Abstract The European eel (Anguilla anguilla) migrates to the Sargasso Sea to spawn. Even though the biology of A. anguilla leptocephali in the Sargasso Sea has been studied for several decades, information regarding their diet has remained unknown until now. Previous dietary studies concerning other species of leptocephali in the Pacific Ocean have been limited to the recognition of identifiable prey remains amongst gut contents. Hence, in this study a molecular approach relying on the detection of prey DNA amongst gut contents was used to study dietary profiles of A. anguilla leptocephali in the Sargasso Sea.   Leptocephali were collected during the circumglobal Galathea 3 expedition in spring 2007 to the Sargasso Sea. DNA extracted from gut contents were PCR amplified using universal primers targeting the nuclear 18S rRNA gene. In order to separate eel amplicons from prey amplicons, PCR products were analyzed by denaturing gradient gel electrophoresis (DGGE). Furthermore, clone libraries were constructed using universal primers targeting a portion of the 18S rRNA and mitochondrial COI gene, respectively. In total, the gut contents of 78 leptocephali were screened by DGGE.   A diverse array of eukaryotic taxa was identified, hence demonstrating the applicability of a universal PCR- DGGE approach to study gut contents of leptocephali. The results presented here show, for the first time, that young stages of A. anguilla leptocephali feed on a large variety of zooplankton of which many were gelatinous (e.g. Hydrozoa, Thaliacea and Ctenophora). Several of the identified taxa also constitute important parts of the Sargasso Sea zooplankton community and are of size ranges (adult or larval stages) that made them reasonable as leptocephali prey.

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Text som utforskar och reflekterar över akustisk ekologi i musik och hur en kompositörs roll inom denna typ av arbete kan se ut. / <p>Ljudmaterial inlämnat till ljudenheten, CD finns bifogad tillsammans text på Kungliga Musikhögskolans Bibliotek.</p>

Rates of habitat alteration and degradation are increasing worldwide due to anthropogenic influence. On coral reefs, the loss of live coral reduces structural complexity while facilitating algal increase. In many coastal lagoons seagrass and corals are cleared to make room for cultivated macroalgae. This thesis deals with reef and lagoon habitat structure and how fish assemblage patterns may be related to physical and biological features of the habitat. It further examines assemblage change following habitat disturbance. Four studies on East African coral reefs concluded that both the abundance and species richness of recruit and adult coral reef fish were largely predicted by the presence of live coral cover and structural complexity (Papers I-III, VI). Typically, recruits were more selective than adults, as manifested by limited distributions to degraded sites. Paper VI compared short- and long-term responses of fish assemblages to the 1997-1998 bleaching event. The short-term response to coral mortality included the loss of coral dwelling species in favour of species which feed on algae or associated detrital resources. Counterintuitively, fish abundance and taxonomic richness increased significantly at one of two sites shortly after the bleaching. However, the initial increase was later reversed and six years after the death of the coral, only a limited number of fish remained. The influence of fleshy algae on fish assemblages was studied in algal farms (Paper IV), and examined experimentally (Paper V). The effects of algal farming in Zanzibar were significant. Meanwhile, manually clearing algal-dominated patch reefs in Belize from macroalgae resulted in short-term increases of abundance, biomass and activity of a few species, including major herbivores. The findings of this thesis demonstrate the significance of habitat as a structuring factor for tropical fish assemblages and predicts that coral death, subsequent erosion and algal overgrowth may have substantial deleterious impacts on fish assemblage composition, abundance and taxonomic richness, with recovery being slow and related to the recovery of the reef framework.

Diss. (sammanfattning) Uppsala : Univ., 2009. / Härtill 5 uppsatser.

ABSTRACT Seven islands in the lake Kolsnaren have been investigated. I have inventoried saproxylic insects and investigated what characters on dead wood and characters at the islands that have affected species number of beetles (Coleoptera) and true bugs (Hemiptera). This study shows a relatively low number of species of beetles and true bugs but the study was too small to estimate a proper result. Probably there is many more species, especially more rare/threatened species. The characters vary between islands, but even the individual islands had different tree species, thickness, degradation stage and sun exposure of dead wood. Therefore there were favourable conditions for many different saproxylic species that have different demands of the habitat to find suitable substrate. The islands are partly isolated by water but no longer distances. With that in mind it was important that there is plenty of dead wood with varying characters around Kolsnaren so they get the opportunity to disperse and recolonise the islands when even the habitats are changing in time. The dead woods thickness and degradation stage was the characters with most impact of the number of species. / SAMMANFATTNING Sju öar i Kolsnaren har undersökts. Jag har inventerat vedlevande insekter och undersökt vilka karaktärer på död ved (art, grovlek, rötstadie och solexponering) samt karaktärer på öarna (storlek, avstånd till land, ljusinsläpp, trädarter samt mängden död ved) som påverkar artantalet av skalbaggar (Coleoptera) och halvvingar (Hemiptera). Denna studie visade på ett relativt lågt artantal av skalbaggar och halvvingar men troligen finns det många fler arter, framförallt fler sällsynta liksom hotade arter. Öarnas karaktärer varierade mellan varandra men även på de enskilda öarna var det variationer i form av olika trädarter, grovlek, rötstadier och solexponering av den döda veden. Därför finns det goda förutsättningar för en mängd olika vedlevande arter med varierande habitatkrav att finna lämpligt substrat. Öarna är delvis isolerade av vatten men det utgör inget större hinder för de flesta skalbaggar. Däremot är det viktigt att det finns gott om död ved med varierande karaktärer runt omkring Kolsnaren så att vedlevande skalbaggar får möjlighet att sprida sig och återkolonisera öarna då även habitaten ändras med tiden. Den döda vedens grovlek och rötstadie var de karaktärerna som hade störst inverkan på antalet arter.

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No description available.

Xeric sand calcareous grasslands or sand steppe is a rare habitat type in Sweden. In our country the occurrence of sand steppe is limited to eastern Scania and a few sites on the Baltic island of Öland. The availability of calcareous sand and a continuous management of the soil surface regulate formation of the sand steppe. A low annual precipitation is also a critical factor. Due to these unique circumstances the habitat type has never had a great distribution in the country. Sand steppe is closely related to the agricultural landscape with a long tradition of extensive arable farming and grazing animals. Patches of bare sand mixed with a sparse cover of low grass vegetation is the characteristic of the habitat. Changes in land use linked to agricultural modernization, and pine-tree plantations in former sand steppe areas, have made the habitat seriously threatened today. The purpose of the survey has been to carry out a detailed mapping of sand steppe on Öland and to study how the habitat changed over the last fourteen years. I wanted to see what such a change analysis could say about the future of the sand steppe on Öland where the assumption was that the habitat is reduced and the overgrowth is inevitable without restoration measures. As with other similar types of culture-guided grasslands the sand steppe habitat is never in a stable equilibrium. Without disturbance of the topsoil layer, grazing animals or human activity the sand steppe will get overgrown. By using the land for cultivation the process of succession is delayed. This process can be illustrated by the three development phases associated with sand steppe, the initial phase (1st class), the optimal phase (2nd class), and the phase of degradation (3rd class). Both the lack of management practices and improper land use is a threat to the habitat. A number of rare and red-listed plant species are associated with the habitat together with the indicator species, Koeleria glauca. Sand steppe is also a very important habitat for insects, order Hymenoptera and order Coleoptera. The current situation of sand steppe on Öland consists of 15 sites all of which can be found on the east side of the island, along the ancient shorelines from the early stages in the development of the Baltic Sea. The sites have been carefully mapped by counting the number of individuals of Koeleria glauca and by the quantification of the three phases of development for each site. The number of Koeleria glauca individuals on Öland (July 2009), is 604 805. A change analysis was carried out to compare the distribution of sand steppe on Öland in 1995 with the distribution in 2009. Because of incomplete data in the 1995 inventory, the result of the analysis is considered to be a trend. The total area of sand steppe on Öland has increased, from 36.5 to 41.5 hectares since the 1995 inventory. This is contrary to the hypothesis that the area of sand steppe had declined. The reason to this total increase is probably due to greater awareness of the habitat sites. The distribution of development phases shows a clear dominance of the 3rd class-surfaces. The reason for such a large increase of the third phase is mainly due to an increased knowledge of the existence of Koeleria glauca at each site. But since the proportion of the initial phase and the optimal phase have been reduced this suggests that the 3.rd class-surfaces has increased at the expense of the 1.st- and 2.nd classes. This provides a future indication for the sand steppe sites on Öland where overgrowth is inevitable, without restorative management measures to create new sand steppe. The assumption that small sites get overgrown faster than large sites has been clearly confirmed. Such a fragmentation process, which also is a result of the overgrowth, is an additional threat in the longer term. At an increased habitat fragmentation risks of isolation and inbreeding might occur and finally a gradual and increasing extinction debt. Since the sand steppe environment also allows for species that have general needs of bare sand the restoration and preservation of the habitat type is of great importance. Thanks to the distinctive character of the habitat there is a large commitment among nature conservation authorities and in the final stages of this work a decision was made regarding Åby sandbackar, a prospective nature reserve on Öland.

It is known that artificial light at night has a role in disrupting many birds’ routines when it comes to timing of dawn song. However, studies show various results on which species that are affected, how much and on what latitude. Birds at northern latitudes is experiencing longer and brighter natural nights during the breeding season as the spring is progressing, compared to birds living in areas more south. The bright nights might affect how the birds respond to the artificial light at night. This study's aim was to investigate how different species of songbirds in Linköping (58°N), Sweden, time their dawn song during breeding season, depending on presence or absence of artificial light at night coming from street lamps. The results show that early singing species are more affected than late singing species. The common blackbird for example, advanced its song because of artificial light, up to over an hour on average. Late singing birds was also affected by the urban lights, though not as strongly as the early singing species. Also shown was that the temperature and the amount of cloudiness, did not affect the difference in timing of dawn song between the locations. Future studies should focus on collecting data from more northern latitudes. The effect the advanced timing of dawn song, both regarding the birds on an individual scale and also regarding the ecosystems in total,should also be investigated further.