure stands of the tree can be particularly dramatic, with lichen-covered branches twisting together and only dead leaves in the deep shade of the forest floor. In addition, the ironwood's yellow leaves turn a faint lilac in the fall.
At the medium elevations between, oriental beech is the dominant tree species in this cloudy zone in pure and mixed stands with other noble hardwoods such as chestnut-leaved oak, Caucasian oak, European hornbeam, Oriental hornbeam and sweet chestnut. From its floristic composition, these beech forests are linked with European forests and with affinities to the beech forests of the Balkans. However, local conditions of aspect and edaphic factors, such as soil moisture and depth, are all of importance in determining the composition of the vegetation, which leads to the establishment of different beech subcommunities.
Upper mountain and subalpine zones are characterized by Caucasian oak, Oriental hornbeam, shrublands and steppes. Alpine tundra and meadows occur at the highest elevations.
Other native tree species include Caspian locust, velvet maple, Cappadocian maple, European ash, Wych elm, wild cherry, wild service tree and lime tree.

Fauna

The Caspian tiger was once the apex predator of the biome before its extinction. The remaining large mammals include the Persian/Caucasian leopard, Eurasian lynx, brown bear, wild boar, wolf, golden jackal, jungle cat, Caucasian badger, and Eurasian otter.
This ecoregion is the main green resting area for birds migrating between central-northern Russia and Africa and thus is a key habitat for many bird species. Notable birds seen here are the greylag goose, white-fronted goose, little bustard, glossy ibis, Eurasian spoonbill, night heron, red-breasted goose, peregrine falcon, Dalmatian pelican, cattle egret, squacco heron, greater flamingo, white-headed duck, and Caspian snowcock.

Endemic species

The Hyrcanian forests are thought to have served as a refugium for certain species during changing climatic conditions. The Iranian edible dormouse is an endemic of this ecoregion, and is thought to have evolved when mid-Miocene climatic change led to the fragmentation of the ancestral Glis population, with one such population fragment surviving in these forests and evolving into a new species. The bat Myotis hyrcanicus is likely also endemic to this region. The region is also known to preserve a unique lineage of bicolored shrew that diverged from the other lineages during the mid-Pleistocene, about 1 million years ago. The Persian mountain salamander is an aquatic salamander endemic to high rainfall regions of the Hyrcanian forest. It is primarily known from its aquatic larvae which live in permanent streams with forest cover. This is a very understudied species and very few adults have ever been found. It is under threat from habitat loss due to logging, agricultural development, and urban sprawl.

Protected areas

The diversity and endemism of the species make the Caspian Hyrcanian forests a priority and unique feature for species conservation. Habitats are threatened by conversion into tea, vegetable, fruit, and vine plantations, unsustainable forestry and poaching.
Protected areas in Azerbaijan include:
Protected areas in Iran include:
  • Golestan National Park
  • Jahan Nama Protected Area
  • Central Alborz Protected Area
  • Lisar Protected Area
  • Siah Keshim Protected Area
  • Dodangeh Wildlife Refuge
  • Neka Miankaleh Wildlife Refuge
  • Selkeh Wildlife Refuge
  • Dashtenaz Wildlife Refuge