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1033 Uppsatser om Species composition - Sida 23 av 69
Nutrient effects on microorganism communities in nutrient poor soils
Better, more efficient fertilizers with great productivity and economic returns are needed, but it is important today to find fertilizers that are also sustainable. It is also important to carefully monitor their impact on the environment, including potential side-effects. In this context, the microbial communities that carry out numerous essential functions contributing to a functional ecosystem are of particular interest.
The present study is a complement to a pot experiment that investigated the potential of different waste products for use as fertilizers and how they affect the microbial community. In the pot experiment, the clearest treatment change in microorganism community function was found in the fully fertilized treatment used as a positive control. The question was whether this was indirect, i.e.
Några vanliga ogräs : en litteraturstudie av arternas biologi samt förebyggande och direkta kontrollåtgärder
The Swedish Board of Agriculture initiated this undergraduate thesis. There is a database on their homepage that includes chemical treatments for different weed species. There is also space for preventive and mechanical control methods. This is an undergraduate thesis that reviews these control methods for the most important weeds in Sweden.
The species reviewed are:
Creeping perennials:
Common Couch Elytrigia repens (L.) Desv. ex Nevski
Creeping Thistle Cirsium arvense (L.) Scop.
Perennial Sow-thistle Sonchus arvensis L.
Field Horsetail Equisetum arvense L.
Colt's-foot Tussilago farfara L.
Stationary perennials:
Dock Rumex L.
Mugwort Artemisia vulgaris L.
Dandelion Taraxacum F.
Smittskyddsrutiner vid flytt av djur mellan djurparker
Animals in zoos live in small enclosed areas. If a pathogen is introduced to the zoo, the animals are extremely vulnerable. The highest risk of introducing new pathogens occurs when new animals are introduced to the collection. Therefore it is essential that zoos have a protocol in place for disease prevention.
This review has studied literature on the subject of disease prevention protocols when translocating animals between zoos.
Individuell tillväxt och substratval hos en lokalt differentierad population av Asellus aquaticus
Local differentiation may occur during a short period of time and is part of the formation of new species. The isopod Asellus aquaticus is an example of a species in which local adaptation has occurred during a short period of time. An establishment of stonewort (Chara spp.) vegetation in Lake Tåkern (in the 2000) resulted in two different Asellus ecotypes; a lighter pigmented, smaller one that lives among stoneworts grazing periphytic algae, and a darker, larger ecotype that feeds on decaying leaves in reed (Phragmites australis vegetation. The purpose of this study was to examine whether there are differences in growth between ecotypes, depending on whether the food was periphytic algae or leaves, and to study the choice of substrates between the two food types. For the study, animals from both habitats were brought in from Lake Tåkern to the laboratory.
Utilization of different habitatsin Colobus angolensis palliatus in the forests of Diani Beach, Kenya
The Angolan black and white colobus monkey (Colobus angolensis palliatus) is an arboreal primate that inhabits coastal forest fragments on the south cost of Kenya and is consequently vulnerable to forest fragmentations. The study was carried out in March and April 2011 in Diani Beach in Kenya where two of the largest populations of the species are distributed. This study is a pilot study to test methods for a Master?s thesis. The aim was to investigate any variations in use of two habitats of C.a.
Tetratermmodellering och regressionsanalyser mellan topografi, tetraterm och tillväxt hos sitkagran och lärk : en studie i norra Island
This study was made in an attempt to give the forest research centre Mógilsá a producedtetratherm map and a better understanding of how topography and temperature influencethe growth of two tree species. The digital tetratherm map model, covering the northernpart of Iceland, was developed to investigate the correlation between tetratherm and thegrowth of Picea sitchensis and Larix (sukaczewii + sibirica). The study confirms theusefulness of digital terrain models in providing data for a lot of different factors and forthe tetratherm model. Hopefully will this tetratherm map be used in future studies.Secondly, investigations were made correlating the growth of the two species againsttopographic factors representing height above sea level, distance to the sea, slope andtopex. Thirdly, investigations were made comparing the aspect and the ground shape tothe growth.The growth rate of Larix had strong significant correlations to the tetratherm and thedistance to the sea- factors.
Tillväxtreaktion på kvarlämnade träd i Hagners "Naturkultur" försök :
The primary goal of this study was to investigate how the radial growth of retained trees responds after thinning-from-above. The National Board of Forestry which initiated this study, was interested in whether there were differences in the growth-response between the tree species Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.). Another question of issue was if there were differences in the growth response between trees of different sizes. It is within the framework of the National Board of Forestry?s, Continuous Forests Project that these urgent questions are to be answered.
Nipahvirus : patologi hos en nyupptäckt zoonos
Nipahvirus is most likely spread from bats to other species and causes lethal encephalitis in humans and respiratory illness in pigs. Different species are affected with varying severity but it seems to have an unprecedented zoonotic capacity and the humans affected either die or receive permanent brain damage. Full recovery is possible but very uncommon. Pigs that live and are bread in the areas that these bats frequent are constantly in danger of contracting pneumonias and meningitis and they can spread the virus further on to the people who work with the pigs and process their carcasses. These workers could then infect other humans in their immediate surroundings, their families for instance.
Mjölkningsfrekvensens påverkan på mjölkproteinets sammansättning och kvalitet :
In modern dairy production the milking frequency is increased in some herds due to introducing of automatic milking systems or the farmers decision to milk high producing dairy cows more than two times a day. With more frequent milkings the milk yield increases while the content of fat and protein decreases. However, how the composition of protein is influenced is not fully evaluated. The purpose of this study was therefore to see if a higher milking frequency had any impact on the milk production and especially on the protein composition.
This study was conducted as a half udder experiment.
Fältinstruktion för skogsbruksplanering av inhemska skogar i Andinska Patagonien :
The thesis first objective was to develop field instructions for forest planning of native forests in Andean Patagonia, and the second objective was to test the plan on an actual property in the area. The thesis was limited to studies in the province of Rio Negro. Today, there are no official forest management plans for native forests in the Argentinean province of Rio Negro; thus, there is an obvious need for an official forest management plan with clear guidelines. To be granted permission to manage, i.e. through thinning, the native forests on a property it is required to have a forest management plan that is approved by the Forestry Board in the province in question (Thill, B.
Studier av koppar i mjölk : en prooxidant med negativa effekter på mjölkkvaliteten
The taste of the dairy product is probably the main factor determining consumer?s dairy products choice. Consequently it is of great importance that the product tastes good and as expected every time. Off-flavors in milk can be caused by for example oxidation of the milk fat. Since copper is a prooxidant, a high copper content in the milk can cause oxidation.
Kunskap är som ballonger - den måste förankras om den inte ska försvinna bort : en studie av vad som påverkar en lärares val av undervisning
The purpose of this essay has been to identify a couple of different factors that matter when a teacher chooses method and raw material for teaching his students. The person interviewed is a man, whose lesson I also observed. The result shows that there are several factors of great importance for his choice. My conclusion of this is that this teacher?s choice depends on the school as institution with all the people that operate there, the composition of the students and the school?s curriculum, but this teacher?s pedagogical basic view also has a great importance for his teaching..
Latitudinal patterns in body size of Roesel?s bush cricketMetrioptera roeselii within and outside the continuous area of its distribution
Over time, species colonize new areas naturally or through humans. The colonizers areoften few and founded populations represent only a fraction of the genetic diversityexisting in the original population. If the established population becomes isolated afterthe colonization event genetic diversity will remain low and if the population, in addition,remains small in size for an extended period this will lead to increased inbreeding andpossibly inbreeding depression. Metrioptera roeselii is a common species with awidespread distribution in continental Europe. During the last century, it has expanded tothe Scandinavian Peninsula which is separated from continental Europe by the Baltic Sea.My aim was to test the hypothesis that individuals in isolated populations in Scandinaviaincluding Denmark and the Baltic Sea islands are smaller than individuals in thecontinuous part of its distribution due to low genetic diversity and lacking incoming geneflow.
Marktäckande, lågväxt vegetation på ställverksmark : en biologisk bekämpningsmetod mot ogräs
Unwanted vegetation on the land of electric transforming stations is a problem, in the sense that it contributes to higher fire risks and also constitutes an obstacle for people performing maintenance operations at the station. Such unwanted vegetation is controlled using herbicides and mechanical measures. Since the use of herbicides implies environmental hazards, there is a need to find alternative ways of fighting the unwanted vegetation.
Investigation into suitable plants for ground cover, trials in the greenhouse, trials in the field, soil analyses and compilation of experiences from similar trials are parts of this work. The paper also contains analyses of possible environmental benefits and economical gains. There is also a final discussion of some proposals regarding alternative weed controlling methods.
Nyckelbiotoper - urskogsrester eller kulturprodukter? : beståndshistorik i tolv nyckelbiotoper i Lycksele kommun
Since 1993 the Swedish Forestry Administration conducts a nation-wide inventory of wood-land key habitats covering all forest land in Sweden. The inventory aims at mapping and describing habitats where redlisted species occur or can be expected to occur. According to the inventory stand history is crucial to the presence of red-listed species. However, the current knowledge of stand history in woodland key habitats is very limited.
The purpose of this work is to describe stand history in woodland key habitats, i.e. fire history, human activities - mainly cuttings - and structural changes.