Search Results (103)

The expansion of human activities can degrade natural habitats, thereby increasing threats to wildlife conservation. The wild populations of many species have declined due to the modification of natural habitats by humans. The Arabian wolf (Canis lupus arabs) is a subspecies of the gray wolf that is of conservation concern across its distribution range. The Arabian wolf is understudied in certain habitats (e.g., mountainous areas), which limits understanding of its overall ecology. Given its vulnerable conservation status, this study aimed to collect relevant data and information on incidents and potential threats facing this predator in the rugged mountainous habitats of western Tabuk province, Saudi Arabia, and how the effects of these threats can be minimized. In these mountain habitats Arabian wolves encounter various severe threats that challenge relevant conservation efforts. Observations of such threats—some of which result in wolf mortality—represent serious challenges to the survival of wild Arabian wolves. Conflicts with humans and livestock represent considerable threats that must be appropriately managed. Additionally, the potential association between Arabian wolves and free-ranging dogs requires further investigation. Various conservation scenarios and mitigation approaches can be applied to help reduce negative impacts on Arabian wolf populations and maximize their likelihood of survival. Overall, ensuring the persistence of such a unique desert-adapted apex predator in this ecosystem must become a conservation priority. Full article

The escalating global contamination of aquatic ecosystems by pharmaceuticals and endocrine-disrupting chemicals (EDCs) stemming from diverse anthropogenic sources represents a critical and pervasive threat to planetary Earth. These contaminants exhibit bioaccumulative properties in long-lived organisms and undergo trophic biomagnification, leading to elevated concentrations in apex predators. This review synthesizes current knowledge regarding the far-reaching impacts of pharmaceutical and EDC pollution on the reproductive biology of aquatic fauna, focusing on the heightened vulnerability of the endangered African penguin. A rigorous literature review across key scientific databases—PubMed, Scopus, Web of Science, and Google Scholar—using targeted search terms (e.g., penguins, contaminants of emerging concern, penguin species, seabird species, Antarctica, pharmaceuticals, personal care products, EDCs) underpins this analysis. This review explores the anthropogenic sources of pharmaceuticals and EDCs in aquatic ecosystems. It discusses the mechanisms by which these chemicals disrupt the reproductive physiology of aquatic fauna. Recent studies on the ecological and population-level consequences of these contaminants are also reviewed. Furthermore, the review elaborates on the urgent need for comprehensive mitigating strategies to address their effects on vulnerable penguin populations. These approaches hold the potential to unlock innovative pathways for conservation initiatives and the formulation of robust environmental management policies aimed at safeguarding aquatic ecosystems and the diverse life they support. Full article

A century ago, wolves ranged throughout Croatia but were eradicated from Slavonia—a region that could serve as a crucial corridor connecting the Carpathian and Dinaric–Balkan wolf populations. Such a corridor would promote genetic exchange and help maintain ecosystem stability. Recent wolf sightings in Slavonia indicate that natural recolonization may be possible. Understanding how this process unfolds under different management scenarios is essential for minimizing conflicts and supporting successful recolonization. In this study, we modeled wolf population dynamics in Slavonia and surrounding areas using 11 scenarios, grouped into three categories: adverse events, increased carrying capacity, and population supplementation. These scenarios encompassed various management strategies, including a baseline scenario and others designed to address system uncertainties. Our results show that scenarios involving corridor construction and wolf translocation have the lowest probability of extinction. In contrast, adverse events carry a high risk of extinction, and simply expanding suitable habitats is not enough to ensure population viability. These findings underscore the importance of integrated conservation strategies that combine habitat corridors, population management, and conflict mitigation. Long-term planning is critical, as differences in outcomes become more pronounced over time. Connectivity with stable neighboring populations is vital for the long-term survival of wolves in the region. Future research should investigate whether protected areas alone are sufficient to sustain wolves as apex predators or if large-scale ecosystem restoration—including trophic rewilding—is necessary for successful recolonization. Full article

The Xingyi Fauna yields abundant and well-articulated skeletons of Ladinian (Middle Triassic, ab. 240 Ma) marine reptiles, associated with fishes, conodonts, crinoids, ammonoids, bivalves, arthropods, and other fossils including nannofossils and coprolites. It represents a new marine ecosystem fully developed after the end-Permian Mass Extinction, and characterized by the appearance of a diversity of large marine reptiles with large ichthyosaurs as the apex predators. Twenty marine reptile and 17 fish species have been reported. The sequence of the Xingyi Fauna records the transition from a marine ecosystem dominated by air-breathing tetrapods extending across the shallow platform to the deep ocean, as indicated by large marine reptiles with a capability for long-distance cruising into the outer sea. The faunal composition of the Lower Assemblage of the Xingyi Fauna, dominated by small- to medium-sized pachypleurosaurids and nothosaurids, is similar to that of the older Anisian Panxian Fauna and the western Tethyan Monte San Giorgio Fauna, but the faunal composition of the Upper Assemblage, with large ichthyopterygians, pistosauroid sauropterygians, and flying fishes, is similar to that of the younger Carnian Guanling Biota as well as the Raibl and Polzberg Faunas in the Alps and California. Therefore, the Xingyi Fauna can be considered a hub of paleobiogeological exchange connecting the western Tethys and the eastern Pathalassa. Full article

Assessing the ranging and dispersal behavior of apex predators and its consequences for landscape connectivity is of paramount importance for understanding population and ecosystem effects of anthropogenic land use change. Here, we synthesize ranging and dispersal ecological information on pumas (Puma concolor) and present estimates of how different land uses affect the space use and dispersal of pumas on fragmented landscapes in an ecotone between biodiversity hotspots in southeastern Brazil. Additionally, we evaluate the effect of animal translocations on dispersal and movement patterns. Using location data for 14 GPS-collared pumas and land use data, we assessed when, how long, and how far individuals dispersed; how forest loss and infrastructure influenced puma home range size; and how movement patterns changed according to land use and proximity to infrastructure, during ranging and dispersal, for residents, natural dispersers, and translocated individuals. We present the first detailed record on the dispersal of pumas in Brazil and in the tropics, including long-distance dispersals, and show that pumas moved faster and more linearly during dispersal than during ranging. Their movement was slower and their home ranges were smaller in more forested areas, underscoring the importance of forest as habitat. In contrast, movement rates were higher in open pastures, mainly during dispersal. Our study underscores the scarcity of research on puma space use and dispersal in South America and reveals partial divergences in dispersal behaviors compared to North America and temperate regions, especially concerning dispersal ages. Furthermore, we give the first steps in presenting how land cover and human infrastructure affect the movement of this apex predator in a tropical ecosystem, an important subsidy for land use management. We call for more comprehensive studies on the movement ecology of carnivores combined with long-term population monitoring, to allow linking individual behavior with metapopulation dynamics and landscape connectivity and drawing more effective measures to sustain their populations. Full article

Research on anticoagulant rodenticides (ARs) in wildlife has primarily focused on apex predators, with less attention given to their potential integration into lower trophic levels and the associated exposure pathways. At the base of the terrestrial food web, invertebrates have been suggested as potential vectors of ARs to insectivorous species such as small mammals, reptiles, and birds. To explore this hypothesis, we analyzed the presence of nine anticoagulant rodenticides—including both first-generation (FGARs) and second-generation (SGARs) rodenticides—in 36 liver samples from Yemen chameleons (Chamaeleo calyptratus) and 98 liver samples from six non-raptorial, predominantly insectivorous bird species from the Canary Islands. Through HPLC-MS/MS analysis, only SGARs were detected in both animal groups collected between 2021 and 2024. Approximately 80% of reptiles and 40% of birds tested positive for at least one SGAR, with brodifacoum being the most frequently detected compound. In more than 90% of positive cases, it was found as the sole contaminant, while co-occurrence with other SGARs was uncommon. Additionally, most concentrations were below 50 ng/g wet weight, except for two bird specimens, suggesting heterogeneous exposure scenarios and potential variability in contamination sources across individuals. These findings provide evidence of AR integration at the base of the terrestrial food web in the Canary Islands and suggest secondary exposure via invertebrates as a plausible route of contamination. Further research directly analyzing invertebrate samples is needed to confirm their role as vectors of ARs to insectivorous wildlife in insular ecosystems. Full article

The Bay of Bengal (BoB) is a global hub for marine elasmobranchs, particularly sharks and rays. These apex predators maintain and structure the balanced marine ecosystem and food webs. Marine elasmobranchs in Bangladesh are under-researched and under-managed, and face threats such as habitat degradation, global warming, pollution, illegal fishing, and overexploitation. This study aimed to evaluate the stock status of marine elasmobranches in the Bay of Bengal (BoB), Bangladesh. This research used catch and effort (CE) data for a period of 21 years (2002–2022). Both the Monte Carlo CMSY and BSM models were applied to assess biomass, exploitation rates, and sustainable yields. The BSM estimated a maximum carrying capacity (k) of 134,000 mt, which is larger than the CMSY estimate of 119,000 mt. The estimated intrinsic annual growth (r) from CMSY was 0.282. The MSY values ranged from 5110 mt (BSM) to 8420 mt (CMSY), with BSM indicating overexploitation, as the 2022 catch (7017 mt) exceeded the BSM-derived MSY. Both models suggested depleted and overfishing stock conditions, with B/B_MSY ratios < 1.0 and F/F_MSY ratios > 1.0. Effective management is crucial to prevent overfishing and ensure sustainable practices. Elasmobranch catches must be kept below the BSM-estimated maximum sustainable yield (MSY) of 5110 metric tons with fishing pressure maintained at or below F/F_MSY = 1.0. It is vital to regulate illegal and unlicensed fishing activities. Because of the aggregation of CE data, the results should be interpreted cautiously and never serve as a substitute for species-level assessments. Full article

Eurasian otters, as apex predators in freshwater ecosystems, are crucial to maintaining nutrient cycling and habitat stability. Although Eurasian otters prefer unaltered natural habitats, their adaptive and opportunistic behavior allows them to occupy suboptimal environments, including urbanized areas. As urbanization increases, the pressure on apex carnivores like the Eurasian otter will continue to grow. To date, urban stream restoration plans have not used the Eurasian otter as a keystone species, but given their influence across the trophic levels, Eurasian otter-focused restoration plans could enhance otter populations and overall biodiversity in urban areas. Here, we lay out six principles designed as a template for enhancing urban habitats for Eurasian otters as well as biodiversity. The principles (enhancing habitat structure complexity, restoring natural riparian vegetation and habitats, safeguarding water quality, providing native prey species, reducing otter mortality, and promoting positive public perception) are essential for urban ecosystem regeneration focused on Eurasian otters. Although there have been no urban restoration projects specifically tailored toward Eurasian otters, initiatives based on similar principles have been effective in promoting biodiversity and otter presence. Overall, an urban habitat restoration plan focused on Eurasian otters will not just increase otter presence but biodiversity across all trophic levels. Full article

On 14 December 2005, there was a catastrophic flood after a failure in the upper reservoir at the Taum Sauk Plant in southern Missouri. While there has been extensive research on the cause of the dam’s failure and the flood’s immediate impact, there has been limited investigation on how vegetation in and around the resulting flood scour has changed since this event. This study fills this gap through a time-series analysis using imagery sourced from GloVis and Planet Explorer to quantify vegetation levels prior to the flood (2005) through to 2024. Vegetation level was calculated using the Normalized Difference Vegetation Index (NDVI), which measures the level of greenness via light reflected by vegetation. Vegetation levels inside of the scour were compared to two 120 m buffer areas surrounding the scour, immediately adjacent (0–120 m) and at 120–240 m from the scour’s edge. Within the scour, NDVI analysis showed a dramatic loss of vegetation immediately after the flood, followed by varying levels for several years, before a steady increase in the proportion of areas with vegetation starting in 2014. The buffer area adjacent to the edge of the scour showed a similar pattern, but at lower magnitudes of change, which likely reflects the ragged edge created by the flood. The buffer area farther from the edge showed a consistent pattern of high vegetation, which likely reflects the broader landscape. While ground truthing confirmed these patterns between 2006 and 2011, in 2012, the ground truthing revealed much recovery in small local areas within the scour that were not apparent though NDVI analysis. These local areas of recovery were reflected in the pattern of recolonization of the scour from nearby glades (i.e., natural habitats of exposed bedrock) by glade flora and by the eastern collared lizard (Crotaphytus collaris collaris), an apex predator adapted to living in rocky, open areas and a bioindicator of vegetation recovery. While recovery of vegetation occurred steadily after 2012, ground truthing indicated that the original oak/hickory forest was now a minor component of this recovery, and that glade species dominated the former forested area. Full article

The conservation of Siberian tigers, the apex predators in the Asia–Pacific region, hinges on a thorough understanding of their physiological statuses and adaptive mechanisms. In order to fill a critical gap in our knowledge of this endangered species, we conducted comprehensive analyses of Siberian tiger whole blood and serum using modern hematology and biochemical analyzers. The blood samples were collected from subadult (2–3 years old) Siberian tigers (n = 15 for hematological analysis and n = 7 for biochemical analysis). In the present study, distinct hematological patterns including an elevated mean platelet volume (MPV) and a higher red cell distribution width coefficient of variation (RDW-CV) were observed, which were possibly triggered by pre-anesthesia resistance movements. Notably, the neutrophil percentage in Siberian tigers was found to be significantly higher than that in domestic cats and Bengal tigers, suggesting species-specific immune adaptations. In addition, serum biochemical analysis provided refined parameter ranges for subadult tigers. Unlike previous studies encompassing a broader age range, our data specifically characterize biochemical profiles in subadult tigers, offering vital baselines for health monitoring and conservation strategies. These results not only enhance our understanding of the biology of Siberian tigers but also provide scientific support for targeted conservation efforts, fostering population recovery and ecological balance in their natural habitats. Full article

(1) Background: Limited information on Echinococcus species among the wildlife in Tanzania has created a significant knowledge gap regarding their distribution, host range, and zoonotic potential. This study aimed to enhance the understanding of Echinococcus felidis transmission dynamics within the great Serengeti ecosystem. (2) Methods: A total of 37 adult Echinococcus specimens were collected from a leopard (Panthera pardus) (n = 1) in Maswa Game Reserve and 7 from a lion (Panthera leo) (n = 1) in Loliondo. Two hydatid cysts were also obtained from warthogs (n = 2) in the Serengeti National Park. (3) Results: Morphological examination revealed infertile cysts in warthogs that were molecularly identified as E. felidis. This marks the first molecular evidence of E. felidis in leopards and warthogs in Tanzania. Pairwise similarity analysis showed 98.7%–99.5% identity between Tanzanian, Ugandan, and South African isolates. Thirteen unique haplotypes were identified, with a haplotype diversity of (Hd = 0.9485) indicating genetic variability. Phylogenetic analysis grouped E. felidis into a single lineage, with the leopard isolate forming a distinct haplotype, suggesting leopards as an emerging host. Lion and warthog isolates shared multiple mutational steps, suggesting possible genetic divergence. (4) Conclusions: This study confirms African lions and leopards as definitive hosts and warthogs as potential intermediate hosts of E. felidis in the Serengeti ecosystem. Our findings highlight disease spillover risks and stress the importance of ecosystem-based conservation in wildlife–livestock overlap areas. Although E. felidis is believed to be confined to wildlife, the proximity of infected animals to pastoralist communities raises concerns for spillover. These findings highlight the importance of ecosystem-based surveillance, especially in wildlife–livestock–human interface areas. Full article

A large data set of new and previously published measurements of δ¹³C values derived from tooth enamel (n = 223, of which 93 are new) are compiled to explore patterns of foraging area preferences of Late Cretaceous mosasaurid squamates over evolutionary time scales (~93–66 Ma). Our results indicate that small-bodied halisaurines are restricted to a relatively nearshore range, overlapping the lower end of the range of plioplatecarpines and some mosasaurine taxa. Most moderately sized plioplatecarpines occupy a relatively narrow foraging area in much of the nearshore and proximal offshore marine foraging area for the majority of their existence. Tylosaurines exhibit a greater offshore marine range than plioplatecarpines, consistent with their large body size and the robustness of their feeding apparatus. The largest tylosaurine taxa are replaced by Mosasaurus in the Late Campanian–Maastrichtian in the offshore foraging range. Mosasaurine taxa are found to occupy the broadest range of foraging areas, but their ranges are taxonomically segregated, consistent with adult body size and the diversity of feeding adaptations such as tooth morphologies and skull architecture seen in that subfamily. Where foraging areas of multiple taxa overlap, differences are typically in tooth form, reflecting prey preference or feeding niche. Foraging area occupation by multiple taxa with similar tooth forms suggests that other factors such as body size and prey acquisition style may have allowed for the finer partitioning of resources. Deep diving and long submergence may have also contributed to the depleted signals recovered for some of the large-bodied durophages and the largest of the macrophagous apex predators. Full article

Mesopredator suppression has implications for community structure, biodiversity, and ecosystem function, but mesopredators with physical defenses may not avoid apex predators. We investigated nine-banded armadillos (Dasypus novemcinctus) in southwestern Oklahoma (USA) to evaluate if a species with physical defenses was influenced by a dominant predator, the coyote (Canis latrans). We sampled nine-banded armadillos and coyotes with motion-activated cameras. We used single-species and conditional two-species occupancy models to assess the influences of environmental factors and coyotes on nine-banded armadillo occurrence and site-use intensity (i.e., detection). We used camera-based detections to characterize the diel activity of each species and their overlap. Nine-banded armadillo occupancy was greater at sites closer to cover, with lower slopes, and further from water, whereas coyote space use was greater at higher elevations; both species were positively associated with recent burns. Nine-banded armadillo occurrence was not influenced by coyotes, but site-use intensity was suppressed by the presence of coyotes. Nine-banded armadillos (strictly nocturnal) and coyotes (predominantly nocturnal) had a high overlap in summer diel activity. Nine-banded armadillos are ecosystem engineers but are often considered a threat to species of concern and/or a nuisance. Thus, understanding the role of interspecific interactions on nine-banded armadillos has important implications for conservation and management. Full article

Heavy metal contamination in marine ecosystems poses a critical environmental challenge, with significant implications for biodiversity, trophic dynamics, and human health. Marine fish are key bioindicators of heavy metal pollution because of their role in food webs and their capacity for bioaccumulation and trophic transfer. This review synthesizes current knowledge on the pathways and mechanisms of heavy metal accumulation in marine fish, focusing on factors that influence the uptake, retention, and tissue distribution. We explore the processes governing trophic transfer and biomagnification, highlighting species-specific accumulation patterns and the risks posed to apex predators, including humans. Additionally, we assess the ecological consequences of heavy metal contamination at population, community, and ecosystem levels, emphasizing its effects on fish reproduction, community structure, and trophic interactions. By integrating recent findings, this review highlights key knowledge gaps and suggests future research directions to improve environmental monitoring and risk assessment. Given the persistence and bioavailability of heavy metals in marine environments, effective pollution control strategies and sustainable fisheries management are imperative to mitigate long-term ecological and public health risks. Full article

This study investigated the presence and levels of five key mycotoxins—aflatoxins (AFs), deoxynivalenol (DON), fumonisin B1 (FB1), ochratoxin-A (OTA), and zearalenone (ZEN) and its metabolite alpha-zearalenol (α-ZOL)—in liver samples from 19 golden jackals (Canis aureus) in southern Hungary. Golden jackals, as apex predators with a diverse diet encompassing both plant and animal matter, can serve as valuable bioindicators of environmental mycotoxin contamination. Genetic analysis confirmed the canid samples as coming from golden jackals, excluding the possibility of domestic dogs or hybrid individuals. All samples tested positive for at least three mycotoxins, with multiple mycotoxins frequently co-occurring. DON was detected in 95% of the samples, followed by FB1 (79%) and ZEN (42%). ZOL, AFs, and OTA were present in all samples. Significant differences in mycotoxin concentrations were observed between age groups and sexes for some mycotoxins. Specifically, adult males exhibited higher ZEN concentrations, adult females had higher OTA levels, and females generally showed significantly higher DON concentrations than males. For all investigated individuals, we found significantly higher concentrations of ZEN, alpha-ZOL, and OTA in adult samples. Malondialdehyde (MDA), an indicator of oxidative stress, was also measured and correlated with mycotoxin levels. Pareto analysis suggested a correlation between MDA and OTA/ZEN. These findings highlight the exposure of golden jackals to a range of mycotoxins in their natural environments, potentially through both plant and animal food sources, and underscore the potential of these canids as sentinels for mycotoxin contamination in ecosystems. Full article