Sök:

Sökresultat:

438 Uppsatser om Vegetation in wetlands - Sida 9 av 30

Sportfiskares slitage på Mörrumsåns stränder och konsekvenser för Tjockskalig målarmussla : - kan spänger skydda från erosion

Mörrumsån har de förutsättningar som krävs för att Tjockskalig målarmussla (Unio crassus) skall kunna leva och föröka sig, men detta sker inte i samma utsträckning som tidigare. Ett samband mellan vattnets riktning söderut mot utloppet till Östersjön och minskad föryngring av Tjockskalig målarmusslas inventerade bestånd i Mörrumsån finns. Föryngringen uteblir samtidigt som man hittat fler döda musslor ju närmre åmynningen man kommer. Orsakerna till detta kan vara flera då denna mussla är beroende av specifika förhållanden under flera faser i sin utveckling och fortplantning. Ett av hoten är grumling av bottnar.

Förekomst av törskate (Cronartium flaccidum, Peridermium pini) på tall (Pinus sylvestris) i relation till markfuktighet och fältskikt : en studie om 2000-talets törskateepidemi i norra Sverige

Resin-top disease is a rust fungi that occurs both as a host alternating form, Cronartium flaccidum G. Winter., and as a non-host alternating form, Peridermium pini Pers. The host alternating form can use a variety of hosts but the most commonly used species in the boreal forest is Melampyrum sylvaticum. In Scandinavia the Resin-top disease infect Scots pine, Pinus sylvestris L. The fungus infects the needles through the stomata and then grows through the branch to the stem where it strangulates the vessels transporting water and nutrition to the treetop, which kills the top.

The shift in forest and tree limits in Troms County - with a main focus on temperature and herbivores

To better understand how various factors affect the establishment of forest and trees around the tree line-ecotone, this study was conducted in Troms County, Norway. The altitude of different forest and tree limits together with the surrounding vegetation type were collected during August 2011. Comparisons of the collected data were made with previously collected data from the same sites conducted 1914 and 1915. On average the forest limit has expanded with 26 meters in altitude, however, an expansion is not statistically significant for the whole area. The tree limit has significantly expanded in altitude.

Viltets inverkan på vegetationsutvecklingen i en Sydsvensk skogsföryngring :

Herbivore impact on the Swedish forest has under a long time been a common subject of debate. There are many different opinions depending on what direction the forest owner has with his/her forest. Populations of moose and roe deer have increased significantly in Sweden during the last decades. The purpose of this study is to get a full picture of the herbivore impact on the regeneration areas. The field work was done once a year for seven years (1999?2005).

Öjingsvallen vid sjön Öjingen : en pollenanalytisk studie av en fäbodvall i Ängersjö, Hälsingland

By using pollen analysis and 14C-dating, the history of vegetation and land use at the old shieling place (Sw: fäbodställe) Öjingsvallen in Ängersjö parish, central Sweden, was studied. The aim of the study was to answer the following questions: 1) When was Öjingsvallen established as a shieling place? 2) What was the land use at Öjingsvallen? 3) Was the use of Öjingsvallen as a shieling place affected by the agricultural crisis in the 14th and 15th centuries? 4) Is there any relation between the establishment and land use of Öjingsvallen as a shieling place and the historically known increase in the number of shieling sites known to have taken place in the 16th and 17th centuries? 5) Was the use of Öjingsvallen as a shieling place affected by the iron production in the area? According to the study, Öjingsvallen was probably established as a shieling place during the period A.D. 300-700. The main land use at this time was forest grazing.

Where has the fertilizer gone? Closing the nutrient budget for a eucalyptus fertilization experiment in southern China

An increasing demand for wood products in China has resulted in large areas invested in fast-growing tree plantations of eucalyptus. Eucalyptus plantations are often associated with an intensive management including fertilization. By understanding the effects of fertilization and where in the ecosystem nutrients are accumulated a more sustainable forest management could be achieved. In this study, a nutrient budget including all biomass and soil components was created for Eucalyptus urophylla. The examined nutrients were nitrogen, phosphorus and potassium.

Importance of mire plant community composition when estimating ecosystem level methane emission

Metan är en stark växthusgas som är viktig att ta med i beräkningarna när det gäller klimatförändringar. Feedback från myrmarker vid en ökad temperatur i samband med klimatförändringar har diskuterats, bland annat eftersom myrmarker är en källa för metan till atmosfären. Det finns många faktorer som påverkar metanemission, och en av dom är vegetation. Olika sorts vegetation tros bidra olika mycket till avgivningen av metan. Syftet med denna studie var att undersöka hur stor betydelse det har att ta med olika växtsamhällens sammansättning i beräkningarna för att uppnå korrekta uppskattningar av metanemission från myrmark på ekosystemnivå.

Referenslandskap som förebild vid vegetationsdesign på golfbanor

Arbetet bottnar i en övertygelse om att ett golflandskap kan uppgraderas både vad gäller upplevelse och spelstrategi med hjälp av progressiv vegetationsdesign. Syftet med uppsatsen är att pröva hur ett antal vegetationskoncept fungerar om de applicerades i ett golflandskap. Vegetationskoncepten är hämtade från referenslandskap med stora upplevelsekvalitéer som t.ex. halvöppna hagmarker. Målet är att skapa alternativ för hur berikande vegetation kan byggas upp och integreras i en golfanläggning med referenslandskap som förebild. Avstamp tas i litteraturstudie som belyser de viktigaste principerna för hur träd och vegetation kan användas på golfbanor.

Skäran i bäcken - En lösfyndsstudie om möjliga senneolitiska offerynd på ön Hven

This paper examines the possibility of identifying votive offerings among a collection of stray finds in a Late neolithic material from one farm land on the island Hven.First, I identify the Late neolithic artefacts in a collection of stray finds and make a register as well as take photographes of the artefacts. Then I compare these stray finds with material from hoards found in Scania to analyz if any similarities arise regarding length, fragmentation and patina. Additionally, I use maps to identify wetlands and a field survey to help identify and discover important areas connected to votive offerings. There is a strong possibility that the stray finds collection contains some votive offerings because similarities can be found between the lengths of the stray finds and the materials from the hoards..

Människan i urskogen : vegetationshistoria i Hamra nationalpark under 2500 år

Pollen analysis of a peat core was used to reconstruct the last 2500 years of vegetation history, with focus on the impact of anthropogenic disturbance, in Hamra National Park, central Sweden. In addition, analysis of pollen in soil samples was performed in an attempt to locate ancient cultivation plots in the National Park. The analysis of the peat core shows a development of the vegetation that can be divided into four stages of different degrees of human impact: A - virgin forest (c. 500 B.C.-A.D. 1300), B - grazed forest (c. A.D.

Bosättning, agrarkris och fäbodväsende : vegetations- och markanvändningshistoria i Läde, Dalarna

By using pollen analysis, 14C-dating and historical sources, I studied the history of vegetation and land use at an abandoned forest settlement near the Lade summer farms in the parish of Mora, Dalama. The aim of this paper is to investigate the agricultural establishment and development, the effects of this on forest vegetation, and the origin and development of summer farming. The analysis of pollen in a peat core revealed that a settlement was established at Lade around 1000 AD. Cereal cultivation, hay-making on the mire and extensive forest grazing were intro-duced as a complete agricultural system. Pollen analysis and the presence of ancient fields suggests that cultivation took place on permanent fields. Barley was the main crop, but rye and hops/hemp were also grown at the settlement.

Bestämning av vattenytor med hjälp av Nätverks-RTK och totalstation : Inmätning av Karlbergsån i Grums kommun

This report is presenting an approach that can be used to measure water surfaces in difficult conditions caused by dense vegetation and lack of nearby known points. The objective was to make a contribution to necessary measures for adaptation against floods in Grums Municipality along the stream Karlbergsån, which may occur when persistent rain raises the level of the stream. Along the river there are low-lying areas prone to flooding. According to Grums Municipality, the stream may widen where the water level differences are large, to create a better flow path and to counteract flooding. Grums Municipality was also interested in survey stormwater discharges which may affect the water level in the stream.

Foraging behaviour of cattle, sheep and goats on semi-arid pastures in Kenya

ABSTRACTThe principal aim of the study was to compare the feeding behaviour of cattle, sheep and goats on pasture and explain any differences between speices. Furthermore, I compared foraging behaviour between dry season and the beginning of the rainy season, in order to see any relationships between weather and behaviour.The study was carried out in Shompole in southern Kenya. Behavioural data were collected by observing herds of cattle, sheep and goats on pasture. The livestock were herded on pasture during the days and kept in bomas, where people live, during the nights. The weather in Shompole is characterized by high ambient temperature and low, bimodal rainfall.

Dygnsvariation av metanemission från en anlagd våtmark

The aim of the study was to investigate if methane emission in a constructed wetland changed in a diurnal pattern correlating to temperature, humidity or light conditions. The gas measurements were carried out with a static chamber technique. The wetland (in Nykvarn outside of Linköping, Sweden) takes care of wastewater to reduce the nitrogen loads. Measurements were carried out at three different occasions in the summer of 1998 on two sites in the wetland. One site was close to the inflow, inhabited by Lemnaceae, and another site was located further downstream inhabited by the emergent macrophyte Typha latifolia.

Ruins of Wilderness : sensual Spaces in between

Ruins and derelict places have since long fascinated and attracted humans. With my starting point in the wild vegetation and the spontaneous activities taking place on derelict land and in industrial ruins, I explore with help from the theoretical sociology, what creates not only this fascination but also fear. The purpose of the thesis is to explore and exemplify how the industrial ruin as a place outside the restrictions and control as well as design intentions of modern society can be used as an inspiration in a landscape architecture context.The modern city consists of areas and places with a well defined purpose. A piece of derelict land or a disused building is instead ambiguous, undefined and open for new purposes. However described in negative terms, these placesare often perceived as places of mystery and magic.

<- Föregående sida 9 Nästa sida ->