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745 Uppsatser om Threatened species - Sida 5 av 50
Detection of Honey Bee Viruses in Apis mellifera and Apis cerana
Two species of bees in the genus Apis, real honey bees, has long been of interest for man. These two are the European honey bee, Apis mellifera, and the Asian honey bee, Apis cerana. In Vietnam, beekeeping is of great importance, both with A.cerana and A.mellifera. The aim of this project was to investigate if the introduction of the European honey bee in Asia has affected the Asian honey bee, and whether different pathogens from A.mellifera have been transferred to A.cerana. Totally 40 samples, 20 from every species, were analysed for 8 different viruses.
Studier av habitatval och revirstrukturer hos vassångare (Locustella luscinioides) i Tåkern
The Savi?s Warbler (Locustella luscinioides) is a recently established bird species in a few reedy shallow lakes of southern Sweden and has only been found nesting for the last twenty years. Little is known about the species' habitat preferences, breeding biology and demands for specific territory structures at breeding sites in Sweden. Knowledge of a newly established species? habitat requirements is essential to maintain a viable population and design action plans.
Effekterna av urbanisering, barksprickedjup och solexponering på lavfloran i sydöstra Sverige
Studies have shown that air pollution, as well as bark fissure depth and sun exposure of a tree can have an effect on lichen growth as well as abundance of lichen species. The aim of this study was to find out the relative importance of these factors. 211 oaks in south eastern Sweden were surveyed for presence of 17 lichen species, as well as the total number of lichen species. Half of the trees were situated in urban areas and half in the countryside. For each tree the bark fissure depth was measured and the sun exposure of the trunk was estimated.
Tesaurer eller ontologier? Eller både och? : En jämförelse mellan två typer av ämnesordssystem med tanke på deras förbättring av effektiv informationsåtervinning
By examine plastic craniums from eight different hominids I wanted to find morfological characteristics that agreed with those of modern humans. The species that were selected had a plastic casting of its cranium in the laboratory at Gotland University. My focus was on species from the family Australopithecius and Homo and only working with their craniums. And this because the cranium and the theeth shows the most visible morfological characteristics between the different hominids. I also wanted,in a small part of the essay, to write about the differences in now living primates and humans skulls.Except from analysing the plastic castings I also studied surveys written by other scientist on the same subject.
Grey-sided vole and bank vole abundance in old-growth forest patches of different size and connectivity
Vole populations in northern Scandinavia vary in cycles with peaks every third or fourth year as described by the National Environmental Monitoring Programme of small mammals (NEMP). Some vole species have declined in population numbers since the NEMP started in 1971, especially the grey-sided vole (Myodes rufocanus) which is nearly extinct in the forested region. Since small mammals are an important food source for several avian and mammalian predators, the decline in vole numbers is expected to have consequences for the whole food chain, especially if other vole species start to decline in numbers. This study tried to test the hypothesis that presence and abundance of M. rufocanus (a specialist species) and Myodes glareolus (a generalist species) can be predicted by patch size and connectivity of forest patches >60 years old with a minimum of 15% pine >100years old.
Tree species traits response to different canopy cover for 34 tree species in an enrichment planted tropical secondary rain forest in Sabah, Malaysia
Tropical rain forests only cover around six percent of the world?s land area and contain around 70 % of the world´s animals and plants. Tropical rainforests have been, and still are, negatively affected by human activities. These activities lead to forest degradation which has negative impacts on production and biodiversity.
Between 1970-1980 forests in Borneo, Sabah, Malaysia, was subjected to intense logging.
Konkurrens mellan rådjur och dovhjort
The main purpose of this report is a first step to cover the scarcely investigated subject of interspecific competition between roe deer, Capreolus capreolus, and fallow deer, Dama dama. The report focuses on the distance between individuals of roe and fallow in the study area as well as which factors that is affecting the variation in distance depending on fallow deer group size and changing population density over time and in two areas. For additional information the history of the populations, such as harvest and distribution, is also investigated.
The report came to the conclusion that interspecific competition between the species do occur. The elevated distance between individuals of the two species is clearly significant. The most important factor affecting the distance seemed to be the size of the fallow groups.
Bentiska evertebraters förekomst i källor på Öland
Abstract The benthic macroinvertebrate fauna of 22 natural springs on Öland was sampled, by using a time-standarized kick/sweep sampling technique, in the end of September and early October. The aim was to determine the number of species and their abundances in the macroinvertebrate communities in springs and how/why these may change between different springs. Likewise there was a purpose to investigate possible differences between springs considering the proportions of the number of species and the abundances of the five functional feeding groups; shredders, collectors, filter-feeders, scrapers and predators. There was also an aim to investigate if the distances betweeen springs had any influence on similarity between the communities of benthic macroinvertebrates of the springs. Analysis from the springs collected material showed several interesting patterns in the number of species and their abundances when compared between springs devided into groups depending on their environmental factors such as depth and pH.
Nya trädgårdsväxter för ett allt varmare Sverige
The aim with this work has been to examine the climate changes and what these has meant, and will mean during the present century, for plants that have not been hardy in Sweden. A lot of new species can probably be grown today in Sweden's most southern parts, due to an increase in the average annual temperature by 1?C. There is a need of information about these new species and their hardiness. The insufficient information about the subject has been the background to this work.
Betula : arter och sorter
As birch is one of the most common trees in Sweden, and probably one of the easiest for
someone who lives here to identify, it is interesting to note that most people do not know
how variable the genus is and how widely it is distributed across the northern hemisphere.
One can find birch growing at both high and low elevations, demanding different soil
conditions and preferring varying amounts of sunlight. Many people may also be surprised to
hear that the colour of the bark can vary from bight white to almost black, and different
shades of pink, orange and red can also be displayed. This, together with the astonishing
beauty of the genus, the important role as a pioneer in many ecological systems and the
difficulty in sorting out the taxonomy of the genus, constitutes the background of this thesis. The thesis is written at the Department of Landscape Development in Alnarp, Sweden with Kenneth Lorentzon, researcher at the Swedish University of Agriculture as a supervisor. The aim of this thesis is to highlight which species and cultivars within the genus Betula could be appropriate for horticultural use in Sweden.
Träd och buskar i kantzoner : en undersökning av kanteffekter i några av östersjöregionens skogar
Around the world, forests are generally being fragmented and as plant populations decline in both sizeand number of individuals, the genetic variation will also decrease whitch in the end leads to totalextinction of the plant. In this paper, I wanted to investigate what specific species of trees and shrubsyou usually find in the edge and core habitats in some of the forests in the Baltic Sea region. I alsowanted to identify the edge effects and their sources and finally compare the results between thedifferent regions.The data sources used are derived from the ongoining research project Landscape structures, patterns ofbiodiversity and conservation strategies in the Baltic Sea region by Kari Lehtilä, Patrik Dinnétz ochTiina Vinter who have made a record of all herbaceous plant species in four randomly chosen forestregions situated around the Baltic Sea: Estonia, Skåne, Södermanland and Germany. I made statisticalanalyses, using the computer program R, concerning the distribution of species in the edge habitats ofthe forests as well as in the core habitats. I performed generalized linear models and then variationanalyses with the factors light and biomass in order to investigate wether edge effects might appear dueto these factors.
Eld som naturvårdare : Kärlväxtflora och vegetationsutveckling efter naturvårdsbränning i två småländska naturreservat
This study has taken place in two nature reserves in the municipality of Uppvidinge in the Kronoberg region in southern Sweden. These have been chosen by the County Administrative Board to be part of a bigger landscape of fire affected nature, and prescribed fire has been implemented in these. The areas are called Ösjöbol and Berga fly and have been burned 2012 and 2013 respectively. Non-burned areas have been inventoried as well. Vascular plants and mineral soil have been inventoried with the Hult-Sernander-Du Rietz scale of five levels. Issues emanate from the County Administrative Board?s goals for prescribed fire: how sticks and herbs were affected, how much soil was uncovered, how the structure and fire favoured species were affected, and how deciduous trees and spruces (Picea abies) were affected. The study shows that the soil increased, as well as the fire favoured species.
Helicobacter species hos katt : patogenes, zoonotisk aspekt och terapi
Helicobacter är en gramnegativ, mikroaerofil, ureas-positiv, skruvformad bakterie som hittas i mag-tarmkanalen, saliv och faeces. Helicobacter pylori orsakar hos människor gastrointestinala sjukdomar, cancer och försvagning av immunsystemet. År 1988 isolerades den första skruvformade bakterien från katt och 1991 fick den namnet Helicobacter felis. De vanligaste arterna hos katt är Helicobacter felis och Helicobacter heilmannii. Mycket av forskningen idag görs för att fastställa patogenesen och för att undersöka om det finns någon zoonosrisk avseende överföring av Helicobacter species från katt till människa eller vice versa.
Gamla tallars betydelse för biologisk mångfald på Gotland
Modern methods for managing pine (Pinus sylvestris) create homogenized forests. This decreases nature?s potential for biodiversity and might threaten species in need of different types of milieu. The main purpose of this study was to investigate how important older pine trees are for biodiversity. In the Hall-Hangvar Reserve in the north-west part of Gotland, insects collected from traps showed that more species were found in old or dead trees compared to younger pine trees.
Vindfällning i naturliga och skapade bryn och kanter :
The aim of this work was to study if the edge of the forest is more resistant to heavy winds than the trees located further in from the edge, and how this edge effect changes between different types of tree species and site types.
The data was collected from an electric power line going from the north to the south of
Sweden. The mean value of the clearcutted area around the power line was 120 meters. The
main direction of the storm in January 2005 was west-southwest and thus the power line was a perfect place for gathering a large data set.
The main parameter studied was the damage frequency at the edge of the forest compared to
the trees located further in from the edge (up to 100 m from the power line). Tree species mixture, soil moisture class, soil type, topography, stand height, stand height of the stand on the other side of the power line and wind exposition was estimated.
The results showed a distinct edge effect. The edge of the forest had clearly lower damage frequency for all tree species.
A marked difference was observed between tree species and damage frequency.