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Conflicts often arise when large predators and free-ranging livestock share a common area. Various compensation schemes are used to attempt solving these conflicts, but the costs of predation to suffering stakeholders are often unknown. Semi-domesticated reindeer husbandry and large carnivores form one such system, where conflicts between predator conservation and the traditional livelihood are common. We apply an age- and sex-structured reindeer-lichen model to examine the effects of predation on reindeer management. Based on the previous studies we specify age- and sex-class-specific mortalities due to various predators, and study optimal reindeer husbandry under predation pressure and the costs of predation. We show that the costs of predation highly depend on the age-class-specific killing rates of reindeer by various predator species, but not on interest rate or pasture conditions. Regarding species that are more likely to kill adult reindeer in addition to calves, the total predation costs are clearly higher than the net slaughtering value of the predated animals. The decrease in steady-state yearly net income is highest for the gray wolf and lower for other predator species. Adapting to predation pressure includes increasing the size of the reindeer population in winter and changing the slaughtering age of males towards young adults, thus reducing the importance of calf harvesting. This result contrasts with the previous results from stage-structured models that do not fully include time lags related to long-living ungulate species. The costs of predation appear to be much higher in an ex post system than in a territorial compensation system, as in an ex post system herders have not adapted to the predation pressure and must search for the predated reindeer to gain compensations. Our results suggest that co-existence of a viable gray wolf population and profitable reindeer husbandry in the same area is not possible in most cases.
Benjamin Folliot, Guillaume Souchay, Jocelyn Champagnon, Matthieu Guillemain, Maurice Durham, Richard Hearn, Josef Hofer, Jacques Laesser, Christophe Sorin, Alain Caizergues
In western Europe, common pochard populations have experienced a sharp decline over the last two decades, together with an increasing proportion of males. Both of these changes were suggested to result from decreasing survival of nesting females (i.e. survival of adult females) owing to increasing predation pressure. To test this hypothesis, we used capture–mark–recapture/recovery data of common pochard ringed during autumn–winter (October–February) in three countries of western Europe (Switzerland, United Kingdom and France). We found no evidence for decreasing survival of individuals ringed in the United Kingdom or in Switzerland over the long term (1977–2011). In France, adult males and juvenile females experienced significant decreasing survival over a shorter interval (2004–2017). Overall, females displayed lower survival than males, although this was only weakly supported by the French dataset. In contrast, only sex differences and no age differences in survival rates were recorded in the UK and Switzerland (females 0.67 ± 0.03 and 0.69 ± 0.03; males: 0.81 ± 0.01 and 0.75 ± 0.01, respectively), while both age and sex differences were recorded for France (adult females 0.62 ± 0.07, adult males 0.66 ± 0.07, juvenile females 0.49 ± 0.08, juvenile males 0.54 ± 0.08). Therefore, decreasing survival of adult females was unlikely the underlying cause of the decline of common pochard populations in western Europe. Using an age-structured two-sex matrix population model, we show that when adult males experience higher survival than adult females (as it is the case for common pochards), decreasing survival of nests and/or juveniles can trigger decreasing population size and increasing proportions of males at the same time.
Hair morphological structure is widely utilized for species identification based on the differentiation of scales and medullar pattern of mammal hairs. To determine what may influence the accuracy of identification using hair morphology, we measured and calculated 11 parameters of hair morphometry of 10 deer species in China. Our results suggested that the morphological parameters of deer hairs have extensive overlap within Cervidae species and we obtained a correct discriminant rate of 90.1% for 10 deer species. For the five sympatric deer species in the northeastern forests of China, 94.2% of hairs can be identified correctly, with a correct discriminant rate of 89.7% and 83.9% when the hair tip or root was absent, respectively. When both hair tip and root were absent, we obtained a correct discriminant rate of 73.6%. In addition, we obtained a correct discriminant rate of 97.9% for five sympatric deer species using a blind test approach to remove observer bias. Hair morphological characteristics are similar within the family or genus because of their close genetic relationships. Furthermore, species with similar living habitat conditions may have similar hair morphological structure. These factors influence discriminant capacity, and we evidently cannot identify them more accurately when using only one morphological parameter of hair. While understanding the above, our quantitative multi-parameter morphometric analyses successfully identified the hairs of deer, and likely have significant applications concerning further mammal species.
Wildlife managers conduct population inventories to monitor species, particularly those at-risk. Although costly and time consuming, grid-based DNA hair-snag sampling has been the standard protocol for grizzly bear inventories in North America, while opportunistic fecal DNA sampling is more commonly used in Europe. Our aim is to determine if low-cost, low-effort scat sampling along roads can replace the current standard. We compare two genetic non-invasive techniques using concurrent sampling within the same grid system and spatially explicit capture–recapture. We found that given our methodology and the present status of fecal genotyping for grizzly bears, scat sampling along roads cannot replace hair sampling to estimate population size in low-density areas. Hair sampling identified the majority of individual grizzly bears, with a higher success rate of individuals identified from grizzly bear samples (100%) compared to scat sampling (14%). Using scat DNA to supplement hair data did not change population estimates, but it did improve estimate precision. Scat samples had higher success identifying species (98%) compared with hair (80%). Scat sampling detected grizzly bears in grid cells where hair sampling showed non-detection, with almost twice the number of cells indicating grizzly bear presence. Based on our methods and projected expenses for future implementation, we estimated an approximate 30% cost reduction for sampling scat relative to hair. Our research explores the application of genetic non-invasive approaches to monitor bear populations. We recommend wildlife managers continue to use hair-snag sampling as the primary method for DNA inventories, while employing scat sampling as supplemental to increase estimate precision. Scat sampling may better indicate presence of bear species through greater numbers and spatial distribution of detections, if sampling is systematic across the entire area of interest. Our findings speak to the management of other species and regions, and contribute to ongoing advances of monitoring wildlife populations.
Food storage (caching, hoarding), which is observed in many species of animals, increases food availability during times of food insecurity. Both species of beaver (Eurasian beaver, Castor fiber, and the North American beaver, C. canadensis) living at northern latitudes where food may be scarce during winter are larder-hoarders, constructing a food cache of branches of woody species during autumn. We studied the food caching behavior of the Eurasian beaver in three northern European countries (Sweden, Norway, Lithuania) to provide additional insight into this important behavior. Thirty-seven of forty-seven (79%) active family groups had food caches by mid-November and 41 of 47 (87%) had caches by December. Water depth of caches ranged from 1 to 2.3 m and depths at caches in Sweden were significantly deeper than in either Norway or Lithuania. Construction of caches began as early as late September (week 39/40) in Sweden and Lithuania and by mid-October (week 42) in Norway. We observed plasticity in timing of cache initiation but the majority of active sites in all areas had food caches by the beginning of November (week 45). Declining air temperature and mean minimum temperatures of 0°C or below were associated with cache initiation. Caches in Lithuania were larger than in Sweden and Norway, which may be associated with colder winter temperatures. We did not find any relationship between family size or length of territory occupancy and cache size at our Norway sites where population demographics were available. Our results are generally consistent with other studies of food caching behavior in both species and suggest general similarities as well as behavioral plasticity in this important evolutionary strategy.
Harvest indices are commonly used as proxies to direct population monitoring but sources of variability, including harvest effort and factors influencing detectability of animals to hunters, are rarely considered. Harvest indices may further be influenced by selective harvesting with regulatory differences in harvest effort across sex and age-classes. To evaluate how sex and age-specific harvests vary as proxies of abundance under selective harvesting, we assessed harvest–abundance relationships (H–A) for moose Alces alces bulls, cows and calves across 58 wildlife management units (WMUs) in Ontario, Canada. Selective harvesting in our study area resulted in more regulated harvest of bulls and cows than calves. We therefore predicted more proportional H–A for calves than bulls and cows, with variability in H–A influenced by harvest effort, in addition to weather and landscape features that may influence moose detectability to hunters. In contrast to our expectation, we found that H–A was more proportional for adult moose than calves. Additionally, we found harvest was proportionally highest for bulls, despite greater harvest effort for calves. A positive effect of harvest effort on harvest as moose abundance increased helped to explain proportional H–A for adult moose. However, the effect of harvest effort on harvest was curvilinear at high effort levels, indicating that harvest will underestimate abundance when effort by hunters is high. Additionally, we found evidence of lower harvest in relation to abundance in WMUs with higher levels of recent disturbance from wildfire burns and clear-cuts. We demonstrate that the relationship between harvest and abundance can vary across selectively harvested sex and age-classes, while variability in H–A can be attributed to spatial variability in harvest effort and the landscape. We caution that sources of variability in H–A, both across and among sex and age-classes, should not be ignored when using harvest indices, especially for selectively harvested species.
Human–wildlife conflict presents major challenges to both wildlife managers and rural livelihoods. Here, we investigated human–wildlife conflict in and around Senkele Swayne's Hartebeest Sanctuary (SSHS). We estimated the densities of wild animals within SSHS and conducted questionnaire interviews about livestock predation and crop raiding patterns with individuals in 378 households occurring <3000 m outside the Sanctuary's borders. Respondents reported that hyenas Crocuta crocuta and African wolves Canis anthus were the only livestock predators and were responsible for combined losses of ∼ 10% (29 207 USD) of their livestock over a three-year period. Hyenas predated cattle, goats, sheep, donkeys and horses, whereas African wolves targeted only goats and sheep. Hyena predation occurred both inside and outside SSHS, whereas African wolf predation occurred mainly near the inside periphery of the sanctuary. Most (58%) of the respondents experienced crop raiding of their farms by Swayne's hartebeest Alcelaphus buselaphus swaynei, warthogs Phacochoerus africanus and/or crested porcupines Hystrix cristata. Nearly two-thirds (64%) of the crop raiding occurred 1–1500 m from the sanctuary. Potatoes and maize were the most commonly raided crops. Local communities used guarding, patrolling, loud noises, smoky fires, flashes of light, fences and trenches as deterrence methods. Of the crop raiding species, only Swayne's hartebeests were regarded positively, while warthogs and crusted porcupines were viewed negatively by respondents. We conclude that although SSHS is of critical conservation value to the Swayne's hartebeest, the surrounding communities endure significant livestock predation and crop raiding by wild animals sheltered in the sanctuary. The survival of this relict population of Swayne's hartebeest in the sanctuary remains at risk unless the human–wildlife conflict in surrounding areas is resolved. This calls for site-specific measures in consultation with the local community.
Plains bison Bison bison bison were extirpated from most of their historical range in the late nineteenth century, and few studies have examined the interactions of bison with gray wolves Canis lupus. The Sturgeon River plains bison (SRPB) population in Prince Albert National Park, Saskatchewan is one of only a few populations of plains bison in their historical range in Canada and have declined around 50% since 2005. This study examined the inter- and intra-annual variation in wolf diet using stable isotope analysis (SIA), to assess the importance of bison and other ungulates to wolf diet relative to the decline of the SRPB. We used wolf hair (n = 35) and blood (n = 29) collected from 30 individuals from 2011 to 2017 to estimate the diet of two packs for summer and winter, and visited potential wolf kill sites (n = 270) during the winter from 2013 to 2017 to collect prey samples. We used wolf scats (n = 465) collected in the winter and summer of 2012–2013 as priors for our Bayesian stable isotope mixing models. We found the percentage of bison (median range: 26–39%), deer/elk (21–24%) and moose (16–33%) consumed in the summer was consistently high, compared to winter when white-tailed deer Odocoileus virginianus comprised the highest percentage of wolf diet (40–49%). We observed small inter-annual variation in wolf diet. We examined differences between packs and found that wolves that had greater overlap with the SRPB had more bison in their diet, particularly in winter (26–40%). Results from SIA were consistent with percentages of prey found at wolf kill sites. Overall, bison constitute a lower proportion of wolf diet compared to other wild ungulates, and our findings support the assumption that wolf predation is not the main contributing factor to SRPB population decline.
Many environmental and behavioral factors can affect offspring survival, and these factors can vary by species. Parental investments, defense or distraction displays, and translocation can potentially affect survival of young. Alterations in parental investment strategies may carry implications for population growth due to lower offspring survival in translocated bobwhites. We hypothesized that translocation would not impact brood defense behaviors in bobwhites as predator communities may be similar between donor sites (Florida) and release sites (North Carolina). However, we hypothesized that brood defense behaviors affect offspring survival rates. We conducted defense behavior observations by approaching brood-rearing bobwhites and recording exhibited behaviors, and assigned scores based on behavioral intensity. We used the corral capture method and modified-suture technique to capture and radio-tag bobwhite chicks. Brood defense behaviors did not differ between resident and translocated bobwhites. We observed seven different brood defense behaviors: fly away, run, labored flight, labored flight with broken wing display, run with broken wing display, hold tight and approach behaviors. We found that time-varying precipitation and behavioral intensity affected bobwhite chick survival. These results indicate that translocation does not impact brood defense behaviors due to behavioral similarities between resident and translocated cohorts. These results portend that some variation in annual chick mortality cannot be mitigated by habitat management. We also provide evidence that translocation does not alter/suppress important behavioral patterns in bobwhite, indicating it is a viable method for restoring bobwhite populations in conjunction with habitat management.
Waterbirds in stochastic environments exhibit nomadism in order to cater for the unpredictable availability of water resources. Lesser flamingos Phoeniconaias minor have long been thought to be nomadic waterbirds. In southern Africa, conservation efforts for lesser flamingos are hampered by a lack of knowledge about their movement trajectories. To investigate their movement ecology in southern Africa, we fitted GPS–GSM transmitters to 12 adults and tracked their movements over four years, from March 2016 to February 2020. Net squared displacement (NSD) was used in nonlinear least squares models classifying trajectories as nomadic, migratory, mixed-migratory, home range restricted or dispersal movement types. Data from eight of the 12 birds met the criteria for the NSD analysis. Model success was good; only 8 out of 120 (6.7%) movement type models failed to reach convergence. Goodness of fit statistics from the NSD models supported migratory and mixed migratory movement types (concordance criteria coefficient (CC) = 0.78) for more than half of the annual trajectories investigated (57.2%). Dispersal, home range-restricted and nomadic movements best described 28.6, 9.5 and 4.8% of annual trajectories, respectively, but all resulted in a mean CC of < 0.4 and thus did not fit observed NSD patterns as well as the migratory movement types. We then used nonlinear mixed effects models to account for annual and individual differences in migration parameters. Variation in the timing and duration of all migrations were more important than variation in migration distance, indicating well-established summer and winter ‘ranges’ and routes between Kamfers Dam (South Africa) and Sua Pan (Botswana). We propose that lesser flamingos in central southern Africa may be partial migrants, not true nomads, as most of their movements followed a regular, repeated pattern between two primary locations.
Sika deer Cervus nippon populations have been increasing on the Japanese archipelago. Their range is expanding to include the alpine zone in central Japan, where they stay during summer before descending to the lower areas during winter. No studies on dietary habits of alpine deer in mainland Japan have been conducted. This study assessed the composition of sika deer diets and compared nutritional quality between the low montane, subalpine and alpine zones. We analyzed sika deer fecal samples from Mt Yatsugatake (YT) and the Japanese South Alps (SA). In the lower mountain in YT, dwarf bamboo comprised 40–55% of the plant compositions in fecal samples, whereas dicots were mostly found in SA samples. In subalpine zones in YT, grasses are an important food item, comprising about 50% of the samples. In SA, monocots (10–20%) and dicots (10–20%) were both prevalent. In the alpine zone of both YT and SA, grasses were present the fecal samples (50% and 10–20%, respectively). Crude protein contents were higher at higher zones (15–20%) than at lower zones (8–12%) in both study areas.
Reference intervals (RIs) describe baseline parameters of healthy animals, providing a powerful tool for wildlife managers to monitor health, identify disease and assess animal welfare. This paper reports haematological, glucose and serum protein RIs for one of Australia's most iconic and managed mammals, the eastern grey kangaroo Macropus giganteus. Blood samples (n = 514) were collected from 11 populations of eastern grey kangaroos, across much of their geographic range. A species-level RI was initially established based on samples collected from four sites (n = 245) and was further partitioned based on significant differences associated with sexual maturity and season. Unique population means were established from a further seven sites to investigate the importance of biotic (sex and sexual maturity) and abiotic (season, site, rainfall, temperature and laboratory) factors on kangaroo health parameters. Random forest analysis of health parameters revealed that abiotic factors (site, rainfall, temperature and season) were largely responsible for differences in haematological, glucose and serum protein values. Sex was found to have no influence, while sexual maturity and laboratory of analysis had moderate effects. Based on these findings, interpretation of individual and population haematological and serum protein values requires careful consideration of the timing of sample collection, environmental conditions and sexual maturity. When assessing kangaroo health, the relevant sexual maturity RI must be considered initially. For populations with similarities to those described (for example high density or captive populations) users should also consider site specific mean haematological and serum protein values. The RIs reported are valuable when establishing the health status of kangaroo populations. Furthermore, understanding the influence of biotic and abiotic factors will improve the utility of these RIs to assess health, disease status and improve welfare in eastern grey kangaroos.
Despite the increasing spatial, temporal and dietary overlap between bobcats Lynx rufus and coyotes Canis latrans, these species live sympatrically throughout much of North America. To determine if differential activity patterns relative to abiotic variables might influence interspecific interactions, we investigated whether these species responded differentially to crepuscular and nocturnal abiotic variables in Texas. Using GPS collars, we calculated hourly movements from sequential locations, and compared bobcat and coyote movements relative to sex, season, moonlight intensity, night period, crepuscularity and temperature. We used generalized linear mixed effects models (GLMM) to investigate the responses of bobcats and coyotes to variables associated to their nocturnal movements. Temperature and its interactions with various abiotic variables influenced bobcat movements. Biological season and its interactions with other abiotic variables influenced coyote movements. Bobcats moved shorter hourly distances than coyotes. Female bobcats moved shorter hourly distances than males. Moonlight intensity seemed to influence coyotes but not bobcats. Differential movements between bobcats and coyotes relative to night period could possibly be due behavioral avoidance of coyotes by bobcats. Reduced crepuscular activity by coyotes may be behavioral avoidance of humans. Differential responses to nocturnal variables may dampen competitive interactions between bobcats and coyotes.
The Irish hare Lepus timidus hibernicus is an endemic subspecies of Mountain hare and Ireland's only native lagomorph. The endoparasite community composition of the Irish hare was examined from 22 carcasses opportunistically sourced from wildlife strike events (with aircraft and vehicles) from three counties in the Republic of Ireland. Three parasite taxa were identified from the stomach and small intestines: Trichostrongylus retortaeformis, Graphidium strigosum and a tapeworm belonging to the genus Mosgovoyia. Overall, 50% of hares examined were host to at least one endoparasite taxon and 18% were host to more than one taxon. There was no significant correlation between parasite burden and host weight. This is the first known study of endoparasites in the Irish hare.
Advances in the technology of biotelemetry are transforming the ways in which we remotely acquire environmental, physiological and behavioural data. Large and heavy batteries, however, continue to reduce the availability of GPS tracking devices for small taxa and for species with morphologies that limit attachment options. Device miniaturisation is beginning to be achieved through the use of in-built solar accumulators, but it is important that the rapid uptake of these technologies does not outpace systematic tests of their precision and performance. Here, we share the technical details of a new 180g solar-powered device originally designed for vultures but adapted for use on terrestrial herbivores. We test the precision and performance of this device using both stationary and animal-borne trials across multiple geographical areas. Our results show exceptionally high fix acquisition success rates and moderate precision error. We also demonstrate that these solar-powered devices maintain a high and stable voltage over long-term animal-borne trials. These results highlight the importance of a-priori testing of new technologies in biotelemetry research and demonstrate how solar-technology can help to address some of the challenges we face in tracking terrestrial mammals.
Spatial patterns in animal behavior can provide insight into habitat quality and the distribution of resources. Understanding how, when, and why animals use certain areas is critical to their conservation and management. We investigated the distribution of pellets of mountain hares Lepus timidus in the Swiss Alps and compared differences between spring and autumn. 1515 pellet locations from 119 individuals (70 males, 49 females) were used. Pellets were collected from 2014 to 2019; individuals were determined using an established, non-invasive genetic technique. We found evidence of an altitudinal shift in the occurrence of pellets from lower elevations in spring to higher elevations in autumn. This seasonal pattern is also supported by altitudinal shifts of three individual core activity areas (2 males, 1 females) and by higher hare activities at the high plateau in autumn. We conclude that the annual ‘wave’ of greening from lower to higher elevations, which correlates with forage availability and quality, explains this shift.
The European beaver Castor fiber is well-known as an ecosystem engineer that greatly affects landscape structure, biodiversity as well as physical and chemical properties of surface water bodies. Beaver ponds alter surface water bodies by raising water elevation, decreasing flow velocity and altering the morphology of streams or drainage ditches, which can reduce the concentrations of organic carbon (OC) and nutrients (N, P). Recent studies indicated that mercury transforms into hazardous and neurotoxic methylmercury (MeHg) in beaver impoundments by biological processes in anaerobic conditions.
However, the knowledge about nutrients and MeHg levels in impounded forest waterbodies is scarce in Lithuania. We aimed to ascertain the alteration in concentrations and stocks of OC, nutrients and MeHg in water and sediments from upstream and downstream, as well as within beaver dams and ponds during the growing seasons of 2016–2018. Results showed higher concentrations of dissolved organic carbon (DOC) and nutrients (P and N) in upstream water samples compared to those of downstream from beaver dams. Meanwhile, in sediments mean stocks of OC, P and N were the highest in the middle part of the ponds and in beaver dams. Moreover, the concentrations and stocks of MeHg in sediments were higher in beaver dams than in any other parts of beaver impoundments (upstream, mid-pond, pond periphery and downstream). We conclude that dam bottom sediments were rich in OC, N and P, and at the same time, contained toxic MeHg. Therefore, beaver dams could act as a trickle filter by improving water quality, in our case, DOC, N and P leaching, from riparian forests and soils, but may also act as hotspots of mercury methylation.
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