Geology topics

Mahmoud-Reza Hemami

Publications and source records attributed to Mahmoud-Reza Hemami.

4 recordsLinked to original sources

USGS2026

When the desert dries: Rainfall drives conflicts and conservation challenges for onager (Equus hemionus onager)

Increasingly, the conservation of large and wide-ranging animals is challenged by environmental variability, static boundaries of protected areas, and the expansion of human activities. The Critically Endangered Onager ( Equus hemionus onager ) exemplifies these issues in Qatrouiyeh National Park (QNP) and the surrounding Bahram-e-Goor Protected Area (BPA) in Iran. Using GPS telemetry data from 9 adult females tracked over 2 years, we examined seasonal patterns in movement and incursions into cultivated lands in 2017 and 2018. Net squared displacement analyses indicated that most individuals exhibited range-resident behavior with occasional nomadic movements, with no evidence for migration (i.e., predictable movements to and from distinct seasonal ranges). Both monthly home range size and monthly movement rate varied seasonally, peaking in late spring and early summer (May–July). Individual home ranges were between 257 and 1,928 km 2 , while the extrapolated population-level home range (718 km 2 ; 95% confidence interval = 276–1368) extended well outside QNP, covering large portions of the BPA. Occurrence distributions also expanded beyond the protected area into adjacent cultivated lands, highlighting the use of human-occupied areas by onagers. We recorded 2,285 (out of 72,168) GPS locations within cultivated lands and their surrounding 50 m buffer, with 60% of these incursions occurring immediately adjacent to QNP. Most incursions occurred at night and were strongly associated with both season and cumulative rainfall over the preceding 9 months. These findings emphasize how rainfall-driven variability in resource dynamics shapes the spatial distribution and behavior of onagers, thus elevating the risk of conflict with humans. The scale and seasonality of Onager movements highlight the need for flexible, landscape-level conservation strategies that extend beyond fixed park boundaries to encompass critical habitats and to mitigate conflict across the broader region.

Bahram-e-Goor Protected Area, Qatrouiyeh National ↗

USGS2024

Rainfall reduces the potential for competitive suppression of a globally endangered ungulate by livestock

Protected areas often are too small to house populations of wide-ranging species. Viability of wildlife populations therefore depends on whether interactions with humans and their land uses are negative, neutral, or positive. In central Iran, we measured interactions between globally endangered onagers (Equus hemionus onager) and livestock by analyzing remotely-sensed vegetation metrics within livestock grazing areas, tracking 9 animals with GPS telemetry, and assessing onagers' diet quality through analysis of fecal samples. Resource selection by onagers depended both on season and the presence of livestock. During the dry season, livestock reduced forage (some combination of forage biomass and forage quality) compared to pre-grazing periods, demonstrating potential for competitive suppression of onagers by livestock when resources are scarce. Additionally, and during both seasons, selection for forage by onagers was accentuated at night when livestock were absent, indicating onager avoidance of livestock. During the wet season, onagers exposed to livestock exhibited higher-quality diets than those that did not co-occur with livestock, suggesting that livestock grazing may potentially enhance forage quality for onagers. Consequently, collaboration with pastoralists to regularly rotate the locations of dry and wet season leases could alleviate negative effects of livestock grazing on onagers. Similar to other cases in multi-use landscapes, temporal shifts in the strength of competition—driven by diel cycles and seasonal rainfall—may characterize wildlife-livestock interactions in Iran and elsewhere in Asian rangelands. Our study highlights the possibility that conservation of an endangered mammal could be compatible with livestock production, at least during wet seasons.

Bahram-e-Goor Protected Area (BPA), Qatrouiyeh Nat↗

USGS2021

Body size and digestive system shape resource selection by ungulates: A cross-taxa test of the forage maturation hypothesis

The forage maturation hypothesis (FMH) states that energy intake for ungulates is maximised when forage biomass is at intermediate levels. Nevertheless, metabolic allometry and different digestive systems suggest that resource selection should vary across ungulate species. By combining GPS relocations with remotely sensed data on forage characteristics and surface water, we quantified the effect of body size and digestive system in determining movements of 30 populations of hindgut fermenters (equids) and ruminants across biomes. Selection for intermediate forage biomass was negatively related to body size, regardless of digestive system. Selection for proximity to surface water was stronger for equids relative to ruminants, regardless of body size. To be more generalisable, we suggest that the FMH explicitly incorporate contingencies in body size and digestive system, with small-bodied ruminants selecting more strongly for potential energy intake, and hindgut fermenters selecting more strongly for surface water.

Ecology Letters↗

USGS2016

Maxent modeling for predicting potential distribution of goitered gazelle in central Iran: the effect of extent and grain size on performance of the model

The spatial scale of environmental layers is an important factor to consider in developing an understanding of ecological processes. This study employed Maxent modeling to investigate the geographic distribution of goitered gazelle, Gazella subgutturosa (Güldenstädt, 1780), in central Iran using uncorrelated variables at a spatial resolution of 250 m. We used spatial downscaling to downscale WorldClim data to 250-m resolution. We evaluated the sensitivity of the model to different grain and extent sizes from 250 m to 3 km. We compared the performance of the model at different scales using suitability indexes (AUC) and predicted habitat areas. Two models performed with AUC values higher than random (AUCun = 0.957, AUCpu = 0.953). The distribution of potential habitats at 250- m grid size was strongly influenced by bioclimatic data, vegetation type and density, and elevation. There were few spatial divergences between uncorrelated and pruned models. The mean AUC across eight different spatial scales ranged from 0.936 to 0.959. There was a significant negative correlation between grain size and AUC (R2 = 0.57). An increase in grain size increased the predicted habitat area. The extent size and AUC showed a positive correlation (R2 = 0.18). Predicted suitability habitat also decreased as extent size increased (R2 = 0.49). Spatial congruence AUC fluctuated within a small range and the maximum difference occurred between models of 1 × 1 and 2.5 × 2.5 km. These results showed that an increase in extent size is more accurate than an increase in grain size, and the maximum accuracy for predicting distribution of goitered gazelle in Iran was obtained if the grain size and extent size were 750 m.

Turkish Journal of Zoology↗