The saiga antelope (Saiga tatarica), a keystone migratory species of the Central Asian steppes and deserts, is increasingly threatened by habitat fragmentation due to the rapidly expanding transport infrastructure in Kazakhstan, which hosts approximately 95% of the species’ global population. This study provides a spatial assessment of railway and road infrastructure across the contemporary ranges of the Betpaqdala, Ustyurt, and Ural saiga populations. Using the literature and our field data from the 1980s to the present day, combined with geographic information system (GIS)-based analysis of 80,427 km of roads and 4021 km of railways, we have quantified infrastructure densities and identified critical barriers to saiga migration using kernel density and minimum convex polygons (MCP) estimations. The results reveal a negative connection between infrastructure density and occurrences of saiga herds, particularly in the Ustyurt population, where a high railway density coincides with severely reduced migratory activity and a reduction in this population’s winter range by 79.84% since 2015. Major railways such as Sekseuildi–Zhezqazgan, Zhezqazgan–Zharyk, and Shalqar–Beineu intersect essential migratory pathways and have contributed to significant range contraction, subpopulation isolation, and northward shifts in seasonal habitats. In contrast, the Ural population (subject to minimal railway infrastructure interference) has shown robust demographic recovery. While roads are more widespread, their impact is less severe due to greater permeability. However, upcoming projects such as the China–Europe transit corridor and the “Center–West” regional development corridor could amplify future threats. We recommend immediately implementing wildlife-friendly infrastructure, including overpasses and ecological corridors, to preserve the connectivity of saiga ranges and support the long-term conservation of this ungulate species.

The negative effects of ionizing radiation on organs and the reproductive system are well known and documented. Exposure to gamma radiation can lead to oligospermia, azoospermia and DNA damage. Up ...

The rapid recovery of wildlife populations can outpace the assumptions of integrated population models and make visually plausible reconstructions difficult to distinguish from diagnostically supported inference. We evaluated this problem for Kazakhstan saiga antelope (Saiga tatarica) using a Bayesian model-ladder sensitivity audit for the Betpak-Dala, Ustyurt, and Ural populations from 1980 to 2025. We fitted a climate-aware, age- and sex-structured baseline model family M0 (climate-aware static-K baseline comparator) and compared it with dynamic carrying-capacity, observation-regime, hierarchical-prior, joint-hierarchical, non-centred, and sampling-optimised development families using predefined-convergence, effective-sample-size, posterior-predictive, and observed-to-latent mismatch gates. The baseline reconstruction captured the broad collapse–recovery dynamics but systematically underpredicted the observed abundance in 2021–2025 across all three populations. The strongest development family M4b R2 (sampling-optimised joint-hierarchical development family) improved the R-hat values and late-series alignment, with 2025 observed-to-latent ratios of approximately 1.77, 1.43, and 1.49 for Betpak-Dala, Ustyurt, and Ural, respectively, but the effective sample sizes remained below the gate of 400. The study therefore provides a transparent diagnostic reconstruction and model-development audit rather than management-ready Bayesian integrated population model (IPM) inference, identifying where the current baseline fails and which structural directions require further validation.

Currently, there is a rapid and continuous decline in wild animal populations, which threatens accelerated loss of biodiversity on a global scale. Along with in situ conservation strategies, ex situ conservation measures such as germplasm cryopreservation should be widely applied. Cryopreservation in combination with assisted reproductive technologies can become an important means of successfully preserving the biodiversity of the animal world. Methods based on obtaining cell cultures are of great importance in scientific research. The resulting cell lines can be frozen and stored in containers with liquid nitrogen for many years. Such cell and tissue biobanks represent a viable source of genetic material and living cells that offer numerous opportunities for further research. The aim of this study was to investigate the scientific basis for cryopreservation of somatic cells of tugai deer, which is a species in need of special protection. Studies were conducted on the viability of tugai deer fibroblasts using various cryopreservation methods. The viability of frozen-thawed tugai deer fibroblasts was determined, and it was shown that the most effective cryopreservation of this species fibroblasts was the use of a cryoprotectant 1.5 M ethylene glycol and a slow equilibrium freezing mode using a programmed freezer.