|Most recent IBA monitoring assessment|
|Year of assessment||Threat score (pressure)||Condition score (state)||Action score (response)|
|1994||medium||not assessed||not assessed|
|For more information about IBA monitoring please click here|
The Sistan basin, at c.470 m on the border between Iran and Afghanistan, contains a complex of freshwater lakes with extensive reedbeds which at times of peak flooding can cover over 200,000 ha. These wetlands are unusual in that the three main lakes, Hamoun-i Puzak (see site 088), Hamoun-i Sabari and Hamoun-i Hirmand, are predominantly freshwater despite lying within an internal drainage basin. The system lies in an extremely arid region, and receives the great bulk of its water from the Hirmand (Helmand), Fara and several other smaller rivers rising in the highlands of central and northern Afghanistan. During long droughts, as in the late 1960s and mid-1980s, these rivers supply sufficient water to flood only the uppermost of the lakes, Hamoun-i Puzak, which lies almost entirely within Afghanistan. However, during years of unusually heavy rain, as in the late 1970s and 1989-1991, the floodwaters sweep through all three lakes and overflow into a vast salt waste to the south-east, flushing the salts out of the system in the process. The Hamoun-i Sabari (31°20'N 61°20'E; up to 101,300 ha), about half of which lies in Iran, receives water from the Fara Rud, which enters in the north-east (in Afghanistan), and overflow from the Hamoun-i Puzak to the east. The Hamoun-i Hirmand (30°50'N 61°15'E; up to 65,600 ha) receives water from the southern (Sistan) branch of the Hirmand and overflow from the Hamoun-i Sabari to the north. During flooding, both lakes support extensive growths of Phragmites, Typha, Carex and Tamarix, as well as abundant submerged aquatic vegetation, but very little emergent growth has re-appeared since the drought of the early and mid-1980s. Other habitats include extensive mudflats, saltmarshes and bare saltflats. The wetlands are bordered to the east and south by vast desertic plains, those to the south consisting of extensive bare saltflats and sparsely vegetated sandy plains with dune areas and some Tamarix scrub. In the west, the hamouns are bounded by a line of low earth cliffs at the edge of a vast undulating desert plain. An isolated flat-topped volcanic plug (Kuh Khvajeh) rises abruptly out of the marshes to 609 m on the east side of Hamoun-i Hirmand and has a ruined settlement of considerable archaeological interest. Much of the land around Zabol and its many satellite villages east of the hamouns is under irrigated cultivation. Livestock grazing, reed-cutting and fishing occur in the wetlands, and in recent years the lakes have been stocked with grass carp Ctenopharyngodon idella. The land is publicly owned.
See box for key species. The wetlands are extremely important as a staging and wintering area for a wide variety of waterbirds, notably pelicans, herons, dabbling ducks and shorebirds, and in years of high water level are also important for many breeding species. Comprehensive ground and aerial censuses between 1969/70 and 1975/76 indicated that numbers of ducks and geese wintering in the Iranian portion of the Sistan wetlands varied from almost nil in exceptionally dry years (e.g. 1970/71) to over 700,000 in wet years (e.g. 1972/73). There has been a dramatic decline in numbers since then, and this has been attributed to the prolonged drought of the early and mid-1980s and large-scale degradation of the aquatic vegetation. The lush vegetation around the wetlands provides a staging area for large numbers of migratory landbirds, while the surrounding deserts support a typical desert avifauna. Other notable species include Circus aeruginosus (over 15 pairs breeding), Aquila clanga, Falco pelegrinoides, Porphyrio porphyrio, Pterocles senegallus, Bubo bubo, Caprimulgus aegyptius, Melanocorypha bimaculata, Ammomanes cincturus, Alauda gulgula, Motacilla citreola and Sylvia nana. Phylloscopus trochiloides nitidus has occurred on autumn passage. At least 170 species have been noted at the site.
Non-bird biodiversity: Mammals: Canis lupus (V), Caracal caracal (rare), Gazella subgutturosa (rare) and Gazella dorcas fuscifrons (V).
Data-sheet compiled by Dr D. A. Scott, reviewed by Dept of Environment.
BirdLife International (2022) Important Bird Areas factsheet: Hamoun-i Sabari and Hamoun-i Hirmand. Downloaded from http://www.birdlife.org on 29/11/2022.