Sökresultat:
918 Uppsatser om Species interactions - Sida 18 av 62
Deadwood in piles or distributed : does it make any difference to saproxylic beetles?
Piles of deadwood are often retained in forests after management to support the biodiversity ofsaproxylic organisms which depend on deadwood to survive. Any knowledge about the crucial role ofpiles as suitable habitat of saproxylic organisms compared to single distributed deadwood objects thatare around the piles would help conservation actors to motivate more forest owners to supportsaproxylic organisms during their management. Therefore to give facts to this the saproxylic fauna ofdifferent pile positions (up and low) was studied and compared to distributed deadwood samplesaround each pile. Our study was focused on saproxylic beetles. Some other parameters such asdiameter, deadwood volume, pile volume and decay stage were assessed to define any effect.
Genomgång av kemikalieförteckning som exempel på uppströmsarbete : en identifiering av utfasningsämnen i spillvattnet
Benthic invertebrates play important roles as feeding resources for many organisms in different food webs. Shifts in predation of these organisms can generate cascading effects and potentially lead to the disappearance of one or more species from a site. Cascading effects can bring impacts to organisms who aren?t even directly involved, why studies in this field are important for understanding sudden changes in ecosystems. I examined the predation from fish and waterfowl on benthic invertebrates in the shallow and eutrophic Lake Tåkern in the plains of Östergötland County, southern Sweden.
Spridningsmönster och potentiella spridningsytor hos invasionsarten stor bockrot (Pimpinella major) i Tullgarns naturvårdsområde : ett framtida problem för områdets diversitet?
An organism that is transferred from one place to another, causing major problems to the native species is termed invasive. Its natural dispersal across barriers may have been prevented but as man has turned able to rapidly travel all over the world organisms are brought to sites where they were never before observed. Adding the increasing global warming organisms may find it necessary to move around even further. This might cause major disturbance to the biological diversity, and hybridization and homogenization is one of many scenarios that could disturb the native diversity. In Sweden more that 2/3 of all alien plant species have been introduced to disturbed areas and the major introduction mechanism is gardening.
Betydelse av lövinslag, död ved och variation i träddiameter för artrikedomen hos småfåglar
Forest management contributes to the changes in forest structure by turning heterogenous forests of varied age into homogenous forests of similar age and thus affect bird species depending on different structures or habitats which are lost during forestry. In this report, a study was made to investigate how the amount of decidious trees, dead wood and variation in tree diameter affect bird diversity. The purpose of this study was to be able to give forest management guidelines to increase bird diversity. This study was conducted by investigating 65 transects in forests of different structure south of Linköping, Sweden. Along the 65 transects, birds were inventoried as well as the vegetation.
Analys av hemområdesstorlek hos mellansvenska vildsvin (Sus scrofa scrofa)
The wild boar population grows rapidly in number in Sweden, and it has been predicted that the annual number of shot wild boar will soon exceed the cull of moose. According to estimates, the Swedish population encompassed some 150 000 individuals in 2010. The mean annual harvest has increased by 30% since 1990, indicating that the wild boar is a species we must learn to manage sustainably. A successful management of the boars aims for a population in balance with agriculture and traffic, and also provides good hunting opportunities. For this to be possible, understandings of several aspects of the ecology of wild boar is needed.
The sows in this study had an average homerange of 707 hectares during summer, and 659 hectares in winter.
Skyddet av arter: en jämförelse mellan amerikanska Endangered Species Act och den svenska fridlysningslagstiftningen
I dagens samhälle är skyddet av hotade och utrotningshotade arter väldigt aktuellt och kontroversiellt. Den problematik som uppstår när man vill skydda arter återfinns i alla länder, därför är det intressant att se hur andra länder valt att genomföra sitt skydd. Ett land med en omtalad och långtgående lagstiftning i detta fall är USA. Därför valde jag att genomföra en jämförelse mellan USA:s Endagered Species Act (ESA) och den Svenska fridlysningslagstiftningen. Den svenska fridlysningslagstiftningen är ingen enhetlig lagstiftning såtillvida att den har samlats upp enbart i miljöbalken (MB).
The major food trees of the Angola black-andwhitecolobus (Colobus angolensis palliatus)in Diani Forest, Kenya
The Angola black-and-white colobus (Colobus angolensis palliatus) is a subspecies of Colobus angolensis inhabiting fragmented forests in coastal Kenya and Tanzania. C. angolensis is regarded as Least Concern in the red list of IUCN because its populations are abundant. However, the populations of C. a.
Föryngringsplan för en svårt stormskadad fastighet i Kronobergs län :
In January 2005 large forest areas in south Sweden were severely damaged by storm. This final thesis describes the work with creating an ecological and landscape-adapted regeneration plan for a severely storm damaged property in Kronobergs region in south Sweden.
This regeneration plan, in difference to more regular plans, are focusing more on the owner?s use and goal?s for the property and seeing the property from a more comprehensive view in the regeneration process. Beside production and environmental values the plan also take in consideration other values as aesthetic, culture history, landscape picture and recreation values.
Grazing behavior of Ankole and Boran cattle in an improved herding production system
To be able to provide the growing human population with food, the productivity of the animals as well as land use needs to be improved and intensified. Hence, understanding the behavior of animals is crucial both for animal welfare and productivity as well as the management of the cattle. There are many factors affecting the grazing behavior of cattle in tropical conditions, such as human-animal interactions, herd management, breed, season and temperature. The purpose of this study was to investigate the grazing behavior of two tropical cattle breeds, Ankole and Boran cattle. Kenyan Boran belongs to a zebu type of cattle and is preferred to many other breeds due to the higher productive and reproductive capacity and adaptability to tropical conditions.
Evaluating six crop mixes used for game fields in southwest Sweden : biomass production, fallow deer preference and species diversity
Game fields are one way to divert animals away from sensitive areas, create shelter and forage, and also to increase the biological diversity. In this study I investigated how the plant composition in six different crop mixes used for game fields affected the biomass production, biomass consumption and biological diversity at the Koberg estate in southwestern Sweden. Six experimental fields were used and each field contained six plots, approximately 1500 m2 each, that was sown with a different crop mix. The crop mixes ranged from a pure grass mix (A), 70 % grass and 30 % leguminous plants (B), 53 % grass, 21 % leguminous plants and 26 % other herbs (C), 100 % leguminous plants (D) to the most complex mixes constituting of 91 % leguminous plants and 9 % other herbs (E) and 87 % leguminous plants and 13 % other herbs (F). The fields were cut weekly during the summer in 2010, to estimate weekly biomass production.
Hur påverkas dvärghamstrar av att vistas i hamsterbollar?
Lately the popularity to keep different species of dwarf hamsters has increased in Sweden.
The requirements of the Swedish legislation to keep hamsters as pets are low which could be a reason for the increasing popularity. Hamsters are in nature generally nocturnal and can travel far distances to find food sources during their active part of the day. Their eyesight is poor, but is compensated by their well-developed hearing and olfaction. ?Run about balls? are made of plastic and the hamster is placed inside it where after the ball is placed on the floor and the hamster can then run protected outside the cage.
Användning av satellitdata för lokalisering av skogsområden där lövröjning bedöms angelägen : en analys av användbarheten med fjärranalys som hjälpmedel till röjningsrådgivning
This master thesis project is a part of a project called ?Järboprojektet? at the regional board of forestry, the district of Gästrikland. The project will give answers to questions regarding if an analysis of satellite images can be used to contact and inform landowners of the located areas where precommercial thinning is useful. The whole project is a part of the National Board of Forestrys IT-stake where the analysis of satellite images will, at the latitudes possible, be adapted to each district in purpose to identify these areas in need of precommercial thinning. This master thesis project is based on a field inventory of identified objects where precommercial thinning is useful.
Ekosystemstödjande och multifunktionella växtval i urban miljö : En fallstudie med utgångspunkt i Nacka stadsbildning
This study has investigated how urban vegetation can be used in a multifunctional way to support ecosystem services in urban environments. Nacka municipality is in the start-up phase of building what is to become Nacka city. This provides a unique possibility to study and analyse what role the vegetation play in making the city a healthy living environment and how it needs to be adapted in order to be resilient against changing climate conditions and how the effects of those changes can be regulated. The study further investigates how airborne pollution, caused by urbanization processes, can be regulated or reduced by vegetation or species selection. Methods used in this study were a combination of qualitative interviews and literature studies, seeking to answer the questions: Which specific ecosystem functions are needed in the urban environment and which aspects will influence the ecosystems ability to deliver the functions in demand? And which plant species have the right mechanisms needed to deliver those functions? These questions have been studied and analysed in a local based context where the local conditions ands site specific needs of Nacka define criteria for plant selection.
Uptake of 137Cs by fungi and plants due to potassiumfertilization in Heby municipality in response to theChernobyl nuclear accident
The fallout from the Chernobyl nuclear accident resulted in large deposits of caesium, iodineand strontium as well as noble gases in various parts of Sweden. 137Cs has a radioactive halflifeof about 30 years and is therefore one of few radio-fission products remaining inmeasurable quantities in the Swedish soil. Radiocaesium behaves similarly to potassium insoil-plant systems and is easily absorbed by plants. It is important to understand how 137Csbehaves in different ecosystems in order to minimize the risk toward humans.The aim of this study was to determine how potassium fertilization influences radiocaesiumcontent in different forest plants and fungi. Potassium fertilizer was spread once in 1992 withapproximately 200 kg KCl per ha.
Vegetationens roll i erosiva vattendrag : en review och fältstudie av två nyckelområden i Rönne å
The vegetation?s impact on erosion control is widely explored, even though research? results are scattered where it suggests a both positive and negative relationship between roots and erosion tendency. Research has measured the roots? impact on erosion by many different methods, hence the aim of this study is to offer a clearance of what factors play an important role in the choice of appropriate species controlling river bank erosion. I have therefore
studied 17 articles concerning vegetation and erosion control, which were found in different databases such as: Web of Knowledge, Biological Sciences, Academic Search Elite and Google Scholar.