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Three species of burnet moths (Zygaena filipendulae, Z. lonicerae and Z. viciae) were studied on the Baltic island Öland, Sweden, in order to reveal the habitat requirements of different life stages. Larvae were found among a higher cover of their most important host plant, Lotus corniculatus, Trifolium medium/pratense or Vicia spp., than were pupae or imagines, and were also observed on plants larger than randomly examined plants. Imagines actively selected nectar plants of Centaurea and Cirsium, growing in sunny conditions, but other red and violet Asteraceae flowers were also favoured. Pupae of Z. filipendulae appeared in taller vegetation than larvae and imagines, probably because the cocoons are spun high on stems of grasses and other plants. The chance of finding such suitable substrates rises with increasing vegetation height. A large scale analysis of occupancy patterns was also made, evaluating the relationship between burnet presence or absence and the area of meadows and pastures within 10 x 10 km grid cells in southern Sweden. All three species showed a positive relationship with increasing area of semi-natural grassland. Thresholds for the amount of habitat, below which the likelihood of occurrence declined more rapidly, could be distinguished around a 40-50 % probability of occurrence. Conservational work should aim at preserving and restoring open and sunny areas, rich in the respective host plants and nectar sources, but vegetation management must be executed with great care or late in the season to not harm unhatched pupae and to maintain substrates suitable for Z. filipendulae pupation.

The aim of this study was to examine what impact restored and constructed pounds and wetlands have on waterfowls in the area of Linköping. The birdlife in five constructed wetlands werechosen to investigate if specific factors like age, size and vegetation affected the avian diversity in wetlands. Also, extra focus has been given to the threatened Horned Grebe (Podiceps Auritus), breeding in the studied area. The results showed that the number of species as well as individuals of waterfowl and Horned Grebe changed over time in what might be a result of succession in the wetlands. Comparing the number of birds to the size of the wetlands showed a clear correlation. Larger areas inhabited greater numbers of species and individuals. However, the Horned Grebe showed a reverse result, as they seem to prefer smaller wetlands. Finally, a correlation between the numbers of observed Black-headed gulls and Horned Grebes could be found. When there was a greater number of Horned Grebes observed there was also a greater numbers of gulls present. Possibly the Horned Grebe takes advantage of the Black-headed gull-colony for protection against predators.

The tropical palm Mauritia flexuosa has highly nutritious fruits and is an important food resource for both humans and wildlife throughout its geographic range in South America. Unsustainable harvesting threatens wild populations. Mauritia f. occurs primarily in wetlands called Aguajales where it can become the dominating canopy species. Seed predation and dispersal can dramatically affect the survival and distribution of plant species in tropical rainforests (Janzen 1970, Connell 1971, Bleher & Böhning-Gaese 2001, Paine & Beck 2007, Mari et al. 2008). Increased knowledge of seed predation and germination requirements is essential for successful management of this commercially and ecologically important palm. Four experiments were conducted in Manu National Park in southeastern Peru to study: (1) Seed survival in the Aguajal, (2) Quantify seed predators on dry land, (3) Insect visitors and consumers of fruits and seeds, and (4) Germination in greenhouse experiments. Seed survival was significantly higher below water compared to on dry micro sites within the Aguajal. Seeds and fruits placed on dry land were preyed upon by both insects and mammals. Terrestrial insects were the most important predators. Different insects visited fruits and seeds, indicating a successive breakdown of different tissues. Seed survival was also higher below water and/or soil in the greenhouse experiment. This may suggest that the distribution of Mauritia f. is highly influenced by seed predation and that water protects seeds from their insect enemies.

Död ved är mycket viktigt för skogens ekosystem. Minskningen av död ved i dagens produktionsskogar har skapat ett stort problem för flertalet vedlevande arter. Denna studie gjordes för att ge en ökad kunskap om vilka faktorer som spelar in när det gäller förekomst och utbredning av de två vedlevande arterna Anastrophyllum hellerianum och Dicranum flagellare. Täckningsgraden av de två arterna undersöktes på lågor, tillsammans med faktorerna: art, diameter, nedbrytningsgrad, antal lågor i närheten, solexponering, markkontakt och fuktighet i mark. Tre typer av skogar inventerades. Studien visade att diameter/tillgänglig area, nedbrytningsgrad och solexponering var de viktigaste faktorerna som påverkade förekomst och utbredning av de två undersökta arterna. Utbredningen och sannolikheten för förekomst av arterna ökade med en ökad diameter samt med mer nedbrutna lågor, men minskade med ökad solexponering. Studien visade även att A. hellerianum föredrog lågor av nedbrytningsklass 5. Fördelningen av nedbruten ved var väldigt olika i de tre undersökta skogarna. I den urskogsartade skogen fanns stor volym död ved och många lågor av olika diameter och nedbrytningsklass. I produktionsskogen fanns endast ett fåtal lågor, varav ingen av större diameter och de flesta i tidigare nedbrytningsstadier. En slutsats av studien var att mängden död ved i brukade skogar verkar vara för liten för de båda undersökta arterna. Därför krävs en större mängd död ved i brukade skogar alternativt tillräckligt stor areal skyddad skog i landskapet för att långsiktligt bevara dessa arter. / Dead wood is a very important element of forest ecosystems. The reduction of dead wood in production forests has created major problems for several dead wood dependent species. This study was made to provide a better understanding of the factors that affect presence and coverage area of the two dead wood dependent species Anastrophyllum hellerianum and Dicranum flagellare. The coverage area of these species on logs was examined in relation to the factors: species of the log, diameter, length, degree of decomposition, number of logs close to the one examined, sun exposure, ground contact and soil moisture. The key finding of the study was that diameter/available area, degree of decomposition and sun exposure was the most important factors that affected the two species. The coverage area and the probability of presence of the species increased with increased log diameter and extent of decomposition, but decreased with sun exposure. Other findings were that A. hellerianum preferred logs of decomposition stage 5. The distribution of decayed wood differed greatly in the studied forests. In the primeval forest there were many logs, of many different diameters and decay stages. In the production forest there were only a few logs, none of larger diameters and most of them less decayed. As a conclusion the amount of dead wood in production forests seem too small for the two studied species to occur. Therefore, a larger amount of dead wood in production forests or sufficiently large areas of protected forests are needed to preserve these species.

In 1994 a new Forestry Act was accepted in Sweden. One of its aims was to raise the consideration for preservation of biodiversity. Since this happened over 15 years ago there is now an interest in analyzing if the law has been effective in its purpose. In this study methods suitable for analysis are being investigated. The study contents a pilot study of methods for five parameters that can validate if the law has been followed. The fieldstudy were executed in Orsa, Dalarna, Sweden in a managed forest and where last clearcut was done after 1994. The work consisted of measuring the parameters in the field and to compare them with data from before 1994. The benefits of the parameters and the current and previous Forestry Act and their differences are discussed in the report. The parameters examined were the distribution of tree species, standing dead wood, smaller areas saved for preservation, big trees and trees with cavities/cavernous trees. All of these plus a few other variables favourable for the diversity of species in the forest are dealt with in the 30 § in the Forestry Act of 1994. The study implied that the variables reported to be favourable for biodiversity, and possible to investigate within the restrictions of this study, seemed to have increased. The results should however be interpreted with care since the study is small and the reference values sometimes were missing or covering larger areas than the field data.

Plant-pollinator networks have shown to be highly dynamic systems as species and interactions change in time and space. Few studies have incorporated several habitats in their network. In this work I investigate interacting plant and pollinator communities of three adjacent habitats at Gotska Sandön, an island in the Baltic Sea. The networks varied in size between the habitats, and the larger networks of the dune and meadow displayed both nested and modular structure while the smaller forest network was more randomly organised. We found species present in more than one habitat that connected the networks by forming inter-habitat modules of tightly linked species. Species took on different topological roles in the networks depending on how many links they formed and where these attached. The habitat generalists were important to overall network structure as role correlated with habitat generalisation level.

Modern methods for managing pine (Pinus sylvestris) create homogenized forests. This decreases nature’s potential for biodiversity and might threaten species in need of different types of milieu. The main purpose of this study was to investigate how important older pine trees are for biodiversity. In the Hall-Hangvar Reserve in the north-west part of Gotland, insects collected from traps showed that more species were found in old or dead trees compared to younger pine trees. A statistically significant difference was found for Coleoptera (beetles). The taxons of greatest interest for this study were Coleoptera and Hymenoptera (wasps). Certain families of Hymenoptera use ducts made by larvae from some families of Coleoptera.These larvae also serve as prey. Relevance concerning enviromental importance to species and diffrenences in inhabiting the three stages of pine trees was of importance.

<p>A tool for management and conservation of valuable forests in Sweden are WKH:s. In this study WKH:s different in size, connectivity, amount of dead wood and quality of logs were investigated for species richness of bryophytes and brackets on coniferous logs. The aim was to clarify which scales and features that was important for the diversity of species as well as for individual species. The results showed that the amount of dead wood was most important on the site scale, and some species were affected at the landscape scale, a positive effect of valuable tracts. On the scale of individual logs, factors such as diameter, sun exposure, succession stage, contact with ground and ground bryophytes cover was most important. Red-listed species preferred logs with large diameter and late successional stages. The conclusion was that the quality of the substrate and the amount of dead wood was most important, but the amount of WKH:s on the landscape scale was also important for some species.</p>

A prey animal can use different strategies to avoid becoming eaten by predators. One such widely recognised strategy is the use of body colouration to decrease the risk of becoming detected, i.e. cryptic colouration. The principles of crypsis that I have studied are background matching, disruptive colouration and distractive markings. Further, I also studied the concealing effect of the visual background habitats. I used artificial prey items and backgrounds, and blue tits (Cyanistes caeruleus) as predators, to investigate prey concealment. In Paper I, I tested if high-contrast markings in prey coloration or in the background would result in a distracting effect. I found that such markings did increase prey search time, even when the prey markings were lighter or darker than the background. In Paper II, I studied the use of chromatic cues by predators when searching for prey. The birds easily detected prey that chromatically deviated from its background. Interestingly, background-matching prey was more difficult to detect when the colour scheme had low ultraviolet and high shortwave reflectance compared to when the reflectance bands were even. In Paper III, I studied optimisation of achromatic contrast within prey colour pattern and also the effect of shape diversity of background pattern elements on prey detection. I found that all prey types were more difficult to detect on the diverse background, but the level of contrast within prey pattern did not influence search times. In Paper IV, I further investigated how a prey should optimise its patterning with respect to background matching. I found that prey with repeated pattern elements was equally hard to detect as prey with more variable pattern. However, prey with a spatially regular pattern (aligned pattern elements) was easier to detect than prey with a spatially irregular pattern. In this paper I also found that high complexity of element shapes in the background, made the search task more difficult. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Manuscript. Paper 2: Accepted