Biology subjects

Cristescu, B.

Publications and source records attributed to Cristescu, B..

3 recordsLinked to original sources

bioRxiv2025

Urbanization drives genetic erosion and population structure in a historically connected carnivore population

Urbanization is a dominant driver of habitat fragmentation globally, creating small, isolated wildlife populations vulnerable to accelerated genetic drift, reduced genetic diversity, and increased population differentiation. We investigated how urban development affects the genetic composition and structure of caracals (Caracal caracal) in Cape Town, South Africa using microsatellites and mitochondrial DNA sequence data. Sampling across four geographically disparate urban and rural populations revealed contrasting temporal patterns: mitochondrial markers indicated historical genetic connectivity among populations, while microsatellite data demonstrated recent genetic structuring driven primarily by urbanization. An extensively isolated urban population showed reduced allelic richness and pronounced genetic differentiation, reflecting urbanization as a strong barrier to gene flow. Within the isolated urban population, GPS-collared caracals demonstrated a degree of spatial genetic organization, with related individuals maintaining significantly higher home range overlap despite inhabiting a severely fragmented urban landscape. This kin-structured space use occurred despite caracals in the system having large home ranges compressed within a relatively small, isolated environment. Our findings reveal that urbanization has rapidly disrupted gene flow in this otherwise geographically widespread and adaptable carnivore, imposing a sufficient barrier to generate detectable genetic consequences within contemporary timeframes. The contrasting signals from historical versus contemporary molecular markers highlight urbanizations role in fragmenting previously connected populations and demonstrates the value of multi-marker approaches for detecting anthropogenic impacts on wildlife populations. These results underscore urbanizations capacity to rapidly alter population genetic dynamics, even in a highly mobile and adaptable carnivore.

genetics↗

bioRxiv2024

Guidelines for evaluating the success of large carnivore reintroductions

Anthropogenic impacts have led to widespread species decline and extirpation, thereby compelling a global movement to protect and regenerate biodiversity through holistic ecosystem restoration including reintroductions. Yet, despite the increasing practice of conservation-driven reintroduction efforts over the past century, peer-reviewed literature and policy providing criteria with which to evaluate reintroduction stages and efficacy remain limited. Without these comprehensive and quantifiable metrics of relative success, such drastic conservation intervention strategies cannot be objectively evaluated nor compared, hindering the advancement of restoration as a discipline. Herein, we systematically reviewed 227 large carnivore reintroductions of 14 terrestrial mammal species across 23 countries since 1930 to contextualize global efforts to date, and from these, have developed a standardized framework to evaluate reintroduction success. We further retrospectively determined the extent to which existing studies met these criteria towards identifying current knowledge gaps and guide future reintroduction efforts. Most large carnivore records were of Felidae (70%) reintroduced into closed systems (69%) across southern Africa (70%). Our proposed framework provides a full suite of stages, indicators, and targets for reintroduction evaluation, which, when retrospectively applied to reviewed studies, indicated that at least one-third lacked sufficient information to effectively evaluate and compare reintroduction outcomes. This comprehensive and prioritized framework provides novel transparency and scalability to large carnivore reintroduction programs, which is increasingly required to secure the sustained support of impacted communities and stakeholder networks. Moreover, the incorporation of this framework into future practice and policy as an applied tool may directly benefit the recovery of at least 30 large carnivore species, while its principles may be applied more broadly across taxonomic groups for faunal rewilding and global ecosystem restoration.

ecology↗

bioRxiv2020

Biogeographical and ecological factors associated with kill rates of an apex predator

AO_SCPLOWBSTRACTC_SCPLOWKill rates and functional responses are fundamental to the study of predator ecology and the understanding of predatory-prey dynamics. As the most widely distributed apex predator in the western hemisphere pumas (Puma concolor) have been widely studied yet a biogeographical synthesis of their kill rates is currently lacking. We reviewed the literature and compiled data on sex- and age-specific kill rate estimates of pumas on ungulates, and conducted analyses aimed at understanding ecological factors explaining the observed variation across their range. Kill rate studies on pumas, while numerous, were primarily conducted in Temperate Conifer Forests (< 10% of puma range), revealing a dearth of knowledge across much of their range, especially from tropical and subtropical habitats. Across studies, kill rates in ungulates/week were highest for adult females with kitten(s) (1.24 {+/-} 0.41 ungulates/week) but did not vary significantly between adult males (0.84 {+/-} 0.18) and solitary adult females (0.99 {+/-} 0.26). Kill rates in kg/day did not differ significantly among reproductive classes. Kill rates of adult pumas increased with ungulate density. Ungulate species richness had a weak negative association with adult male kill rates. Neither scavenger richness, the proportion of non-ungulate prey in the diet, nor regional human population density had a significant effect on ungulate kill rates. Our results had a strong temperate-ecosystem bias highlighting the need for further research across the diverse biomes pumas occupy in order to make species level inferences. Data from more populations would also allow for multivariate analyses providing deeper inference into the ecological and behavioural factors driving kill rates and functional responses of pumas, and apex predators in general.

ecology↗