Zagros Research Articles

A guide to conserve amphibian species in Iran

ABSTRACT Globally, amphibians are one of the most threatened vertebrate groups and are hypersensitive to human-imposed habitat changes. Here we explore ways to conserve amphibians in two of the least-known biodiversity hotspots on earth, the Caucasus and Irano–Anatolian regions. We used two techniques: (ⅰ) combining species richness, endemism, and endangerness indices and (ⅱ) a species distribution model (SDM) to identify high-priority areas for Iran’s seven endemic and/or threatened amphibian species. The identified amphibian high-priority areas were then targeted to assess the levels of protection granted by the network of conservation areas (CAs) in Iran. We also computed the species-specific extent of occurrence (EOO) and the area of occupancy (AOO) to detect conservation gaps for the targeted species. Our results indicate that amphibian high-priority areas in Iran are mostly distributed across the Hyrcanian forest in the north and Zagros Mountains in the west. The gap analysis revealed that based on the most optimistic metric, 40% of amphibian hotspots are covered by CAs in Iran. However, the species-specific gap analysis showed that Iran’s CAs perform poorly at representing the EOO of all of the endemic and/or threatened amphibian species. These results suggest that expansion of CAs in Iran is essential for amphibian conservation.

Determining the distribution factors of an endangered large carnivore: A case study of the brown bear Ursus arctos population in the Central Zagros Mountains, Southwest Iran

Determining the distribution factors of an endangered large carnivore: A case study of the brown bear Ursus arctos population in the Central Zagros Mountains, Southwest Iran

Illuminating the complexity of hydrogeological regimes in fault-influenced, anticlinal karst aquifers: Insights into the recharge patterns in tectonically complex karst catchments

For many countries, karst aquifers are a significant source of potable water; thus, understanding their hydrogeological behavior is of great importance. However, in tectonically complex karst areas, knowledge of their hydrogeological behaviors has remained largely limited due to the high heterogeneity, often necessitating the use of costly and time-consuming techniques. In this study, spring discharge hydrographs, water balance estimates, hydrochemical and stable isotopic analyses, geomorphological surveys, and a consideration of the geological and structural setting of the study area were used to investigate the hydrogeological function of karst aquifers drained by two large permanent springs: the Bibitalkhone (Bt) and Sabzab (Sa) springs, located in a highly faulted catchment in the Zagros Mountains (southwest Iran). The results obtained from these different approaches suggested that fault-controlled, external waters from neighboring karst aquifers are responsible for more than two-thirds of the total discharge recorded at both springs. In this study, this predominantly conduit-type recharge is referred to as “regional (or external) autogenic recharge”. A smaller portion of the springs’ discharge (∼25% and ∼5% of the Bt and Sa springs’ discharge, respectively) originates from internal waters associated with the springs’ host aquifer, which is supplied by rainfall and infiltrates into the subsurface via joints and fractures. This type of recharge is largely diffuse and is referred to here as “local (or internal) autogenic recharge”. A relatively large portion of the Sa Spring’s discharge (∼35%) originates from a nearby dam reservoir, which can leak into the host spring aquifer through joints and fractures. This type of recharge is described as “local (or internal) allogenic recharge” and is primarily diffuse. The results of this study demonstrate that the karst aquifers in the downstream catchments can supply a stable and continuous source of potable groundwater that can meet the region’s annual consumption, agricultural, and industrial demands. This study will provide insights into the hydrogeological regimes of fault-influenced aquifers, contributing to the sustainable development and proper management of water resources in tectonically complex karst catchments.

Species distribution modeling of two poorly known populations of Spalerosophis diadema (Reptilia: Colubridae): are the Zagros Mountains a true barrier for fragmentation in this species?

ABSTRACT Predictive models of species distribution can be beneficial for identifying the most important and influential environmental factors in species distribution and understanding the current and future habitat suitability of species. In this study, we used species distribution modeling to find out the potential distribution and habitat suitability of two spatially separated populations of Spalerosophis diadema and show the most important environmental factors that affect their habitat separation. The findings of SDM analyses demonstrated that the most important factors for the two populations are annual mean temperature, precipitation of coldest quarter, NDVI in May, and elevation, as these factors contributing about 80–85% of the environmental factors to the whole model. Two populations react similarly to these environmental predictors and there is no significant difference between the important, and influential environmental factors of their habitats. Although our results show some overlap of the potential distributions of populations among Mesopotamian plain and Afghanistan, there is no confirmed report or voucher specimen proving the overlap distribution in these regions. Our results support the hypothesis that the Zagros Mountains acted as a barrier to the east–west fragmentation of these two populations.

The 12 November 2017 Mw 7.4 earthquake in Sarpol-e-Zahab (Iran–Iraq): a complex fault rupture in the Zagros Mountains

The 12 November 2017 Mw 7.4 earthquake in Sarpol-e-Zahab (Iran–Iraq): a complex fault rupture in the Zagros Mountains

Mineralogical and Grain Size Analysis of Bai Hassan Formation Terraces in Al-Teeb Area, SE Iraq

Bai Hassan Formation is exposed as remnants of beds from previous formations due to severe erosion that were removed. Results from grain size analysis revealed that most of the studied sediments were coarse-grained sediments ranging from coarse sand to gravel. The study shows that the sediments are poorly sorted. The values of skewed coefficients ranged from fine to strongly skewed, and the negative values indicate the occurrence of hard changes in the environment. Meanwhile, the kurtosis values for the studied sediment indicate that the differences in these values are due to changes in the flow and sediment sorted in a relatively high energy environment. Light minerals like quartz, and feldspars, and rock fragments are identified. Heavy minerals such as chlorite, amphibole, pyroxene, mica, epidote, zircon, garnet, tourmaline, rutile, kyanite, and staurolite can provide information about the geological processes and environments that occurred in a particular area. These minerals can be indicative of specific rock types, metamorphic or igneous formations, that are derived from high Zagros mountains. The collision between the Arabian Plate and the Eurasian Plate resulted in the formation of the Zagros Fold and Thrust Belt, leading to the uplift and deformation of the Zagros Mountains. The Bai Hassan Formation in Iraq originated during the Miocene epoch from fluvial and alluvial fan environments. Sediments carried by rivers and streams from the elevated mountains in Iraq and Iran were deposited, forming conglomerates, sandstones, and mudstones that reflect various depositional settings such as braided river channels and floodplains indicating a rapidly sinking basin with freshwater and lacustrine environments.

Evidence for enhanced aridification since 13 Ma in the Qom back-arc basin, Central Iran

The Iranian Plateau was once occupied by the Neotethys Sea, which connected with the Indian Ocean in the southeast and the proto-Mediterranean in the west during most of the Cenozoic era. However, the Neotethys Sea has undergone a stepwise retreat, and the Tethyan Seaway also closed in the Miocene driven by both Arabia-Eurasia collision and global eustatic sea-level drop. Changes in the land-sea distribution and uplift of the Zagros Mountain belt must have affected paleoclimatic changes in Iran. To date, a high-resolution paleoclimatic record is lacking for Iran. In this paper, we present new environmental magnetic and color parameter data for terrestrial sediments in the Qom back-arc basin, Central Iran from the middle to late Miocene (17–11.5 Ma). All of our parameters indicate an abrupt climatic change at ∼13 Ma. We suggest that the less reddish color and a shift in environmental magnetic parameters after ∼13 Ma implies weakened chemical weathering under a colder/drier climate. Enhanced aridification was mainly controlled by closure of the Tethyan Seaway and shrinkage of the Neotethys Sea after ∼13 Ma, which greatly reduced moisture transport to the downwind Central Iran by westerlies, whereas the rain shallow effect of the initially uplifted Zagros Mountain belt and reduced seawater evaporation related to lower sea-surface temperatures after the Mid-Miocene Climatic Transition only played minor roles. Therefore, our results provide a window to discuss relationships between plate tectonic movements, land/sea distribution, and climatic change in a tectonically active region during the late Cenozoic.

Anisotropic gradients in Iran: Quasi-Love waves illuminate the deep structure and deformation style of the Zagros, Alborz, and Kopet Dagh

We investigate the presence of the quasi-Love wave (qL) at 51 seismic stations of a temporary seismic network across the western Arabia-Eurasia collision zone. We quantify the intensity of the qL observations from the April 12, 2014 Solomon Islands earthquake by calculating the peak-to-peak amplitude ratios of the qL and Love waves, and compare them with predicted qL intensities from previous shear-wave splitting results. We determine the polarity, timing, and period-dependence of the qL observations within the period range of 50–100 s. Our analysis reveals that the qL observations at stations in the Zagros and Alborz mountain belts exhibit opposite characteristics. In contrast to the Alborz stations, the intensity of qL observations at the Zagros stations exhibits relatively negligible dependence on the period, while their receiver-scatterer distances are considerably period-dependent. We approximately locate the anisotropic gradients that generate the qL waves. Our results suggest that a lithospheric gap is responsible for the shallow and abrupt variation in the belt-parallel trend of fast-axis orientations in the westernmost part of the Zagros. Additionally, the period/depth dependence of the anisotropic gradients along the boundary between the central Zagros and central Iran provides insight into the variation in the downward dip of the Arabian lithosphere. The anisotropic gradient located to the north of the Doruneh fault in eastern Iran indicates its role as a major shear zone and lithospheric boundary. Finally, we observe that the spatial distribution of the anisotropic gradient in northeastern Iran matches the higher strain-rate areas in the Kopet Dagh Mountains, suggesting coupling between the lithospheric mantle and crust in that region.

Herbivore enamel carbon and oxygen isotopes demonstrate both Homo sapiens and Neanderthals exploited similar habitats in the Zagros Mountains

ABSTRACTThe extinction of Neanderthal populations has been attributed to the onset of cold and dry climatic conditions during Marine Isotope Stage 3 or their competition with anatomically modern humans for large game resources. However, decoupling climate from competition has long proved difficult. Loess sequences and pollen cores provide regional‐scale environmental information but are less well‐suited to providing local‐scale habitat information contemporaneous with hominin habitation of occupation sites. The relationship between climate and resource availability is particularly unknown in the Zagros mountain range where archaeological evidence for both Neanderthals and Homo sapiens occupation is documented. Here, we analyse carbon (δ13C) and oxygen (δ18O) stable isotopes measured from herbivore tooth enamel carbonates recovered from the Neanderthal and modern human occupation sites of Bawa Yawan Rockshelter and Shanidar Cave to trace local‐scale floral biome dynamics and climate conditions that influence the distribution and availability of large prey targeted by both hominin species. Shared isotopic composition of herbivorous fauna, largely represented by wild goats, from both sites spanning Neanderthal and Homo sapiens occupation indicate both hominin species exploited similar habitats during climatically similar phases.

The upper crustal shear wave structure of the Zagros collision zone from local earthquake Rayleigh wave tomography

The Zagros fold-and-thrust belt is the principal response to the Arabia–Eurasia continental collision, which generates significant seismic activity in Iran. Surface wave tomography can be a proper tool for crustal structure imaging in this region. We used observed dispersion curves of Rayleigh wave derived from high-quality local-earthquake waveforms to obtain 2D tomographic maps in the period range 1–28 s beneath the Zagros collision zone. Subsequently, local pseudo-dispersion curves for individual grid points are inverted for shear-wave velocity structure, in order to obtain a 3D velocity model of the crust. Our results indicate shallow low-velocity structures near the suture zone. Moreover, a low-velocity flexure shape in the south of the Zagros Mountain Front Fault could be due to the thick sedimentary basin beneath the Dezful embayment. Relatively an uplifting of the deeper structures beneath Sanandaj-Sirjan and the high Zagros might could be led to high-velocity structures at mid-crustal depths. The variation of shear-wave velocity along the Zagros indicates the inhomogeneous structures along this folding and thrust belt.

INVENTION OF FLOATING GATES BASED ON ARTIFICIAL INTELLIGENCE DESIGING FOR MARED DAM AND WATERWAY

The Karun River is oriented from Zagros Mountains. In the MARED pump station, flat dam and waterway should be constructed to prohibit the intrusion of Persian Gulf tide waves. First layout belonged to SWECO consulting engineering in 1975 that were decided to build ship lock and dam by cubic concrete boxes as the main structure. Dam bed should be stabled to pass barges through waterway (500 tons capacity) and concrete piles ($30ˏ000ˏ000 in 2010). Second scheme of dam and waterway were designed to make with steel pipe piles, steel gates, concrete walls and embankment at 2018 more than $100ˏ000ˏ000 cost. Invention design could be replaced in the MARED dam and waterway. Floating steel gates must be rotated vertically by AI Designing. Steel gates shall be designed to add air inside the gate body. Movable gates are simulated through the fish swim bladder to operate the system that can be adapt with the water fluctuation. Air could be inserted into the simulated swim bladder by the compressor to buoy the gates. Also, it can be discharge the air automatically when the water level needs to be down. The effective depth is more than +18m therefore floating gates should be made by the hollow steel box. The total cost of the third scenarios may be estimated less than $10ˏ000ˏ000 for AID at 2023. Main dam was made to reduce costs using the pipes piles and buoyancy gates. Sediment flow can easily pass through the dam bottom and monitoring floating gates.

Modeling Forest Fire Behaviour in Controlled and Accidental Ignitions in ian Northern Zagros Forests, with an Emphasis on Fuel Load

Modeling Forest Fire Behaviour in Controlled and Accidental Ignitions in ian Northern Zagros Forests, with an Emphasis on Fuel Load

Sedimentology, Mineralogy of Al-Dujaila River Sediments Project, Southeastern Kut City, Iraq

A sedimentological and mineralogical study was carried out on sediments of Al-Dujaila River Project, one of the branches of the Tigris River, southeastern Kut City, Iraq. The study aims to identify the nature and maturity of sediments in order to deduce the provenance of these sediments and the source area. The results of grain size analysis of ten river sediment samples indicated that the averages are: silt (44.97%), clay (34.06%), and sand (20.96%). According to Folk's classification (1974), the sediments are classified as sandy mud. A microscopic study of five sand fraction samples has shown the presence of light and heavy minerals. Light minerals (average 94.6%) include on average: a major share of rock fragments (64.8% including dominant carbonate, chert, igneous, metamorphic, and mudstone), quartz (24.1% including dominant monocrystalline and polycrystalline), feldspars (5% including orthoclase and plagioclase) while evaporates, and coated clays are subordinate. Heavy minerals (average 5.4 %) include opaques (average 54.2%) and non-opaques (average 45.8%) including pyroxene, amphibole, epidote, garnet, staurolite, chlorite, biotite, muscovite, zircon, tourmaline and rutile. Based on the mineralogical signatures, light and heavy minerals reflect metamorphic, mafic and felsic igneous rocks of the active margin of the unstable shelf in addition to carbonate, evaporate and mud of sedimentary rocks that could be sourced from the floodplain. According to sediment diversity and very poor grain sorting in the study area, as well as the values of indices of mineral maturity MI (0.34), MMI (0.76), and the ZTR (23.5%), all these results indicate that sediments are immature to extremely immature, which means the source area represents rather elevated topography, rapid erosion and transport in arid to the semi-arid environment and a short distance of transportation. The tectonic provenance of Al-Dujaila River sediments can be characterized as a lithic reworked of the recycled orogen as a result of the collision range of Taurus and Zagros Mountain range.

Pre-Eocene Arabia-Eurasia collision: New constraints from the Zagros Mountains (Amiran Basin, Iran)

Abstract The timing of continental collision between Arabia and Eurasia is a highly controversial issue, on which new constraints are here provided from the Amiran Basin (Zagros Mountains, Iran). Upper Cretaceous carbonate ramps grown along the Arabian northern margin are overlain by the siliciclastic deep-water Amiran and shallow-water Kashkan Formations, dated biostratigraphically as 64–60 Ma (Paleocene) and 56–52 Ma (earliest Eocene), respectively. Abundant ophioliticlastics, detrital Cr-spinel geochemistry, and detrital zircons with positive εHf(t) values dated as 110–80 Ma, 180–160 Ma, and 260–200 Ma indicate that the Amiran Formation was derived from the obducted Kermanshah ophiolite and Sanandaj-Sirjan zone. Besides sharing similar composition and zircon-age spectra, the overlying Kashkan Formation contains recycled detritus and one new zircon-age component with negative εHf(t) values dated as 250–200 Ma, suggesting supply from additional sources in Central Iran. The Amiran Formation thus indicates that the Kermanshah ophiolite, obducted in the Late Cretaceous, was subaerially exposed to erosion in the Paleocene. The Kashkan Formation testifies to the establishment of a new fluvial system, sourced from Central Iran and flowing across the Zagros suture zone. This implies that continental collision between Arabia and Eurasia took place before the beginning of the Eocene (56 Ma) in the Lorestan region (Iran).

Vegetation and climate dynamics at the dawn of human settlement: multiproxy palaeoenvironmental evidence from the Hashilan Wetland, western Iran

ABSTRACTThe scarcity of high‐resolution palaeoclimate records from the interior of West Asia has limited our understanding of the mechanisms of past climate change and their potential impacts on early human societies of the Eastern Fertile Crescent. Here, we present a multiproxy sedimentological, geochemical and palynological record from the Hashilan Wetland in the central Zagros Mountains, spanning the time interval from 22 to 2.2 kcal bp. Our results indicate a cold, dry climate for the last deglaciation (22 to 10 kcal bp) with amplified aridity during the Last Glacial Maximum, Heinrich Stadial 1, the Younger Dryas and the 8.2 and 3.2 ka events. The Early Holocene (11.6 to 7.8 kcal bp) is characterised by prolonged dry summers, frequent spring/summer dust storms and restricted oak woodlands that gradually expanded as summers shortened toward the second half of the Holocene (<6 kcal bp). We show an out‐of‐phase Holocene moisture variation between the interior of West Asia and the Indian Summer Monsoon domain and conclude that summer insolation‐driven latitudinal shifts of the Hadley cell played a key role in seasonality changes in the interior of West Asia by modulating the strength and pathway of the subtropical high‐pressure cells. Finally, we explore possible impacts of these changes on regional prehistoric human communities.

Potential field survey of subsurface structures of the NW segment of the Zagros Fold‐Thrust Belt, Kurdistan Region

AbstractThis study reports results of gravity and magnetic surveys conducted for the first time in the western segment of the Zagros Fold‐and‐Thrust Belt in the Kurdistan Region. This study attempts to delineate deep structures in an area, which has not been surveyed before. CG‐5 Autograv gravimeter and G‐857 portable proton‐precession magnetometer were used to acquire gravity and magnetic data from 750 stations along over eleven traverses across and parallel to the Zagros trend (NW–SE). Six of these traverses are parallel to the Zagros trend, whereas the others are perpendicular to the trend of the other traverses and can be tied where they intersect. The total length of the traverses is about 1000 km. Tilt Angle of horizontal gradient method is used to detect regional gravity and magnetic lineaments. The mapped lineaments from regional gravity and magnetic surveys are divided into two categories: the NE–SW lineaments, which represent transversal faults in the study area, and the NW–SE lineaments, which represent the Zagros Thrust Faults, some of which may be linked to the inverted basement normal faults of Arabian passive margin (the NW–SE Najd Fault system). The results show that there is a relationship between the regional gravity and magnetic lineaments outlining the same deep geological features. The data presented here confirm the presence of regional longitudinal and transversal lineaments documented in other studies (e.g. Anah‐Qalat Dizeh Fault, Surdash‐Tikrit Fault, Sirwan Fault, Khanaqin Fault, Zagros Mountain Front Fault, Baranan Back Thrust Fault and High Zagros Reverse Fault) and outlines new lineaments not mapped before. Most of the detected regional lineaments in the current study coincide with the previously confirmed lineaments, which have played a significant role in the tectonic evolution of the Zagros Fold‐and‐Thrust Belt. As such, this study contributes to a better understanding of the subsurface structure of the Kurdistan segment of the Zagros Fold‐and‐Thrust Belt and probably the rest of the belt.

Landscape ecological security response to urban growth in Southern Zagros biome, Iran

Analyzing the relationship between urbanization and landscape ecological security (LES) is necessary for environmental protection during development. The concept of LES refers to the ecological state of the environment, which depends on the sustainability of ecosystem services and ultimately human well-being. Here, the effect of urban growth on the LES in Iran’s Kohgiluyeh and Boyer Ahmad province (KBP) was evaluated. Urbanization evaluation indicators were defined from demographic-spatial dimensions and the LES system defined the landscape approach. Decoupling theory and global and local Moran's correlation methods, and classical statistics were used to analyze the interaction between the urban growth index and the LES during 1990–2020. The results showed that the intensity of urban growth in the counties of KBP had an upward trend, in which the sprawl growth decreased by 67% and the average Landscape ecological security index (LESI) of the land surface decreased by 3.3%. In addition, 80 percent of the province's counties have reached or crossed the insecure threshold in terms of the LESI, while only Basht and Lendeh counties have been less destroyed. The evaluation of spatial patterns and analytical indices showed a negative relationship between urban growth and LESI. In terms of the decoupling theory, a strong relationship (ε = 0.03) was observed between them. Overall, monitoring and investigating the dimensions of urban growth and its effects on the LES can lead to sustainable spatial planning without destroying the environment.

Daya Cave: A Place of Worship of Mesopotamian and Persian Gods in the West Central Zagros Mountains, Iran

In the winter of 2021, a previously unknown and almost inaccessible cave called Aškawt-i Daya was discovered in the heart of Bakhakuh Mountain in the west central Zagros Mountains of Iran. An exceptional feature of the cave is its collection of paintings on the walls and ceiling with animal and human motifs, rendered in black pigment, both singly and in groups involved in scenes of hunting and slaughter. As with other rock paintings in Iran, establishing a date for these paintings is difficult, but there are hints both from the presence of certain motifs and from accompanying inscriptions that the paintings were probably created from the Achaemenid (550–330 BCE) to the Parthian period (247 BCE–224 CE). A depiction of a bull-man, as well as the appearance in the inscriptions of the names of divinities such as Nergal, Marduk, Sin, and Šamaš, suggest that the original gods to be worshiped in the cave were Mesopotamian. The use of the cave as a place of worship continued into the Seleucid (312–63 BCE) and then the Parthian and early Sassanian periods, by which time the cave had been transformed into the setting for a cult of Mithra.1

An evaluation of isolation by distance and isolation by resistance on genetic structure of the Persian squirrel (Sciurus anomalus) in the Zagros forests of Iran

AbstractFor the conservation of wild species, it is important to understand how landscape change and land management can affect gene flow and movement. Landscape genetic analyses provide a powerful approach to infer effects of various landscape factors on gene flow, thereby informing conservation actions. The Persian squirrel is a keystone species in the woodlands and oak forests of Western Asia, where it has experienced recent habitat loss and fragmentation. We conducted landscape genetic analyses of individuals sampled in the northern Zagros Mountains of Iran (provinces of Kurdistan, Kermanshah, and Ilam), focusing on the evaluation of isolation by distance (IBD) and isolation by resistance (IBR), using 16 microsatellite markers. The roles of geographical distance and landscape features including roads, rivers, developed areas, farming and agriculture, forests, lakes, plantation forests, rangelands, shrublands, and rocky areas of varying canopy cover, and swamp margins on genetic structure were quantified using individual‐based approaches and resistance surface modeling. We found a significant pattern of IBD but only weak support for an effect of forest cover on genetic structure and gene flow. It seems that geographical distance is an important factor limiting the dispersal of the Persian squirrel in this region. The results of the current study inform ongoing conservation programs for the Persian squirrel in the Zagros oak forest.

Admixture and introgression obscure evolutionary patterns in lesser whitethroat complex (Currucacurruca; Passeriformes; Aves)

Determining the limits of species is still a major area of contention, particularly when diagnostic differentiating characters are subtle and there is a contradiction between morphological and genetic data. The lesser whitethroat (LWT) complex Curruca curruca represents an interesting study system to address this issue. Here, we use phylogeny‐, admixture‐ and principal component analysis‐ (PCA‐) based analyses on whole‐genome sequence data of the parapatric LWT taxa C. c. curruca, C. c. halimodendri, C. c. zagrossiensis and C. c. althaea to investigate the prevalence and importance of gene flow in a geographical area where morphological evidence suggests a clinal transition between populations. The results suggest that LWT populations of the Zagros Mts zagrossiensis may represent a lineage historically diverged from topotypical curruca, the two lineages later coming into secondary contact with extensive gene flow as a result. There is no evidence of a hybrid zone or cline between zagrossiensis and althaea in the Zagros Mts. On the other hand, there is evidence for gene flow between althaea and halimodendri. The results also show possible evidence of admixture from other populations in the LWT complex, extralimital to the sampled area, but the nature of this needs to be evaluated based on a larger data set.