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745 Uppsatser om Threatened species - Sida 34 av 50

Betydelsen av taggbuskar, ljus och hävd vid föryngring av ek (Quercus robur)

Many species and hence biodiversity depend on old, large oaks (Quercus robur) with hollow trunks. The populations of oak-living organisms have to migrate to a nearby old oak in order to survive the death of the host. The oak district south of Linköping, Sweden, is unique in area and the number of old oaks. It is anyway doubtful whether regeneration of oak will secure future continuity. Oaks are light-demanding and thrive in open pastures.

Hund som komparativ modell för autoimmuna sjukdomar :

In this essay dog as a compatible model were put against human. The major histocompatibility complex (MHC) genes were compared between dogs, human, cat and mouse. To evaluate dog as a model and study similarities and differences was the aim with this review. Dog as a model contributes to understand mechanisms behind autoimmune diseases and showed clearly histological similarities between human and dogs concerning the skin disease mucous membrane pemphigoid (MMP)/cicatricial pemphgioid (CP). Further genetic evidence motivated the choice of using dog as a comprehensive model when the MHC-complex correlated with hypothyroiditis in Doberman dog as it does in human. Physiological similarities with low levels of thyroid hormones (T3 and T4) together with high level of thyroid releasing hormone (TSH) were found in the same way as in human.

När förmänniskan blev den moderna människan

The subject of this bachelor-level thesis in archaeology in the transition from archaic sapiens to anatomically modern humans, and what might have caused this transition. A part of the study aims to prove or disprove whether an increased consumption of shellfish might have caused this development. Another part of the essay deals with the connection of said evolution and the suggested emergence of cultural and ritual practices in South Africa circa 100 000 BP and an evaluation of the arguments concerning the aquatic ape hypothesis, and their usefulness for the subject.The result of investigation of the theory about the increased consumption of marine resources as a probable cause of the last biological step of creating our species points to the conclusion that it is a probable explanation. There is even some evidence that there could be a connection between consumption of marine resources and the "Out of Africa 2"-theory. It is harder to find a proven connection between the suggested emergence of cultural and ritual practices, even some evidence seems to strengthen the idea.

Miljökemikaliers påverkan på isbjörnars (Ursus maritimus) reproduktion och hur dessa kemikalier når djuren

Environmental chemicals are transported to the Arctic through the air and oceans, once within the Arctic they spread through rivers, lakes and other watercourses. Polar bears and sledge dogs in-gest high concentrations of environmental chemicals since many of the chemicals are fat-soluble and their diet mainly consists of marine mammals. The aim of this study is to describe how environmental chemicals spread in nature, how they reach the polar bears, and finally how they affect the animals reproduction, with reproductive hormones and genitals in focus. The animals are exposed to a cocktail effect which complicates the assessment of the chemicals impact on the reproduction. Studies show that the genitals can decrease in size or become malformed, sexual maturation can be affected and the reproductive hormones can be disturbed.

Naturvårdande skötsel (NS) - blir resultatet som man tänkt sig? : en fältstudie över föryngring, trädslagsfördelning och död ved 14 år efter åtgärd

A new Swedish political approach to forestry was initiated 1993, that put goals of production and environmental issues into equal importance to Swedish Forestry Law. Earlier nature conservation very often declaimed preservation the best way to conserve nature, but recently it is clear that many highly biological values are due to former land use or disturbance. Many old pastures or cultivations dominated by deciduous trees are today characterized by a dense overgrowth of Norway spruce. By actively paying attention to nature in forestry (nature restoration), it is possible to partly reconstruct habitats or disturbances that are necessary to favour the biological values. The aim with this master thesis is to study the nature restoration, (NS, Swedish abbreviation), performed in 11 forest sites in the middle of Sweden 8-14 years ago. Since NS recently have become applied, it has never yet been evaluated.

Habitatpreferenser hos tjockskalig målarmussla (Unio crassus) med avseende på vattendjup och beskuggning.

The thick-shelled river mussel (Unio crassus) is a red listed species classified as Endangered (EN) and is also considered within the Habitats Directive. The distribution in Sweden is fragmented and it is mostly occurring in the south eastern parts. We investigated the presence of Unio crassus in a section of the stream Storån, Östergötland County, from Falerum to the inflow into Lake Åkervristen. The environmental parameters investigated were water depth, bottom substrate, shading, water velocity and the slope over the water surface. In this thesis I have focused mainly on water depth and shading, comparing sites with and without mussels.

Rissepareringens effekter på viltets nyttjandegrad av GROT

Successful forest regeneration is a prerequisite for sustainable forest management. Therefore, it is important to prevent browsing damage on the commercially important tree species Scots pine. In this study I have tested a new alternative way to increase the available amount of forage and increase the use of these resources by especially moose. The method is based on a slash treatment at harvest, where the accessibility of slash as forage is increased during final felling or commercial thinning by gathering the slash and putting the Scots pine slash on top of the slash piles. This study has compared the availability of forage, the amount of browsed biomass and the number of fecal pellet groups between conventional and slash treated stands after final felling and commercial thinning in southern Sweden.

Mating behaviour and hierarchy among male warthogs (Phacochoerus africanus) in Kenya

Warthogs live under natural conditions in matriarchal groups, bachelor groups and yearling groups. Just like all pig species do warthogs have a complex behaviour repertoire. The semi-wild warthog population at Kichwa Tembo Lodge, outside Masai Mara National Reserve, lives in a fenced area with access to food all over the year and is protected from predators. The aim of this study was to observe the male warthogs? mating behaviour and their hierarchy during the mating season.

Habitat diversity and composition among growing wild boar (Sus scrofa L.) populations in Sweden

The wild boar (Sus scrofa L.) has expanded across Europe and Sweden in the last decades. It is a generalist species which utilizes a variety of habitats, and its presence has been shown to have both positive and negative effects for people and the landscape they are in. The abundance and increase of wild boar has previously been shown to differ between counties in Sweden, but there have been few explanations as to why. In this study, I investigated correlations between the per capita rate of change (r) among wild boar populations in Sweden and a variety of different habitats on the county level. I also investigated if fragmentation per se or in certain habitats could be associated with the wild boar?s per capita rate of change. My results show that fragmentation/diversity per se was not correlated with wild boar r.

Rotavirus zoonotiska potential : kan infekterade föl smitta människa?

Rotavirus causes diarrhea in young mammals all over the world, including infant humans. The diarrhea leads to severe dehydration that can be fatal if left untreated. The dehydration can be treated with fluid therapy and the infection heals itself. Despite the relatively easy treatment half a million children under the age of five dies every year due to diarrhea caused by rotavirus. Rotavirus sorts into the family Reoviridae and is a double-stranded RNA virus with a segmented genome.

Återförvilda Sverige?: En studie av rewilding som strategi för att bevara kulturlandskapet och gynna biologisk mångfald

Through millennia, humans have shaped the European landscapes. Agriculture, hunting andforestry have influenced virtually every ecosystem on the continent and formed what we todaythink of as the cultural landscape; a mosaic pattern of cropland, fields, pasture and forests. Thepast two centuries, globalization, industrialization and urbanization have come to pose a threatto the existence of these landscapes. European farmlands are now being abandoned at analarming rate, and the associated loss of landscape preservation, biodiversity and ecosystemservices is a concern to the scientific community and public alike.This thesis studies if the implementation of the relatively new conservation strategy rewilding(recreating self-sustaining ecosystems and reintroducing keystone species) can be a part of thesolution to preserve cultural landscapes and biodiversity in Sweden. Through interviewssupplemented with studies of published works, expertise from different fields has beencompiled to provide an overall picture of the capacity of rewildings as conservation method.

Biologisk mångfald i staden och dess närhet : möjligheter att som landskapsarkitekt främja biologisk mångfald

In a time of increasing urbanization the human tenure effects on the land has lead to a decrease and fragmentation of areas that are valuable to urban wildlife. These actions have had a detrimental effect on the species and habitats that exist in cities and towns.This paper investigates, through the study of relevant literature and the undertaking of interviews and field visits, the role that biodiversity plays in our society. The current attitude towards urban biodiversity and the responsibility for its promotion within the landscape architect profession has been explored.This paper includes three English case studies and a design proposal investigating how one can work to promote biodiversity on a smaller scale.This paper concludes that urban biodiversity is multi-functional ? being of ecological, social and cultural significance. The landscape architecture profession must be aware of the need to combine a variety of different factors such as economical, social and environmental aspects.

Skogsbolagens syn på vindskadeförebyggande åtgärder efter stormen Dagmar

On the night of the 26th December 2011, large parts of southern Norrland were struck by the storm ?Dagmar? that caused serious damage to the forests. In the past 10 years wind damage has become a hot topic after several major storms. Forest companies own 25% of the Swedish forest and thus influenced largely by wind damage. The main purpose of this study was to examine whether forest companies attitude towards preventive wind damage actions were changed after the storm ?Dagmar?. The result was developed by doing interviews with two forestry companies.

Vänner med förmåner : positiva effekter av interaktion mellan människa-hund

The aim of this review was to examine scientific literature to determine what kind of physiological and psychological benefits derive from human-dog interaction, as well as attempt to uncover a possible mechanism behind these benefits and whether or not they are mutually beneficial. A growing body of research indicates there are physiological and psychological benefits associated with human-dog interaction. Significant cardiovascular benefits have been linked with human-dog interaction, as have lowered blood pressure, cortisol and heart rate. Interaction with dogs is often associated with a feeling of social support and well-being, and dogs also seem to facilitate social interaction between people. Dogs? ability to buffer and reduce stress is also well documented. A strong indication was found regarding a relationship between physical contact and benefits associated with human-dog interaction.

Indirekt blodtrycksmätning hos hund och katt :

The objective of this study was to study the agreement between two methods of indirect bloodpressure measurement in dogs and cats and to establish the within-method variation for the methods. The utility and practicality in the clinical setting were also evaluated for the both methods. The techniques evaluated were the oscillometric method and the Doppler ultrasonographic method. Thirtytwo dogs and 26 cats were used in the study and seven dogs and five cats out of these animals had diseases that may effect the bloodpressure. Bloodpressure was measured in both anesthetized and in conscious animals.

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