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40 Uppsatser om Predators - Sida 3 av 3

Migration losses of Atlantic salmon (Salmo salar L.) smolts at a hydropower station area in River Åbyälven, Northern Sweden : passage fates at a reservoir, a power house and a bypass structure

A large number of rivers in northern Sweden have hydropower developments that cause negative effects on both up- and downstream migrations of anadromous species like Atlantic salmon. So far, most attention has focused on the hindrances of adult fish during their upstream spawning migration. However, since turbines in power stations cause losses on downstream passing fish, the focus on negative effects on smolts has increased. The aim of this study was to compare three different causes of losses of salmon smolts passing downstream through a power station area in the flow-controlled River Åbyälven in northern Sweden.A total of 61 wild salmon smolts were caught and radio-tagged in the River Åbyälven during their downstream migration in June 2009. The salmon smolts were released at three locations, 1.1 km upstream from the power station, in the turbine intake and in the upper part of a fishway, acting both for up- and downstream fish passage.

Food preference in African Elephants (Loxodonta Africana) and the impact of Bomas in the vicinity of and in Masai Mara National Reserve

In the Maasai Mara National Reserve the native people, the Maasai, have lived for a long time following their own traditions. Their traditional lifestyle is that of a nomadic people, leading their cattle to the best grazing. Sharing their land with a large variation of different animals, one of them being the African Elephant (Loxodonta africana), the Maasi people have since long adapted to a life side by side with these giants, as well as the fierce Predators living in the area.The aim of this study is to determine whether the Maasai settlement, known as Boma, has any impact on the elephants in the surrounding area. In order to conclude whether the bomas has an impact or not, observations of the wildlife were carried out. Observations were conducted in two different seasons, in December 2003 and May/June in 2004.

Kan man genom kartstudier förutse häckningsframgång för ängshök (Circus pygargus) i Uppland? :

Montagu´s harrier (Circus pygargus) is a diurnal, Eurasian raptor, which migrates from its northern breeding grounds to winter in sub-Saharan Africa. In Sweden, its core breeding area is centred on the island of Öland, with a stable breeding population of approximately 40 pairs. The province of Uppland is on the northern end the distribution range, where 4-8 pairs have regularly bred since the 1980s. In Sweden, the Montagu?s harrier is classified as an endangered (EN) species. This classification is partly due to a lack of preferred nesting habitat, such as shrub-lands or dense wetlands with Claudium spp.

Effects of brown bear (Ursus arctos) odour on the patch choice and behaviour of different ungulate species

The return of large Predators to regions where they were previously extirpated has created a need for knowledge about their effect on prey species, not only their lethal but also their behavioural or risk effects. In this study the behavioural risk effects of brown bear (Ursus arctos) were tested on fallow deer (Dama dama), roe deer (Capreolus capreolus), red deer (Cervus elaphus), moose (Alces alces) and wild boar (Sus scrofa). This was done by using patches of fur to simulate the presence of the novel predator (brown bear), a novel nonpredator (reindeer (Rangifer tarandus) and no fur as control. These three treatments were then compared. The response variables measured were increased vigilance, decreased feeding time and change in patch use.

Träning av sydafrikansk pälssäl och afrikansk stäppelefant på djurpark - skillnader och likheter

Training of zoo animals started when the first zoo opened in 1752. The difference between then and now is that from the beginning the zookeepers did not focus so much on animal welfare. Nowadays animal welfare is the most important thing in the training. Therefore, the zookeepers are training the animals mainly for veterinary purposes and activation. The training makes the animals less stresses during handling. When the zookeepers started to train elephants they used unpleasant stimuli such as a whip when the elephant did something wrong.

Betydelsen av skogens ålder och förekomst av lavar för renars val av vinterbetesområde :

This is a study on winter groups, ?siida?, of semi-domesticated mountain-migrating reindeers that move to lichen pastures in the lowland boreal forests during winter. The aim of the study was to determine reindeer habitat use in their winter ranges in a managed forest landscape. The reindeers use of three different types of forests was determined, 1) 100-130 year old, 2) 20-40 year old forest and 3) clear-cut areas. All sites were dominated by Scots pine, Pinus sylvestris, and had the same types of ground vegetation.

Diversitet hos jordlöpare (Col: Carabidae) i hävdade strandnära gräsmarker :

Diversity of ground beetles (Col: Carabidae) in managed riparian grasslands. The carabid community in moist seminatural grasslands was studied at three different sites in mid-Sweden. Pitfall trapping was carried out during six weeks in spring and early summer 2003. Eight transects, each containing seven pitfall traps, were placed in three different management regimes, either late or continous grazing, or meadow. The species composition was analysed by ordination analyses, i.e. DCA and CCA.

Effekter av predationsrisk på sånglärkors (Alauda arvensis) habitatval på åkermark

Along with other European farmland birds, the skylark (Alauda arvensis) has declined rapidly since the 1970?s. Between 1975 and 2003, the Swedish population of skylarks declined with 64 %. In Britain, the decline is often explained by alterations in farming practices in general and the shift from spring-sown to winter-sown cereals in particular. The dense vegetation structure of winter cereals is limiting the number of breeding attempts possible, causing the entire population to decline.

Vad har zebran för strategier för att undkomma rovdjur?

Som bytesdjur måste zebran ständigt vara på sin vakt för att undvika att falla offer för ett rovdjur. De tre zebraarter som finns i världen är bergzebra, stäppzebra och Grevyzebra. De olika arterna lever på olika platser och de har även olika sociala strukturer. Inom flocken använder zebrorna sig av olika strategier som gör att rovdjuren får svårare att anfalla dem. En del av dessa strategier är zebrornas vaktbeteende då de hjälps åt att vakta flocken mot rovdjur i olika situationer.

Ekologiskt uppfödda kycklingar : en jämförelse mellan två olika foder

Organic rearing of broilers is not a large production in Sweden. In order to create a sustainable yet efficient production of organically produced poultry meat, at a price that the consumers are willing to pay, much more knowledge is needed. It is therefore important to do more research on organic broilers under Swedish conditions. This report is aimed to be a base for further studies. In the study 2000 broilers of the hybrid Ross 308 divided in to two equal groups. The broiler hybrids that are used in Sweden are selected for a high growth rate and are normally slaughtered at the age of 5 to 6 weeks, with a slaughter weight of 1.7-2 kg.

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