| 1. |
- Allen, Andrew, et al.
(författare)
-
The impacts of landscape structure on the winter movements and habitat selection of female red deer
- 2014
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 60, s. 411-421
-
Tidskriftsartikel (refereegranskat)abstract
- An area of research that has recently gained more attention is to understand how species respond to environmental change such as the landscape structure and fragmentation. Movement is crucial to select habitats but the landscape structure influences the movement patterns of animals. Characterising the movement characteristics, utilisation distribution (UD) and habitat selection of a single species in different landscapes can provide important insights into species response to changes in the landscape. We investigate these three fields in female red deer (Cervus elaphus) in southern Sweden, in order to understand how landscape structure influences their movement and feeding patterns. Movements are compared between two regions, one dominated by a fragmented agriculture-forest mosaic and the other by managed homogenous forest. Red deer in the agriculture-dominated landscape had larger UDs compared to those in the forest-dominated area, moved larger distances between feeding and resting and left cover later in the day but used a similar duration for their movements, suggesting faster travelling speeds between resting and feeding locations. The habitat selection patterns of red deer indicate a trade-off between forage and cover, selecting for habitats that provide shelter during the day and forage by night. However, the level of trade-off, mediated through movement and space use patterns, is influenced by the landscape structure. Our approach provides further understanding of the link between individual animal space use and changing landscapes and can be applied to many species able to carry tracking devices.
|
|
| 2. |
|
|
| 3. |
- Champagnon, Jocelyn, et al.
(författare)
-
Low survival after release into the wild : assessing “the burden of captivity” on Mallard physiology and behaviour
- 2012
-
Ingår i: European Journal of Wildlife Research. - 1612-4642 .- 1439-0574. ; 58:1, s. 255-267
-
Tidskriftsartikel (refereegranskat)abstract
- Captive-reared animals used in reinforcement programs are generally less likely to survive than wild conspecifics. Digestion efficiency and naive behaviour are two likely reasons for this pattern. The Mallard is a species with high adaptability to its environment and in which massive reinforcement programs are carried out. We studied physiological and behavioural factors potentially affecting body condition and survival of captive-reared Mallards after being released. Digestive system morphology and an index of body condition were compared among three groups: captive-reared birds remaining in a farm (control), captive-reared birds released into the wild as juveniles (released) and wild-born birds (wild). We also compared behaviour and diet of released vs. wild Mallards. Finally, we conducted a 1-year survival analysis of captive-reared birds after release in a hunting-free area. Gizzard weight was lower in control Mallards, but the size of other organs did not differ between controls and wild birds. The difference in gizzard weight between released and wild birds disappeared after some time in the wild. Diet analyses suggest that released Mallards show a greater preference than wild for anthropogenic food (waste grain, bait). Despite similar time-budgets, released Mallards never attained the body condition of wild birds. As a consequence, survival probability in released Mallards was low, especially when food provisioning was stopped and during harsh winter periods. We argue that the low survival of released Mallards likely has a physiological rather than a behavioural (foraging) origin. In any case, extremely few released birds live long enough to potentially enter the breeding population, even without hunting. In the context of massive releases presently carried out for hunting purposes, our study indicates a low likelihood for genetic introgression by captive-reared birds into the wild population.
|
|
| 4. |
- Champagnon, Jocelyn, et al.
(författare)
-
Low survival after release into the wild : assessing “the burden of captivity” on Mallard physiology and behaviour
- 2012
-
Ingår i: European Journal of Wildlife Research. - : Springer Verlag. - 1612-4642 .- 1439-0574. ; 58:1, s. 255-267
-
Tidskriftsartikel (refereegranskat)abstract
- Captive-reared animals used in reinforcement programs are generally less likely to survive than wild conspecifics. Digestion efficiency and naive behaviour are two likely reasons for this pattern. The Mallard is a species with high adaptability to its environment and in which massive reinforcement programs are carried out. We studied physiological and behavioural factors potentially affecting body condition and survival of captive-reared Mallards after being released. Digestive system morphology and an index of body condition were compared among three groups: captive-reared birds remaining in a farm (control), captive-reared birds released into the wild as juveniles (released) and wild-born birds (wild). We also compared behaviour and diet of released vs. wild Mallards. Finally, we conducted a 1-year survival analysis of captive-reared birds after release in a hunting-free area. Gizzard weight was lower in control Mallards, but the size of other organs did not differ between controls and wild birds. The difference in gizzard weight between released and wild birds disappeared after some time in the wild. Diet analyses suggest that released Mallards show a greater preference than wild for anthropogenic food (waste grain, bait). Despite similar time-budgets, released Mallards never attained the body condition of wild birds. As a consequence, survival probability in released Mallards was low, especially when food provisioning was stopped and during harsh winter periods. We argue that the low survival of released Mallards likely has a physiological rather than a behavioural (foraging) origin. In any case, extremely few released birds live long enough to potentially enter the breeding population, even without hunting. In the context of massive releases presently carried out for hunting purposes, our study indicates a low likelihood for genetic introgression by captive-reared birds into the wild population.
|
|
| 5. |
- Chapron, Guillaume
(författare)
-
Overestimates of maternity and population growth rates in multi-annual breeders
- 2013
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 59, s. 237-243
-
Tidskriftsartikel (refereegranskat)abstract
- There has been limited attention to estimating maternity rate because it appears to be relatively simple. However, when used for multi-annual breeder species, such as the largest carnivores, the most common estimators introduce an upward bias by excluding unproductive females. Using a simulated dataset based on published data, we compare the accuracy of maternity estimates derived from standard methods against estimates derived from an alternative method. We show that standard methods overestimate maternity rates in the presence of unsuccessful pregnancies. Importantly, population growth rates derived from a matrix model parameterized with the biased estimates may indicate increasing populations although the populations are stable or even declining. We recommend the abandonment of the biased standard methods and to instead use the unbiased alternative method for population projections and assessments of population viability.
|
|
| 6. |
- Dessborn, Lisa, et al.
(författare)
-
Geographical and temporal patterns in the diet of pintail Anas acuta, wigeon Anas penelope, mallard Anas platyrhynchos and teal Anas crecca in the Western Palearctic
- 2011
-
Ingår i: European Journal of Wildlife Research. - : Springer Verlag. - 1612-4642 .- 1439-0574. ; 57:6, s. 1119-1129
-
Tidskriftsartikel (refereegranskat)abstract
- Dabbling ducks are important quarry species, and as a result, they are relatively well studied. Over the last century, considerable effort has been made to describe their diet and food requirements. In this review, we compile present knowledge about the diet of four widespread dabbling ducks (wigeon, pintail, mallard and teal) in the Western Palearctic. Previous diet research has a spatio-temporal bias towards autumn/winter and the western parts of Europe. The limited number of studies from the breeding season reveals an increase in invertebrates in the diet compared to other seasons, but with some differences between adults and ducklings. Adult ducks eat a larger proportion of benthic invertebrates, whereas ducklings feed relatively more on emerging invertebrates. The most important plant species (seeds) based on frequency occurrence was found to vary with a geographic gradient. Carex spp., Hordeum vulgare and Hippuris vulgaris are common in the diet of birds at northern latitudes, whereas taxa such as Oryzasativa, Potamogeton pectinatus and Scirpus spp. are common in the south. The reviewed studies are based on the contents of different parts of the digestive system and on a variety of methods to quantify food items. The variations in sampling techniques and shortage of articles from the breeding season and some geographic regions highlight the need for future studies. In the future, it is important to standardize sampling techniques to improve the possibility to compare studies and to obtain a more representative view of the diet of dabbling ducks in Europe.
|
|
| 7. |
- Gavier-Widén, Dolores
(författare)
-
Testosterone production and spermatogenesis in free-ranging Eurasian lynx (Lynx lynx) throughout the year
- 2014
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 60, s. 569-577
-
Tidskriftsartikel (refereegranskat)abstract
- Seasonal variation in reproduction is common in mammals as an adaptation to annual changes in the habitat. In lynx, male reproduction activity is of special interest because female lynxes are monoestric with an unusual narrow (about 1 month) breeding season. In Eurasian lynx, mating occurs between January and April depending on the latitude. To characterize the seasonal pattern of sperm and testosterone production in free-ranging Eurasian lynxes, long-term frozen-stored testis material obtained postmortem from 74 hunted or road-killed lynxes in Sweden was used to analyze annual changes in testis mass, testicular testosterone content, and spermatogenetic activity. Values of most gonadal parameters obtained in subadult lynxes were significantly different from the values observed in adult males. In adult lynxes, a moderate annual fluctuation of gonadal parameters was found which was most profound for testis weight and testicular testosterone concentration reaching highest values in March (median of 2.18 g and 2.67 mu g/g tissue respectively). Grouping the data of pre-/breeding (January-April) and postbreeding season (May-September) revealed significant changes in testis weight and testosterone concentration. The relative spermatogenetic activity remained high in postbreeding testes. However, net sperm production decreased according to reduction of testis mass and a tendency to lower cauda epididymal sperm numbers in the postbreeding period was observed. Our results demonstrate that it is possible to analyze the gonadal activity of frozen testis/epididymis tissue postmortem and that male Eurasian lynxes show-opposite to the females-only moderate seasonal changes in their reproductive capacity.
|
|
| 8. |
- Gunnarsson, Gunnar, et al.
(författare)
-
Density dependence in ducks : a review of the evidence
- 2013
-
Ingår i: European Journal of Wildlife Research. - : Springer Verlag. - 1612-4642 .- 1439-0574. ; 59:3, s. 305-321
-
Tidskriftsartikel (refereegranskat)abstract
- Density dependence (DD) is a central concept in population ecology and in the management of harvested populations. For example, DD underpins the idea of additive versus compensatory mortality and is a tenet in the paradigm of resource limitation and regulation. Yet the prevalence and importance of DD remains disputed in most organisms, including ducks, which are focal in game management, conservation and zoonotic diseases. Based on 154 data entries from 54 studies in the peer-reviewed literature, we here synthesize and evaluate the prevalence of DD in breeding ducks in relation to (1) species and guild (dabbling versus diving ducks), (2) stage in the breeding cycle (nesting, duckling, recruitment) or, alternatively, in terms of population dynamics, (3) study type (descriptive/nonmanipulative versus experimental), (4) continent (Europe versus North America), (5) spatial level (wetland, landscape, regional, continental) and (6) biome (tundra, boreal, nemoral, prairie, mediterranean). One conclusion from this review is that it is difficult to find general patterns about the prevalence of DD unless data are broken down to subsets, for example, to stage or spatial level. With respect to stage, DD effects occur at all stages of the breeding cycle. During the nesting and duckling stages, the frequency of cases detecting versus not detecting DD is roughly the same. However, in cases referring to the recruitment stage, i.e. to survival of fledged ducks until 1 year old at the most, DD was the rule, suggesting that DD processes may operate mainly outside the breeding season. Further subdivision of data shows that spatial scale is important to the prevalence of DD in nesting ducks—rare on the wetland level and more common on higher spatial levels. In studies of population dynamics (i.e. based on time series data only), DD was more often found in diving than in dabbling ducks. This corroborates previous suggestions that dabbling ducks largely should be considered as r-selected species, in contrast to more K-selected diving ducks, which start to reproduce at an older age and often breed in more stable wetland environments where resources may be easier to track and populations thus often are closer to carrying capacity. However, the picture of DD in ducks is far from complete, and knowledge gaps for future studies to address include: (a) data from Russia, which holds a large part of the breeding ducks in the Northern hemisphere, (b) experimental studies on more species to separate density-dependent factors from other drivers of population change and to tease apart spatial and temporal interactions in the underlying processes, (c) time series analyses addressing population dynamics, especially from outside North America, (d) studies relating duck numbers to limiting resources, which arguably is the most relevant measure of density, (e) the timing of DD processes in relation to harvest and natural mortality.
|
|
| 9. |
- Gunnarsson, Gunnar, 1976-, et al.
(författare)
-
Density dependence in ducks : a review of the evidence
- 2013
-
Ingår i: European Journal of Wildlife Research. - : Springer Verlag (Germany). - 1612-4642 .- 1439-0574. ; 59:3, s. 305-321
-
Tidskriftsartikel (refereegranskat)abstract
- Density dependence (DD) is a central concept in population ecology and in the management of harvested populations. For example, DD underpins the idea of additive versus compensatory mortality and is a tenet in the paradigm of resource limitation and regulation. Yet the prevalence and importance of DD remains disputed in most organisms, including ducks, which are focal in game management, conservation and zoonotic diseases. Based on 154 data entries from 54 studies in the peer-reviewed literature, we here synthesize and evaluate the prevalence of DD in breeding ducks in relation to (1) species and guild (dabbling versus diving ducks), (2) stage in the breeding cycle (nesting, duckling, recruitment) or, alternatively, in terms of population dynamics, (3) study type (descriptive/nonmanipulative versus experimental), (4) continent (Europe versus North America), (5) spatial level (wetland, landscape, regional, continental) and (6) biome (tundra, boreal, nemoral, prairie, mediterranean). One conclusion from this review is that it is difficult to find general patterns about the prevalence of DD unless data are broken down to subsets, for example, to stage or spatial level. With respect to stage, DD effects occur at all stages of the breeding cycle. During the nesting and duckling stages, the frequency of cases detecting versus not detecting DD is roughly the same. However, in cases referring to the recruitment stage, i.e. to survival of fledged ducks until 1 year old at the most, DD was the rule, suggesting that DD processes may operate mainly outside the breeding season. Further subdivision of data shows that spatial scale is important to the prevalence of DD in nesting ducks—rare on the wetland level and more common on higher spatial levels. In studies of population dynamics (i.e. based on time series data only), DD was more often found in diving than in dabbling ducks. This corroborates previous suggestions that dabbling ducks largely should be considered as r-selected species, in contrast to more K-selected diving ducks, which start to reproduce at an older age and often breed in more stable wetland environments where resources may be easier to track and populations thus often are closer to carrying capacity. However, the picture of DD in ducks is far from complete, and knowledge gaps for future studies to address include: (a) data from Russia, which holds a large part of the breeding ducks in the Northern hemisphere, (b) experimental studies on more species to separate density-dependent factors from other drivers of population change and to tease apart spatial and temporal interactions in the underlying processes, (c) time series analyses addressing population dynamics, especially from outside North America, (d) studies relating duck numbers to limiting resources, which arguably is the most relevant measure of density, (e) the timing of DD processes in relation to harvest and natural mortality.
|
|
| 10. |
- Jarnemo, Anders, et al.
(författare)
-
Movement pattern of red deer during drive hunts in Sweden
- 2014
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 60, s. 77-84
-
Tidskriftsartikel (refereegranskat)abstract
- We investigated the movement pattern of GPS-collared red deer (Cervus elaphus) during drive hunts with loose dogs. In 46 flights of hinds (N = 9), the median flight distance was 2.5 km (range 0.4-15.0). In 28 % of the flights, the hind left its home range. Average time before returning to home range was 23 h (range 2-88). Hinds in a less forested site left their home ranges more often, fled longer distances, moved at higher speed, and returned later than hinds in a homogenous forest. Speed of movement increased with number of hunts in the less forested site. In eight flights of stags (N = 4), the median flight distance was 5.1 km (range 2.2-13.3). The start of hunting season seemed to trigger stags' departure to their wintering areas. Knowledge of reactions to disturbance can aid game management to choose hunting methods and dogs that cause less disturbance but may also be used to deter deer from areas where they damage crops and forest plantations.
|
|
| 11. |
- Lundmark, Carina, et al.
(författare)
-
Adaptive co-management: How social networks, deliberation and learning affect legitimacy in carnivore management
- 2014
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 60:4, s. 637-644
-
Tidskriftsartikel (refereegranskat)abstract
- Adaptive co-management (ACM) is a key concept in science and an increasingly adopted policy response in conservation, associated with a number of positive outcomes. However, the effects and mechanisms of co-management arrangements, including the conditions under which ACM gives rise to higher levels of internal and external legitimacy, are yet to be explored. This endeavor, in turn, requires theoretically driven models providing assumptions and outlining testable hypotheses. Considering the social challenges of ACM and using an institutional change within the Swedish carnivore management system aimed at achieving legitimacy through co-management as an illustrative example, this article develops a conceptual model that encompasses conditions and possible explanations to ACM outcomes. More specifically, drawing on lessons from social theory, we model the impact of three key factors-social networks, deliberation and learning-on the external and internal legitimacy resulting from ACM arrangements. Based on the model proposed, the popular assumptions of ACM outcomes can thus be empirically scrutinized and the conditions for increased legitimacy through ACM arrangements better comprehended.
|
|
| 12. |
- Meijer, Tomas, 1980-, et al.
(författare)
-
Endoparasites in the endangered Fennoscandian population of arctic foxes (Vulpes lagopus)
- 2011
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 57:4, s. 923-927
-
Tidskriftsartikel (refereegranskat)abstract
- The Fennoscandian arctic fox (Vulpes lagopus) population is endangered due to overharvest and competition with the larger red fox (Vulpes vulpes). In this study, we have screened the population in Sweden for endoparasites by analysis of non-invasively faecal samples collected at reproductive dens during two summers, one with low food abundance (2008) and the other with high food abundance (2010). Eggs, larvae and oocysts of a total of 14 different endoparasites were identified with a species richness per inhabited den of 3.2 (CI95% +/- 0.48) in 2008 and 2.7 (CI95% +/- 0.72) in 2010. Capillariidae-like eggs was identified at 59% of the dens in 2008 and 57% in 2010 and Toxocara canis with 7% (2008) and 30% (2010); Toxascaris leonina with 93% (2008) and 65% (2010); Uncinaria stenocephala 65% (2008) and 39% (2010); Crenosoma vulpis 3% (2008) and 4% (2010); Trichuris sp. 7% (2008) and 4% (2010); Cystoisospora canis-like oocysts 28% (2008) and 26% (2010); Cystoisospora ohiensis-like oocysts 38% (2008) and 4% (2010); Eimeria sp. 7% (2008) and 9% (2010); Sarcocystis sp. 3% (2008) and 9% (2010); Taenia sp. 10% (2008) and 4% (2010); Mesocestoides sp. 3% (2008) and 0% (2010); Balantidium sp. 0% (2008) and 9% (2010) and Spiruroidea-like eggs 0% (2008) and 4% (2010). To our knowledge, Balantidium sp., Sarcocystis sp. and Trichuris sp. has never been described before in wild arctic foxes.
|
|
| 13. |
- Meijer, Tomas, et al.
(författare)
-
The impact of maternal experience on post-weaning survival in an endangered arctic fox population
- 2011
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 57:3, s. 549-553
-
Tidskriftsartikel (refereegranskat)abstract
- Behavioural differences in parental care can influence offspring survival through variation in e.g. antipredator behaviour and ability to provide food. In a broad range of species, offspring survival has been found to be higher for experienced females compared to inexperienced first-time breeders. The increase in offspring survival for experienced females has mainly been explained by improved experience in providing food. In this paper, we have studied post-weaning juvenile survival in relation to maternal experience in an endangered population of arctic foxes (Vulpes lagopus) in Fennoscandia. For cubs raised by inexperienced and experienced females, the survival rate was 0.42 (CI 95% +/- 0.31) and 0.87 (CI 95% +/- 0.08), respectively. There was no difference in body condition between the cubs and no observations of starvation. We suggest that the difference in survival was due to lack of experience to one of the most common predators, the golden eagle (Aquila chrysaetos). Golden eagles were mainly observed on dens with litters where the females were inexperienced first-time breeders. From a conservation perspective, it is therefore important to increase adult survival through actions to enlarge the proportion of experienced breeders.
|
|
| 14. |
- Månsson, Johan, et al.
(författare)
-
Can pellet counts be used to accurately describe winter habitat selection by moose Alces alces?
- 2011
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 57, s. 1017-1023
-
Tidskriftsartikel (refereegranskat)abstract
- Pellet counts have been used to measure habitat selection of a variety of ungulate species often under the assumption that this method gives an unbiased sample of the true distribution of the species among habitats. The validity of this method has been questioned and comparisons with other methods have sometimes showed divergent results. We tested the validity of pellet group distribution as a tool for habitat selection studies by comparing the distribution of moose pellet groups in four different forest age categories (forest age <30, 31-60, 61-90, >90 years) and mire with GPS positions from collared moose (Alces alces). Sample plots (n=531) were cleaned from pellet during the fall 2007 and the number of new pellet groups were counted in spring 2008, thus resulting in a defined period of accumulation. In addition, pellet groups were counted in paired, uncleaned, control plots. GPS data from 15 collared moose monitored during the same period were used for comparison with habitat composition and distribution of pellet groups. Both the distribution of pellet groups and GPS positions differed significantly from the habitat composition within the study area. Young forest stands (<30 years) were significantly more used than both forests >30 years and mire. The selection by moose, as calculated by Manly's alpha, showed identical ranking among habitat classes for cleaned sample plots and GPS data whereas uncleaned plots showed a shifted rank order for two of the habitat classes. We conclude that pellet group counts can be used to accurately predict habitat use for moose during winter.
|
|
| 15. |
- Neumann, Wiebke, et al.
(författare)
-
Does off-trail backcountry skiing disturb moose?
- 2010
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 56, s. 513-518
-
Tidskriftsartikel (refereegranskat)abstract
- The advancement of recreational activities into wildlife habitat calls for a better knowledge about the effects of human-induced disturbances, particularly in systems where humans dominate wildlife mortality. We exposed nine adult free-ranging female moose repeatedly to off-trail backcountry skiing to study moose behavior and habituation using a controlled field experiment in Northern Sweden. Moose response was short-term, but distinct. Moose moved 33-fold faster during the first hour following disturbance, resulting in almost a doubling of the energetic usage per kilogram body weight. Movement rates increased 3 h following disturbances, came along with enlarged activity ranges at the day of disturbance, and resulted in moose leaving the original area. We found no evidence for habituation. Because of the short-term response, the effect of single skiing disturbance events on the overall energy budget of large-bodied animals in good body condition is likely to be negligible. We recommend off-trail skiers to avoid following wildlife tracks because such disturbances bear risk for more severe consequences on wildlife's energy budget if wildlife resists habituation, if an animal's risk perception is high, or when the frequency of disturbance increases.
|
|
| 16. |
|
|
| 17. |
- Persson, Jens, et al.
(författare)
-
Space use and territoriality of wolverines (Gulo gulo) in northern Scandinavia
- 2010
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 56, s. 49-57
-
Tidskriftsartikel (refereegranskat)abstract
- Space use and territoriality influence population structure and dynamics and is therefore an important aspect in understanding the ecology of animals. We investigated spatial and temporal space use of wolverines (Gulo gulo) in northern Scandinavia. We estimated home ranges of 24 radio-marked individuals (17 females and seven males). Male home ranges (mean 669 km(2); SE = 211) were significantly larger than female home ranges (mean 170 km(2); Wilcoxon-Mann-Whitney; P = 0.001) and encompassed or included parts of up to five different females. Home range sizes of reproducing (170 km(2); SE = 51) and barren (171 km(2); SE = 63) adult females did not differ. Wolverines in Scandinavia exhibit intrasexual territoriality, with male home ranges totally exclusive and female home ranges either exclusive or with little home range overlap. Overlap between wolverine territories is most likely explained by intrasexual tolerance and kinship.
|
|
| 18. |
- Persson, Sara, et al.
(författare)
-
Influence of age, nutritional status and season on the reproductive system in wild male mink (Neovison vison)
- 2011
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 57:5, s. 1057-1063
-
Tidskriftsartikel (refereegranskat)abstract
- The objectives of this study on the reproductive system of wild male mink (Neovison vison) were to determine the influence of age, nutritional status and season on reproductive traits and to produce baseline data that may be used in environmental monitoring programmes. The 117 male mink included in the study were killed by hunters all over Sweden (from latitude 56 degrees N to 67 degrees N) during August to the end of April from 2005 to 2008. The weights of penis, testes, and epididymides were lower, the anogenital distance was shorter and the diameter of seminiferous tubules was less in juveniles compared with adult mink (p<0.0001-p=0.0024). There was a positive effect (p<0.05) of nutritional status on the baculum length and on the anogenital distance, but not on any of the other reproductive traits. The season of sampling influenced the penis, testes and epididymes weights and the diameter of seminiferous tubules (p=0.008-p<0.0001). During spring, 86% of the mink had sperm in their epididymides, whereas the corresponding figure for autumn was 3%; in addition, when the average diameter of the tubules reached 138 mu m, sperm were present in the epididymides. Sperm morphology was analysed in 29 of the mink, and the percentage of morphologically defect sperm were generally low. Taken together, this study suggests that when assessing male reproductive data in wild mink populations, season must be taken into account as well as whether the individuals are juvenile or adult. In contrast, the nutritional status seems not to be of any major significance.
|
|
| 19. |
- Rydell, Jens, et al.
(författare)
-
Mortality of bats at wind turbines links to nocturnal insect migration?
- 2010
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 56:6, s. 823-827
-
Forskningsöversikt (refereegranskat)abstract
- This note is based on a literature search and a recent review of bat mortality data from wind farms in Europe (published elsewhere). We suggest that mortality of bats at wind turbines may be linked to high-altitude feeding on migrating insects that accumulate at the turbine towers. Modern wind turbines seem to reach high enough into the airspace to interfere with the migratory movements of insects. The hypothesis is consistent with recent observations of bats at wind turbines. It is supported by the observation that mortality of bats at wind turbines is highly seasonal (August-September) and typically peaks during nights with weather conditions known to trigger large-scale migratory movements of insects (and songbirds). We also discuss other current hypotheses concerning the mortality of bats at wind turbines.
|
|
| 20. |
|
|
| 21. |
- Sjöberg, Kjell, et al.
(författare)
-
Born to cope with climate change? : experimentally manipulated hatching time does not affect duckling survival in the mallard Anas platyrhynchos
- 2011
-
Ingår i: European Journal of Wildlife Research. - 1612-4642 .- 1439-0574. ; 57:3, s. 505-516
-
Tidskriftsartikel (refereegranskat)abstract
- Two main hypotheses proposed to explain the seasonal decline in reproductive performance in birds are (1) deterioration of environmental conditions and (2) lower parental quality of late breeders. Previous experimental work addressing these hypotheses generally have problematic biases pertaining to delay of hatching, costs of re-laying and incubation, as well as variation in the quality of eggs, territories, offspring and parental traits. We address these biases in an experimental test of the timing hypothesis (i.e. (1) above) in a precocial bird. Using a 2-year cross-over design and game-farm mallard (Anas platyrhynchos) eggs originating from a number of hens and a standardised delay procedure, we introduced early and late broods with a foster female onto boreal oligotrophic lakes and monitored subsequent duckling survival. Standardised invertebrate sampling was done concurrently to get a measure of lake-level abundance of aquatic prey, a likely causative agent of putative seasonal difference in duckling survival. Survival data and covariates (duckling age; days) were analysed by an information theoretic approach. There was no effect of treatment (i.e. manipulation of hatching date) on duckling survival, which was higher in 2005 than in 2004. In contrast to observational studies from more seasonal wetlands, our experiment demonstrates that duckling survival on boreal lakes was not affected by a 12-day delay in hatching date. Since we did not find any consistent trends in abundance of aquatic prey, i.e. neither clear peaks nor differences between treatment periods, we hypothesise that moderate climate change has minor effects on resource abundance and hence also on mallard duckling survival in boreal environments.
|
|
| 22. |
- Sjöberg, Kjell, et al.
(författare)
-
Born to cope with climate change? : experimentally manipulated hatching time does not affect duckling survival in the mallard Anas platyrhynchos
- 2011
-
Ingår i: European Journal of Wildlife Research. - : Springer Verlag. - 1612-4642 .- 1439-0574. ; 57:3, s. 505-516
-
Tidskriftsartikel (refereegranskat)abstract
- Two main hypotheses proposed to explain the seasonal decline in reproductive performance in birds are (1) deterioration of environmental conditions and (2) lower parental quality of late breeders. Previous experimental work addressing these hypotheses generally have problematic biases pertaining to delay of hatching, costs of re-laying and incubation, as well as variation in the quality of eggs, territories, offspring and parental traits. We address these biases in an experimental test of the timing hypothesis (i.e. (1) above) in a precocial bird. Using a 2-year cross-over design and game-farm mallard (Anas platyrhynchos) eggs originating from a number of hens and a standardised delay procedure, we introduced early and late broods with a foster female onto boreal oligotrophic lakes and monitored subsequent duckling survival. Standardised invertebrate sampling was done concurrently to get a measure of lake-level abundance of aquatic prey, a likely causative agent of putative seasonal difference in duckling survival. Survival data and covariates (duckling age; days) were analysed by an information theoretic approach. There was no effect of treatment (i.e. manipulation of hatching date) on duckling survival, which was higher in 2005 than in 2004. In contrast to observational studies from more seasonal wetlands, our experiment demonstrates that duckling survival on boreal lakes was not affected by a 12-day delay in hatching date. Since we did not find any consistent trends in abundance of aquatic prey, i.e. neither clear peaks nor differences between treatment periods, we hypothesise that moderate climate change has minor effects on resource abundance and hence also on mallard duckling survival in boreal environments.
|
|
| 23. |
- Söderquist, Pär, et al.
(författare)
-
Longevity and migration distance differ between wild and hand-reared mallards Anas platyrhynchos in Northern Europe
- 2013
-
Ingår i: European Journal of Wildlife Research. - : Springer Verlag (Germany). - 1612-4642 .- 1439-0574. ; 59:2, s. 150-166
-
Tidskriftsartikel (refereegranskat)abstract
- The mallard Anas platyrhynchos is the world’s most widespread and numerous dabbling duck. It is also farmed and released to the wild by the millions each year, but the effects of this on wild populations remain little studied. By using historical national ringing–recovery data from Sweden and Finland, we here address three predictions based on previous studies: (1) longevity is higher in wild than in hand-reared mallards, (2) wild mallards migrate longer than hand-reared, and (3) migration distance in wild ducks surviving long enough to start fall migration has decreased over the last 50 years. Indeed, wild mallards lived longer than hand-reared (19 versus 9 months in Swedish birds and 13 versus 4 months in Finnish birds). Compared to wild mallards, a smaller proportion of hand-reared birds survived long enough to have the chance to enter the wild breeding population; less than 25 % of the Swedish birds and less than 10 % of the Finnish birds lived a year or longer. Wild birds migrated farther than hand-reared (mean distance in Swedish birds, 676 versus 523 km; in Finnish birds, 1,213 versus 157 km), a pattern caused by both shorter life span and lower migration speed in hand-reared birds. Mean migration distance in wild Swedish mallards was 787 km in 1947–1972 but 591 km in 1977–1993. This difference was not statistically significant, though, possibly due to the limited sample size and lack of data from the last two decades. In general, our study provides a conservative test of the predictions addressed, calling for more research about the consequences of restocking duck populations.
|
|
| 24. |
|
|
| 25. |
- Thulin, Carl-Gustaf, et al.
(författare)
-
Differences in body mass, health status and genetic variation between insular and mainland brown hares (Lepus europaeus) in Sweden
- 2012
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 58:6, s. 897-907
-
Tidskriftsartikel (refereegranskat)abstract
- Introduced populations can be affected by random processes such as genetic drift, deterministic processes given by the local environmental conditions and anthropogenic factors such as hunting and management. Geographically constrained populations are particularly exposed to these processes, and altogether, these factors may result in rapid differentiation from the ancestral populations. The introduced European brown hare (Lepus europaeus) population on the island Ven is isolated from the Swedish and Danish mainland. Undocumented observations suggest that the hares on the island have been increasingly diseased in recent years and also decreased in body size. To test the substance of these observations, as well as the potential for inbreeding depression in this geographically constrained population, a total of 321 hares from Ven and three reference populations on the Swedish mainland were analysed with respect to body mass, general health status and genetic variation. The results confirm that the hares on Ven have lower body mass than hares on the mainland, but there are no indications of health deficits. We argue that the difference in body mass primarily is an island effect of stress and/or nutritional shortage, possibly induced by high population density, anthropogenic selection regimes and absence of mammalian meso-predators. Further, the genetic data indicate that the insular population is substructured, and subadults from these two subpopulations differ in body mass. This apparent substructuring could be due to chance effects, but may also be related to assortative mating or presence of sustained populations with different ancestry.
|
|
| 26. |
- Thurfjell, Henrik
(författare)
-
Mortality rates of wild boar Sus scrofa L. in central Europe
- 2013
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 59, s. 805-814
-
Tidskriftsartikel (refereegranskat)abstract
- In many parts of Europe, wild boar Sus scrofa population increase, and thus, high densities and dispersal into new areas are accompanied by economic problems. Due to many factors like insufficient hunting strategies as well as underestimation of population densities and reproduction rates, harvest rates seem to be insufficient. Thus, we calculated mortality rates of several wild boar populations from 1998 to 2009, to show the efficiency of hunting within several studies distributed over eight European states. For calculating mortality rates, the daily probability of survival of radio telemetrically observed wild boar was analysed according to Mayfield (Wilson Bull 73:255-261, 1961) and with survival analysis in R for three age classes (0, 1, a parts per thousand yen2 years) and both sexes. The mortality rates of wild boar per annum, especially piglets, were comparably low (about 0.5 for piglets and similar for total population). About three third of all observed animals survived at least until the next period of reproduction. Mortality rates differed between some study areas, the sexes and age classes. The sex ratio of the shot piglets equals the sex ratio of captured piglets; there seems to be no sex-biased hunting in this age class, but in an older age. Shooting was the main cause of death; only very few animals died by natural causes, e.g. diseases. The comparative analysis of all studies reflects a low mortality of wild boar in highly productive populations. Our results certified the findings of several studies that predation, natural mortality, and road mortality have only small impact on wild boar populations, whereas especially, nutrition or hunting are mainly decisive. Assuming net reproduction rates of more than 200 % according to literature data, our results indicate that harvest rates are not sufficient at our study sites. In all our studies, mortality rates and, thus, harvest rates are less than the assumed total net reproduction. Especially, the harvest rate of piglets seems to be insufficient. Thus, the population will increase further. High reproduction has to be counteracted by regulating mainly the reproductive animals. For regulating a population, combined and effective hunting methods have to be conducted to harvest at least the net reproduction. Thus, we recommend higher hunting rates of piglets (80 % of the offspring should be harvested) and of adult females. Intensified hunting of piglets by drive hunts and at an early age as well as intensified single hunt on adult females might help regulating wild boar populations.
|
|
| 27. |
- Widemo, Fredrik, et al.
(författare)
-
Trapping in predator management: catching the profile of trap users in Sweden
- 2014
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 60, s. 681-689
-
Tidskriftsartikel (refereegranskat)abstract
- Many populations of wildlife, including large- and medium-sized predators are increasing in Europe. Trapping can be one way to reduce negative impacts of predators on human interests, such as game species and threatened species, but there is little knowledge of trap usage and motivation behind it. We used a mail survey in Sweden (n = 3,886 respondents) to compare predator trappers with hunters who used other methods to kill predators, and with other hunters who did not kill predators, in regard to sociodemographics, beliefs, behaviors, and constraints. During 12 months prior to the survey 19 % of respondents had trapped any small- or medium-sized predator, while 15 % of respondents had trapped and 55 % had hunted (without using traps) red fox (Vulpes vulpes), European badger (Meles meles), or corvid birds. Reducing predator numbers was an important reason for hunting predators with traps. Of predator trappers, 97 % had hunted species that were potentially prey of the targeted predators (e.g., roe deer [Capreolus capreolus], hare [Lepus spp.], and grouse), 94 % believed that there were too many red foxes, badgers, or corvids on their main hunting ground, and 64 % believed it to be very important to reduce predator numbers to benefit other game species. We conclude that the use of traps is widespread among Swedish hunters, and that increasing wildlife populations, increased presence of wildlife in urban areas, and management of invasive species calls for effective management actions, of which trapping can be one.
|
|
| 28. |
- Wilhelmsson, Erik
(författare)
-
Hunting in European mountain systems: an economic assessment of game gross margins in nine case study areas
- 2014
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 60, s. 933-936
-
Tidskriftsartikel (refereegranskat)abstract
- Wildlife occupies a very relevant place in ecosystems by providing multiple goods and services to society, gaining an important role in mountain systems. In this manuscript, we calculate gross margin figures associated with game hunting activity in nine European mountainous case study areas. Information about local game population and their management were collected by means of a structured questionnaire completed by the managers in charge of game species in the case study areas. Results show that in most of the cases, gross margins per hectare are negative, indicating that in these instances, the current market apparently does not justify maintaining hunting in some European mountain systems. Although more sampling efforts should be done to confirm our findings at a wider scale, our analysis reinforces the idea that other social factors, such as cultural heritage or self-consumption associated with hunting, may be crucial to wholly understand hunting in mountain systems. So we urge scientists to estimate non-market values related to hunting to better explain society priorities and therefore to efficiently guide future conservation, management, and policies in marginal and least favored mountain systems.
|
|
| 29. |
- Zehtindjiev, Pavel, et al.
(författare)
-
Haemosporidian infections in skylarks (Alauda arvensis): a comparative PCR-based and microscopy study on the parasite diversity and prevalence in southern Italy and the Netherlands
- 2012
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 58:1, s. 335-344
-
Tidskriftsartikel (refereegranskat)abstract
- Changes in agricultural management have been identified as the most probable cause for the decline of Skylark (Alauda arvensis) populations in Europe. However, parasitic infections have not been considered as a possible factor influencing this process. Four hundred and thirty-four Skylarks from the Southern Italy and the Netherlands were screened for haemosporidian parasites (Haemosporida) using the microscopy and polymerase chain reaction (PCR)-based methods. The overall prevalence of infection was 19.5%; it was 41.8% in Italian birds and 8.3% in Dutch birds. The prevalence of Plasmodium spp. was 34.1% and 6.5% in Skylarks from Italy and Netherlands, respectively. Approximately 15% of all recorded haemosporidian infections were simultaneous infections both in Italian and Dutch populations. Six different mitochondrial cytochrome b (cyt b) lineages of Plasmodium spp. and three lineages of Haemoproteus tartakovskyi were found. The lineage SGS1 of Plasmodium relictum was the most prevalent at both study sites; it was recorded in 24.7% of birds in Italy and 5.5% in the Netherlands. The lineages SYAT05 of Plasmodium vaughani and GRW11 of P. relictum were also identified with a prevalence of <2% at both study sites. Two Plasmodium spp. lineages (SW2 and DELURB4) and three H. tartakovskyi lineages have been found only in Skylarks from Italy. Mitochondrial cyt b lineages SYAT05 are suggested for molecular identification of P. vaughani, a cosmopolitan malaria parasite of birds. This study reports the greatest overall prevalence of malaria infection in Skylarks during the last 100 years and shows that both Plasmodium and Haemoproteus spp. haemosporidian infections are expanding in Skylarks so it might contribute to a decrease of these bird populations in Europe.
|
|
