In response to the “Leave No One Behind” principle (the central promise of the 2030 Agenda for Sustainable Development), reliable estimate of the total number of citizens living in slums is urgently needed but not available for some of the most vulnerable communities. Not having a reliable estimate of the number of poor urban dwellers limits evidence-based decision-making for proper resource allocation in the fight against urban inequalities. From a geographical perspective, urban population distribution maps in many low- and middle-income cities are most often derived from outdated or unreliable census data disaggregated by coarse administrative units. Moreover, slum populations are presented as aggregated within bigger administrative areas, leading to a large diffuse in the estimates. Existing global and open population databases provide homogeneously disaggregated information (i.e. in a spatial grid), but they mostly rely on census data to generate their estimates, so they do not provide additional information on the slum population. While a few studies have focused on bottom-up geospatial models for slum population mapping using survey data, geospatial covariates, and earth observation imagery, there is still a significant gap in methodological approaches for producing precise estimates within slums. To address this issue, we designed a pilot experiment to explore new avenues. We conducted this study in the slums of Nairobi, where we collected in situ data together with slum dwellers using a novel data collection protocol. Our results show that the combination of satellite imagery with in situ data collected by citizen science paves the way for generalisable, gridded estimates of slum populations. Furthermore, we find that the urban physiognomy of slums and population distribution patterns are related, which allows for highlighting the diversity of such patterns using earth observation within and between slums of the same city. 

Due to its hemizygous inheritance and role in sex determination, the X-chromosome is expected to play an important role in the evolution of sexual dimorphism and to be enriched for sexually antagonistic genetic variation. By forcing the X-chromosome to only be expressed in males over >40 generations, we changed the selection pressures on the X to become similar to those experienced by the Y. This releases the X from any constraints arising from selection in females and should lead to specialization for male fitness, which could occur either via direct effects of X-linked loci or trans-regulation of autosomal loci by the X. We found evidence of masculinization via up-regulation of male-benefit sexually antagonistic genes and down-regulation of X-linked female-benefit genes. Potential artefacts of the experimental evolution protocol are discussed and cannot be wholly discounted, leading to several caveats. Interestingly, we could detect evidence of microevolutionary changes consistent with previously documented macroevolutionary patterns, such as changes in expression consistent with previously established patterns of sexual dimorphism, an increase in the expression of metabolic genes related to mito-nuclear conflict and evidence that dosage compensation effects can be rapidly altered. These results confirm the importance of the X in the evolution of sexual dimorphism and as a source for sexually antagonistic genetic variation and demonstrate that experimental evolution can be a fruitful method for testing theories of sex chromosome evolution.

Rising temperatures, because of climate change, will have major consequences for the world's fish populations, including the Atlantic salmon Salmo salar L. The greatest temperature changes are expected to occur during winter, which will affect S. salar since the eggs are developing during this time of year. Several studies have shown that elevated temperatures during embryogenesis cause morphological changes, in S. Salar, that are shown in later life stages. Some of these studies indicate that eggs incubated at high temperatures should generate parr with deeper bodies. To investigate whether high temperatures during the egg stage cause changes in body shape, parr from normal and high temperature incubated eggs, referred to as as “cold” and “warm” fish, respectively, were examined. A box-truss of euclidean distances between 10 landmarks on the fish body and a discriminant function analysis (DFA) was used to determine which of the distances best discriminated between the two groups. The test showed a significant discrimination between cold and warm parr regarding body shape where cold parr had greater heads and warm parr were deeper over the tail region and showed greater distances between the pelvic fin and the front attachment of the anal fin. 67,3 % of all parr where correctly classified by the test. These results support those notions that indicates that the incubation temperature is important for the morphological development of S. salar although it does not support the hypothesis.

Contorta (Pinus contorta) is a coniferous tree species from western North America that has been introduced mainly in northern Sweden. The purpose of this work was to evaluate how far and to what extent (number of self-dispersal seedlings/ha) Contorta has spread from older populations in southern Sweden. The result can be used in assessing the risk of spreading in southern Sweden. The three forest stands used for this work were located in southern Östergötland and northern Småland, Sweden. The data collection was done in three stages in each stand: 1. Assessment if contorta can be disseminated and established from stocks in southern Sweden. 2. Subjective inventory of Contorta plants in selected areas. 3. Quantitative inventory of contorta plants along defined corridors, 2 meters wide and 250 meters long, in four directions from the edge of the stock. In the inventory of subjectively selected areas, contorta plants were found 350 meters from a contorta stand and in the objective inventory 50 meters from a contorta stand. A total of 27 contorta plants (equivalent to 450 plants/ha) was found in subjectively inventory and 18 contorta plants (45 plants/ha) were found in the quantitative inventory. All Contorta seedlings were found on disturbed ground and where the canopy cover of trees was zero, i.e. where the access to light was highest. On the other hand, based on this study, it is not possible to say which factor is most important for the establishment, field disturbance or light supply.

Today, it is well known that biological diversity is decreasing worldwide, and the presence of indicator species can identify areas with high biological diversity. Environments with a high presence of indicator species are important to protect and preserve in the form of, for example, nature reserves as these environments indicate high nature values. The aim of this study is to find out whether the coniferous forest's indicator species have the greatest species density and occurrence within the boundaries of the nature reserves in Dalarna, Sweden. The distribution of 10 different indicator species within the coniferous forests of Dalarna, Sweden, was mapped in the QGIS software and the total species density inside as well as outside the nature reserves of Dalarna was compared in the statistical program SPSS. The species density of five selected indicator species was compared inside versus outside of the reserves. The result for the 10 indicator species showed that there was no significant difference between inside versus outside of the reserves, although there were a higher species density per hectare outside the boundaries of the nature reserves. The result for the five selected indicator species showed no significant difference between inside versus outside of the reserves, however, the species density of both R.subpinnatus and P.grossa were higher within the boundaries of the nature reserve. More sightings of indicator species outside the boundaries of nature reserves may indicate that the public is more inclined to report sightings in unprotected areas, rather than reporting sightings in protected areas that have already been established as having high nature values. Many species observations are found just outside the boundaries of the nature reserve, which may indicate that high nature values occur there as well. Further studies about potential buffer zones and their impact on indicator species are encouraged.

Over recent decades recreational fisheries have grown substantially throughout the world. Despite this increase, catches from recreational fisheries have often been ignored in fisheries management, although this is now being remedied. Monitoring recreational fisheries can be expensive, and the primary means used for monitoring is angler (creel) surveys, typically funded from sales of fishing licences. The studies presented in this thesis examine different approaches to monitoring recreational trolling fisheries’ catch and effort, where fishing licenses are not required and there are no reporting requirements. I present results from a complemented roving/mail-in survey undertaken during 2013-2014 to estimate recreational effort and catch of Atlantic salmon (Salmo salar) and brown trout (S. trutta) in the largest lake in the European Union, Lake Vänern, Sweden. I also evaluate different angler catch reporting methods (mail-in, tournament reports and face-to-face interviews) and compare catch rates within and among spring and fall fishing periods. In addition, mail-in survey data are examined for recall bias.

I estimate that 28.7 tonnes of salmon and trout combined were harvested by the recreational trolling fishery in 2014, more than the commercial and subsistence fisheries combined. Seasonal differences in both recreational effort and catch were observed. Effort, in boat hours, was significantly higher in spring than in fall. Catch rates of trout were higher in fall than in spring, but there were no seasonal differences in catches of salmon. Harvest per boat day did not differ significantly among catch reporting methods, indicating that all three methods could be useful for managers interested in harvest rates. In contrast, total and released catch per boat day differed among reporting methods, with tournament anglers catching more fish in total. Finally, there was little evidence for recall bias in mail-in surveys, indicating that mail-in surveys are useful for collecting unbiased catch data. My study is the most comprehensive angler survey to date for Lake Vänern, and my results should be of immediate use to local fisheries managers and should also be of interest to researchers and managers interested in estimating catch and effort for fisheries at large spatial scales.

In boreal catchments, stream water chemistry is influenced and controlled by several landscape factors. The influence of spatially distributed variables is in turn dependent on the hydrological scale. Headwater streams have larger variability of water chemistry, and thus together represent a large biodiversity, and therefore need to be monitored in official environmental assessments. One objective of this study was, using Geographical Information Systems (GIS), to analyse co-variation between landscape variables and water chemistry and to determine which of the landscape variables have a major influence on the concentration of dissolved organic carbon (DOC) in headwater streams. Another objective was to find a simple method for predicting sources of DOC, using official map data and publically available GIS applications.

Totally 85 headwater catchments (0.1-4 km²) in the county of Värmland, western south Sweden, were used in the study. Water chemistry was analysed for water sampled at low, medium and high flows, and landscape variables were extracted from official map data sources: topographic maps, a digital elevation model (DEM, 50 m grid), and vegetation data. Statistical analyses showed that topography (mean slope and mean topographic wetness index (TWI)) and wetland cover often correlated well with DOC in headwater catchments. Official map data could satisfactorily extract landscape variables (mean slope, mean TWI) that were useful in predicting stream water chemistry (DOC).

A high-resolution elevation model, which was generated by interpolation of photogrammetric data, was used to calculate and evaluate two different wetness indices and their ability to predict the occurrence of wetlands in six catchments of different sizes and topography. The SAGA (System for Automated Geoscientific Analyses) wetness index (SWI) gave substantially better results than the TWI. The effects of resolution of DEMs on calculations of the SWI were investigated using 5, 10, 25 and 50 m grids. The results showed that SWI values increased with increasing cell size. The near linear increment of mean values for resolutions 10-50 m suggests a independence of terrain type and catchment size, which supported previous findings that indicated that mean slope and mean wetness index calculated from coarse elevation models may be used for prediction of DOC in headwater streams.

The freshwater mussel family Unionoida lives a complex life with its host animals and the freshwater mussel family’s existence is threatened worldwide. One of these species, the pearl mussel (Margaritifera margaritifera), is a “responsibility species” for Scandinavia and a lot of work is ongoing to save the species. In Scandinavia there are still existing populations, but in many waters recruitment of juvenile mussels is completely lacking or insufficient. To support recruitment and also reintroduce the mussel into suitable watercourses, more knowledge about its complex life cycle and how it affects its host brown trout (Salmo trutta), is required. Attempts have been made to introduce gravid mussels or already infected trout in order to try to rejuvenate or to reintroduce mussels in some rivers. In this study, 293 trout individuals were captured from three watercourses in western Sweden with no or inadequate recruitment of juvenile pearl mussels. The brown trout were treated with mussel infection by being kept in containers with the presence of gravid mussels and compared to a control group where no mussels were present. Growth, condition factor and habitat selection were investigated and checked after treatment by scanning the trout with a mobile scanner and recaptured for control. The analyzes showed a significantly lower growth on those trout treated with mussel infection during the time they were stored in the containers. After a month in freedom in the streams, there was no differences in growth or condition factor. Habitat choice studies showed that trout with a higher degree of infection chose calmer water with a bottom layer of finer sediment. The study showed that this method could be a simple way of increasing the reproduction success of pearl mussel. The method requires relatively little work effort and small disturbance to host fish or the aquatic environment.

By analyzing otolith microchemistry, we examined the use of freshwater and marine environments by brown trout Salmo trutta L. that spawn in the Swedish River Emån and migrate to the Baltic Sea. We estimated the time juveniles spent in freshwater and the number of times the fish returned to freshwater, presumably to spawn. Twenty-six percent of the fish migrated to sea by 1 year of age. However, 13% spent less than one year in the river. Most brown trout (48%) migrated to the sea between 1 and 2 years of age. On average, brown trout, which averaged 4.4 years in age (range 3–6 years), returned to freshwater 2.3 times, and there was an inverse relationship between time spent in freshwater after hatching and the number of visits to freshwater. Our results do not support the classical life history pattern, where brown trout spend one or more years in freshwater before migrating to the sea. Here, we found evidence that part of the population leaves freshwater during their first year. While the cause for precocial migration in the River Emån is not known, our results from this permanently flowing river do not support the idea proposed for other Baltic Sea populations, where the risk of drought has been suggested to be the cause. 

The propensity to kill and consume conspecifics (cannibalism) varies greatly between and within species, but the underlying mechanisms behind this variation remain poorly understood. A rich literature has documented that consistent behavioural variation is ubiquitous across the animal kingdom. Such inter-individual behavioural differences, sometimes referred to as personality traits, may have far-reaching ecological consequences. However, the link between predator personality traits and the propensity to engage in cannibalistic interactions remains understudied. Here, we first quantified personality in Eurasian perch (Perca fluviatilis), measured as activity (time spent moving) and sociability (time spent near conspecifics). We then gave perch of contrasting behavioural types the option to consume either conspecific or heterospecific (roach, Rutilus rutilus) prey. Individual perch characterized by a social-active behavioural phenotype (n = 5) selected roach before being cannibalistic, while asocial-inactive perch (n = 17) consumed conspecific and heterospecific prey evenly. Thus, asocial-inactive perch expressed significantly higher rates of cannibalism as compared to social-active individuals. Individual variation in cannibalism, linked to behavioural type, adds important mechanistic understanding to complex population and community dynamics, and also provides insight into the diversity and maintenance of animal personality.

The salinization of freshwaters is a global threat to aquatic biodiversity. We quantified variation in chloride (Cl-) tolerance of 19 freshwater zooplankton species in four countries to answer three questions: (1) How much variation in Cl- tolerance is present among populations? (2) What factors predict intraspecific variation in Cl- tolerance? (3) Must we account for intraspecific variation to accurately predict community Cl- tolerance? We conducted field mesocosm experiments at 16 sites and compiled acute LC(50)s from published laboratory studies. We found high variation in LC(50)s for Cl- tolerance in multiple species, which, in the experiment, was only explained by zooplankton community composition. Variation in species-LC50 was high enough that at 45% of lakes, community response was not predictable based on species tolerances measured at other sites. This suggests that water quality guidelines should be based on multiple populations and communities to account for large intraspecific variation in Cl- tolerance.

Symbiosis with endomycorrhiza is found in a majority of plant-fungal symbioses. The symbiosis helps with various stressors such as drought and malnutrition. This study looked at how four different field, meadow and brook plants - Centaurea cyanus, Galium verum, Viscaria vulgaris and Veronica beccabunga - are affected by mycorrhiza and fertilizer treatment. The hypotheses tested whether mycorrhiza occurrence and fertilizer treatment affected the total number and number of mature and open flowers in C. cyanus as well as whether mycorrhiza occurrence and fertilizer treatment affected the aboveground biomass and the underground biomass of the four plant species. The study looked at 160 plants and a total of 40 plants of each species were planted. Per species, there were 10 control plants, 10 pots with mycorrhiza and 10 pots with fertilizer as well as 10 pots with both mycorrhiza and fertilizer. The pot arrangement was randomized. Mycorrhizal fungi were collected together with plant roots from different grass and forest habitats. The fertilizer treatment was applied once a week and lasted for six weeks. Two-way ANOVA was used in the analyses of the number of flowers in C. cyanus and three-way ANOVA was used in the analyses of aboveground and underground biomass. Fertilizer treatment had statistically significant effects on both the total number of flowers and the number of mature and open flowers. Fertilizer treatment also increased the aboveground of the selected species as well as the underground biomass of C. cyanus. The underground biomass of the other species decreased. However, the study could not find any significant effect of mycorrhiza treatment nor any significant interaction between mycorrhiza treatment and fertilizer treatment. The study did not test whether or how much of the mycorrhiza colonization was successful and the nonsignificant result may be due to several reasons. More research is needed to confirm the results in this study.

The fungal domain has one of the highest biodiversities among eukaryotes and species within the domain fill important ecological roles, such as mutualistic mycorrhiza, decomposers, parasites and pathogens. The development of forest ecosystems and their related processes has not only been linked to fungal diversity but the composition and abundance of fungi benefits the abundance and diversity of other species as well. In this study three questions concerning the differences in the fungal communities between mixed forests and coniferous forests were considered. Inventories were done in coniferous forest and mixed forest areas classified as nature reserves and later statistically analyzed. The study could show that while the probability of finding ectomycorrhiza was significantly higher in mixed forests than coniferous forests, the probability of finding saprotrophs was significantly higher in coniferous forests than in mixed forests. Results in contrast to other studies were also found. The study revealed that more is needed to be done on the topic of forest fungi in mixed forest and coniferous forest areas.

Anthropogenic activities, e.g. urbanization, have contributed to the loss to biological diversity. One method that has been proposed to combat urban biodiversity loss is to introduce green areas and to plant trees in urban areas. The hypotheses that were tested in this study are that; there is a significant difference in tree species richness and diversity between urban areas and surrounding natural forests in central Sweden; also, that the species richness and diversity varies between different habitats in urban areas. The study was performed in four municipalities in Dalsland: Bengtsfors, Åmål, Dals-Ed and Mellerud. Trees were inventoried in five different habitats per municipality within a suburban area, and in a natural forest area located near the locality. The number of tree species, individual trees, as well as the tree species diversity within each municipality were accounted for, with the use of Shannon-Weaver’s diversity index for the latter. A significant difference in tree species richness and diversity were found between suburban areas and surrounding natural forest areas (median of 10 and 3,5 respectively). The species richness was the highest in Bengtsfors’ municipality with 13 tree species, and the species diversity was the highest in Dals-Ed’s municipality (H’ = 1,22). A significant difference in tree species richness was found, but not in tree species diversity. In the suburban areas, sites near to water bodies had the highest average tree species richness, alongside kindergartens with 4 tree species. The former also has the highest average tree species diversity (H’ = 1,07). The results matched with the first hypothesis but did not match with second hypothesis. In conclusion, it is beneficial to maintain or restore green areas and trees in urban areas, and it requires more research, to propose strategies to protect biodiversity and cities from climate change and other dangers.

Differences between individuals in behavioral type (i.e. animal personality) are ecologically and evolutionarily important because they can have significant effects on fitness components such as growth and predation risk. In the present study we are used the invasive round goby (Neogobius melanostomus) from an established population in controlled experiments to examine the relationships among personality, metabolic performance, and growth rate (inferred as size-at-age). Boldness was measured as the time to return to normal behavior after a simulated predator attack, where fish with shorter freezing times were categorized as "bold" and fish with longer times were categorized as "shy." We show that bold fish have significantly higher standard metabolic rate (SMR) than their shy conspecifics, whereas there was no difference between personality types in their maximum metabolic rate (MMR) or aerobic scope (AS). Bold fish furthermore had a smaller size-at-age as compared to shy fish. Together this provides evidence of a metabolic underpinning of personality where the high-SMR bold fish require more resources to sustain basic life functions than their low-SMR shy conspecifics, indicating that bold round goby from established populations with high densities (and high competition for food) pay a price of reduced growth rate.

In salmonids, the decision to migrate or remain resident is influenced by the status, and hence condition, of individuals. Status has been suggested to arise from the temperament of fish. In this study the links between standard metabolic rate and the levels of aggressiveness and shy/boldness were examined for 0+, hatchery-raised brown trout (Salmo trutta). I hypothesized, from the results of earlier studies (Cutts et al., 1998; Yamamoto et al., 1998), that high metabolic rates (MR) would be positively correlated to levels of aggression and boldness. The study was conducted in 200 L aquaria in which aggressiveness was measured by allowing each fish to interact with a mirror image of itself, and shy/boldness was tested by measuring the amount of time a fish used before exploring a new area. Standard metabolic rate was measured in a flow-through respirometer. In contrast to my expectations, there was no correlation between the different behavioural measures and the metabolic rate of fish. Also, no correlation between boldness and aggressiveness of fish was found. In additional testing aggressiveness correlated positively with the condition of fish (in coherence with Harwood et al., 2003) but, contrary to earlier studies (Överli et al., 2004; Schjolden & Winberg, 2007), not with the speed of acclimatization. The difference in results between this test and earlier studies, concerning the degree of correlation between MR and aggressiveness, suggests that the strength of this link differs between species of salmonids. Also, it may suggest changeability in the MR – behaviour link in different environments. Last, the status and condition of individuals cannot be unambiguously explained by temperament alone, but arise from a wider array of physiological and environmental factors.

The purpose of this paper is to determine the extent to which trout used fishways to swim past two power plants at Finsjö in River Emån. Two different methods of  collecting data were used, radiotelemetry to determine if fish find the fishways (attraction efficiency) and PIT-tags to measure the number of fish that passed through the fishways (passage efficiency). The study showed that passageefficiency, being 89 % at lower Finsjö and 100 % at upper Finsjö, was high compared to other similar studies. Attraction efficiency was 75 % at lower Finsjö and 59 % at upper Finsjö, which indicates that the fish have difficulty finding the fishway entrances, particularly at upper Finsjö.

Freshwater mussels are one of the most endangered groups of organisms worldwide, with the thick-shelled river mussel (Unio crassus) being classified as critically endangered according to the IUCN:s red list of threatened species. Conservation efforts have been undertaken in southern Sweden, where the thick-shelled river mussel has been reintroduced to Klingavälsån and Fyleån. Genetic relatedness is typically used as the starting point when reintroducing mussels, but if this information is not available, the population closest geographically is chosen. The objective of this study was to investigate whether the distance between four watercourses, namely Bråån, Tommarpsån, Klingavälsån and Fyleån affects juvenile survival and to determine which population of mussels from Bråån and Tommarpsån is best suited for reintroduction to Fyleån and Klingavälsån. The hypotheses are that (1) Bråån mussels have the highest growth rate in Bråån, followed by Klingavälsån, Fyleån and Tommarpsån, and (2) Tommarpsån mussels have the highest growth rate in Tommarpsån, followed by Fyleån, Klingavälsån and Bråån. Fertilized mussels were collected from Bråån and Tommarpsån in May 2016, and the mussels released glochidia larvae, which were used to infect fish. European bullheads (Cottus gobio) were electrofished from Tommarpsån and European minnows (Phoxinus phoxinus) were electrofished from Bråån, and then the European bullheads were infected with glochidia larvae from Tommarpsån and European minnows were infected with glochidia larvae from Bråån. Juvenile mussels let go of the fish 25 – 35 days later and were fed throughout the summer, after which the mussels were placed in boxes in the four watercourses. Survival of the mussels was measured and documented on two occasions. Four Kruskal-Wallis tests were performed where “survival” was compared with “watercourse” for Bråån mussels and for Tommarpsån mussels. The results did not match the hypothesis for either Bråån mussels or Tommarpsån mussels, except for the fact that Bråån mussels had the lowest survival rate in the most remote stream at the second measurement occasion. The survival of the Bråån mussels differed between several of the streams, but for the Tommarpsån mussels there were no significant difference in survival. The Bråån mussels seemed more suitable for reintroduction into Fyleån compared to Klingavälsån, and Tommarpsån mussels did not seem less suitable for reintroduction to either Fyleån or Klingavälsån. In summary, survival did not appear to generally depend on geographic proximity. Factors such as local adaptation, water quality and diseases likely also have an impact on the survival of juvenile mussels. 

Alarming amounts of microplastics have recently been shown to accumulate in the environment. Recent focus has been on synthetic material contaminating the marine environment, while effects on freshwater habitats and organisms have received less attention. We here confirm and analyse occurrence of microplastics in the duck mussel, Anodonta anatina, in a Swedish river. All analysed mussels contained microplastics, and the number of microplastic debris found in the mussels increased with mussel size. In addition, we demonstrate higher concentrations of microplastics downstream urban areas with wastewater treatment plants compared to a rural upstream location. Both fibres and particles were found in the mussels, indicating that the emissions of these pollutants may have varying origin. Our study indicates that microplastics can be suspended in the water column in streams and that concentrations are higher downstream anthropogenic activity. We discuss our results in light of potential pathways in rural versus surrounding arable land, and highlight a number of required research directions in the aquatic system. 

Populations of migratorysalmon and trout have worldwide shown a decline due to human activities. Overthe years numerous measures have been undertaken to maintain these populations,and conservation of migratory salmonids requiresunderstanding of their ecology at multiple scales, combined with assessinganthropogenic impacts. Theregulated River Klarälven and Lake Vänern host endemic populations oflandlocked Atlantic salmon (Salmo salar) and brown trout (Salmo trutta). The historically high abundances of the salmonids in theRiver Klarälven in the early 1800s have decreased dramatically, reachingall-time lows after the completion of all nine Swedish hydroelectric powerstations in the 1960s. After an extensive stocking program and transportationof spawners past eight hydroelectric plants catches from commercial,maintenance and sport fishing have again increased. Recently, increases in theproportion of wild salmon returning to the River Klarälven have generated interestsin establishment of wild salmon inhabiting the entire River Klarälven, includingupstream of the Norwegian border. How well are we equipped to meet these newdreams, taking into account our limited knowledge of the species different lifestages, coordination between different actors involved in the conservationprocesses, and our skills to communicate and understand everybody’s role inthis conservation process?

Data från 1800-talet visar att fångsterna av lax och öring i både älv och sjö varit mycket högre än idag. Storskaliga dämmen, kraftigt fiske i Dejeforsen, nio kraftverk i den svenska delen av Klarälvens huvudfåra, och användandet av älven för timmerflottning har bidragit till detta. Efter att utsättning av kompensationsodlad fisk startade ökade fångsten igen, även om den fortfarande är låg.

Fältundersökningar av vild laxsmolt visade att 16 % av smolten klarade sig hela vägen förbi de åtta kraftverken mellan Edebäck och Forshaga. Under studien var vattenföringen, och därmed spillet, lågt, vilket troligen bidragit till de höga förlusterna. Normalt spills det inte under hela smoltvandringsperioden, vilket är olyckligt.

Lax och öring uppfödda under normala odlingsförhållanden är oftast större och fetare än vild fisk. Vi födde upp lax med olika fodertyper och fodermängder. Mängden föda påverkade laxens tillväxt och smoltmognad, och lax som fått fettfattigt foder var mest ”naturlik”. Den klarade också vandringen bäst, 80 % tog sig till Vänern medan 55 % av laxen som fått normalt eller lite foder. Bara 20 % av tidigt könsmogna hanar tog sig till Vänern.

Rapporten avslutas med implikationer och förslag till åtgärder och fortsatta studier.

Co-management is of increasing interest for fisheries management. We explore possibilities for, and barriers to, developing a co-management system, using threatened populations of landlocked Atlantic Salmon and Brown Trout as examples. Good management of natural resources requires not only knowledge about the resource but also suitable tools to collect information and make decisions. In large ecosystems this can be difficult because many actors are involved, and various societal borders and traditions become barriers. Vänern is the largest lake in the EU and it holds several distinct populations of large-bodied landlocked Atlantic Salmon and Brown Trout. The lake is used for commercial, subsistence, and sport fishing as well as for other recreational activities, and in Klarälven, the largest river entering Vänern, sport fishing is popular. These salmonid populations were at critically low levels during the 1960s, but a stocking program since then has maintained the fishery, and at least one wild stock appears to be recovering since being protected in 1993. Ecosystem users all have different needs: in the lake, sport fishermen say that catches of hatchery fish have declined, and commercial fishermen have focused on other species. In the river, wild salmon may be recovering: sport fishing is popular and an ongoing project investigates the possibilities for salmon to be able to circumvent hydro-electrical plants and reach historical Norwegian spawning areas. Not only do we lack information about the salmonids’ different life stages, we also lack a suitable socio-political organization to find sustainable solutions to the different needs of diverse user groups. We argue that a co-management system that enfranchises user groups in the Vänern-Klarälven ecosystem will improve sustainable management of wild and hatchery fish.

The topography within arctic-alpine landscapes is very heterogeneous, resulting in diverse snow distribution patterns, with different snowmelt timing in spring. This may influence the phenological development of arctic and alpine plant species and asynchronous flowering may promote adaptation of plants to their local environments.We studied how flowering phenology of the dominant dwarf shrub Empetrum hermaphroditum varied among three habitats (exposed ridges, sheltered depressions and birch forest) differing in winter snow depth and thus snowmelt timing in spring, and whether the observed patterns were consistent across three different study areas.Despite significant differences in snowmelt timing between habitats, full flowering of E. hermaphroditum was nearly synchronous between the habitats, and implies a high flowering overlap. Our data show that exposed ridges, which had a long lag phase between snowmelt and flowering, experienced different temperature and light conditions than the two late melting habitats between snowmelt and flowering.Our study demonstrates that small scale variation seems matter less to flowering of Empetrum than interannual differences in snowmelt timing.

This study examined whether there is any evidence for density-dependent growth and survival of juvenile brown trout (Salmo trutta L.) in eleven nursery locals in the river Dammån-Storån and its tributaries Lekarån and Bastuån 1995-2010. Regression analyses were used to test for correlations between (i) density of 0+ and mean length of 1+ and (ii) density of 0+ and density of 1+. Thereafter three one-way ANOVAs were used to test for (i) any differences in mean length of underyearlings among these eleven locals during the same time period, (ii) differences in mean length between years and (iii) differences in maximum length of 0+ among locals.

The results revealed weak negative correlations between density of 0+ and mean length of 1+,  and weak positive correlations between density of 0+- and 1+-brown trout. The analysis of variance on mean length of 0+ showed significant differences in mean length between the locals. The ANOVA on differences in mean length between years showed slight differences, and the ANOVA on differences in maximum length of 0+ showed significant differences. This study suggests that there is not strong evidence for density dependence in these populations, and that local conditions in time and space are important determinants of fish growth.

Australian swamp stonecrop (Crassula helmsii) is an amphibious plant native to Australasia and highly invasive in Europe. Managing the spread and impacts of this invader is challenging due to its ability to regenerate from small vegetative plant fragments. In several infested water systems in the Netherlands, the dispersal of this species is currently being prevented using water filters with a mesh size as small as 1 mm2 in their outflows. However, it remains unclear whether these filters are truly capable of preventing the spread of small regenerative fragments. To identify potential shortcomings in the management of C. helmsii dispersal, we investigated the regeneration of detached vegetative fragments. A laboratory experiment was conducted to study the regenerative capacity of C. helmsii fragments of varying sizes (0.5–2 mm). We examined the growth performance (stem count, cumulative stem length) of fragments originating from nodes, leaves, shoots, roots, and meristem tissue cuts. All fragments originating from nodal tissue were able to successfully regenerate. Isolated meristem tissue of 0.5 mm was able to regenerate but exhibited malformed growth. Shoot tips demonstrated the best growth performance. While we successfully isolated protoplasts from C. helmsii node tissue, our cultures were compromised, and regeneration could not be assessed. Our research indicates regenerative potential from node fragments as small as a cluster of apical meristem cells. These findings suggest shortcomings in current measures for dispersal prevention of C. helmsii, as they do not prevent the dispersal of plant fragments with a length <2 mm. We recommend re-evaluating the effectiveness of various types of dispersal barriers currently applied in vulnerable natural areas to prevent the spread and subsequent regeneration of small vegetative fragments of C. helmsii.

This study explores the perception of wolverines, a carnivore in decline, by youths in northern Canada, the future generation of stakeholders. To accomplish this, we analysed 165 drawings from children and 22 interviews with Indigenous adults in the Northwest Territories and Quebec. Overall, children primarily drew wolverines in healthy environments, with only a minority depicting the wolverine's environment negatively. All children demonstrated a basic understanding of the wolverine's physical appearance and biology/ecology, with few differences in how the wolverine was depicted among the different research areas. Among interviewed adults, the ecological role played by wolverines was less prominent among the themes explored by Naskapi participants than was their role as a thief or pest, when contrasted to Dene participants. These results indicate that information about wolverine habitat or biology is still being acquired by children in areas where wolverines are extirpated, but that a lack of exposure to this species may negatively influence children's understanding of its ecological role. These results suggest that informing the public about this carnivore's ecological role may improve public support and, therefore, the likelihood of successful conservation programmes.

The wolverine (Gulo gulo), a carnivore species of ‘Special Concern’ for its western population and ‘Endangered’ for its eastern population, is of special management concern in Canada. Hence understanding human-wolverine relationships and human perceptions toward this carnivore species has become important. Moreover, wolverines are harvested for fur in northern Canada, thus hunters and trappers who live in the vicinity with this species are key stakeholders. Using semi-structured interviews and questionnaires we analysed human-wolverine interactions and perceptions among Dene and Métis hunters and trappers in the Canadian Northwest Territories. We found that hunters and trappers had comprehensive knowledge about wolverine ecology and behavior. Values associated with this species ranged from respect for their tenacious character and strength, to describing the wolverine as a trickster. Stories emphasizing the wolverines’ mischievous nature were also common. Dene and Métis hunters and trappers acknowledge the importance of the wolverine in the socio-ecological system and have observed the cumulative impacts that climate and human-induced landscape change have had on wolverine habitat and population dynamics. Listening to hunters and trappers is one path towards more insightful management options in situations involving conflicts with wolverines.

The spreading of the invasive plant Garden Lupine (Lupinus polyphyllus) has become a matter of national importance in Sweden, due to it posing a threat to native plant and pollinator diversity. The effective attraction of bumblebees (Bombus spp.) as pollinators facilitates the production of large numbers of seeds, which are key to the Garden Lupine’s success. Possible self-pollination could also provide a competitive edge for the plant. The objective of this study was to study the relationships between Garden Lupine color morphs, pollinator attraction and seeding. Inflorescences of three color morphs were studied during the flowering period, and bumblebee behavior was observed on the site. After seeding, any produced seeds were collected and analyzed, as well as experimentally germinated to provide insight into their viability. A subset of inflorescences of each color morph was prevented access to pollinators, to study potential self-pollination effects. Bumblebees preferred blue flowers over pink, but no difference in pollination between the color morphs was found. Flower color did not affect seed production or seed morphology. Self-pollinated inflorescences produced fewer seeds than those with access to pollinators, but no difference in seed morphology or germinative success between the pollination methods could be established. The results suggest that seed production and germination are less dependent on pollination than expected. The ability to germinate through self-pollination provides insight into the invasive potential of Garden Lupine, suggesting that further studies are needed to successfully counteract its spread.

Rivers networks represent hierarchical dendritic habitats within terrestrial landscapes and differences in connectivity and land use influence dispersal, and consequently biodiversity patterns. We, therefore, measured variation in water chemistry and fish abundance and related these to a number of landscape characteristics (e.g., wetland, urban, wooded, and agricultural) in the River Klaralven and its 30 permanently flowing tributaries. We hypothesized that these environmental attributes would differ between tributary and main stem habitat and that these differences would be driven by landscape attributes including land use. We found considerable intertributary variation in temperature and nutrient levels, and between the tributaries and the main stem. Generally, water temperature was lower in the tributaries, whereas nutrient levels were higher in the tributaries. The lower water temperature has implications for coldwater fishes, and we found two fishes, burbot and lamprey, associated with coldwater tributaries. We also found an inverse relationship between water quality and anthropogenic land use. Protecting tributaries with low anthropogenic impact will likely become increasingly important with ongoing global warming as they can function as thermal refugia for coldwater fishes. Hence, this study underscores the need to evaluate water courses at regional scales to identify spatial refuges and ensure connectivity.

1. Isotopic ratios of nitrogen are often used in food-web studies to determine trophic position (including food chain length) and food sources, with greater ratios of 15N/14N (d15N) usually considered indicative of higher trophic position. However, fasting and starving animals may also show a progressive increase in d15N over time as they catabolise their own tissues.

2. To determine the importance of starvation, we conducted a 4-month laboratory experiment testing effects of starvation on body condition and isotope ratios in the muscle tissue of freshwater guppies (Poecilia reticulata). We also compared laboratory results and conclusions with analyses of body condition and isotope ratios in various small species of fish collected in four seasons from the Kansas River in north-eastern Kansas, U.S.A.

3. Fish starved in our laboratory experiment had significantly higher 15N values and poorer body condition than those fed more regularly. The diverse group of fish species collected in summer (July) from the Kansas River had higher weight-to-length ratios and lower 15N values than those retrieved in other seasons. Overall body condition resulting from reduced food consumption explained 44 and 53% of the variability in 15N for field and laboratory fish, respectively.

4. These results are applicable to a wide variety of food-web research but are especially pertinent to studies of organisms that undergo large changes in life history, dormancy, extended fasts or periods of significant nutritional allocation to young.

Historically, ecological engineered solutions for fish passage across anthropogenic barriers in rivers has mainly focused on facilitating upstream passage for long-migrating diadromous fish, such as salmonids. More recently, passage solutions have shifted their focus to a more holistic ecological perspective, allowing passage for species with different swimming capacity, both upstream and downstream. This experiment investigated whether the addition of cobble in the passageway of a surface bypass could facilitate downstream movement of a cyprinid fish, the common roach Rutilus rutilus. Surface bypasses were constructed in large experimental flumes and roach were released into the flumes and monitored for bypass passage using PIT-telemetry through 11-h night-trials. Behavior was scored using four continuously-recording video cameras at the bypass construction. There was a negative effect of substrate-treatment on the passage rate through the bypass. The majority of the fish in the No substrate treatment had successfully passed within 4 h, while a lesser proportion of the fish in the Substrate treatment had done so (additional fish in the latter treatment passed later in the trials). Fish exposed to cobble substrate in the bypass passageway showed more avoidance-like behaviors at the ramp section of the bypass and tended to return back upstream more often than the fish in the no-substrate control trials. When reaching the passageway, the substrate-exposed fish expressed no behaviors that could be indicative of reduced passage success, as compared to controls. We conclude that passage was not hindered by the presence of cobble substrate, but passage was delayed due to avoidance behavior at the bypass ramp when cobble substrate was present. Based on these results, the addition of cobble substrate in a surface bypass cannot be recommended as a measure to facilitate the downstream passage performance of the common roach through surface bypasses.

An important metric of environmental health is food web structure because it reflects species richness, natural history diversity, and resource availability. While bulk-tissue stable isotope analysis has proven valuable for food web studies, field conditions may severely restrict its use and data can be quite variable. Amino acid stable isotope analysis potentially reduces this variability, in part by eliminating the need for signatures near the trophic base because a single top consumer contains both the primary producer signature (constant phenylalanine signature) and information reflecting number of trophic transfers (a progressively increasing d15N signature of glutamic acid). To evaluate the ecological sensitivity and cost/benefits of the techniques, we conducted a laboratory food chain experiment with four trophic levels. Water fleas (Daphnia magna) were cultured on a diet of powdered algae and then fed daily to guppies (Poecilia reticulata) for three months. These invertivorous fishes were then consumed by piscivororus bluegill sunfishes (Lepomis macrochirus) for a subsequent three months. All members of the food web were analyzed for 15N values and degree of fractionation using both bulk-tissue and amino acid stable isotope techniques. Our experiment demonstrated that the amino acid technique more accurately identified the true trophic position (TP) and food chain length (FCL ¼ maximum TP) with significantly less variability around mean values for each consumer trophic level. Moreover, use of amino acids requires significantly fewer replicates to identify TP. We discuss here the relative advantages and disadvantages of both approaches for determining TP and FCL and recommend that investigators switch as soon as possible to the amino acid isotope technique for determining FCL.

Multidimensional data are integral to many community-ecological studies and come in various forms, such as stable isotopes, compound specific analyses (e.g., amino acids and fatty acids), and both biodiversity and life history traits. Scientists employing such data often lack standardized metrics to evaluate communities in niche space where more than 2 dimensions are involved. To alleviate this problem, we developed a graphing and analytical approach for use with more than two variables, based on previously established stable isotope bi-plot metrics. We introduce here our community metrics as R scripts. By extending the original metrics to multiple dimensions, we created n-dimensional plots and metrics to characterize any set of quantitative measurements of a community. We demonstrate the utility of these metrics using stable isotope data; however, the approaches are applicable to many types of data. The resulting metrics provide more and better information compared to traditional analytic frameworks. The approach can be applied in many branches of community ecology, and it offers accessible metrics to quantitatively analyze the structure of communities across ecosystems and through time.

Biodiversity loss is one of the biggest threats to our planet, and in freshwater, populations of migratory fish species have declined by 76% since the 1970s. The eel is a species threatened with extinction due to anthropogenic impact, mainly due to power plant dams that fragment habitat and prevent the species' vital migration up and down streams through lack of passage solutions. The purpose of the study was to investigate the possibility of further developing eel passage solutions with the substrate EF-16, by testing the climbing success of glass eels at two different passage ramps and at two different flows (3 l/min and 9 l/min). Each passage solution consisted of four passage ramps positioned widthwise, with EF-16 mounted either flat or lateral v-shaped every other ramp. The study shows that the optimized v-shaped passage ramps gave significantly more climbs at high flows, and that the location of the ramps also had a significant impact on the choice of ramp. The body weight of eels, on the other hand, had no effect on passage success. This study emphasizes the importance of the development of efficient passage solutions for glass eels that can be applied at large variations in flow at power plant dams. By allowing more eels to migrate upstream watercourses past hydropower plants to their spawning grounds, the eel population can hopefully be saved.

All organisms depend on phosphorus (P) and nitrogen (N) to grow and survive; therefore these nutrients are added in high doses to agricultural land in the form of fertilizers. Agriculture together with increased precipitation can increase the runoff of nutrients (mainly P and N) from agricultural land to watercourses. As part of this, structural liming can be used to improve soil structure so that P remains in the soil, thereby reducing P loading and eutrophication in catchment areas. The aim of this study was to investigate whether the structural liming carried out on Dalboslätten during 2020 and 2021 has had any effect on eutrophication in the nearbywatercourses. The hypothesis was that structural liming has reduced eutrophication in the form of a reduced amount of total P in the four catchment areas. Access to water chemistry data in catchment areas has taken place via Dalsland’s environmental office. Total P was investigated with one-way ANOVA and Kruskall-Wallis for the four watercourses Dalbergsån, Krokån, Lillån and Hakerudsälven during 2019-2021. Since precipitation can affect total P in the watercourses, the relationship between total P and precipitation was also investigated through linear regression for each watercourse. Dalbergsån and Krokån had less total P in 2021 compared to previous years, while Hakerudsälven and Lillån had no reduction in total P. Precipitation did not affect the amount of total P in any of the watercourses during 2019-2021. This, in turn, may mean that the structural liming has had an effect in two of the watercourses as well as a more easily worked soil, but to get a more reliable result the study would have to be conducted over several years. As the population increases, it puts further pressure on the efficiency of agriculture, where less fertilizer should produce more crops. By selecting crops that require a smaller amount of added nutrients and by the population changing their diet to more vegetarian options, added P in agriculture can be reduced and thus eutrophication in catchment areas. Along with structural liming, wetlands and phosphorus ponds can beconstructed to obtain longer-term protection against the eutrophication on Dalboslätten.

Climate change and its impact can be seen in a multitude of ways. Earlier spring migration is one and has been observed in several bird species. This can be a result of phenological change amongst migrant birds who rely on photoperiod and climatic conditions to time their autumn and spring migration as weather is not a sufficient nor reliable way of understanding the temperature at their summer habitats from their wintering grounds Many birds with breeding grounds in Sweden are known to migrate, either fully (short or long-distance migrants) or partially (partial migrants). Passerine birds are the largest of the avian class, making up approximately two thirds of all bird species. This makes them great study subjects for many different areas of biological studies such as ecology. Among the passerines are the warblers, a group of songbirds whose migration patterns have been studied previously. This study aims to test if there has been an advancement of spring arrival of six warbler species (willow warbler (Phylloscopus trochilus), wood warbler (Phylloscopus sibilatrix), sedge warbler (Acrocephalus schoenobaenus), reed warbler (Acrocephalus scirpaceus), lesser whitethroat (Sylvia curruca), and garden warbler (Sylvia borin)) in two regions of Sweden (north and south). Additionally, I compared the regions to each other and discussed if there are possible connections to climate change. The hypotheses are that 1) the date when migratory birds first arrive to Sweden is earlier than 20 years ago, 2) there is a difference in arrival date amongst the chosen species and 3) a spatial difference in spring arrival between the chosen regions. To answer the hypotheses, data was collected from the citizen science database SLU Artdatabanken with the first date of report from each year over a 21-year period between 2003-2023 for all six species. An ANOVA and Post-Hoc tests were performed in SPSS to answer the hypotheses as well as a Kendall tau-b test and independent samples t-test to confirm the results of the ANOVA and Post-Hoc tests. The results showed that there had not been an advancement in spring arrival and the null hypotheses cannot be rejected. The results of the study are surprising as many other studies are showing the opposite effect. This could be due to how the data was collected (only first reported date and not an average), or that the climate at their wintering grounds have not changed enough during the last 20 years to generate phenological change as well as not requiring to match certain events. To further our understanding of phenological change and migration across species, studies at wintering grounds would be beneficial. 

Krynickillus melanocephalus was first seen in Sweden 2015. It is now labeled as an invasive species and it potentially poses a threat to the ecosystem, but the slug has not yet shown to have great negative impact in gardens and agricultural fields. There is limited ecological knowledge about the species. This study aims to increase the knowledge about habitat preference of the species during oviposition. Fifty slugs were placed in experimental arenas containing four compartments, each containing a different substrate: birch leaves, gravel, potting soil and sphagnum moss. The position of the slugs were recorded daily for three consecutive days. Further, position of laid eggs were recorded at two different times. Slugs showed a preference for leaves at oviposition, and 88 % of the eggs were laid in this substrate, and the fewest eggs were laid in moss (0,6 %). The slugs were found the most in contact with the leaves. The result has expanded our knowledge about the species, which is important to develop ways to hinder and slow down its invasion. Future research about substrate preference in this species should focus on how humidity and temperature may affect the substrate preference, as well as on movement behaviour during oviposition, perhaps by means of PIT telemetry. The study provides practical advice regarding how to deal with garden waste in areas that are inhabited by the species, where, in particular birch leaf compost should not be moved around.

Animal migration is an amazing phenomenon that has fascinated humans for long. Many freshwater fishes also show remarkable migrations, whereof the spectacular mass migrations of salmonids from the spawning streams are the most well known and well studied. However, recent studies have shown that migration occurs in a range of freshwater fish taxa from many different habitats. In this review we focus on the causes and consequences of migration in freshwater fishes. We start with an introduction of concepts and categories of migration, and then address the evolutionary causes that drive individuals to make these migratory journeys. The basis for the decision of an individual fish to migrate or stay resident is an evaluation of the costs and benefits of different strategies to maximize its lifetime reproductive effort. We provide examples by discussing our own work on the causes behind seasonal migration in a cyprinid fish, roach (Rutilus rutilus (L., 1758)), within this framework. We then highlight different adaptations that allow fish to migrate over sometimes vast journeys across space, including capacity for orientation, osmoregulation, and efficient energy expenditure. Following this we consider the consequences of migration in freshwater fish from ecological, evolutionary, and conservation perspectives, and finally, we detail some of the recent developments in the methodologies used to collect data on fish migration and how these could be used in future research.

Green (vegetated) roofs provide many beneficial environmental services but can also pose a disservice by leaching nutrients and metals, via storm water runoff, to downstream aquatic ecosystems. Current estimates of water quality impacts rely on limited samples (snapshots in time) and may not accurately reflect the true influence of green roof ecosystems, which likely vary temporally as do natural ecosystems. Using a 46 m(2) green roof in Cincinnati, OH, we analyzed runoff from >80 events over two years for pH, conductivity, and concentrations of dissolved nutrients, base cations, and metals. We related the variation in water chemistry to environmental variables including air temperature, storm event magnitude, and estimated antecedent moisture. We observed strong seasonal patterns in bioactive elements, with carbon, nitrogen, phosphorus, and base cation concentrations highest in the summer, and positively correlated with temperature. This suggests temperature-mediated processes such as microbial mineralization of organic matter, desorption or weathering, rather than plant uptake or hydrologic variation among storms, are the major controlling mechanisms for runoff water quality in this newly constructed green roof. The large temporal variation in green roof effluent water quality supports the need for long-term studies to characterize the complexity of these engineered ecosystems and their responsiveness to environmental variation. (C) 2016 Elsevier B.V. All rights reserved.

Fiskarter som är beroende av att kunna röra sig mellan sötvatten och hav för att fullfölja sina livscykler stöter ofta på problem i reglerade vattendrag, eftersom vattenkraftverk skapar vandringshinder. Vanligen försöker man lösa dessa problem genom att anlägga fiskvägar vid hindren, för att åter göra det möjligt för fisken att passera. Fokus för sådana åtgärder har legat på just uppströms passage, medan nedströms passage av kraftverk sällan uppmärksammats och ytterst sällan åtgärdats. Denna rapport beskriver nedströmspassagen för ål vid ett vattenkraftverk i Ätran, före och efter åtgärd.

Före åtgärd satt en fingaller med 20 mm spaltvidd och 63,4° lutning i intagskanalen till Ätrafors kraftverk i Ätran. Förlusten för ål på väg nedströms mot havet var omfattande och dödligheten var 72 %. De flesta ålar som dog klämdes fast på intagsgallret eller skadades vid turbinpassage. Åtgärden bestod i att sätta in ett nytt fingaller i intagskanalen med 18 mm spaltvidd och 35° lutning. Dessutom anlades flyktöppningar i gallrets övre del för att erbjuda ålen en alternativ väg förbi kraftverket. Efter åtgärd minskade dödligheten för ål till 10%. Ca. 80% av ålarna hittade ut genom flyktöppningarna och ingen av dem fastnade på det nya gallret. Det nya gallrets utökade yta ledde även till att fallförlusten minskade med som mest 170 mm, vilket innebär en ökad framtida produktion vid kraftverket om man lyckas med att hålla gallret rent från löv och drivgods.