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.

The addition of dams into a riverine system causes a wide range of changes (i.e., sedimentation, erosion, thermal) to the river as well as to the fish assemblages of that river. Although there have been many studies documenting the changes that occur to the fish assemblages in the impounded river, there have been fewer studies examining the effects of a reservoir on the fish inhabiting the tributaries upstream of the impoundment. One possible impact of a reservoir could be to act as a barrier to fish migration between streams. To determine if reservoirs restrict migration, the genetic diversity of two species of darter, the rainbow darter Etheostoma caeruleum Storer and the Highland Rim darter Etheostoma kantuckeense Ceas and Page, was determined from populations inhabiting the Barren River Lake drainage basin. Between ten and twenty-six individuals of each species were collected from each of 6 sites. Three streams were directly connected to Barren River Lake and three streams were directly connected to Barren River upstream of the reservoir. Allelic variation at 3 microsatellite loci was analyzed to determine the degree to which each population is isolated. If the reservoir is restricting gene flow between populations, the populations in streams adjacent to Barren River Lake would be predicted to have lower allele diversity and heterozygosity than those adjacent to the Barren River. Consistently high levels of allelic diversity (total number of alleles, N), observed heterozygosity (Ho), and effective number of alleles (Ae) across both reservoir and river study sites led to the rejection of the hypothesis that the reservoir is acting as a genetic barrier to darters. M-ratios differed between species, with Etheostoma caeruleum exhibiting consistently higher M--ratios than Etheostoma kantuckeense. The low M- seen in E. kantuckeense could be due to small sample sizes (largest sample for this species showed the highest M-), and could also be due to small natural populations. With the exception of Salt Lick Creek, high allelic diversity was observed at most sites for E. kantuckeense. A low M- coupled with high allelic diversity in most E. kantuckeense populations, may indicate that all of the study populations are recovering from a bottleneck event. These results indicate Etheostoma kantuckeense is sensitive to changes in the environment. When conservation agencies assess fish populations in South Central Kentucky, it is advantageous to know which species are currently at risk, which species are sensitive to environmental changes, and which species or populations are recovering from events that were detrimental to their genetic diversity.

Loricariidae is a very diverse family of catfishes found primarily in the Amazon River basin. These catfishes have a unique characteristic feature of having fenestrae (holes) in the skull region (compound pterotic bone) adjacent to their bi-lobed swim bladder. Since the swim bladders and the compound pterotic may act as an external ear for hearing in this taxon, I hypothesized that these swim bladders structures have an acoustical functional in the loricariid Otocinclus affinis. In order to understand the development of these structures in O. affinis, I first monitored the ontogeny of the compound pterotic bone by clearing and staining of fish ranging total length from 0.75 to 3.5 cm. the swim bladders and fenestrated compound pterotic bone were developed at early larval stages (by 5.25 mm TL). Second I examined the role of swim bladders in hearing in adult O. affinis, by testing the hearing sensitivity before and after swim bladder deflation. Hearing thresholds were determined electrophysiologically by recording auditory evoked potentials (AEP). Swim bladder deflation increased hearing thresholds by 19 – 23 decibels (dB). I then tested the role of the compound pterotic bone fenestrae in hearing by covering them with a tissue adhesive (n-butyl cyanoacrylate) and recording the hearing thresholds. Covering fenestrae increased hearing thresholds by 4 – 11 dB. Future experiments are required to more precisely determine the acoustical role of these peripheral auditory structures in O. affinis.

Successful stock enhancement of hatchery-reared fish depends heavily on the release of individuals able to demonstrate strong survival skills. Overall survival of fishes is a reflection of a successful blend of physiology, anatomy, and behavior. With fishes being highly phenotypically plastic, the potential exists for all aspects of hatcheryreared fish to vary significantly from their wild counterparts while having potentially adverse effects on their survival after release. Previous analyses have demonstrated significant differences between the feeding behavior of hatchery-reared and wild caught largemouth bass (Micropterus floridanus) in the laboratory, as well as differences in the development of the skull between these two groups. The aim of this study was to determine if oral and pharyngeal jaw dentition differed between hatchery and wild bass. Scanning electron micrographs of the oral and pharyngeal jaws from an overlapping size range of 30 hatchery-reared and 30 wild bass were compared for the number and characteristics of oral and pharyngeal teeth. Wild bass were found to have features which would presumably allow more efficient capture of prey. The results of the study suggested that wild bass exhibited greater number of teeth when compared to hatchery reared bass. They also exhibited oral and pharyngeal teeth which were greater in length, and pharyngeal teeth that were greater in width when compared to hatchery-reared bass. This deficiency in dentition could have a significant effect on prey-capture success when introduced into the wild. We suggest that exposure to wild prey during the grow-out phase of aquaculture could provide the necessary adaptive plasticity of hatchery-reared bass dentition

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.

Våtmarker som anläggs på jordbruksmark kan förhindra att fosfor från åkrarna når sjöar och vattendrag och hjälper därmed till att minska övergödningen. Det är viktigt att utforma våt-marken på ett sådant sätt att så mycket som möjligt av den biotillgängliga fosforn hålls kvar. Syftet med studien var att undersöka om det finns ett positivt samband mellan lerinnehåll och fosfors biotillgänglighet i en anlagd våtmarks sediment. Syftet var även att undersöka om partikelstorleken minskar gradvis med avståndet från inloppet, det vill säga om mer lera sedimenterar närmare utloppet. Prover togs längs tre transekter från sedimentet i en våtmark i västra Östergötland och fosfor- samt partikelstorleksanalyser gjordes. Genom extraktion med ammoniumklorid (NH4Cl) kunde lättillgänglig fosfor bestämmas. Partikelstorleksanalysen gjordes med en modifierad pipettmetod, baserad på att större partiklar sedimenterar fortare än mindre partiklar. Regressionsanalys visade att partikelstorleken minskade signifikant från inlopp till utlopp i våtmarken. Däremot hittades inte några signifikanta samband mellan partikelstorlek och lättillgänglig fosfor eller totalfosfor, i motsats till resultat i andra studier. Halterna av både lera och olika fosforfraktioner i sedimentet var relativt låga och likartade vid olika provpunkter i våtmarken vilket kan ha påverkat resultaten.

This thesis research consists of two separate studies. The first study presents the assessment and representation of the effects of soil macropores on the soil hydraulic properties in land surface models for more accurate simulations of soil moisture and surface hydrology. Hydraulic properties determine the soil water content and its transport in the soil. They are provided in most current climate models as empirical formulas by functions of the soil texture. Such is not realistic if the soil contains a substantial amount of macropores. A two-mode soil pore size distribution is incorporated into a land surface model and tested using an observational dataset at a tropical forest site with aggregated soils. The result showed that the existence of macropores greatly affects the estimation of hydraulic properties. Their influence can be included in land models by adding a second function to the pore-size distribution. A practical hydraulic scheme with macropore considerations was proposed given that the existing schemes are not applicable for large-scale simulations. The developed scheme was based on the physical attributes of the water in soil capillary pores and the statistics of several global soil databases. The preliminary test showed that it captures part of soil macropore hydraulic features without sacrificing the estimation accuracy of hydraulic properties of water in soil matrix. The second study presents the development of an integrated land/ecosystem model by combining the advanced features of a biophysically based land model, the Community Land Model, and an ecosystem biochemical model. The results from tests of the integrated model at four forest sites showed that the model reasonably captures the seasonal and interannual dynamics of leaf area index and leaf nitrogen control on carbon assimilation across different environments. With being coupled to an atmospheric general circulation model (AGCM), the integrated model showed a strong ability to simulate terrestrial ecosystem carbon fluxes together with heat and water fluxes. Its simulated land surface physical variables are reasonable in both geographic distribution and temporal variation with considering the interactive vegetation parameters.

This thesis consists of two parts. Part one includes the design procedure and implementation of the building blocks for an RF tuner module used in the Digital Video Broadcasting ¡V Terrestrial ¡]DVB-T¡^system. It contains the comparison of several RF tuner architectures, frequency planning, and link-budget analysis. Measurement results for the designed tuner operating in the frequency range from 50 to 860 MHz show that the maximum power gain ranges from 49 to 57.6 dB. The entire range for gain control is over 60 dB. In the maximum gain state, the noise figure ranges form 6.8 to 11.5 dB, the output third-order interception point¡]OIP3¡^ranges from 11.7 to 13.8 dBm, and the image rejection is over 50 dB. By applying the simplified single-carrier modulation signals, the tuner can pass the DVB-T system specifications with respect to the adjacent-channel and overlapping-channel protection ratios. In part two, an RFIC design for low-noise variable-gain amplifier that can be used in the RF front end of DVB-T system is presented. It operates from 100 to 900 MHz and dissipates 59.4 mW under a 3.3-V power supply. In the maximum gain state, measurement results for this RFIC show that the noise figure is less than 4 dB, the maximum gain is more than 14 dB, and the OIP3 is about 6.8dBm. The entire gain control range is over 40 dB.