| 1. |
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| 2. |
- Arzel, Céline, et al.
(författare)
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Average mass of seeds encountered by foraging dabbling ducks in western Europe
- 2007
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Ingår i: Wildlife Biology. - 0909-6396 .- 1903-220X. - 0909-6396 ; 13:3, s. 328-336
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Tidskriftsartikel (refereegranskat)abstract
- Many dabbling ducks Anas spp. are largely granivorous, consuming a variety of seeds chiefly from aquatic plants. To assess the relative value and carrying capacity of wetlands for dabbling ducks, species-specific information about seed mass is needed, but it is still largely missing or scattered in the literature. By combining weights of seeds collected in the field with a literature review, we provide a reference table for seed mass of 200 western European plant taxa frequently encountered by foraging dabbling ducks. Seeds collected in the field were sampled in microhabitats and at depths at which ducks were observed to forage, and study sites represent wintering, staging as well as breeding areas within a flyway in western Europe. When combined with calorimetric data, the present reference table will aid managers and scientists in assessing the importance of seed food resources at different sites and during different parts of the annual cycle.
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| 3. |
- Elmberg, Johan, 1960-, et al.
(författare)
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The scientific basis for a new and sustainable management of migratory European ducks
- 2006
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Ingår i: Wildlife Biology. - 0909-6396 .- 1903-220X. ; 12:2, s. 121-127
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Tidskriftsartikel (refereegranskat)abstract
- It is an axiom in ecology that knowing the sheer number of individuals in a population is of very little help if the objective is to understand future and past changes in population size. Yet, this is exactly how migratory European ducks are monitored, many of which are important quarry species in several countries. We argue that present monitoring is insufficient to address objectives of wise use and sustainability such as those emphasised in recent management directives and multilateral international agreements. The two main problems are the almost total lack of reliable data on recruitment and mortality. We advocate a pan-European monitoring system based on undisputed scientific principles; i.e. a long-term, coordinated and standardised scheme that produces data about vital rates of duck populations as well as about harvest size. Data from such a scheme can be used by game biologists to produce predictive tools, thus providing a functional basis for management decisions for adaptive harvesting and conservation alike.
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| 4. |
- Elfström, M, et al.
(författare)
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Selection of denning habitats by Scandinavian brown bears Ursus arctos
- 2008
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Ingår i: Wildlife Biology. - 0909-6396 .- 1903-220X. ; 14:2, s. 176-187
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Tidskriftsartikel (refereegranskat)abstract
- We analyse the selection of denning habitats by Scandinavian brown bears Ursus arctos and test if there are differences related to sex and age. At the landscape level, the vegetation types within a 500-m radius around 250 dens used during 1990–2000 in south-central Sweden were analysed using a Geographical Information System (GIS). Compositional analysis (CA) was used to test if bears selected or avoided certain habitat types for denning. There were relatively few differences in habitat selection among bears of differences age or sex. Overall, as a group the bears showed distinct preferences in selection of denning habitats; selecting for open canopy (Scots pine Pinus sylvestris) forests and habitats with moist soil with rich vegetation, before closed canopy (older Norway spruce Picea abies and Scots pine) forests, young forest and clear cuts, mountain coniferous forests and bogs. Denning bears avoided water, alpine mountain-birch forest, deciduous forest, peat, exposed bedrock and gravel pits. Bears denned more on lower altitudes, easterly aspects and steeper slopes than was available. Furthermore, bears avoided intermediate-size roads, perhaps because they are the source of human disturbance, providing a combination of easy winter access (because they are ploughed) and relatively high traffic intensity.
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| 5. |
- Hedmark, Eva, et al.
(författare)
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Paternity and mating system in wolverines Gulo gulo
- 2007
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Ingår i: Wildlife Biology. - 0909-6396 .- 1903-220X. ; 13:Suppl.2, s. 13-30
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge of the wolverine Gulo gulo mating system is limited. In this study, we use 20 microsatellite loci for paternity testing in 145 wolverine offspring with known mothers. Samples were collected during > 10 years in two Scandinavian populations, mainly in connection with radio-telemetry studies and as part of long-term population monitoring. In total, 51% of the offspring were assigned a father. Our results demonstrate that the wolverine exhibits a polygamous mating system as some males were shown to produce offspring with more than one female in a single year. Females often reproduced with the same male in subsequent breeding years, but sometimes changed their partner, potentially as a consequence of a change in the territory-holding male in the area. In the majority of litters, siblings were unambiguously assigned the same father, indicating that multiple paternity is rare. Of 23 breeding pairs, for which telemetry data were available, 20 had overlapping home ranges, suggesting that pair formation generally is consistent with the territories held by wolverine males and females.
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| 6. |
- Rönnegård, Lars, et al.
(författare)
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Evaluation of four methods used to estimate population density of moose Alces alces
- 2008
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Ingår i: Wildlife Biology. - 0909-6396 .- 1903-220X. ; 14:3, s. 358-371
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Tidskriftsartikel (refereegranskat)abstract
- Various survey methods are used to monitor and manage ungulate popualations. The choice of optimal method depends on estimation accuracy, management objective and financial constraints. Here we compare estimates produced by four different methods for estimating population size, i.e. aerial counts, hunter observations, pellet group counts and cohort analysis. A Swedish moose Alces alces population was studied during 1973-2005 in the Grimso Wildlife Research Area (135 km(2)). The highest correlation was found between cohort analysis and aerial counts (r = 0.69. P < 0.05). and the hunter observations and the aerial counts (r = 0.76. P < 0.10). The different methods produced relatively consistent trends in population estimates over years. Pellet group counts prior to 1997 were not significantly correlated with the other methods. probably due to unrepresentative spatial sampling. A comparison of the aerial and pellet group counts in 2002 and 2006, showed that the average defecation rate was estimated at approximately 14 pellet groups per day per moose. Our results show the importance of having representative spatial sampling in pellet group surveys and indicate that hunter observations can be a useful tool for estimating long-term population trends even in moderately sized areas.
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| 7. |
- Andren, Henrik, et al.
(författare)
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Modelling the combined effect of an obligate predator and a facultative predator on a common prey: lynx Lynx lynx and wolverine Gulo gulo predation on reindeer Rangifer tarandus
- 2011
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Ingår i: Wildlife Biology. - : Wiley. - 0909-6396 .- 1903-220X. ; 17, s. 33-43
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Tidskriftsartikel (refereegranskat)abstract
- In conservation and management of large predators, effects of species are often considered separately. However, predators often interact with one another in different ways (e.g. interspecific competition, intra guild predation and kleptoparasitism) that may influence the total predation on a common prey. We estimated the total number of semi-domestic reindeer Rangifer tarandus killed by Eurasian lynx Lynx lynx and wolverine Gulo gulo at different relative abundances of the two species using a model based on diet, food requirements of lynx and wolverine and amount of food available on a reindeer. Our model suggests that total predation decreases by approximately 7.9% (+/- 4.8 SD) if wolverines scavenge on lynx-killed reindeer, compared to a model without scavenging. If the management goal is a constant number of predators, the model suggests that the total kill rate will be lowest in areas with only wolverines, as the estimated wolverine kill rate is much lower than the lynx kill rate. Our model showed that it is unlikely that the lowest number of reindeer killed per predator individual will be at a certain lynx-wolverine ratio, which would appear if lynx consumption of killed reindeer is low and wolverines are very efficient finding lynx-killed reindeer. However, if the management goal is a constant number of lynx and wolverines, the model suggests that the total predation is lower, if lynx and wolverines coexist in the same area compared to existing separately in different areas. The total predation by wolverine and lynx on reindeer is very important for the management of lynx and wolverine in the reindeer husbandry area in Sweden, as the current compensation scheme for predator-killed semi-domestic reindeer is based on the number of predators present within a reindeer herding district, and the compensation for wolverine and lynx is added independently of one another.
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| 8. |
- Andren, Henrik, et al.
(författare)
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Season rather than habitat affects lynx survival and risk of mortality in the human-dominated landscape of southern Sweden
- 2022
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Ingår i: Wildlife Biology. - : Wiley. - 0909-6396 .- 1903-220X. ; 2022
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Tidskriftsartikel (refereegranskat)abstract
- Landscapes are mosaics of habitat associated with different risks and resources, including human activities, which can affect individual survival in wildlife. Different relationships between habitat characteristics and human-caused and natural mortality can result in attractive sinks. We used individual-based data from 97 Eurasian lynx Lynx lynx monitored for 160 exposure-years to link adult survival and the risk of mortality to home range habitat characteristics in the human-dominated landscape of southern Sweden. Human-caused mortality (i.e. legal hunting, poaching and vehicle accidents) dominated mortality causes (24 out of 37 deaths). We did not detect any strong effects of habitat characterises explaining the variation in mortality risk in lynx. Although the density of roe deer affects several aspects of lynx ecology, we could not detect any effects of roe deer density on lynx survival, probably because roe deer density was sufficiently high in our study area. Instead, seasonal variation was the main factor influencing mortality in lynx. Mortality was highest during the hunting season for lynx (16 February-31 March), as well as during autumn and winter, probably because lynx poaching occurs opportunistically during the hunting season for moose and roe deer. We did not find any indication that human activity created attractive sinks for lynx, since there were no contrasting patterns between human-caused and natural mortality in terms of habitat characteristics. One explanation for the limited influence of the home range characteristics may be that lynx in our study died from multiple causes. Therefore, it is less likely that one or a few habitat characteristics could explain the risk of mortality at the home range scale. There is strong evidence that lynx can coexist with humans in multi-use and human-dominated landscapes, even without large protected areas, if the management regimes are favourable.
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| 9. |
- Andren, Henrik
(författare)
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Wind energy facilities affect resource selection of capercaillie Tetrao urogallus
- 2021
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Ingår i: Wildlife Biology. - : Wiley. - 0909-6396 .- 1903-220X. ; 2021
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Tidskriftsartikel (refereegranskat)abstract
- The recent increase in wind energy facilities (WEF) has led to concerns about their effect on wildlife. While the focus of most studies has mainly been on increased mortality of birds and bats due to collision, indirect effects, such as behavioural responses, arc currently gaining attention. Indeed, effects of WEF on the behaviour of forest dwelling wildlife still remain largely unknown. Using GPS-tracking of 16 individuals, we studied how seasonal resource selection of the capercaillie Tetrao urogallus, a forest grouse species known as sensitive to disturbance by human presence and infrastructure, was related to wind turbines and other environmental covariates in a wind farm in Sweden. During the lekking season, the probability of site-selection by capercaillic decreased with increasing turbine noise, turbine visibility and turbine shadow. During summer, we found reduced resource selection with increasing proximity to the turbines (up to 865 m), turbine density, noise, shadow and visibility. Furthermore, we found an avoidance of turbine access roads. Due to the high collinearity of the wind turbine predictors it was not possible to identify the specific mechanism causing turbine avoidance. Our study reveals that forest dwelling species with known sensitivity to other forms of human disturbance (i.e. recreation) are also likely to be affected by wind turbine presence. In addition, we provide proximity thresholds below which effects are likely to be present as a basis for conservation planning.
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| 10. |
- Bergqvist, Göran, et al.
(författare)
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Effects of female body mass and climate on reproduction in northern wild boar
- 2018
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Ingår i: Wildlife Biology. - : Wiley. - 0909-6396 .- 1903-220X.
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Tidskriftsartikel (refereegranskat)abstract
- Mammalian life history strategies depend on climate conditions. Hence, reproductive parameters may vary regionally, and knowledge on such patterns are important for sustainable management. Wild boar research has been biased towards south and central Europe. Here we investigate the effects of mother's carcass mass, season and climate (summer temperature and precipitation as well as January temperature) on pregnancy rate and litter size in 601 free-ranging female wild boar from hemiboreal Sweden, close to the north border of wild boar distribution range in Europe. Pregnancy rate was on average 33.4 +/- 1.94% (mean +/- SE), whereas average litter size of pregnant females was 4.7 +/- 0.12. Pregnancy rate was highest during the seasonal reproduction peak in winter and spring, and both pregnancy rate and litter size increased significantly with increasing female body mass. The probability of a female being pregnant exceeded 50% when carcass mass exceeded 58 kg, equivalent to a live mass of 113 kg, and litter size increased by one for each 16 kg increase in female carcass mass. We found no significant effects of temporal variations in climate, and suggest that such variations were not sufficiently large to affect wild boar reproduction. Alternatively, the reproductive strategy of wild boar may be adjusted to prevailing regional climate conditions. In that case, other life history traits, such as mortality, may be more sensitive to short-term climate fluctuations. Wild boar management needs to take temporal variations in reproduction, as well as in resource availability, into consideration when deciding on prudent management actions.
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