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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Hävdens inverkan på fenologi och artrikedom i ängen

Nilsson, Emelie January 2015 (has links)
Gotland is the richest place in the world when it comes to wooded meadows. Traditional management with haymaking and raking for centuries have turned wooded meadows into exceptionally species rich habitats in the agricultural landscape. Since the early 1900’s the area of managed meadows has decreased rapidly. The aim of this study was to investigate if there are differences between continuously managed areas and areas that had been left out, in Lojsta and Gerum on southern Gotland. The results show that there are significant differences in species diversity between the two types of management in both meadows. There was also a relationship between the two parameters temperature and growth. The conclusion of this study is that if it is of interest to conserve wooded meadows with all its species, it is important to continue with the yearly cycle of traditional management.
2

Påverkar avståndet från vindkraftverk artdiversitet och individantal hos dagfjärilar i vindpark Örbacken

Lennartsson, Anna January 2024 (has links)
Not much is known if butterflies can get affected by wind turbines. There are different possibilities how they can affect butterflies. How high the risk is that they can get killed by wind turbines and that butterflies might loose habitats by constructions. But there can also be factors that indirectly makes butterflies thrive better in wind farms. More road edges giving the butterflies resources of nectar from herbal plants growing next to the roads is one of them. This study examines if the distance from wind turbines can affect butterflies density and species diversity within and close to the Windfarm of Örbacken. In total 504 individuals of butterflies of 18 species got recorded within distance of 0-1km from wind turbines for three days. Within the distance of 200-500m from wind turbines 228 individuals of 12 species were recorded and had the highest mid value recorded of both the amount species and individuals. There was significance on the number of species being located within areas 200-500m away from wind turbinesand 0-200m from wind turbines. This suggests that the 200-500m areas from these wind turbines that were within the windfarm, may have a higher species diversity of butterflies. The species diversity of butterflies can possibly be affected by less nectar plants and shelter from the wind in areas close to wind turbines compared to areas 200-500m away from them.
3

Förändring av kärlväxters artsammansättning vid återupptagen hävd i skogligt avgränsade ängs- och hagmarker / Changes in vascular plant species composition when resuming traditional management of isolated meadows and pastures

Backius, Helena January 2011 (has links)
I det äldre jordbrukslandskapet finns en biologisk mångfald som man bl.a. försöker bevara genom att via EU:s miljöstöd stimulera lantbrukare att hävda betesmarker och slåtterängar med gammaldags metoder. Men är åtgärderna effektiva och uppfyller de sitt ändamål? Syftet med denna studie var att återinventera 10 stycken provytor från 2002 på gården Brofallet, för att se hur artsammansättningen hos kärlväxter hade påverkats av nio säsongers återupptagen hävd. Gården ligger helt omgiven av skog, isolerad från annan jordbruksmark. Ingen signifikant generell förändring kunde noteras hos hävdgynnade kärlväxtarter. Kvalitativa observationer kunde däremot visa en ökning av vissa hävdgynnade arter. Slutsatsen är att de femåriga åtaganden som lantbrukare gör för att få miljöstöden inte är tillräckliga sett till den totala mångfalden av kärlväxtarter på en gård som Brofallet, men att förändringar däremot kan tänkas ske snabbare på andra nivåer i ekosystemet. I studien diskuteras att även miljöåtgärderna och dokumentationen borde präglas av mångfald, där det småskaliga extensiva jordbruket kan visa sig vara viktigt i det totala strävandet efter ett hållbart samhälle både när det gäller att utnyttja extensiva marker för livsmedelproduktion och för att behålla biodiversiteten på landskapsnivå. / Old agricultural landscapes house a great biodiversity. To conserve this diversity the European Union award financial support in the form of environmental grants to encourage farmers to maintain pastures and hay meadows using old-fashioned methods. But are the measures effective and do they meet their purpose? The purpose of this study was to re-inventory ten sample plots from 2002 on the farm Brofallet to see how species composition of vascular plants had been affected by the nine seasons of using these old-fashioned methods management. The farm is completely surrounded by forest, isolated from other agricultural land. No significant overall change was observed concerning the composition of vascular plant species favored by traditional management. Qualitative observations, however, showed an increase in some species favored by traditional management. The conclusion is that the five-year commitment that farmers make to receive the environmental grants is not adequate enough to be able to detect changes in total diversity of vascular plants on a farm such as Brofallet, but that changes may occur faster at other levels in the ecosystem. Moreover, a ramification of this study is the idea that even environmental measures and documentation should be characterized by diversity. In summary, small-scale extensive farming may prove to be important in the overall quest for a sustainable society, both to exploit land for food production using extensive farming, and to maintain biodiversity at the landscape level.

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