Prevalence of renal calculi in wolverine (Gulo gulo) from northwestern Canada

Wolverines (Gulo gulo) in the Arctic: Revisiting distribution and identifying research and conservation priorities amid rapid environmental change

Wolverines (Gulo gulo) occupy most of the globe’s Arctic tundra. Given the rapidly warming climate and expanding human activity in this biome, understanding wolverine ecology, and therefore the species’ vulnerability to such changes, is increasingly important for developing research priorities and effective management strategies. Here, we review and synthesize knowledge of wolverines in the Arctic using both Western science sources and available Indigenous Knowledge (IK) to improve our understanding of wolverine ecology in the Arctic and better predict the species’ susceptibility to change. To accomplish this, we update the pan-Arctic distribution map of wolverines to account for recent observations and then discuss resulting inference and uncertainties. We use these patterns to contextualize and discuss potential underlying drivers of distribution and population dynamics, drawing upon knowledge of food habits, habitat associations, and harvest, as well as studies of wolverine ecology elsewhere. We then identify four broad areas to prioritize conservation and research efforts: (1) Monitoring trends in population abundance, demographics, and distribution and the drivers thereof, (2) Evaluating and predicting wolverines’ responses to ongoing climate change, particularly the consequences of reduced snow and sea ice, and shifts in prey availability, (3) Understanding wolverines’ response to human development, including the possible impact of wintertime over-snow travel and seismic testing to reproductive denning, as well as vulnerability to hunting and trapping associated with increased human access, and (4) Ensuring that current and future harvest are sustainable.

High prevalence, intensity, and genetic diversity of Trichinella spp. in wolverine (Gulo gulo) from Yukon, Canada

Background

Species of Trichinella are globally important foodborne parasites infecting a number of domestic and wild vertebrates, including humans. Free-ranging carnivores can act as sentinel species for detection of Trichinella spp. Knowledge of the epidemiology of these parasites may help prevent Trichinella spp. infections in northern Canadian animals and people. Previous research on Trichinella spp. in wildlife from Yukon did not identify risk factors associated with infection, or the diversity and identity of species of Trichinella in regional circulation, based on geographically extensive sampling with large sample sizes.

Methods

In a cross-sectional study, we determined the prevalence, infection intensity, risk factors, and species or genotypes of Trichinella in wolverine (Gulo gulo) in two regions of Yukon, Canada, from 2013–2017. A double separatory funnel digestion method followed by mutiplex PCR and PCR-RFLP were used to recover and identify species of Trichinella, respectively.

Results

We found larvae of Trichinella in the tongues of 78% (95% CI 73–82) of 338 wolverine sampled. The odds of adult (≥ 2 years) and yearling (1 year) wolverine being Trichinella spp.-positive were four and two times higher, respectively, compared to juveniles (<1 year). The odds of Trichinella spp. presence were three times higher in wolverine from southeast than northwest Yukon. The mean intensity of infection was 22.6 ± 39 (SD, range 0.1–295) larvae per gram. Trichinella T6 was the predominant genotype (76%), followed by T. nativa (8%); mixed infections with Trichinella T6 and T. nativa (12%) were observed. In addition, T. spiralis was detected in one wolverine. Out of 22 isolates initially identified as T. nativa in multiplex PCR, 14 were analyzed by PCR-RFLP to distinguish them from T. chanchalensis, a recently discovered cryptic species, which cannot be distinguished from the T. nativa on multiplex PCR. Ten isolates were identified either as T. chanchalensis alone (n = 7), or mixed infection with T. chanchalensis and T. nativa (n = 2) or T. chanchalensis and Trichinella T6 (n = 1)].

Conclusions

Wolverine hosted high prevalence, high larval intensity, and multiple species of Trichinella, likely due to their scavenging habits, apex position in the food chain, and wide home range. Wolverine (especially adult males) should be considered as a sentinel species for surveys for Trichinella spp. across their distributional range.

UROLITHIASIS IN FREE-RANGING AND CAPTIVE OTTERS (LUTRA LUTRA AND AONYX CINEREA) IN EUROPE

Between 1996 and 1998, 477 dead otters from different Central European countries were examined for urolithiasis, including 449 free-ranging Eurasian otters (Lutra lutra) as well as 17 Eurasian otters and 11 Asian small-clawed otters (Aonyx cinerea) from captivity. In the free-ranging specimens, uroliths (sand or stones) were found in 105 animals (23.4%), with no significant difference (P = 0.77) between the sexes. Uroliths were not present in any juveniles (n = 26) and urolithiasis was not considered the main cause of death in any individual. In captive specimens, uroliths were found in 11 out of 17 Eurasian otters (64.7%; four males and seven females), and in 3 out of 11 Asian small-clawed otters (27.3%). Histology could not find any signs of inflammation in examined kidneys (n = 179) or urinary bladders (n = 66). Analyzed stones of free-ranging and captive Eurasian otters were composed mainly of ammonium acid urate. The stones of three captive Asian small-clawed otters consisted mainly of calcium oxalate. The difference in prevalence of uroliths between free-ranging and captive Eurasian otters was significant (P < 0.001). Nevertheless, the prevalence in free-ranging specimens of this study is higher than reported before. Differences between various habitats, environmental changes, and genetic predisposition all represent potential hypothetical explanations for these findings.