Mängden död ved i brukade skogar har minskat med ungefär 90 %jämfört med naturliga skogar. Vid slutavverkning minskar mängden ytterligare. Att lämna naturhänsyn vid avverkning är ett viktigt steg för att bevara biologisk mångfald i skogslandskapet. Denna studie undersöker om naturhänsyn tas bort efter slutavverkning. På 63 % av de inventerade lokalerna hade naturhänsyn tagits bort, mestadels vindfälld tall. Det medförde en genomsnittlig minskning av mängden död ved med 2,0 m3 ha-1, vilket är en tredjedel av den totala volymen död ved lämnad vid slutavverkning. En enkät skickades till privata skogsägare. Den främsta orsaken till att man tagit bort träd var relaterade till ekonomi och produktion. Hur ekonomiskt beroende skogsägaren var av sin skog eller om man certifierat sin skog eller inte hade dock ingen betydelse för hur man hanterade naturhänsynen efter slutavverkning. Det berodde snarare på skogsägarnas attityd till produktion kontra bevarandet av biologisk mångfald. Skogsägare som tagit bort hänsynsträd var överlag mer tveksamma till att lämna olika former av naturhänsyn vid slutavverkning. Denna studie utvärderar även mängd och kvalitet på naturhänsyn lämnad efter slutavverkning i Östergötland.

Nutrient enrichment is the main cause of the increasing eutrophication process in the Baltic Sea during last century. A prerequisite counteract this process the load of nutrients to the Sea must be investigated. The large contribution of nutrients to the Sea is caused by emission from the rivers within the drainage basin. For the total emission of nutrient into the Sea the retention process in the rivers has big influence. This process in the river system has been assumed as a not important part of the nutrient cycle. However some investigators have pointed out that the retention process occurs in the river and be an important part of the nutrient dynamics in the river. For the object of investigation the Odra River Basin was chosen, as an example of a large river basin in the Baltic Sea Drainage Basin. The Odra River is mainly localized in Poland and contributes substantially to the eutrophication of the Baltic Proper. The Odra River is one of the least dammed major rivers of the Baltic Proper and as such of especial interest in retention studies. The phosphorus was chosen as an example of nutrient in the eutrophication process. The purpose of the investigation is to determine the phosphorus retention within the river. Two different models were used to calculate the retention process in the river. The"Multiple Regression Model"turned out to be insignificant, therefore the results were computed by using a “similarity model”, based on similarities between load from monitored tributary basins and the rest of the sub-basin. The retention in the Odra River in the amounted to -4608 t yr-1, which is 43% of the total phosphorus emission to the Odra River. There is also stated that in the Notec and the Warta rivers the retention process occur in the amount of -1940 t yr-1 and -3007 t yr-1 respectively.

Sedan 1992 har Jönköpings kommun drivit en naturskola i form av en exkursionsbuss, ekobussen. Verksamheten har varit inriktad mot dagsexkursioner för grundskolans senare år och gymnasieskolan under ledning av utbildad och engagerad personal. Genom åren har, i dialog med kommunens undervisande lärare, en pedagogisk modell för praktisk ekologiundervisning etablerats, där jämförande undersökningar av olika biotoper har utgjort tyngdpunkten. Man har använt ett undersökande och elevaktivt arbetssätt. Bussens utrustning har kunnat användas för avancerade mätningar och examination av djur och växter men tillhandahåller även personlig utrustning som stövlar och regnkläder. Det innebär stor flexibilitet i verksamheten. I föreliggande studie berörs hur ett upplevelsebaserat lärande kan främja ett ökat miljömedvetande. I sex gymnasieklasser har undersökts i vilken mån uppfattningarna om den pedagogiska modellen förenas hos deltagarna. Vidare har undersökts hur exkursionen integreras i övrig undervisning i ekologi- och miljöundervisningen på skolorna. Slutligen besvaras frågan hur detta uppfattats av eleverna. Studien har både kvantitativa inslag i form av enkäter till cirka deltagande 150 elever, före och efter exkursion, och kvalitativa delar som innefattar deltagande observation under sex exkursioner, intervjuer med de sju lärare och även med initiativtagaren och den ansvarige för ekobussen. Undersökningen har huvudsakligen genomförts under maj månad år 2004. Resultaten visar att verksamheten är mycket efterfrågad, både av lärare och av elever. Eleverna är i stort väl förberedda både teoretiskt och praktiskt och att upplevelserna under dagen används i efterarbetet. Hårt bokningstryck ger dock praktiska problem att inordna exkursionen i ordinarie undervisning. Exkursionsledaren kör bussen men styr också den pedagogiska verksamheten. Det finns en dynamik i processen att välja arbetsformer och parera för händelser under dagen. Det har över tid skett en förskjutning av fokus från kvantifiering av data till mera upplevelsebaserade erfarenheter. En tendens till passiv elevroll finnsi vissa situationer, när klassen lyssnar till exkursionsledarens genomgångar. Under praktiska arbetspass sker redovisningar genom att gruppen samtalar om resultaten, även om de flesta elever också får skriva en formell rapport i efterhand. Det finns en stark ambition att vara en utomhuspedagogisk modell för skolorna. Man förefaller också lyckas vara den impuls till pedagogisk utveckling av arbetsformerna som styrdokumenten för skolan uppmuntrar till. Genom sin breda kontakt med kommunens lärare påverkar ekobussens pedagogiska modell ekologi- och miljöundervisningen på ett positivt sätt. Detta kan därmed vara ett värdefullt bidrag till ett ökat miljömedvetande.

<p>In Ethiopia industrial effluents containing high contents of organic matter, nitrogen and heavy metals are discharged into inland surface waters with little or no pre-treatment. Significant pollution concerns related to these effluents include dissolved oxygen depletion, toxicity and eutrophication of the receiving waters. This has not only forced the government to formulate regulations and standards for discharge limits but also resulted in an increasing interest and development of methods and systems by which wastewater can be recycled and used sustainably. The need for technologies for environmentally friendly treatment of industrial wastes such as tannery wastewaters is therefore obvious. Biological processes are not only cost effective but also environmentally sound alternatives to the chemical treatment of tannery wastewaters.</p><p>The aim of the research presented in this thesis was to develop and optimize processes for biological nitrogen removal from tannery wastewaters and to identify the most efficient denitrifying organisms in tannery wastewaters laden with toxic substances. A pilot plant consisting of a predenitrification anoxic system, aerated nitrification compartment and a sedimentation tank (clarifier) all arranged in series was developed and installed on the premises of Addis Ababa University, Ethiopia. In spite of high influent chromium and sulphide perturbations over the successive feeding phases, the performance of the pilot plant was encouraging. The overall removal efficiency of the pilot plant over the experimental feeding phases varied between 82-98% for total nitrogen, 95-98% for COD, 96-98% for BOD5, 46-95% for ammonia nitrogen, 95-99% for sulphide and 93-99% for trivalent Chromium. Six isolates from over 1000 pure cultures were identified as the most efficient denitrifying bacteria. From both cellular fatty acid profiles and 16S rRNA gene sequencing, the six selected strains were phylogenetically identified as Brachymonas denitrificans in the β-subdivision of the Proteobacteria. All the six strains contain cd1-type nitrite reductase. The efficient isolates characterized in this study are of great value because of their excellent denitrifying properties and high tolerance to the concentrations of toxic compounds prevailing in tannery wastewaters. Bio-augmentation of the pilot plant with this bacterium showed a clear correlation between in situ denitrifying activities measured by nitrate uptake rate, population dynamics of the introduced B.denitrificans monitored by fluorescent in situ hybridization and the pilot plant performance, suggesting that the strategy of introducing this species for enhancing process performance has potential applications.</p><p>Moreover, the nitrate-reducing, sulphur-oxidizing bacteria (NR-SOB) were also found in the pilot plant in abundance with steady sulphide removal efficiency during the study period. This could provide opportunities for the application of biologically mediated simultaneous removal of sulphide and nitrogen from tannery effluents. In addition to enriching high consortia of denitrifiers in the anoxic system to attain high denitrification efficiency and also improving the overall nitrification efficiency of the system, the predenitrification-nitrification pilot process plant stimulated the activity of indigenous NR-SOB to simultaneously remove sulphide from the system. Thus, the pilot plant was found to be operationally efficient for the removal of nitrogen, organic matter and other pollutants from tannery wastewaters.</p><p><b>Keywords:</b> Biological nitrogen and sulphide removal, denitrifying bacteria, nitrate-reducing, sulphur-oxidizing bacteria, nitrate uptake rate, fluorescent in situ hybridization, pollution, tannery effluents.</p>

Benthic diatoms are valuable tools for biological monitoring and paleo-ecological reconstruction of past environmental conditions. This thesis aims at describing size-related properties of benthic diatoms and suggests that data assessment for community analysis can be improved by considering the importance of scale. It investigates which environmental factors structure epilithic diatom communities on the coast of the Gulf of Bothnia and identifies environmental factors correlated with phytobenthic biomass. It also contributes to the floristic knowledge of the Baltic Sea. Diatom species show large variation in size. The responses of large species (≥1000 μm3) in diatom communities to environmental factors are underestimated if solely measured as relative abundance, as is the common practice. However, relative abundance gives the best gradient resolution, as compared to surface area and biovolume, if species are counted separately in two biovolume classes. Small and large species in the same community may respond differently to the same environmental factors. To assess the principal environmental factors structuring diatom communities in the Gulf of Bothnia, 270 quantitative samples were collected from submerged stones. Sampling was carried out in spring in four areas of the Bothnian Bay, characterized by a stable north-south salinity gradient (0.4-3.3 psu), and in three areas of the Bothnian Sea which has a rather uniform salinity of ca. 5 psu. Canonical correspondence analysis (CCA) identified salinity and exposure to wave action as the principal factors structuring the diatom communities of the Bothnian Bay, whereas exposure to wave action was the principal factor in the Bothnian Sea. Measurements of relative ignition loss suggested that the cover of macroalgae, and thereby the higher abundance of epiphytic diatoms in the epilithic samples, was positively correlated with salinity in the Bothnian Bay and with water movement in the Bothnian Sea. Two new brackish water species are described, Navicula sjoersii S. Busse &amp; Snoeijs and N. bossvikensis S. Busse &amp; Snoeijs. The new species are compared with N. perminuta Grunow, a common brackish-water species.

The work in this thesis deals with (1) the effects of woody debris on stream channel morphology and retention of organic material, and (2) the dynamics of woody debris and its relation to riparian forest history and composition. The studied stream reaches are situated in mature, productive forests in the boreal zone of Sweden. Wood variables were important predictors of the frequency of debris dams, pool area, the proportion of pools formed by wood, and variation in the bankfull channel width. Pools formed by woody debris were mainly created by damming and had larger surface areas and residual depths than pools formed by other agents. Stream reaches intersecting old-growth forest (with minor influence of forest management) had coarser and longer woody debris pieces, greater amounts of wood, more debris dams, and wood-formed pools compared to streams surrounded by forests influenced by selective logging. The influence of past forest management on the quality and quantity of woody debris in streams were analyzed by using dendrochrnological methods. Selective loggings and absence of forest fires after 1831 resulted in lower input rates and a gradual replacement of pine by sruce over time. Residence times in stream channels of woody debris (&gt;10 cm in basal diameter) were long and the oldest dated pieces of pine and spruce were over 300 and 100 years, respectively. Dynamics of woody debris were explored by comparing wood volumes and characteristics between stream channels and their riparianforests and between old growth and managed sites. Wood volumes recorded in the stream channels exceeded, but were related to, the volumes found in the riparian forests. Limited input of woody debris by bank cutting and absence of slope processes suggest that recruitment processes of woody debri to stream channels are similar as in riparian forests and slow decay in channels results in greater volumes. The retentiveness of organic material in stream channels was examined by using release and capture experiments in multiple reaces during varying discharges using different sizes of leaf mimics. Sixty eight percent of the variation in retention was explained by a multiple regression model including discharge and leaf mimic siz. Between 44 and 80% of the variation in retention among reaches was explained by channel constraint, gravel coverage, and woody debris variables as the most important. Estimates from a partial least squares (PLS) model suggest an increase in mean transport distances by 22 to 53% in managed forest streams compared to old growth conditions and in a low wood scenario, mean transport distances increased by 38 to 99% with larger increases for higher discharges and larger particle sizes. To regain more pristine conditions of stream channels, management and restoration are needed to increase the amount of woody debris that recreates lost channel structures and increaes the retention of organic material.

<p>The purpose of this thesis is to analyse interactions between freshwater flows, terrestrial ecosystems and human well-being. Freshwater management and policy has mainly focused on the liquid water part (surface and ground water run off) of the hydrological cycle including aquatic ecosystems. Although of great significance, this thesis shows that such a focus will not be sufficient for coping with freshwater related social-ecological vulnerability. The thesis illustrates that the terrestrial component of the hydrological cycle, reflected in vapour flows (or evapotranspiration), serves multiple functions in the human life-support system. A broader understanding of the interactions between terrestrial systems and freshwater flows is particularly important in light of present widespread land cover change in terrestrial ecosystems. </p><p>The water vapour flows from continental ecosystems were quantified at a global scale in Paper I of the thesis. It was estimated that in order to sustain the majority of global terrestrial ecosystem services on which humanity depends, an annual water vapour flow of 63 000 km3/yr is needed, including 6800 km3/yr for crop production. In comparison, the annual human withdrawal of liquid water amounts to roughly 4000 km3/yr. A potential conflict between freshwater for future food production and for terrestrial ecosystem services was identified. </p><p>Human redistribution of water vapour flows as a consequence of long-term land cover change was addressed at both continental (Australia) (Paper II) and global scales (Paper III). It was estimated that the annual vapour flow had decreased by 10% in Australia during the last 200 years. This is due to a decrease in woody vegetation for agricultural production. The reduction in vapour flows has caused severe problems with salinity of soils and rivers. The human-induced alteration of vapour flows was estimated at more than 15 times the volume of human-induced change in liquid water (Paper II). </p>

<p>The thesis analyses relationships between ecological and social systems in the context of coastal ecosystems. It examines human impacts from resource extraction and addresses management and governance behind resource exploitation. The main premises are that a lack of ecological knowledge leads to poor ecosystem management and that the dichotomy between social and natural systems is an artificial one. The thesis illustrates the importance of basing resource management on the ecological conditions of the resource and its ecosystem. It also demonstrates the necessity of accounting for the human dimension in ecosystem management and the challenges of organising human actions for sustainable use of ecosystem services in the face of economic incentives that push users towards short-term extraction.</p><p>Many Caribbean coral reefs have undergone a shift from coral to macroalgal domination. An experiment on Glovers Reef Atoll in Belize manually cleared patch reefs in a no-take zone and a fished zone (Papers I and II). The study hypothesised that overfishing has reduced herbivorous fish populations that control macroalgae growth. Overall, management had no significant effect on fish abundance and the impacts of the algal reduction were short-lived. This illustrated that the benefits of setting aside marine reserves in impacted environments should not be taken for granted. </p><p>Papers III and IV studied the development of the lobster and conch fisheries in Belize, and the shrimp farming industry in Thailand respectively. These studies found that environmental feedback can be masked to give the impression of resource abundance through sequential exploitation. In both cases inadequate property rights contributed to this unsustainable resource use. </p><p>The final paper (V) compared the responses to changes in the resource by the lobster fisheries in Belize and Maine in terms of institutions, organisations and their role in management. In contrast to Maine’s, the Belize system seems to lack social mechanisms for responding effectively to environmental feedback. The results illustrate the importance of organisational and institutional diversity that incorporate ecological knowledge, respond to ecosystem feedback and provide a social context for learning from and adapting to change.</p>

<p>Modern food production is a complex, globalized system in which what we eat and how it is produced are increasingly disconnected. This thesis examines some of the ways in which global trade has changed the mix of inputs to food and feed, and how this affects food security and our perceptions of sustainability. One useful indicator of the ecological impact of trade in food and feed products is the Appropriated Ecosystem Areas (ArEAs), which estimates the terrestrial and aquatic areas needed to produce all the inputs to particular products.</p><p>The method is introduced in Paper I and used to calculate and track changes in imported subsidies to Swedish agriculture over the period 1962-1994. In 1994, Swedish consumers needed agricultural areas outside their national borders to satisfy more than a third of their food consumption needs. The method is then applied to Swedish meat production in Paper II to show that the term “Made in Sweden” is often a misnomer. In 1999, almost 80% of manufactured feed for Swedish pigs, cattle and chickens was dependent on imported inputs, mainly from Europe, Southeast Asia and South America. Paper III examines ecosystem subsidies to intensive aquaculture in two nations: shrimp production in Thailand and salmon production in Norway. In both countries, aquaculture was shown to rely increasingly on imported subsidies. The rapid expansion of aquaculture turned these countries from fishmeal net exporters to fishmeal net importers, increasingly using inputs from the Southeastern Pacific Ocean.</p><p>As the examined agricultural and aquacultural production systems became globalized, levels of dependence on other nations’ ecosystems, the number of external supply sources, and the distance to these sources steadily increased. Dependence on other nations is not problematic, as long as we are able to acknowledge these links and sustainably manage resources both at home and abroad. However, ecosystem subsidies are seldom recognized or made explicit in national policy or economic accounts. Economic systems are generally not designed to receive feedbacks when the status of remote ecosystems changes, much less to respond in an ecologically sensitive manner. Papers IV and V discuss the problem of “masking” of the true environmental costs of production for trade. One of our conclusions is that, while the ArEAs approach is a useful tool for illuminating environmentally-based subsidies in the policy arena, it does not reflect all of the costs. Current agricultural and aquacultural production methods have generated substantial increases in production levels, but if policy continues to support the focus on yield and production increases alone, taking the work of ecosystems for granted, vulnerability can result. Thus, a challenge is to develop a set of complementary tools that can be used in economic accounting at national and international scales that address ecosystem support and performance.</p><p>We conclude that future resilience in food production systems will require more explicit links between consumers and the work of supporting ecosystems, locally and in other regions of the world, and that food security planning will require active management of the capacity of all involved ecosystems to sustain food production.</p>

<p>Conservatism is a central theme of organismic evolution. Related species share characteristics due to their common ancestry. Some concern have been raised among evolutionary biologists, whether such conservatism is an expression of natural selection or of a constrained ability to adapt.</p><p>This thesis explores adaptations and constraints within the plant reproductive phase, particularly in relation to the evolution of fleshy fruit types (berries, drupes, etc.) and the seasonal timing of flowering and fruiting. The different studies were arranged along a hierarchy of scale, with general data sets sampled among seed plants at the global scale, through more specific analyses of character evolution within the genus <i>Rhamnus </i>s.l. L. (Rhamnaceae), to descriptive and experimental field studies in a local population of <i>Frangula alnus</i> (Rhamnaceae). Apart from the field study, this thesis is mainly based on comparative methods explicitly incorporating phylogenetic relationships. The comparative study of <i>Rhamnus</i> s.l. species included the reconstruction of phylogenetic hypotheses based on DNA sequences.</p><p>Among geographically overlapping sister clades, biotic pollination was not correlated with higher species richness when compared to wind pollinated plants. Among woody plants, clades characterized by fleshy fruit types were more species rich than their dry-fruited sister clades, suggesting that the fleshy fruit is a key innovation in woody habitats. Moreover, evolution of fleshy fruits was correlated with a change to more closed (darker) habitats.</p><p>An independent contrast study within <i>Rhamnus</i> s.l. documented allometric relations between plant and fruit size. As a phylogenetic constraint, allometric effects must be considered weak or non-existent, though, as they did not prevail among different subclades within <i>Rhamnus</i> s.l. Fruit size was correlated with seed size and seed number in <i>F. alnus</i>. This thesis suggests that frugivore selection on fleshy fruit may be important by constraining the upper limits of fruit size, when a plant lineage is colonizing (darker) habitats where larger seed size is adaptive.</p><p>Phenological correlations with fruit set, dispersal, and seed size in <i>F. alnus</i>, suggested that the evolution of reproductive phenology is constrained by trade-offs and partial interdependences between flowering, fruiting, dispersal, and recruitment phases. Phylogenetic constraints on the evolution of phenology were indicated by a lack of correlation between flowering time and seasonal length within <i>Rhamnus cathartica</i> and <i>F. alnus</i>, respectively. On the other hand, flowering time was correlated with seasonal length among <i>Rhamnus</i> s.l. species. Phenological differences between biotically and wind pollinated angiosperms also suggested adaptive change in reproductive phenology.</p> / <p>Äpplet faller inte långt från trädet. Men varför? Den biologiska mångfalden präglas i stor utsträckning av fylogenetiskt bevarade karaktärsdrag; närbesläktade arter är lika. Det pågår en diskussion bland evolutionsbiologer om i vilken utsträckning denna konservatism är ett resultat av naturlig selektion eller av en begränsad anpassningsförmåga.</p><p>Denna avhandling diskuterar begreppet evolutionära begränsningar i relation till den reproduktiva fasen hos växter. I fokus ligger särskilt evolutionen av bärliknande (endozoochora) frukter respektive evolutionen av säsongsmässiga mönster (fenologi) för blomning och fruktsättning. Avhandlingen är hierarkiskt organiserad så att olika delstudier gjordes på olika skalnivåer: fenologi- och fruktevolution analyserades för fröväxter respektive gömfröiga växter; inom brakvedssläktena Rhamnus och Frangula (Rhamnaceae); samt för en lokal population av brakved (Frangula alnus). Populationsstudien baserades på såväl experimentella som deskriptiva data, medan övriga studier i huvudsak genomfördes med fylogenetisk komparativ metodik baserade på litteraturdata. Som en del av de komparativa studierna rekonstruerades fylogenetiska hypoteser för Rhamnus s.l. utifrån DNA-sekvenser (ITS, trnL-F), vilka gav stöd för att Frangula och Rhamnus är monofyletiska systersläkten.</p><p>I en biogeografiskt kontrollerad fylogenetisk kontrastanalys upptäcktes inga skillnader i artrikedom mellan djur- och vindpollinerade växter. Bärliknande frukter verkar dock vara en betydelsefull karaktär (key innovation) i skogsmiljöer. För det första var fylogenetiska klader med bärliknande frukter mer artrika än systerklader med torra frukter. Dessutom var uppkomster av bärliknande frukt korrelerad till habitat med mer sluten vegetation.</p><p>En fylogenetisk kontrastanalys av allometriska effekter visade på en positiv korrelation mellan växtindividens och fruktens storlek inom Rhamnus s.l. Upprepade analyser av dessa allometriska samband i olika monofyletiska subklader inom Rhamnus s.l. indikerar dock att allometri, såsom evolutionär begränsning, är svag. I populationsstudien av F. alnus var fruktstorlek positivt korrelerad till såväl fröantal som frövikt. En generell hypotes utifrån denna avhandling blir därför att frugivorer (de djur som äter bären och därmed sprider växtens frön) utövar ett starkt selektionstryck på växter som koloniserar ett habitat där fröstorlek är adaptivt, eftersom fruktstorlek påverkar frugivorernas (ssk. fåglars) sätt att hantera frukten.</p><p>Reproduktiv fenologi var korrelerad till fruktsättning, fröspridning och fröstorlek hos F. alnus. Detta stödjer tanken att evolutionen av blomnings- och fruktsättningstider begränsas av avvägningar (trade-offs) och partiella beroenden mellan blomning-, fruktsättnings-, spridnings och rekryteringsfaserna. Inomartsvariation i blomningstid för F. alnus respektive getapel (Rhamnus cathartica) över en nordeuropeisk latitudinell transekt var inte korrelerad till säsongslängd, vilket antyder att utvecklingen av blomningstider är evolutionärt begränsad. Å andra sidan påvisades en sådan korrelation mellan blomningstid och säsongslängd i en mellanartsstudie inom Rhamnus s.l. Den fylogenetiska kontrastanalysen mellan djur- och vindpollinerade växter visade också på adaptiva skillnader i fenologi. Blomningstiderna inom en klad med biotiskt pollinerade arter var mer åtskilda än inom den vindpollinerade systerkladen, och den välkända iakttagelsen att vindpollinerade träd blommor tidigare på säsongen fick även stöd i ett fylogenetiskt komparativt perspektiv.</p>