Global ETD Search

1	Miljökonsekvenser av biogasutvinning ur ekologiska vallgrödor Samuelsson, Angelika January 2004 (has links) No description available. Lilla Edets kommun Biogas Växtekologi
2	Miljökonsekvenser av biogasutvinning ur ekologiska vallgrödor Samuelsson, Angelika January 2004 (has links) No description available. Lilla Edets kommun Biogas Växtekologi
3	Myrvegetation i sydvästra Värmland / Mire vegetation in south-western Värmland, Sweden Fransson, Sven January 1972 (has links) <p>With an English summary</p> Wetlands Swamps Våtmarker Växtekologi myrar Växtsamhällen
4	The natural holocene vegetation development and the introduction of agriculture in northern Norrland, Sweden : studies of soil, peat and especially varved lake sediments Segerström, Ulf January 1990 (has links) The Holocene vegetation history of northern Norrland was studied by pollen analysis of sediement, peat and soil samples, with the aim to improve our knowledge about vegetation development in northern Norrland, and also about the history of man and the introduction of agriculture in the area. Earlier made pollen analyses from the four northernmost provinces were summarized and a series of new analyses from northern Norrland added. Pollen anlyses were conducted on sediment and peat profiles from four sites in the Luleälv valley, in Norrbotten, and from Kassjön in coastal Västerbotten. Furthermore, the hypothesis was tested that pollen analysis of thin mor humus soils could be used to trace and identify ancient cultivated fields. When the interior parts of the Luleälv valley were deglaciated about 9500 BP, an open ecosystem formed dominated by shrubs and dwarf-shrubs. A few hundred years later Betula and Pinus invaded and rapidly formed forests, and by 9000 BP Alnus had immigrated and become common in most of Norrland. With climatic improvement Betula and Alnus increased in abundance, and nemoral broad-leaved trees colonized from south to north: between 6000-3500 BP Ulmus and Corvlus had become common as far north as Västerbotten. In Norrbotten, however, Betula and Alnus were the dominant deciduous trees. Around 3400 BP Picea abies reached the coast of Norrland from Finland, established itself and within 300 years became the major forest tree along a coastal zone. It occupied the moist, fine sediment substrates in those areas which earlier had been mainly dominated by Alnus and Betula. Climatic deterioration resulted in a steady retreat of the more southerly forest elements, and by 2000 BP only small, remnant stands at isolated sites were left. Over the last 2000 years little natural change has occurred in the forest vegetation. Man invaded the area soon after the deglaciation. These first occupants were hunters and fishermen, however, and their impact on the vegetation development was minor and restricted to small camp clearings. Not until an agricultural economy became established, did the influence of man become pronounced. In coastal Västernorrland and Västerbotten, traces of agriculture and animal husbandry occurred between 4700-2500 BP, but these first cereal cultivations were temporary, short-lived and occurred primarily at coastal sites. In those areas, permanent cultivation developed due to changed settlement structure during the first centuries AD. In the Luleälv valley in Norrbotten, cereal cultivation and animal husbandry was introduced between 500-1000 AD, although the hunter/gatherer economy continued to dominate, as it did in most of interior Norrland. Concomitant with the general agricultural expansion in Västernorrland and Västerbotten between 1000-1200 AD, permanent field cultivation developed in the coastal parts of the Luleälv valley. In the interior of northern Norrland, however, agriculture did not become important until the 17th-19th centuries. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1990, härtill 4 uppsatser.</p> / digitalisering@umu Jordbruk-- Sverige -- Norrbotten Växtekologi-- Sverige -- Norrbotten Lule älvdal
5	Cellulär automat simulerar utbredning av Taraxacum Bergman, Jimmy January 2012 (has links) I detta arbete undersöks vilken grad av inomartskonkurrens som ger upphov till ett observerat utbredningsmönster av maskrosor (Taraxacum sect. Ruderalia). Maskrosor har både fröspridning och vegetativ förökning. Studien hypotiserar att utbredningen kan beskrivas utifrån enkla regler för spridning och konkurrens. Dessa används i simuleringar med en binär cellulär automat där utveckling sker i deterministiska tidssteg. Modellen består av ett rutnät där en tom cell antingen kan förbli tom eller koloniseras, medan en upptagen cell antingen kan överleva eller dö ut. Reglerna efterliknar situationer med hög respektive låg känslighet för inomartskonkurrens. De mått på jämförelse mellan observation och simulering som används är mönstrets fraktala dimension, mönstrets tendens att aggregera och storleken på den enklaste algoritm som beskriver datan. Två olika initialvillkor används för att testa modellens robusthet. Den observerade utbredningen kontrolleras även mot slumpmässig fördelning. Resultaten visar att den observerade utbredningen är klusterartad. Simulering med en högre inomartskonkurrens beskriver utbredningen väl sett till aggregering och fraktal dimension. Lägre inomartskonkurrens beskriver dock maskrosornas verkliga utbredning sett till algoritmisk komplexitet, vilket tolkas som att individer kan leva närmare inpå varandra än vad regeln om högre inomartskonkurrens förutsätter. För vald klusterstorlek är simuleringarna ej känsliga för initialvillkoren, men då hela fördelningen av antal celler per klusterstorlek i stickprov på ett tidssteg analyseras har initialvillkoren fakstiskt betydelse. Sett till fördelningen av cell per klusterstorlek liknar ingen simulering den observerade utbredningen. Därmed kan modellen tänkas inrymma den vegetativa förökningen medan fröspridningen, som är stokastisk, ej inryms på samma vis. växtekologi cellulär automat simulering utbredning organisation komplexitet taraxacum maskrosor modellering dynamik utbredningsmönster fraktal
6	Vegetation development and sheep grazing in limestone grasslands of South Öland, Sweden Rosén, Ejvind January 1982 (has links) No description available. Ekologi: botanik [Ekologi] Växter Får botanik Växtgeografi Floror Växter Botanik Naturvetenskap Sverige Växtekologi Ekologi Geografi Öland Götaland Ekologi: botanik
7	Makrofossilanalys som ekologiskt verktyg : En metodutvärdering Pettersson, Siri January 2017 (has links) Approximately 50 percent of all endangered species in Scandinavia are associated with old agricultural landscapes. During the agricultural industrialization of the past century the traditional practices and methods that created these environments have been phased out. This has brought on a serious decline and fragmentation of biomes that many endangered species depend on. Knowledge of traditional agricultural landscapes and their species dynamics is needed to make well informed decisions regarding their care and restoration. One way to acquire such knowledge is to study fossil plant remnants from old agricultural contexts. In this study sub-fossil Cyperaceae achenes were analyzed in an attempt to identify them. The achenes had been preserved in three Iron Age wells (80-980 AD) at the Gilltuna settlement in central Sweden and were found during an archeological investigation in 2010. The purpose of this study was to identify the achenes to species level, make conclusions about the ecology of the surrounding landscape, and construct simple species identification key as well as evaluate archaeobotany as an ecological tool. The identification attempt resulted in 14 determined species, which were in consistency with previous landscape analyses made using ecological species distribution. The resulting identification key is a suggestion, to be expanded in the future. This method can undoubtedly provide further knowledge of prehistoric and historical biomes, but in order to draw useful conclusions the identification technique further as well as knowledge of present regional ecology must be developed, especially concerning different Cyperaceae species‟ response to different kinds of stress. macro fossil analysis cyperaceae sedge seed archaeobotanic paleo ecology sweden conservation makrofossilanalys arkeobotanik paleoekologi växtekologi ekologi historisk ekologi cyperaceae halvgräs makrofossil subfossil achen nöt frukt frö metodutvärdering artidentifiering identifiering järnålder vikingatid romersk järnålder Gilltuna västerås län naturvård äng ängsmark hage gräsmark Ecology Ekologi Botany Botanik Archaeology Arkeologi

1

Page generated in 0.0408 seconds