Iran is often recognized for its ancient history and complex geography, but it harbors a surprising degree of natural diversity. This biological wealth results from its location at a transition point where three major biogeographic realms meet: the Palaearctic, the Afro-tropical, and the Oriental. This position creates an ecological crossroads, blending species from Europe, Asia, and Africa. The resulting ecosystems range from humid, temperate forests to hyper-arid deserts, supporting a high number of endemic species.
Geographical and Climatic Drivers of Biodiversity
The foundation of Iran’s extensive biodiversity lies in its dramatic topographical features and the steep climatic gradients they create. Two massive mountain chains, the Alborz in the north and the Zagros in the west, act as climatic barriers, trapping moisture and creating distinct ecological zones. The Alborz range, running along the southern edge of the Caspian Sea, intercepts humid air masses, leading to heavy precipitation on its northern slopes.
The rain shadow created by these mountains results in the vast, arid Central Plateau, which dominates the interior of the country. This interior plateau experiences extreme temperature fluctuations and very low rainfall, generating desert and semi-desert conditions. Iran also borders three major water bodies—the Caspian Sea, the Persian Gulf, and the Gulf of Oman—each contributing unique marine and coastal habitats. This interplay of high mountains and coastal proximity causes a rapid shift in climate over short distances, fostering high levels of species variation and endemism.
Defining Iran’s Major Ecosystems
The geographical forces at play have sculpted four major biomes across the Iranian landscape.
Hyrcanian Mixed Forests
Stretching along the southern coast of the Caspian Sea, these forests are a unique relic of deciduous broadleaf forests that covered much of the northern hemisphere during the Tertiary period. Characterized by high humidity and heavy rainfall, they support dense stands of ancient trees on the northern slopes of the Alborz mountains.
Central Arid Plateau
This Iran-Turani ecological zone contains the immense salt deserts of the Dasht-e Kavir and the Dasht-e Lut. Defined by extreme heat and aridity, it covers the majority of the country’s interior. The environment is harsh, supporting specialized vegetation adapted to desert and steppe conditions.
Zagros Montane Forest Steppe
Extending across the Zagros mountain chain, this biome is characterized by open, scrub oak forests. These forests thrive under a climate of cold winters and hot, dry summers. These oak woodlands are interspersed with steppe vegetation and are crucial for water management in the western provinces.
Coastal and Marine Ecosystems
The southern coastline features the Persian Gulf and Oman Sea ecosystems. The warm, shallow waters support specialized habitats, including dense Avicennia mangroves, known locally as Hara forests. The Persian Gulf also holds coral reefs and supports a diverse array of tropical marine life.
Unique Flora and Vegetation Zones
Iran is home to approximately 8,200 species of vascular plants, with nearly 1,900 of these species being endemic to the country. The Hyrcanian forests showcase a temperate-zone hardwood flora, with dominant species including Oriental beech, various oaks, hornbeam, and Persian ironwood. These relic forests are significant as a haven for species that largely disappeared from Europe during the last glacial period.
The Zagros forests are dominated by scrub oak species, forming open woodlands adapted to the seasonal dryness and mountainous terrain. Interspersed within these montane regions are wild relatives of commercially important species, such as wild pistachio and almond trees. The vast Iran-Turani zone of the central plateau supports a specialized desert and steppe flora. Plants here, such as Tamarix, Haloxylon, and Artemisia, have adapted to conserve water, often exhibiting small leaves or deep root systems.
Distinct Fauna and Wildlife
The diversity of Iran’s ecosystems supports a rich fauna, including many of the world’s most charismatic and threatened species. The Asiatic Cheetah, a critically endangered subspecies, survives exclusively in the fragmented semi-desert habitats of the central plateau, particularly in protected areas like Khar Turan National Park. The Persian Leopard, the largest leopard subspecies, roams the mountainous regions across the Alborz and Zagros ranges.
The high mountains and steppes are home to diverse ungulates, including the Persian Fallow Deer and the Persian Onager, a subspecies of wild ass found in protected desert areas. Wild sheep, such as the Urial, and Bezoar goats navigate the steep rocky terrain, forming the primary prey base for the larger carnivores. Iran also lies on a major migratory flyway, hosting over 500 bird species, including the endemic Iranian ground jay, found only in the central steppes.
In marine environments, the Persian Gulf supports sea turtles, dugongs, and numerous fish species within its coral reef and mangrove habitats. The Caspian Sea is home to several endemic species, most famously the sturgeon, which is a source of high-value caviar.
Conservation Efforts and Protected Areas
Iran has established a framework for preserving its natural heritage, managed primarily by the Department of the Environment (DoE). This network of protected areas is structured into four main categories:
- National Parks
- Wildlife Refuges
- Protected Areas
- National Natural Monuments
These zones encompass high-biodiversity ecosystems such as Golestan National Park and the Touran Protected Area, which serve as havens for endangered species. Protected areas currently cover approximately 8 to 11 percent of the country’s total land area, with goals set to increase this coverage to 20 percent.