| 1. |
- Belton, L. E., et al.
(författare)
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Anthropogenic influences on spotted hyaena diet in the Kruger National Park, South Africa
- 2018
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Ingår i: Mammal Research. - : Springer Science and Business Media LLC. - 2199-2401 .- 2199-241X. ; 63:3, s. 315-323
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Tidskriftsartikel (refereegranskat)abstract
- Rapid urban expansion has led to an increase in carnivores that live close to human dominated environments. Some carnivore species have successfully adapted to these novel conditions and taken advantage of opportunities associated with human habitation. Whilst many studies have compared carnivores living in protected areas to those in an urban setting, few have looked at the relationships between carnivores and human habitation within protected areas. In this study, we examined the effects ofhuman habitation on the diet of spotted hyaenas (Crocuta crocuta) in the Kruger National Park (KNP), South Africa. Our results suggested a limited effect of anthropogenic resources on spotted hyaena diet in the KNP. We found neither temporal nor spatial variation in the amount of, nor types of, anthropogenic material in spotted hyaena scats, despite observations of more road side litter close to large anthropogenic sites. We therefore suggest that anthropogenic resources may not have been utilised completely according to abundance. We encourage further research evaluating potential secondary effects of human activity and infrastructure on spotted hyaena diet and also stable isotope approaches that may provide further insights into the importance of anthropogenic food for spotted hyaenas inside the KNP.
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| 2. |
- Bergenius, Mikaela
(författare)
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Reproductive rate and nutritional status of Baltic ringed seals
- 2019
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Ingår i: Mammal Research. - : Springer Science and Business Media LLC. - 2199-2401 .- 2199-241X. ; 64, s. 109-120
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Tidskriftsartikel (refereegranskat)abstract
- The Baltic ringed seal (Pusa hispida botnica) population started to increase in numbers in the 1990s after a population decrease caused by hunting and environment pollutants. The annual growth rate of this population is about 5%, while in a fast-growing seal population, it could be as high as 10-12%. The reasons behind the fairly slow population growth rate are not known. In the current study, we investigated reproductive rate and nutritional status of ringed seals in the Bothnian Bay, the largest subpopulation in the Baltic Sea. The aims of the present study were (1) to estimate reproductive rate of females and (2) to examine especially annual variation in nutritional status (blubber thickness) in relation to prey quality and quantity as it affects reproductive rate. The proportion of females with corpus albicans (an estimate of birth rate) in Baltic ringed seals has increased from low values since the late 1990s and is at present about 72%. It was highest among females at the age of 5-12years and declined thereafter, especially after the age of 20. Uterine occlusions, which earlier caused sterility to females, were rare in recent years. Blubber thickness of both pups and older seals decreased during spring and increased during the rest of the year. Average blubber thickness of sub-adults and adults declined until the early 2000s and increased thereafter, except in adult females, and correlated positively especially with average weight of herring (Clupea harengus). In sub-adults, blubber thickness correlated also with the weight and catch size of vendace (Coregonus albula). These results suggest that the quality and quantity of important prey fish may affect the nutritional status of seals. In recent years, average blubber thickness of adult females in spring declined, although herring quality increased. This may be partly due to stress caused by poor ice conditions in the nursing period in late winter. The declining nutritional status of adult females may, at least partly, be responsible for the relatively low birth rate and population growth rate of ringed seals in the Bothnian Bay.
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| 3. |
- Cortazar-Chinarro, Maria, et al.
(författare)
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Sign surveys for red fox (Vulpes vulpes) censuses : evaluating different sources of variation in scat detectability
- 2019
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Ingår i: Mammal Research. - : Springer Science and Business Media LLC. - 2199-2401 .- 2199-241X. ; 64:2, s. 183-190
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Tidskriftsartikel (refereegranskat)abstract
- Wildlife monitoring is essential for assessing the size of species of conservation or management concern. Wildlife monitoring could be undertaken by selected volunteers when limited resources are available. Here, we study the sources of variation in the detectability of red fox scats and to improve the monitoring of the species by means of volunteers who were briefly trained. We selected nine transects to experimentally evaluate the differences in red fox scat detectability between observers, microsite, and scat abundance. Scats were deposited in five microsites, where we simulate low, medium, and high fox scat abundance. We tested the proposed effects by using GLMM analysis incorporating observer effect as a random factor. Our results indicated effects on scat detectability of observer identity and microsite type. We did not observe the effects of scat abundance on detectability of scats. Detectability was lower for scats located in the middle of the transect and on the rocks. We conclude that large-scale red foxes surveys might be conducted using volunteers, but due to the moderate differences detected among observers should be minimized using a training period.
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| 4. |
- Cromsigt, Joris
(författare)
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Comparing the impact of a grazing regime with European bison versus one with free-ranging cattle on coastal dune vegetation in the Netherlands
- 2018
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Ingår i: Mammal Research. - : Springer Science and Business Media LLC. - 2199-2401 .- 2199-241X. ; 63, s. 455-466
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Tidskriftsartikel (refereegranskat)abstract
- Woody plant encroachment has increased across the globe and threatens biodiversity associated with open habitats. In order to prevent or reduce woody encroachment, conservation managers across Europe introduce large mammalian herbivores. While up to recently, managers were mostly using free-ranging domestic cattle and horses for this, there is an increasing interest in the use of European bison for nature management. However, we lack studies that compare the impact of these different grazers on vegetation. We report results from a unique grazing pilot in the National Park Zuid-Kennemerland, a heterogeneous coastal dune landscape in the Netherlands, where European bison, horses, and cattle were introduced to reverse the encroachment of grass and shrub species. We present results of an 8-year study on the development of woody and grassy vegetation on fixed transects in three different grazing areas within the national park; one area with European bison and horses, one area with cattle and horses, and one area where these large grazers were excluded. In all three areas, rabbit, fallow deer, and roe deer were present. Over time, we observed strong reductions in the vitality of several woody species, such as spindle tree, and this decline was similar across all areas. Grass height and cover also declined and the proportion of herbs increased in all three grazing areas in similar ways. However, the type of herbivore use (debarking, foraging on buds, branches) of several woody species differed significantly among areas. For instance, maple tree was only debarked in the E. bison area, while hawthorn branches were eaten significantly more in the cattle than in the bison area. Due to differences in herbivore densities among areas, it was difficult to draw strong conclusions on how the different herbivore species differed in their impact, but, importantly, we found that grazing regimes with bison can lead to as strong effects on vegetation structure and composition as grazing regimes with cattle. This is an important result since certain conditions, such as legal aspects, may motivate managers to introduce a wild large grazer rather than a domesticated one.
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| 5. |
- Cromsigt, Joris
(författare)
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Opportunistic feeding by lions: non-preferred prey comprise an important part of lion diets in a habitat where preferred prey are abundant
- 2020
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Ingår i: Mammal Research. - : Springer Science and Business Media LLC. - 2199-2401 .- 2199-241X. ; 65, s. 235-243
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Tidskriftsartikel (refereegranskat)abstract
- Optimal foraging theory predicts less diverse predator diets with a greater availability of preferred prey. This narrow diet niche should then be dominated by preferred prey, with implications for predator-prey dynamics and prey population ecology. We investigated lion (Panthera leo) diets in Hluhluwe-iMfolozi Park (HiP), South Africa, to assess whether lions in a site with a high density of preferred prey (prey species weighing 92-632 kg as estimated from a published meta-analysis) have a narrow diet, consisting primarily of preferred prey. HiP is a useful study site to investigate this prediction because it is a productive landscape (with a high density of prey) where lion-preferred prey constitutes up to 33% of the prey available to lions. Furthermore, to investigate whether lions in HiP exhibit sex-specific diets as documented in other southern African populations, we estimated male and female lion diets separately. We were specifically interested in testing whether traditional approaches of estimating lion diets at the population level mask sex-specific predation patterns, with possible implications for management of lions in small to medium-sized fenced reserves. Lions in HiP preferred larger prey species (63-684 kg) and had diets with a larger proportion of preferred prey than reported in an African-wide meta-analysis. However, despite the high density of preferred prey species, 36% of lion diets still consisted of typically non-preferred species such as nyala (Tragelaphus angasii). This finding suggests that lions in HiP maintain a degree of opportunism even when preferred prey are abundant. Therefore, abundant, non-preferred prey are likely to be an important resource for lion populations. Sex-specific differences in lion diets were evident in HiP, suggesting that estimation of lion resource use and carrying capacity should consider opportunistic hunting and sex-specific differences in lion diets.
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| 6. |
- Engman, Mattias, et al.
(författare)
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Towards streamlined bank vole odor preference evaluation using Y-mazes
- 2020
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Ingår i: Mammal Research. - : Springer Science and Business Media LLC. - 2199-2401 .- 2199-241X. ; 65, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Seed consumption by rodents causes substantial economic losses in agriculture and forest restoration. Rodents rely on their sensitive sense of smell to gather information about their environment. However, comparably little is known about how rodents use olfaction to locate food. We used bank voles to measure attraction to acorn odors in a Y-maze. Preferences were measured using two behaviors: approaching (time spent in odor preference zones) and investigation (numbers of nose pokes in odor nozzle), which yielded similar results. Shorter time intervals (15 and 30 s) in the preference zones were at least as good as the longer time interval (60 s) for detecting differences in approaching behavior. In this way, it is possible to reduce the measurement time with approximately 50%. Investigation, which was evaluated using only one time interval (180 s), yielded longer measurement time. Acorns were as preferred as the familiar, standard food (rodent chow) while an acorn aeration extract did not produce any response. We conclude that short measurement times for the evaluation of attractive odors makes it possible to efficiently assay the wide range of volatile compounds from bank voles' natural foods which may be important in studies wishing to develop new rodent control methods.
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| 7. |
- Felton, Annika, et al.
(författare)
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Interactions between ungulates, forests, and supplementary feeding: the role of nutritional balancing in determining.
- 2017
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Ingår i: Mammal Research. - : Springer Science and Business Media LLC. - 2199-2401 .- 2199-241X. ; 62, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- People provide wild ungulates with large quantities of supplementary feed to improve their health and survival and reduce forest damage. Whereas supplementary feeding can positively affect the winter survival of ungulates and short-term hunting success, some of the feeds provided may actually reduce ungulate health and increase forest damage. Here, we highlight how recent advances in ungulate nutritional ecology can help explain why supplementary feeding can lead to undesirable outcomes. Using Europe's largest cervid, the moose (Alces alces), as a model species, and Sweden, as the socio-ecological context, we explain the concept of nutritional balancing and its relevance to supplementary feeding. Nutritional balancing refers to how animals alter their food intake to achieve a specific nutritional target balance in their diet, by selecting balanced food items or by combining items with nutritional compositions that are complimentary. As the most common supplementary feeds used contain higher concentrations of non-structural carbohydrates than the ungulates' normal winter diet, the consumption of such feeds may cause animals to increase their intake of woody browse, and thereby exacerbate forest damage. We also explain how animal health may be negatively affected by large intakes of such feed if complementary browse items are not available. We therefore suggest that the use of inappropriate feed is an additional means by which supplementary feeding may result in negative outcomes for hunters, forest owners, and wild animals.
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| 8. |
- Hofmeester, Tim
(författare)
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The Mostela: an adjusted camera trapping device as a promising non-invasive tool to study and monitor small mustelids
- 2020
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Ingår i: Mammal Research. - : Springer Science and Business Media LLC. - 2199-2401 .- 2199-241X. ; 65, s. 843-853
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Tidskriftsartikel (refereegranskat)abstract
- In spite of their potential important role in shaping small mammal population dynamics, weasel (Mustela nivalis) and stoat (Mustela erminea) are understudied due to the difficulty of detecting these species. Furthermore, their conservation status in many countries is unknown due to lack of monitoring techniques. There is thus an important need for a method to detect these small mustelids. In this study, we tested the efficiency of a recently developed camera trapping device, the Mostela, as a new technique to detect mustelids in a study area near Dieren, the Netherlands. We placed Mostelas in linear landscape features, and other microhabitats thought to be frequently visited by weasels, from March to October 2017 and February to October 2018. We tested for yearly and monthly differences in site use and detectability, as well as the effect of entrance tube size, using an occupancy modelling framework. We found large seasonal differences in site use and detectability of weasels with the highest site use in June to October and highest detection probability in August and September. Detection probability was approximately two times higher for Mostelas with a 10-cm entrance tube compared with 8-cm. Furthermore, we were able to estimate activity patterns based on the time of detection, identify the sex in most detections (69.5%), and distinguish several individuals. Concluding, the Mostela seems promising as a non-invasive monitoring tool to study the occurrence and ecology of small mustelids. Further development of individual recognition from images would enable using the Mostela for density estimates applying capture-recapture models.
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| 9. |
- Kauhala, K., et al.
(författare)
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The effect of prey quality and ice conditions on the nutritional status of Baltic gray seals of different age groups
- 2017
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Ingår i: Mammal Research. - : Springer Science and Business Media LLC. - 2199-2401 .- 2199-241X. ; 62:4, s. 351-362
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Tidskriftsartikel (refereegranskat)abstract
- We analyzed a long-term data set of the body condition of Baltic gray seals (Halichoerus grypus) over time and investigated how average subcutaneous blubber thickness of different age groups of seals corresponds to environmental factors. Blubber thickness of pups declined until 2010. The decreasing weight of 5-6-year-old herring (Clupea harengus), the main prey fish for Baltic gray seals, explained well the decline. In the Gulf of Finland, the blubber thickness of pups declined also in recent years (2011-2015) with declining number of days with permanent ice cover. In other regions, the blubber thickness of pups increased during recent years with increasing weight of herring. The blubber thickness of sub-adults in Baltic Proper and that of hunted adult females in the Bothnian Bay also increased during recent years, and the weight of age 6+ or 7-year-old herring best explained the increase. The blubber thickness of all age groups of seals was thinnest in the Bothnian Bay where also herring weight was lowest. There was a negative correlation between blubber thickness of seals and herring catch size (an index of herring abundance) suggesting that herring quality, not the quantity, is important for the nutritional status of Baltic gray seals. Nutritional status of gray seals may thus reveal changes in the marine food web which affect herring quality. Marine food web, in turn, may be affected, e.g., by climate change. The warming climate also has an impact on ice cover and thus body condition of seal pups.
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| 10. |
- Kjellander, Petter
(författare)
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Challenges and science-based implications for modern management and conservation of European ungulate populations
- 2017
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Ingår i: Mammal Research. - : Springer Science and Business Media LLC. - 2199-2401 .- 2199-241X. ; 62, s. 209-217
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Tidskriftsartikel (refereegranskat)abstract
- Wildlife management systems face growing challenges to cope with increasingly complex interactions between wildlife populations, the environment and human activities. In this position statement, we address the most important issues characterising current ungulate conservation and management in Europe. We present some key points arising from ecological research that may be critical for a reassessment of ungulate management in the future.
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| 11. |
- Pertold, Cino, et al.
(författare)
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Prevalence of skull pathologies in European harbor seals (Phoca vitulina) during 1981–2014
- 2018
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Ingår i: Mammal Research. - : Springer Science and Business Media LLC. - 2199-2401 .- 2199-241X. ; 63:1, s. 55-63
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Tidskriftsartikel (refereegranskat)abstract
- Harbor seals (Phoca vitulina) inhabit the seas surrounding Denmark and are an important top predator in the marine food chain. This trophic position exposes them to environmental contaminants with disease epi- demics and hunting being additional threats to this popu- lation. It is therefore important to study how environmen- tal pollution at the current order of magnitude affects the health of the population. Earlier studies have shown that occurrence of periodontitis could be linked to the amount of pollution the seals were subjected to. In order to inves- tigate this further, 380 skulls and 141 mandibles of harbor seals (Phoca vitulina) from the Wadden Sea, the Limfjord, and Kattegat collected during the period 1970–2014 were examined. The skulls were examined for pathological le- sions. The Hounsfield Units (HU) which are correlated to the bone mineral density (BMD) were measured in a sub- sample (n= 34) using CT scans. The macroscopic examination revealed (with the exception of the Swedish part of Kattegat) a significant increase of pathological lesions over the study period of 1981–2014. The exami- nation of HU showed that median HU measured at mul- tiple sites was highest in the healthy skulls compared to the skulls with one or more of the lesions. A discriminant analysis allowed high discriminatory capacity to separate healthy skulls from the skulls with pathologies, simply by the utilization of the HU data. Former studies of BMD in marine mammals have shown that exposure to environ- mental chemicals alter BMD and cause periodontitis. The present study, based on temporal and spatial trends in BMD, confirms the results of previous studies Prevalence of skull pathologies in European harbor seals (Phoca vitulina) during 1981–2014 (PDF Download Available). Available from: https://www.researchgate.net/publication/320586176_Prevalence_of_skull_pathologies_in_European_harbor_seals_Phoca_vitulina_during_1981-2014 [accessed Dec 15 2017].
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| 12. |
- Rautiainen, Heidi, et al.
(författare)
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Nutritional niche separation between native roe deer and the nonnative fallow deer-a test of interspecific competition
- 2021
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Ingår i: Mammal Research. - : Springer Science and Business Media LLC. - 2199-2401 .- 2199-241X. ; 66, s. 443-455
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Tidskriftsartikel (refereegranskat)abstract
- On an evolutionary time scale, competition for food drives species formation by genetic adaptations to the environment and subsequent niche separation. On a short-term scale, animals use different strategies to meet their nutritional requirements, which ultimately influence their fitness. Understanding these adaptations in herbivores is especially important in temperate climates where animals have adapted both physiologically and behaviorally to seasonal variations in order to meet their nutritional requirements. The aim of this project was to investigate temporal variation in chemical composition of rumen content between two coexisting species of large herbivores, the native roe deer (Capreolus capreolus L.) and the introduced fallow deer (Dama dama L.), as well as a potential effect of competition on niche separation (interspecific differences in rumen nutrient composition). We analyzed 345 rumen samples collected from animals at one 95 km(2) estate, Koberg, in southwestern Sweden. Based on samples from all seasons, temporal variation in nutrient composition and interspecific differences between the two deer species were investigated under two contrasting fallow deer population densities. Results revealed that nutrient composition varied between species and across seasons. Roe deer had a higher proportion of rumen protein compared to fallow deer, with the highest proportions in spring. In contrast, fallow deer had a higher proportion of rumen hemicellulose compared to roe deer in spring, while no differences in nutrient composition between species could be found in fall. Overall, there were greater differences between the two species when fallow deer density was high and competition likely more pronounced than when fallow deer density was low. The results from this study can be used to understand interspecific competition and how it fosters niche separation between coexisting large herbivores.
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| 13. |
- Willebrand, Tomas, et al.
(författare)
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Snow tracking reveals different foraging patterns of red foxes and pine martens
- 2017
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Ingår i: Mammal Research. - : SPRINGER HEIDELBERG. - 2199-2401 .- 2199-241X. ; 62:4, s. 331-340
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Tidskriftsartikel (refereegranskat)abstract
- Red fox (Vulpes vulpes) shares similar prey preferences and co-occurs with several other carnivores, and is together with pine marten (Martes martes), the most common mesocarnivore in the northern boreal forest. Voles are important prey for both species, but it is unclear to what extent they compete for the same food resources in winter. Here, we use 2139 km and 533 km of meticulous snow tracking of red foxes and pine martens to evaluate their food niches. We measured hunting and digging behaviour, whether successful or not, and the effect of snow depth and temperature. Pine martens were restricted to forested habitats, whereas red foxes used a wide range of habitats. Red foxes were found to dig more often than pine martens, 0.67 vs. 0.39 digging events per kilometre. Hunting was less common and similar in both species, about 0.1 hunting event per kilometre. Pine martens were more efficient in hunting and finding food remains compared to red foxes. Increasing snow depth reduced hunting success and also reduced dig success of red foxes. Food niche overlap was small. Red foxes used mostly voles and carrion remains of ungulates, whereas pine martens used cached eggs and small birds. We suggest that caching eggs is an important strategy for pine martens to survive winter in northern latitudes. Snow depth was important for capturing voles, and thick snow cover appeared to mask the effect of vole peaks. Intensified land use, as clear-cutting and leaving slaughter remains from harvest, will benefit red foxes on the expense of pine martens. The ongoing climate change with warmer winters and less snow will likely further benefit the red fox.
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| 14. |
- Zmihorski, Michal
(författare)
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Empty in summer, crowded during migration? Structure of assemblage, distribution pattern and habitat use by bats (Chiroptera: Vespertilionidae) in a narrow, marine peninsula
- 2016
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Ingår i: Mammal Research. - : Springer Science and Business Media LLC. - 2199-2401 .- 2199-241X. ; 61, s. 45-55
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Tidskriftsartikel (refereegranskat)abstract
- According to scarce available data, the use of coastal habitats by bats appears to be the most intensive during spring and autumn migrations, when coasts become migratory corridors. Migrating bats might seasonally enrich the fauna of sea islands and peninsulas, which often are poor in bats outside the migratory season. Hel Peninsula is part of the Polish Baltic Coast that extends the most into the sea; thus, it gives unique opportunity to assess that phenomenon quantitatively. To test for seasonal variation in structure of bat assemblage and bat activity, we recorded echolocation calls on walking transects. Seven species were recorded in total, with predominance of sedentary Eptesicus serotinus in June-July and migratory Pipistrellus nathusii in August-September. Occurrence of bats was the highest in deciduous and coniferous forests and the lowest in coasts and ports. Interaction of day of year and distance to mainland was highly significant, indicating that occurrence of bats was increasing from spring to autumn but this increase depended on location. Far from mainland, the mean occurrence of bats was rather stable over time. On transects located close to the mainland, bat occurrence was low at the beginning of the season but after mid-August increased rapidly. We confirmed that some topographically isolated parts of the sea coasts can host only very impoverished summer bat fauna. Bat activity in such sites increase in autumn; however, Hel Peninsula presumably does not act as a migratory corridor, but only as a target of local dispersal from mainland.
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