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20 Uppsatser om Herbivores - Sida 1 av 2

Förutsättningar för återintroduktion av stora gräsätare i Sverige

Biodiversity is under threat in Sweden and many species are on the brink of extinction. This is mainly due to the large-scale drainage projects during the 19th and 20th century and the increasingly intensive land use in agriculture and forestry. The intensive land use with sharply defined boundaries between the production units has in many cases led to either overgrazing or overgrowing. As a result many species have been pushed back to "leftover" habitats like shooting ranges, power line corridors, roadsides, dumps, embankments and other similar areas. Therefore the question has been raised, wether or not it is needed to re-introduce large Herbivores into the wild in order to maintain the biodiversity that is related to the extensive land use.This study has been conducted as a literature review and will focus on the European bison?s (Bison bonasus) impact on other species and biodiversity; conditions for reintroducing large Herbivores in Sweden are also discussed.Free roaming populations of large Herbivores have a positive impact on plants, insects and many other groups of organisms.

Betesskador på lärkplantor

The purpose of this study was to show how the Hybrid Larch (Larix eurolepis x) are used by large Herbivores in terms of grazing and fraying. More specifically I studied how impact on the seedlings was affected by forest stand area, tree height and stem density (stems/ha).The survey was done in Jönköpings county in southern Sweden. About 50 % of all stems that are measured are damaged by grazing and 5,8 % was damaged from fraying. The conclusion of the study is that the biggest influencing factor is the height of the seedlings. The size of the stands and number off seedlings per hectare have almost no impact on the injuries on the seedlings. Fraying are common on trees smaller than 3 meters, and doesn?t occur on trees above that height.

Metodundersökning av tre metoder för kvävemätning i en arktisk äng : Jämförelse mellan mätmetoderna extraktion, inkubation och jonbytesmembran (PRS-sond)

The purpose with this report was to compare three commonly occurring methods for measuring plant available nitrogen in soils. The methods extraction, incubation and Plant root simulator (PRS) probe - an ion exchange membrane (Western Ag Innovations, Inc., Saskatoon, Canada) method were used and comparison between these methods were conducted. A full factorial experiment were set up in northern Finland with the treatments excluding Herbivores, warming and fertilization to see how the inorganic nitrogen content in the soil was effected by the treatments. Soil cores were taken and from them a subsample was incubated for 18 days and thereafter analyzed for inorganic N in laboratory. PRS- probes were in the ground for 1 month.

The influence of active bomas on habitat choice of the common warthog (Phacochoerus africanus)

The common warthog (Phachocoerus africanus) is a relatively long-legged pig with noticeable curved tusks, a short neck and three pairs of facial warts. It has four recognized subspecies. The common warthog is a non-migratory ungulate living on the African savannah. It is a hindgut fermenter and predominantly dependent on high-quality foods. It prefers open areas for grazing but use bushes for cover.

Nyckeltal för älg och fodertillgång på tall Pinus sylvestris och rönn Sorbus aucuparia

It has been shown that moose can affect plant community composition and structure. Selective browsing with other damages of large Herbivores on tree species with different tolerance to disturbance could reshape the tree layer in both managed and natural forests. Rowan Sorbus aucuparia is widely distributed throughout Sweden and Europe. Research has shown that browsing by moose may prevent rowan from reaching browsing safe heights. The goal has been formulated that, where rowan is indigenous, it should have a good competition status and be able to reach tree level.

Klimatinducerade fenologiförändringar och dess effekter i näringsväven

The climate affects animal populations through several processes. These processes includereproduction, phenology and the success of hunting. By influencing the phenology of species theclimate also affects the way species interact. If a climate-induced phenology change promotes abasal species to bud earlier in the spring for example, this will affect the links to other species inthe food web due to a time lag in the tropic levels above. This dependence, that a predator has tobeing synchronous to its prey, is called the match/mismatch hypothesis (MMH).

Vivesholm : djurbenen belyser den gotländska medeltida borgens husdjurshållning samt husgrundernas användningsområden

The castle Vivesholm is located about two miles north of Klintehamn on the west side of Gotland. The castle was built around year 1395 and burned down in the end of the 14thcentury. Around the 17th and the 18th century the castle was re-used. However, the emphasis on its use is during the middle ages.This paper aims at getting an insight in the animal husbandry at Vivesholm by analyzing the osteological material. The analysis revealed that bones from sheep/goat were more common than bones from cattle.

Feeding preferences and foraging in Larvae of Manduca sexta and Spodoptera littoralis : a laboratory study based on olfaction

Larvae of Lepidopteran Manduca sexta and Spodoptera littoralis are pests of economical importance in several horticultural and agricultural crops. Knowledge of insect feeding preferences and behavior is crucial in order to find economically and ecologically sustainable solutions to the problems caused by these Herbivores. The aim of this thesis was to study the behavior and the induced feeding preferences in larvae of M. sexta and S. littoralis when reared on certain host plants. The hypothesis was that larvae of M. sexta would have an innate preference for plants of the Solanaceae family and therefore discriminate the previously experienced nonhost when faced with the choice between a true host and the previous food source.

Effect of Bacillus mediated priming on different natural genetic variants of Arabidopsis thaliana

In two feeding experiments Bacillus induced priming of plant defense was tested for its effect against the generalist insect pest Spodoptera littoralis. The main hypothesis for the study was that Bacillus induced priming would enable the plant Arabidopsis thaliana to defend itself better against this insect herbivore since this priming seems to involve jasmonic acid, known to be important for plant defense to insects. A secondary objective of the study was to examine if any differences in a primed defense capability could be seen between different natural genetic variants (ecotypes) of A. thaliana reflecting habitat differences in pest pressure. The methods used for plant cultivation and Bacillus inoculation were aimed at reflecting conditions that can be expected in an agricultural cropping system. This meant that all plants were cultivated in soil, and the feeding experiments were conducted with the plants growing intact in the soil system.

Diurnal rhythm of the savannah elephant (Loxodonta africana africana) in Maasai Mara National Reserve, Kenya

Elephants are hindgut fermenters, which affects their diurnal rhythm. To reach their nutrient demands, elephants must eat almost constantly throughout the light part of the day. Sexual dimorphism may also affect their behavioral patterns. To understand the elephants' normal living habits and foraging behaviour, we conducted a pre-study in the Mara Triangle, the north-western part of the Maasai Mara National Reserve. Each of four to six observers randomly chose a focal animal within the group of elephants by the criteria that they were adults and visible.

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.

Foraging and anti-predation behavior of Thomson?s gazelles (Gazella thomsoni) and Grant?s gazelles (Gazella granti) at a waterhole

Prey species make behavioral decisions to reduce the perceived risk of predation and the time spent vulnerable to predation. Behavioral responses to predators are for example selection of specific habitat types and the presence of predators influence individual vigilance. Furthermore, there is a variation in feeding niches with different Herbivores focusing their foraging effort on different vegetation types which is also expected to affect the choice of habitat. Behavioral data on anti-predation and foraging behavior at on waterhole is collected from Thomson?s and Grant?s gazelles at Ol Pejeta Conservancy (0°00?N, 36°56?E) located in semiarid bushed grassland in Laikipia district of central Kenya.

Parasite detection in extensively hold Gotland ponies

Horses are Herbivores that spend almost all day grazing. While grazing they are infected by different endoparasites through ingestion of infective eggs or larvae on pasture. The most significant equine endoparasites in Sweden are the equine roundworm Parascaris equorum, small (Cyathostominae) and large strongyles (Strongylus spp), the tapeworm Anoplocephala perfoliata and the pinworm Oxyuris equi. For many years have horses been dewormed on regularly basis, which has resulted in the development of resistance to many anthelmintic classes. Because of the problems with resistance it is since 2007 necessary to have a prescription on anthelmintics and faecal sampling is also recommended.

Fågelbär (Prunus avium L.) - överlevnad, höjdutveckling och skador i unga planteringar på småländska höglandet :

Plant survival, plant damage and height growth were studied in nine wild cherry (Prunus avium L.) plantations in southern Sweden established between 2000 and 2002. All stands were located to the county of Småland. The survey was conducted during May and June in 2007. During the survey the height, diameter and quality of the cherry trees were recorded. In one stand, red ? berried Elder (Sambucus racemosa L.) was a dominant species.

The effect of domestication on insect resistance in cotton : bioassays with the insect herbivores Spodoptera littoralis and Agriotes spp.

A plant's defensive ability against herbivore attack can be influenced by many different factors, one of them being domestication. During human selection to improve the yield of plants, the resistance against herbivore attack can have been lowered, due to a trade-off for use of resources between these traits in the plants. In this thesis I investigated the effect of domestication on resistance against herbivorous insects in cotton plants. I used different varieties and species of wild and domesticated cotton in three different experiments. A feeding assay was conducted, the mortality, development time and pupal weight of larvae of the Egyptian cotton leaf worm Spodoptera littoralis was studied. In a second experiment the preference of the root-feeding beetle Agriotes spp.

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