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488 Uppsatser om Habitat preferences - Sida 1 av 33
Pre-spawning habitat selection of subarctic brown trout (Salmo trutta L.) in the river Vindelälven, Sweden
Habitat selection of migratory brown trout at the upper reaches of River Vindelälven, wasstudied in September during the pre-spawning period. The fish migrate from down- orupriver lakes for spawning in the river and data was collected by habitat mapping andradio-telemetry. Habitat selection of fish was analysed with preference curves andstatistical modelling, using the physical variables; depth, stream velocity and streambedsubstrate. Preference curves were derived by comparing fish habitat use with their nearbyavailable environment while the statistical modelling aimed to answer three main questions.1) Do the trout have a specific preference of depth, water velocity and streambed substrate?2) Is there any difference in habitat selection between sexes? 3) Is there a shift in habitatselection over time? The preference curves indicated that trout favored water depths of 1-2m, velocity compositions characterized as glides (c.
Flottledsåterställning i norra Sverige: : effekter på habitatkvalitet och populationstätheter av juvenil öringar (Salmo trutta L.)
In an effort to evaluate the effects of restorations of float ways on population density of stream dwelling fish in relation to the changes in habitat, I studied the physical habitat restored and channalized sites and their population density of brown trout (Salmo trutta L.) in three streams in the municipality of Sorsele.
The differences between the channalized and the restored sites where most noticeable regarding substrate which where generally coarser in the restored sites. The analyses showed that the proportion of habitat that where suitable to the age class 0+ where significantly lower in the restored sites compared to the channalized sites. Regarding age class ?2+, no statistical differences in habitat quality were found.
Habitat preference and foraging behaviour in adult red-tailed monkeys (Cercopithecus ascanius)
The red-tailed monkey (Cercopithecus ascanius) is a small, alert and active animal inhabiting forests with dense vegetation and as such hard to observe in its natural habitat. The principal aim of this study was to scrutinize whether the methods, previously used in a behavioural study of the blue monkey (Cercopithecus mitis) can be applied in studies of the red-tailed monkey?s behaviour as well. Additionally, habitat preference and foraging behaviour of the red-tailed monkey were examined. The study was carried out between the 16th and the 22nd of March 2009 in the Sabaringo forest, located on the western border of the Masai Mara National Reserve.
Vilken preferens har tjockskalig målarmussla (Unio crassus) för bottensubstrat och vattenhastighet i Storån, Östergötland?
The thick shelled river mussel (Unio crassus) has a fragmented distribution in southern Sweden. It is a threatened and protected species. In both the Swedish red list and the IUCN Red List of Threatened Species Unio crassus is classified as Endangered (EN). Causes for this classification are for instance differentiated bottom substrate and deterioration in water quality. In this study, Habitat preferences of Unio crassus were investigated to assist in future restoration work.
Att påverka sina preferenser: en analys av rationalitet och preferensdynamik (v 1.1)
Actors deliberately change their preferences, contrary to the assumptions of rational decision models. This study shows why, and to some extent how. Preferences are necessarily ambiguous and unstable. Rationality is a regulating myth which has had a profound influence on Western conceptions of what an actor is.The aim of this study is to help individual actors understand the theoretical grounds of their actions. The analysis provides tools for examining decision methods and preference changes.
Squatting i Alexandra : Om illegal bosättning i Sydafrika och hur landets bostadspolitik påverkats av Habitat II
Squatting innebär att människor illegalt bosätter sig på mark eller ockuperar tomma hus för att ha någonstans att bo. I samband med att världens storstäder växer, växer även squattingområden. För att förbättra situationen för bland annat squatters, hölls 1996 en FN-konferens, Habitat II.Syftet med uppsatsen är att belysa problemet med squatting och undersöker om Habitat II:s beslut haft någon inverkan på det deltagande landet Sydafrika. Den teoretiska ansatsen är realism och managerialism, där man menar att bostadssegregation beror på sociala och rumsliga hinder, samt att det är de med makt som ansvarar för bostadsituationen. De dokument från Habitat II har studerats som berör squatters samt sydafrikanska bostadspolitiska dokument.
Man blir påverkad av sitt kön vare sig man vill eller inte : En kvalitativ studie om skillnader i män och kvinnors musikpreferenser
Music has always been an important form of communication and it can be found in many different contexts including aesthetical, cultural and emotional forms. In the globalized society of today music can be distributed fast through radio, TV, CD: s and the Internet. For many people consumption of music is an important part of the daily life and it can contribute to shape an individual?s attitudes and personality.The main purpose of this study is to find out whether there are any differences between men and women?s musical preferences. I will apply an explorative approach using qualitative interviews to describe what causes the differences.
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.
Fåglar i urbana miljöer : kvaliteten på urbana habitat och om beståndstäthet är ett bra mått på habitatkvalitet
The urbanization of the world is increasing. How it affects bird populations have been well studied during the last decade, and comparisons between urban and non-urban habitats have been carried out. A common method for measuring habitat quality is to calculate the population density. This method is easy to use, but have been criticized during the last couple of years. In this study, data of population densities was compared with data on reproduction success.
Habitat preferences and reproductive success forthe threatened longhorn beetle Plagionotusdetritus
Plagionotus detritus is a threatend longhorn beetle that only exists at one site in Sweden. It is saproxylic and depending on recently dead coarse oak wood for its larval development. Trees at Djurgården, Stockholm that have been colonized by Plagionotus detritus has been studied to find out the Habitat preferences of the species and to see what affects the density of beetles in a tree. The bark of some trees and wood from the breeding project at Nordens Ark has also been studied to find out what affects the species reproductive success. The reproductive success was measured in two ways, the larval mortality and the size of the hatching holes.
Studier av habitatval och revirstrukturer hos vassångare (Locustella luscinioides) i Tåkern
The Savi?s Warbler (Locustella luscinioides) is a recently established bird species in a few reedy shallow lakes of southern Sweden and has only been found nesting for the last twenty years. Little is known about the species' Habitat preferences, breeding biology and demands for specific territory structures at breeding sites in Sweden. Knowledge of a newly established species? habitat requirements is essential to maintain a viable population and design action plans.
En undersökning av Bergvik skogs och Skogsstyrelsens gallringsmallar mot en gallringsoptimering på simulerade typbestånd
The purpose of this study was to analyze the two thinning models: Bergvik Skog´s thinning model, which is based on total stems and dominant height, And Swedish forest agency´s thinning model which is based on basal area, habitat index, dominant height and recommended number of stems at final felling in Heureka´s StandWise and PlanWise.
The data we chosen for our study were taken from the Swedish National Forest Inventory and we were creating a simulated stand based on a great number of sample plots in Region three from The Swedish National Forest Inventory. We had chosen to create one stand with low habitat index (T20) and one with high habitat index (T24). Our purpose were to come as close as possible to a natural stand in central Sweden. We performed the thinning in StandWise and analyzed the data I Excel files. Our thinning optimizing´s were performed and analyzed in PlanWise.
There wasn´t any big differences between the thinning on the lower habitat index.
Habitat diversity and composition among growing wild boar (Sus scrofa L.) populations in Sweden
The wild boar (Sus scrofa L.) has expanded across Europe and Sweden in the last decades. It is a generalist species which utilizes a variety of habitats, and its presence has been shown to have both positive and negative effects for people and the landscape they are in. The abundance and increase of wild boar has previously been shown to differ between counties in Sweden, but there have been few explanations as to why.
In this study, I investigated correlations between the per capita rate of change (r) among wild boar populations in Sweden and a variety of different habitats on the county level. I also investigated if fragmentation per se or in certain habitats could be associated with the wild boar?s per capita rate of change.
My results show that fragmentation/diversity per se was not correlated with wild boar r.
Influence of the habitat on the potential for cannibalism and population dynamics in stream-dwelling European grayling (Thymallus thymallus L.)
Cannibalism can have major influence on fish population dynamics. A prerequisite for cannibalism is that the cannibal and the potential victim meet, and besides density effects, the encounter rate between cannibals and their victims is therefore also largely dependent on habitat use and habitat heterogeneity. In this study I quantified and compared the potential for cannibalism in stream-dwelling European grayling populations in three rivers in Jämtland by means of habitat classifications. I also analyzed population dynamic consequences of varying the potential for cannibalism in terms of intensity, using a physiological structured population model. Findings based on habitat characteristics were that the potential for cannibalism is in general not favourable in these types of streams.
Elevtexter - en analys av elevers skriftspråksutveckling och syn på musik från grundskolan till gymnasiet
The purpose of the present study is to explore differences in the musical opinions and preferences and the quality of written language between pupils of two age groups (12 and 17 resp). Two classes were chosen, one from each age level. Each class/group was also divided by gender. The pupils asked to write an essay on their musical opinions and preferences. The essays were analyzed with respect to musical content and linguistic form.