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  • 1. Ardehed, Angelica
    et al.
    Johansson, Daniel
    Schagerström, Ellen
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Johannesson, Kerstin
    Pereyra, Ricardo T.
    Complex spatial clonal structure in the macroalgae Fucus radicans with both sexual and asexual recruitment2015In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 5, no 19, p. 4233-4245Article in journal (Refereed)
    Abstract [en]

    In dioecious species with both sexual and asexual reproduction, the spatial distribution of individual clones affects the potential for sexual reproduction and local adaptation. The seaweed Fucus radicans, endemic to the Baltic Sea, has separate sexes, but new attached thalli may also form asexually. We mapped the spatial distribution of clones (multilocus genotypes, MLGs) over macrogeographic (>500km) and microgeographic (<100m) scales in the Baltic Sea to assess the relationship between clonal spatial structure, sexual recruitment, and the potential for natural selection. Sexual recruitment was predominant in some areas, while in others asexual recruitment dominated. Where clones of both sexes were locally intermingled, sexual recruitment was nevertheless low. In some highly clonal populations, the sex ratio was strongly skewed due to dominance of one or a few clones of the same sex. The two largest clones (one female and one male) were distributed over 100-550km of coast and accompanied by small and local MLGs formed by somatic mutations and differing by 1-2 mutations from the large clones. Rare sexual events, occasional long-distance migration, and somatic mutations contribute new genotypic variation potentially available to natural selection. However, dominance of a few very large (and presumably old) clones over extensive spatial and temporal scales suggested that either these have superior traits or natural selection has only been marginally involved in the structuring of genotypes.

  • 2. Ardehed, Angelica
    et al.
    Johansson, Daniel
    Sundqvist, Lisa
    Schagerström, Ellen
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Zagrodzka, Zuzanna
    Kovaltchouk, Nikolaj A.
    Bergström, Lena
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Rafajlovic, Marina
    Pereyra, Ricardo T.
    Johannesson, Kerstin
    Divergence within and among Seaweed Siblings (Fucus vesiculosus and F. radicans) in the Baltic Sea2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 8, article id e0161266Article in journal (Refereed)
    Abstract [en]

    Closely related taxa provide significant case studies for understanding evolution of new species but may simultaneously challenge species identification and definition. In the Baltic Sea, two dominant and perennial brown algae share a very recent ancestry. Fucus vesiculosus invaded this recently formed postglacial sea 8000 years ago and shortly thereafter Fucus radicans diverged from this lineage as an endemic species. In the Baltic Sea both species reproduce sexually but also recruit fully fertile new individuals by asexual fragmentation. Earlier studies have shown local differences in morphology and genetics between the two taxa in the northern and western Bothnian Sea, and around the island of Saaremaa in Estonia, but geographic patterns seemin conflict with a single origin of F. radicans. To investigate the relationship between northern and Estonian distributions, we analysed the genetic variation using 9 microsatellite loci in populations from eastern Bothnian Sea, Archipelago Sea and the Gulf of Finland. These populations are located in between earlier studied populations. However, instead of bridging the disparate genetic gap between N-W Bothnian Sea and Estonia, as expected from a simple isolation-by-distance model, the new populations substantially increased overall genetic diversity and showed to be strongly divergent from the two earlier analysed regions, showing signs of additional distinct populations. Contrasting earlier findings of increased asexual recruitment in low salinity in the Bothnian Sea, we found high levels of sexual reproduction in some of the Gulf of Finland populations that inhabit extremely low salinity. The new data generated in this study supports the earlier conclusion of two reproductively isolated but very closely related species. However, the new results also add considerable genetic and morphological complexity within species. This makes species separation at geographic scales more demanding and suggests a need for more comprehensive approaches to further disentangle the intriguing relationship and history of the Baltic Sea fucoids.

  • 3. Barboza, Francisco R.
    et al.
    Kotta, Jonne
    Weinberger, Florian
    Jormalainen, Veijo
    Kraufvelin, Patrik
    Molis, Markus
    Schubert, Hendrik
    Pavia, Henrik
    Nylund, Göran M.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Schagerström, Ellen
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Rickert, Esther
    Saha, Mahasweta
    Fredriksen, Stein
    Martin, Georg
    Torn, Kaire
    Ruuskanen, Ari
    Wahl, Martin
    Geographic variation in fitness-related traits of the bladderwrack Fucus vesiculosus along the Baltic Sea-North Sea salinity gradient2019In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758Article in journal (Refereed)
    Abstract [en]

    In the course of the ongoing global intensification and diversification of human pressures, the study of variation patterns of biological traits along environmental gradients can provide relevant information on the performance of species under shifting conditions. The pronounced salinity gradient, co-occurrence of multiple stressors, and accelerated rates of change make the Baltic Sea and its transition to North Sea a suitable region for this type of study. Focusing on the bladderwrack Fucus vesiculosus, one of the main foundation species on hard-bottoms of the Baltic Sea, we analyzed the phenotypic variation among populations occurring along 2,000 km of coasts subjected to salinities from 4 to >30 and a variety of other stressors. Morphological and biochemical traits, including palatability for grazers, were recorded at 20 stations along the Baltic Sea and four stations in the North Sea. We evaluated in a common modeling framework the relative contribution of multiple environmental drivers to the observed trait patterns. Salinity was the main and, in some cases, the only environmental driver of the geographic trait variation in F. vesiculosus. The decrease in salinity from North Sea to Baltic Sea stations was accompanied by a decline in thallus size, photosynthetic pigments, and energy storage compounds, and affected the interaction of the alga with herbivores and epibiota. For some traits, drivers that vary locally such as wave exposure, light availability or nutrient enrichment were also important. The strong genetic population structure in this macroalgae might play a role in the generation and maintenance of phenotypic patterns across geographic scales. In light of our results, the desalination process projected for the Baltic Sea could have detrimental impacts on F. vesiculosus in areas close to its tolerance limit, affecting ecosystem functions such as habitat formation, primary production, and food supply.

  • 4. Bergström, Lena
    et al.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Malm, Torleif
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Rosenberg, Rutger
    Wahlberg, Magnus
    Capetillo, Nastassja Åstrand
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Wilhelmsson, Dan
    Effects of offshore wind farms on marine wildlife-a generalized impact assessment2014In: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 9, no 3, p. 034012-Article in journal (Refereed)
    Abstract [en]

    Marine management plans over the world express high expectations to the development of offshore wind energy. This would obviously contribute to renewable energy production, but potential conflicts with other usages of the marine landscape, as well as conservation interests, are evident. The present study synthesizes the current state of understanding on the effects of offshore wind farms on marine wildlife, in order to identify general versus local conclusions in published studies. The results were translated into a generalized impact assessment for coastal waters in Sweden, which covers a range of salinity conditions from marine to nearly fresh waters. Hence, the conclusions are potentially applicable to marine planning situations in various aquatic ecosystems. The assessment considered impact with respect to temporal and spatial extent of the pressure, effect within each ecosystem component, and level of certainty. Research on the environmental effects of offshore wind farms has gone through a rapid maturation and learning process, with the bulk of knowledge being developed within the past ten years. The studies showed a high level of consensus with respect to the construction phase, indicating that potential impacts on marine life should be carefully considered in marine spatial planning. Potential impacts during the operational phase were more locally variable, and could be either negative or positive depending on biological conditions as well as prevailing management goals. There was paucity in studies on cumulative impacts and long-term effects on the food web, as well as on combined effects with other human activities, such as the fisheries. These aspects remain key open issues for a sustainable marine spatial planning.

  • 5. Dias, P. Joana
    et al.
    Fotedar, Seema
    Munoz, Julieta
    Hewitt, Matthew J.
    Lukehurst, Sherralee
    Hourston, Mathew
    Wellington, Claire
    Duggan, Roger
    Bridgwood, Samantha
    Massam, Marion
    Aitken, Victoria
    de Lestang, Paul
    McKirdy, Simon
    Willan, Richard
    Kirkendale, Lisa
    Giannetta, Jennifer
    Corsini-Foka, Maria
    Pothoven, Steve
    Gower, Fiona
    Viard, Frederique
    Buschbaum, Christian
    Scarcella, Giuseppe
    Strafella, Pierluigi
    Bishop, Melanie J.
    Sullivan, Timothy
    Buttino, Isabella
    Madduppa, Hawis
    Huhn, Mareike
    Zabin, Chela J.
    Bacela-Spychalska, Karolina
    Wojcik-Fudalewska, Dagmara
    Markert, Alexandra
    Maximov, Alexey
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Jaspers, Cornelia
    Kotta, Jonne
    Parnoja, Merli
    Robledo, Daniel
    Tsiamis, Konstantinos
    Kupper, Frithjof C.
    Zuljevic, Ante
    McDonald, Justin I.
    Snow, Michael
    Establishment of a taxonomic and molecular reference collection to support the identification of species regulated by the Western Australian Prevention List for Introduced Marine Pests2017In: Management of Biological Invasions, ISSN 1989-8649, Vol. 8, no 2, p. 215-225Article in journal (Refereed)
    Abstract [en]

    Introduced Marine Pests (IMP, = non-indigenous marine species) prevention, early detection and risk-based management strategies have become the priority for biosecurity operations worldwide, in recognition of the fact that, once established, the effective management of marine pests can rapidly become cost prohibitive or impractical. In Western Australia (WA), biosecurity management is guided by the Western Australian Prevention List for Introduced Marine Pests which is a policy tool that details species or genera as being of high risk to the region. This list forms the basis of management efforts to prevent introduction of these species, monitoring efforts to detect them at an early stage, and rapid response should they be detected. It is therefore essential that the species listed can be rapid and confidently identified and discriminated from native species by a range of government and industry stakeholders. Recognising that identification of these species requires very specialist expertise which may be in short supply and not readily accessible in a regulatory environment, and the fact that much publicly available data is not verifiable or suitable for regulatory enforcement, the WA government commissioned the current project to collate a reference collection of these marine pest specimens. In this work, we thus established collaboration with researchers worldwide in order to source representative specimens of the species listed. Our main objective was to build a reference collection of taxonomically vouchered specimens and subsequently to generate species-specific DNA barcodes suited to supporting their future identification. To date, we were able to obtain specimens of 75 species (representative of all but four of the pests listed) which have been identified by experts and placed with the WA Government Department of Fisheries and, where possible, in accessible museums and institutions in Australasia. The reference collection supports the fast and reliable taxonomic and molecular identification of marine pests in WA and constitutes a valuable resource for training of stakeholders with interest in IMP recognition in Australia. The reference collection is also useful in supporting the development of a variety of DNA-based detection strategies such as real-time PCR and metabarcoding of complex environmental samples (e.g. biofouling communities). The Prevention List is under regular review to ensure its continued relevance and that it remains evidence and risk-based. Similarly, its associated reference collection also remains to some extent a work in progress. In recognition of this fact, this report seeks to provide details of this continually evolving information repository publicly available to the biosecurity management community worldwide.

  • 6. Eriksson, Britas Klemens
    et al.
    van Sluis, Christiaan
    Sieben, Karin
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Råberg, Sonja
    Stockholm University, Faculty of Science, Department of Botany.
    Omnivory and grazer functional composition moderate cascading trophic effects in experimental Fucus vesiculosus habitats2011In: Marine Biology, ISSN 0025-3162, E-ISSN 1432-1793, Vol. 158, no 4, p. 747-756Article in journal (Refereed)
    Abstract [en]

    We tested the relative strength of direct versus indirect effects of an aquatic omnivore depending on the functional composition of grazers by manipulating the presence of gastropod and amphipod grazers and omnivorous shrimp in outdoor mesocosms. By selectively preying upon amphipods and reducing their abundance by 70-80%, omnivorous shrimp favoured the dominance of gastropods. While gastropods were the main microalgal grazers, amphipods controlled macroalgal biomass in the experiment. However, strong predation on the amphipod by the shrimp had no significant indirect effects on macroalgal biomass, indicating that when amphipod abundances declined, complementary feeding by the omnivore on macroalgae may have suppressed a trophic cascade. Accordingly, in the absence of amphipods, the shrimp grazed significantly on green algae and thereby suppressed the diversity of the macroalgal community. Our experiment demonstrates direct consumer effects by an omnivore on both the grazer and producer trophic levels in an aquatic food web, regulated by prey availability.

  • 7. Florin, Ann-Britt
    et al.
    Mo, Kerstin
    Svensson, Filip
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Schagerström, Ellen
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Bergström, Lena
    First records of Conrad´s false mussel, Mytilopsis leucophaeata (Conrad, 1831) in the southern Bothnian Sea, Sweden, near a nuclear power plant2013In: BioInvasions Records, ISSN 2242-1300, Vol. 2, no 4, p. 303-309Article in journal (Refereed)
    Abstract [en]

    The invasive, biofouling, Conrad's false mussel Mytilopsis leucophaeata was first recorded in Sweden during spring 2011 in the cooling water system of the power plant of Forsmark in the southern Bothnian Sea. The cooling water discharge area offers a favourable environment for growth, survival, and reproduction of M. leucophaeata and may provide a stepping stone for further spread. We present three different studies in the area, revealing a rapid increase in mussels in the artificially heated area, with densities of the magnitude of thousands of individuals m-2, as well as mussels living in surrounding waters, indicating an on-going expansion in the region.

  • 8.
    Forslund, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Grazing and geographic range of the Baltic seaweed Fucus radicans (Phaeophyceae)2012In: Marine Biology Research, ISSN 1745-1000, E-ISSN 1745-1019, Vol. 8, no 4, p. 322-330Article in journal (Refereed)
    Abstract [en]

    The range of the recently described seaweed Fucus radicans is limited to the Bothnian Sea and the northern Baltic Sea while the range of the sympatric Fucus vesiculosus extends outside the Baltic Sea. Here we present results from a survey of the distribution and relative abundance of F. radicans and F. vesiculosus and abundance of associated herbivores along the range of F. radicans in Sweden. Both Fucus species were equally common. Herbivores were found in significantly higher numbers on F. radicans. The range of the herbivore Idotea balthica overlaps the southern range of F. radicans and is known to decrease the abundance of fucoids through grazing. We therefore hypothesized that if I. balthica has a preference for F. radicans it could affect the range of F. radicans. To test the preference of I. balthica we performed a bioassay where it had a choice between F. radicans and F. vesiculosus. Another bioassay was performed with the most common herbivore in our survey, Gammarus spp. Both herbivores consumed significantly more F. radicans than F. vesiculosus. Our results indicate that grazing may be an important factor in limiting the southern range of F. radicans along the Swedish coast.

  • 9.
    Forslund, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Reproduction and reproductive isolation in Fucus radicans (Phaeophyceae)2013In: Marine Biology Research, ISSN 1745-1000, E-ISSN 1745-1019, Vol. 9, no 3, p. 262-267Article in journal (Refereed)
    Abstract [en]

    Recent morphological and genetic studies show that Fucus radicans is a separate species from the sympatric F. vesiculosus. Fucus radicans recently diverged from F. vesiculosus in the Baltic Sea where populations grow in mixed stands. Thus, strong reproductive barriers are expected to be in place to prevent introgression. The seasonal timing of reproduction of the two species in Estonia was shown to be different, likely forming an effective pre-zygotic reproductive barrier. In Sweden, however, no such temporal difference was found. We artificially crossed Swedish F. radicans and F. vesiculosus to identify other potential reproductive barriers. Fertilization success and survival was equally high within and between species in the artificial crossings, suggesting no early post-zygote barriers. Both species recruit new thalli both sexually and asexually, but F. radicans is generally more asexual than F. vesiculosus. By studying their reproductive efforts we found that Swedish F. radicans allocates more resources to adventitious branches than to gamete production compared to F. radicans in Estonia and F. vesiculosus in both Sweden and Estonia. This indicates that Swedish F. radicans has an asexual reproductive strategy while Estonian F. radicans and F. vesiculosus have sexual reproductive strategies.

  • 10.
    Forslund, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Reproduction and reproductive isolation in Fucus radicans (Phaeophyceae)In: Marine Biology Research, ISSN 1745-1000, E-ISSN 1745-1019Article in journal (Refereed)
    Abstract [en]

    Recent morphological and genetic studies show that Fucus radicans is a separate species from the sympatric F. vesiculosus. Fucus radicans recently diverged from F. vesiculosus in the Baltic Sea where populations grow in mixed stands. Thus, strong reproductive barriers are expected to be in place to prevent introgression. The seasonal timing of reproduction of the two species in Estonia was shown to be different, likely forming an effective pre-zygotic reproductive barrier. In Sweden, however, no such temporal difference was found. We artificially crossed Swedish F. radicans and F. vesiculosus to identify other potential reproductive barriers. Fertilization success and survival was equally high within and between species in the artificial crossings, suggesting no early post-zygote barriers. Both species recruit new thalli both sexually and asexually, but F. radicans is generally more asexual than F. vesiculosus. By studying their reproductive efforts we found that Swedish F. radicans allocates more resources to adventitious branches than to gamete production compared to F. radicans in Estonia and F. vesiculosus in both Sweden and Estonia. This indicates that Swedish F. radicans has an asexual reproductive strategy while Estonian F. radicans and F. vesiculosus have sexual reproductive strategies.

  • 11. Haglund, Peter
    et al.
    Malmvärn, Anna
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Bergek, Sture
    Bignert, Anders
    Kautsky, Lena
    Nakano, Takeshi
    Wiberg, Karin
    Asplund, Lillemor
    Are the sources of polybrominated dibenzo-p-dioxins found in Baltic Proper fish and shellfish anthropogenic or natural?2007In: 4th International Workshop on Brominated Flame Retardants: BFR 2007 Amsterdam, 2007Conference paper (Other (popular science, discussion, etc.))
  • 12. Haglund, Peter
    et al.
    Malmvärn, Anna
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Bergek, Sture
    Bignert, Anders
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Nakano, Takeshi
    Wiberg, Karin
    Asplund, Lillemor
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Brominated dibenzo-p-dioxins - A new class of marine toxins?2007In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 41, no 9, p. 3069-3074Article in journal (Refereed)
    Abstract [en]

    Levels of polybrominated dibenzo-p-dioxins (PBDDs) were measured in marine fish, mussels, and shellfish. PBDDs were nondetectable in samples from freshwater environments, and their levels were successively higher in samples from the marine environments of the Bothnian Bay and Bothnian Sea, the West Coast of Sweden, and the Baltic Proper. In Baltic Proper littoral fish the levels of PBDDs generally exceeded those of their chlorinated analogues (PCDDs). This is alarming as some Baltic fish species already are contaminated by chlorinated dioxins to such an extent that they cannot be sold on the European market. By comparing spatial trends in PBDD and PCDD distributions, and PBDD patterns in fish, mussels, and algae, we show that the PBDDs are probably produced naturally, and we propose a route for their biosynthesis. We further show that the levels of PBDDs are high (ng/g wet weight) in mussels, and that the levels increase over time. Finally, we discuss the possibility that the PBDDs have adverse biological effects, and that the levels are increasing as a result of global warming and eutrophication.

  • 13.
    Hansen, Joakim
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Wikström, Sofia
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Axemar, Hanna
    Stockholm University, Faculty of Science, Department of Botany.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Distribution differences and active habitat choices of invertebrates between macrophytes of different morphological complexity2011In: Aquatic Ecology, ISSN 1386-2588, E-ISSN 1573-5125, Vol. 45, no 1, p. 11-22Article in journal (Refereed)
    Abstract [en]

    This study explores: (1) whether the abundance of macroinvertebrates differs between macrophytes differing in both morphological complexity and tolerance to nutrient enrichment; (2) whether the distribution of invertebrates between macrophytes is due to active habitat choice; and (3) whether invertebrates prefer structurally complex to simple macrophytes. Macroinvertebrate abundance was compared between two common soft-bottom plants in the Baltic Sea that are tolerant to eutrophication, Myriophyllum spicatum and Potamogeton pectinatus, and one common plant that is sensitive to eutrophication, Chara baltica. Both field sampling and habitat choice experiments were conducted. We recorded higher total macroinvertebrate abundance on the structurally complex M. spicatum than on the more simply structured P. pectinatus and C. baltica, but found no difference in macroinvertebrate abundance between P. pectinatus and C. baltica. In accordance with the field results, our experiment indicated that the crustacean Gammarus oceanicus actively chose M. spicatum over the other macrophytes. Besides, we found that G. oceanicus actively preferred complex to simply structured artificial plants, indicating that the animal distribution was at least partly driven by differences in morphological complexity between plant species. In contrast, the gastropod Theodoxus fluviatilis did not make an active habitat choice between the plants. Our findings suggest that human-induced changes in vegetation composition can affect the faunal community. Increased abundance of structurally complex macrophytes, for example, M. spicatum, can result in increased abundance of macroinvertebrates, particularly mobile arthropods that may actively choose a more structurally complex macrophyte.

  • 14.
    Hansen, Joakim
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Wikström, Sofia
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Effects of water exchange and vegetation on the macroinvertebrate fauna composition of shallow land-uplift bays in the Baltic Sea2008In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 77, no 3, p. 535-547Article in journal (Refereed)
    Abstract [en]

    Shallow bays with soft sediment bottoms are common habitats along the Swedish and Finnish Baltic Sea coastline. These bays undergo a process of geomorphometric evolution with the natural isostatic land-uplift process, whereby open bays and sounds decrease in depth and are gradually isolated from the sea, forming bays with narrow openings. This study tested the relationship between the morphometric isolation of the bays from the sea and the macroinvertebrate fauna community of these bays. Additionally, we tested the specific role of the submerged vegetation as an indicator of the macroinvertebrate fauna community. We chose two environmental factors for the analyses, water exchange of the bays and the taxon richness of the macroflora in the bays. We found a hierarchical relationship between water exchange, flora taxon richness, and fauna biomass and taxon richness using structural equation modelling: decreased biomass and taxon richness of fauna were related to decreased flora taxon richness, which in turn was related to decreased water exchange. Using multivariate redundancy analysis, the two environmental factors included in the model were found to explain 47.7% of the variation in the fauna taxon composition and 57.5% of the variation in the functional feeding groups of the fauna. Along the morphometric isolation gradient of the bays, the fauna assemblages changed from a community dominated by gastropods, bivalves, and crustaceans, to a community mainly consisting of a few insect taxa. Moreover, the proportion of predators, gathering collectors, and shredders increased while that of filtering collectors and scrapers decreased. Our results indicate that the density and taxon richness of macroinvertebrate fauna are higher in less morphometrically isolated bays than in more isolated bays in the Baltic Sea. Furthermore, we suggest that the taxon richness of macroflora can serve as an indicator of the fauna community.

  • 15.
    Hansen, Joakim
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Wikström, Sofia
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Taxon composition and food-web structure in a morphometric gradient of Baltic Sea land-uplift bays2012In: Boreal environment research, ISSN 1239-6095, E-ISSN 1797-2469, Vol. 17, no 1, p. 1-20Article in journal (Refereed)
    Abstract [en]

    Shallow Baltic Sea bays undergo a process of morphometric isolation from the sea due to post-glacial land uplift. Recent studies have documented that both flora and fauna communities change along this gradient. Changes in taxon composition may in turn alter feeding ecology and trophic relationships. In addition, the relative importance of carbon from terrestrial sources may increase with bay isolation. In accordance with previous studies, we found a change in the community composition of both flora and fauna with bay isolation. Results of stable isotope analysis (δ13C, δ15N) suggested that epiphytes and periphyton are the major carbon sources for most benthic primary consumers, but that their importance in relation to angiosperms and charophytes decreased with bay isolation. The results also indicated that filter feeders utilize terrestrially derived carbon, but its importance could not be critically related to bay isolation. Trophic positions of the consumers were similar across the bay isolation gradient.

  • 16.
    Hansson, Sture
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Bergström, Ulf
    Bonsdorff, Erik
    Härkönen, Tero
    Jepsen, Niels
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Lundström, Karl
    Lunneryd, Sven-Gunnar
    Ovegård, Maria
    Salmi, Juhani
    Sendek, Dmitry
    Vetemaa, Markus
    Competition for the fish - fish extraction from the Baltic Sea by humans, aquatic mammals, and birds2018In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 75, no 3, p. 999-1008Article in journal (Refereed)
    Abstract [en]

    Seals and fish-eating birds have increased in the Baltic Sea and there is concern that they compete with fisheries. Using data from around year 2010, we compare consumption of different fish species by seals and birds to the catch in the commercial and recreational fishery. When applicable this is done at the geographical resolution of ICES subdivisions. Predation by birds and mammals likely has limited impact on the populations of the commercially most important species (herring, sprat, and cod). In the central and southern Baltic, seals and birds consume about as much flatfish as is caught by the fishery and competition is possible. Birds and seals consume 2-3 times as much coastal fish as is caught in the fishery. Many of these species are important to the fishery (e. g. perch and whitefish) and competition between wildlife and the fishery is likely, at least locally. Estimated wildlife consumption of pike, sea trout and pikeperch varies among ICES subdivisions and the degree of competition for these species may differ among areas. Competition between wildlife and fisheries need to be addressed in basic ecosystem research, management and conservation. This requires improved quantitative data on wildlife diets, abundances and fish production.

  • 17.
    Hansson, Sture
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Bergström, Ulf
    Bonsdorff, Erik
    Jepsen, Niels
    Lundström, Karl
    Lunneryd, Sven-Gunnar
    Ovegård, Maria
    Salmi, Juhani
    Sendek, Dmitry
    Vetemaa, Markus
    Response to comments by Heikinheimo et al. (in press) on Hansson et al. (2018): competition for the fish—fish extraction from the Baltic Sea by humans, aquatic mammals, and birds2018In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 75, no 5, p. 1837-1839Article in journal (Refereed)
    Abstract [en]

    As discussions and debates are crucial to science, we appreciate the comments by Heikinheimo et al. (in press) on our article on competition for Baltic Sea fish resources between fishery and wildlife. We cannot see that the comments by Heikinheimo et al. changes the general conclusion derived in our original article—that there are cases of competition between wildlife and fisheries in the Baltic Sea, although not for all species and not to the same extent everywhere. Our responses are structured in the same order as the comments by Heikinheimo et al.

  • 18. Johannesson, Kerstin
    et al.
    André, Carl
    Kautsky, Lena
    Stockholm University, Faculty of Science, Stockholm University Centre for Marine Research (SMF).
    Snabb evolution i Östersjön2007In: Forskning och Framsteg, ISSN 0015-7937, no 3, p. 34-38Article in journal (Other (popular science, discussion, etc.))
  • 19. Johannesson, Kerstin
    et al.
    Forslund, Helena
    Stockholm University, Faculty of Science, Department of Botany.
    Åstrand Capetillo, Nastassja
    Stockholm University, Faculty of Science, Department of Botany.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Johansson, Daniel
    Pereyra, Ricardo T.
    Råberg, Sonja
    Stockholm University, Faculty of Science, Department of Botany.
    Phenotypic variation in sexually and asexually recruited individuals of the Baltic Sea endemic macroalga Fucus radicans: in the field and after growth in a common-garden2012In: BMC Ecology, ISSN 1472-6785, E-ISSN 1472-6785, Vol. 12, p. 2-Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Most species of brown macroalgae recruit exclusively sexually. However, Fucus radicans, a dominant species in the northern Baltic Sea, recruits new attached thalli both sexually and asexually. The level of asexual recruitment varies among populations from complete sexual recruitment to almost (> 90%) monoclonal populations. If phenotypic traits have substantial inherited variation, low levels of sexual activity will decrease population variation in these traits, which may affect function and resilience of the species. We assessed the level of inherited variation in nine phenotypic traits by comparing variation within and among three monoclonal groups and one group of unique multilocus genotypes (MLGs) sampled in the wild.

    RESULTS: Of the nine phenotypic traits, recovery after freezing, recovery after desiccation, and phlorotannin content showed substantial inherited variation, that is, phenotypic variation in these traits were to a large extend genetically determined. In contrast, variation in six other phenotypic traits (growth rate, palatability to isopod grazers, thallus width, distance between dichotomies, water content after desiccation and photochemical yield under ambient conditions) did not show significant signals of genetic variation at the power of analyses used in the study. Averaged over all nine traits, phenotypic variation within monoclonal groups was only 68% of the variation within the group of different MLGs showing that genotype diversity does affect the overall level of phenotypic variation in this species.

    CONCLUSIONS: Our result indicates that, in general, phenotypic diversity in populations of Fucus radicans increases with increased multilocus genotype (MLG) diversity, but effects are specific for individual traits. In the light of Fucus radicans being a foundation species of the northern Baltic Sea, we propose that increased MLG diversity (leading to increased trait variation) will promote ecosystem function and resilience in areas where F. radicans is common, but this suggestion needs experimental support.

  • 20. Johannesson, Kerstin
    et al.
    Johansson, Daniel
    Larsson, Karl H.
    Huenchunir, Cecilia J.
    Perus, Jens
    Forslund, Helena
    Stockholm University, Faculty of Science, Department of Botany.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Pereyra, Ricardo T.
    FREQUENT CLONALITY IN FUCOIDS (FUCUS RADICANS AND FUCUS VESICULOSUS; FUCALES, PHAEOPHYCEAE) IN THE BALTIC SEA2011In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 47, no 5, p. 990-998Article in journal (Refereed)
    Abstract [en]

    Asexual reproduction by cloning may affect the genetic structure of populations, their potential to evolve, and, among foundation species, contributions to ecosystem functions. Macroalgae of the genus Fucus are known to produce attached plants only by sexual recruitment. Recently, however, clones of attached plants recruited by asexual reproduction were observed in a few populations of Fucus radicans Bergstrom et L. Kautsky and F. vesiculosus L. inside the Baltic Sea. Herein we assess the distribution and prevalence of clonality in Baltic fucoids using nine polymorphic microsatellite loci and samples of F. radicans and F. vesiculosus from 13 Baltic sites. Clonality was more common in F. radicans than in F. vesiculosus, and in both species it tended to be most common in northern Baltic sites, although variation among close populations was sometimes extensive. Individual clonal lineages were mostly restricted to single or nearby locations, but one clonal lineage of F. radicans dominated five of 10 populations and was widely distributed over 550 x 100 km of coast. Populations dominated by a few clonal lineages were common in F. radicans, and these were less genetically variable than in other populations. As thalli recruited by cloning produced gametes, a possible explanation for this reduced genetic variation is that dominance of one or a few clonal lineages biases the gamete pool resulting in a decreased effective population size and thereby loss of genetic variation by genetic drift. Baltic fucoids are important habitat-forming species, and genetic structure and presence of clonality have implications for conservation strategies.

  • 21.
    Kautsky, Lena
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Lago-Lestón, Asunción
    Mota, Catarina
    Pearson, Gareth
    Functional divergence in heat shock response following rapid speciation of Fucus spp. in the Baltic Sea2010In: Marine Biology, ISSN 1432-1793, Vol. 157, no 3, p. 683-688Article in journal (Refereed)
    Abstract [en]

    In the Baltic Sea, the broadly distributed brown alga Fucus vesiculosus coexists in sympatry over part of its range (south west Gulf of Bothnia) with the Baltic endemic F. radicans sp. nov, while further north in colder and lower-salinity areas of the Baltic F. radicans occurs alone (north west Gulf of Bothnia). F. radicans appears to have arisen via rapid speciation from F. vesiculosus within the recent history of the Baltic (ca. 7500 BP). Possible functional divergence between the two species was investigated by comparing stress-responsive gene expression in a common-garden experiment. The experiment used two allopatric populations of Fucus vesiculosus from the Skagerrak (North Sea) and Central Baltic, as well as F. radicans from the same Central Baltic site. The two species in sympatry displayed divergent heat shock responses, while F. vesiculosus populations from allopatric sites did not. F. radicans was more sensitive to heat shock at 25°C, either alone or together with high irradiance and desiccation, than Baltic or Skagerrak F. vesiculosus. The results indicate that rapid functional divergence in the inducible heat shock response has occurred between sympatric species on a timescale of thousands of years.

  • 22.
    Kautsky, Lena
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Qvarfordt, Susanne
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Schagerström, Ellen
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Fucus vesiculosus adapted to a life in the Baltic Sea: impacts on recruitment, growth, re-establishment and restoration2019In: Botanica Marina, ISSN 0006-8055, E-ISSN 1437-4323, Vol. 62, no 1, p. 17-30Article in journal (Refereed)
    Abstract [en]

    Fucus vesiculosus is common both on the tidal coasts of the North Atlantic and in the Baltic Sea, where it has adapted to low salinity and nontidal conditions over the last 7000 years. During the late 1970s and early 1980s, extensive declines of F. vesiculosus populations were reported in the Baltic Proper, mainly attributed to high nutrient loads. During the past 30-40 years, considerable efforts have been made to reduce nutrient runoff to coastal areas but few successful initiatives to restore F. vesiculosus populations have been performed. In this paper, we present how substratum manipulation, i.e. clean rocky surfaces, brushing rocks, Hildenbrandia rubra cover and different filamentous algae, as well as different algal exudates, affect the recruitment and survival of juvenile F.vesiculosus. Further, we show through a 5-year field experiment that it will take at least 4-5 years to reach reproductive age for F. vesiculosus in the Baltic Sea. We also present transplantation studies from two different areas, showing that epiphytic load, light, grazing and type of substratum are some of the factors that need to be taken into consideration in order to achieve successful restoration of F. vesiculosus.

  • 23.
    Löfstrand, Karin
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Environmental Chemistry.
    Haglund, Peter
    Umeå universitet, Kemiska institutionen.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Environmental Chemistry.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Asplund, Lillemor
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Environmental Chemistry.
    Hydroxylated and methoxylated polybrominated diphenyl ethers and polybrominated dibenzo-p-dioxins in algae and blue mussels from the Swedish coast line - patterns and correlationsManuscript (preprint) (Other academic)
  • 24.
    Malmvärn, Anna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Zebühr, Yngve
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Asplund, Lillemor
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Hydroxylated and methoxylated polybrominated diphenyl ethers and polybrominated dibenzo-p-dioxins in red alga and cyanobacteria living in the Baltic Sea2008In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 72, no 6, p. 910-916Article in journal (Refereed)
    Abstract [en]

    Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and methoxylated polybrominated diphenyl ethers (MeO-PBDEs) are present in the ecosystem of the Baltic Sea. OH-PBDEs are known to be both natural products from marine environments and metabolites of the anthropogenic polybrominated diphenyl ethers (PBDEs), whereas, MeO-PBDEs appear to be solely natural in origin. Polybrominated dibenzo-p-dioxins (PBDDs) are by-products formed in connection with the combustion of brominated flame retardants (BFRs), but are also indicated as natural products in a red alga (Ceramium tenuicorne) and blue mussels living in the Baltic Sea. The aims of the present investigation were to quantify the OH-PBDEs and MeO-PBDEs present in C. tenuicorne; to verify the identities of PBDDs detected previously in this species of red alga and to investigate whether cyanobacteria living in this same region of the Baltic Sea contain OH-PBDEs, MeO-PBDEs and/or PBDDs. The red alga was confirmed to contain tribromodibenzo-p-dioxins (triBDDs), by accurate mass determination and additional PBDD congeners were also detected in this sample. This is the first time that PBDDs have been identified in a red alga. The SigmaOH-PBDEs and SigmaMeO-PBDEs concentrations, present in C. tenuicorne were 150 and 4.6ngg(-1) dry weight, respectively. In the cyanobacteria 6 OH-PBDEs, 6 MeO-PBDEs and 4 PBDDs were detected by mass spectrometry (electron capture negative ionization (ECNI)). The PBDDs and OH-PBDEs and MeO-PBDEs detected in the red alga and cyanobacteria are most likely of natural origin.

  • 25.
    Mellbrand, Kajsa
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Enskog, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Hambäck, Peter
    Stockholm University, Faculty of Science, Department of Botany.
    Individual variation between spiders on shores in the utilization of aquatic subsidiesManuscript (Other academic)
    Abstract [en]

    Intrapopulation variation is common in nature, and many generalist species actually consists of individual specialists. In food web ecology, stable isotope analysis is a common tool for examining energy and nutrient flows both between and within ecosystems, but large intrapopulation variation in isotopic values may lead to over- or underestimations of dietary variation between populations or species. Such large intraguild variation is common in spiders, which often are generalist predators. In this study we have used carbon and nitrogen stable isotope analysis to examine diets of shore-dwelling spiders, in relation to aquatic inflows to shore ecosystems. The study was carried out on shores inside and outside a eutrophicated bay in the Baltic Sea, using carbon and nitrogen stable isotope analysis. Aquatic subsidies consisted of inflows of algae (mainly green filamentous algae) and emerging insects (Chironomidae). We found that spiders inside the bay all utilized mainly terrestrial prey, while spiders outside the bay, in particular wolf spiders, were separated into individuals utilizing either terrestrial or aquatic prey. The total population niche width was therefore larger outside than inside the bay. This individual specialization may be related to differences in nutrient enrichment in the aquatic ecosystem and/or salinity between sites inside and outside the bay, and we suggest that eutrophication decreases total niche width by affecting prey availability and prey choice of individual predators. We also conclude that while stable isotope analysis remains a useful tool for examining flows across ecosystem boundaries, caution is needed in the interpretation of data with large intrapopulation variation.

  • 26. Pereyra, R. T.
    et al.
    Huenchunir, C.
    Johansson, D.
    Forslund, Helena
    Stockholm University, Faculty of Science, Department of Botany.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Jonsson, P. R.
    Johannesson, K.
    Parallel speciation or long-distance dispersal?: Lessons from seaweeds (Fucus) in the Baltic Sea2013In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 26, no 8, p. 1727-1737Article in journal (Refereed)
    Abstract [en]

    Parallel evolution has been invoked as a forceful mechanism of ecotype and species formation in many animal taxa. However, parallelism may be difficult to separate from recently monophyletically diverged species that are likely to show complex genetic relationships as a result of considerable shared ancestral variation and secondary hybridization in local areas. Thus, species' degrees of reproductive isolation, barriers to dispersal and, in particular, limited capacities for long-distance dispersal will affect demographical structures underlying mechanisms of divergent evolution. Here, we used nine microsatellite DNA markers to study intra- and interspecific genetic diversity of two recently diverged species of brown macroalgae, Fucus radicans (L. Bergstrom & L. Kautsky) and F.vesiculosus (Linnaeus), in the Baltic Sea. We further performed biophysical modelling to identify likely connectivity patterns influencing the species' genetic structures. For each species, we found intraspecific contrasting patterns of clonality incidence and population structure. In addition, strong genetic differentiation between the two species within each locality supported the existence of two distinct evolutionary lineages (F-ST=0.15-0.41). However, overall genetic clustering analyses across both species' populations revealed that all populations from one region (Estonia) were more genetically similar to each other than to their own taxon from the other two regions (Sweden and Finland). Our data support a hypothesis of parallel speciation. Alternatively, Estonia may be the ancestral source of both species, but is presently isolated by oceanographic barriers to dispersal. Thus, a limited gene flow in combination with genetic drift could have shaped the seemingly parallel structure.

  • 27.
    Råberg, Sonja
    et al.
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    A comparative biodiversity study of the associated fauna of perennial fucoids and filamentous algae2007In: Estuarine, coastal and shelf science, ISSN 0272-7714, Vol. 73, p. 249-258Article in journal (Refereed)
    Abstract [en]

    Anthropogenic activities worldwide have contributed to vegetation changes in many coastal areas, changes that may in turn affect faunal and algal assemblages in the involved ecosystems. In the northernmost part of the Baltic Sea the salinity is extremely low (3–4) and the only structurally complex alga present is Fucus radicans. Since in this area F. radicans is living at its salinity tolerance limit, it is potentially very sensitive to environmental changes. Any change in salinity could thus alter the overall algal community, changing it to one dominated solely by filamentous algae. To determine the importance of F. radicans to the associated faunal community, we examined differences between the two main vegetation types present, i.e., F. radicans and filamentous algae, in the Kronören marine reserve in the northernmost part of the Baltic Sea. A similar study was conducted in the Askö area in the northern Baltic Proper, where the more-investigated F. vesiculosus is the only large fucoid present. The biomass of associated fauna was significantly higher in both the F. radicans and F. vesiculosus than in the filamentous algal vegetation at some, but not all, sites. The F. radicans community also displayed a greater diversity of associated fauna in 3 of 5 investigated Kronören sites, whereas no difference in diversity was detected between F. vesiculosus and the filamentous algal vegetations in the Askö sites. Furthermore, the F. radicans community displayed a different faunal community, being the only investigated algal community with a faunal community dominated by K-strategy species, according to abundance–biomass comparison curves. This pattern may be due to the low epiphytic load on these Fucus plants. In contrast, the F. vesiculosus community, as well as the algal communities with no Fucus in both areas, had high biomasses of filamentous algae and an invertebrate fauna dominated by Chironomidae, occurring in great abundance but only a low biomass. ANOSIM analyses of faunal composition demonstrated a significant difference between the two vegetation types in both areas, largely due to greater abundance of Gammarus spp. and Theodoxus fluviatilis in the fucoid vegetation. Differences observed between the F. radicans and filamentous algal vegetation types were generally more pronounced than those between F. vesiculosus and nearby filamentous algal vegetation. These observations may be due to abiotic factors that differ between the two investigated areas, factors such as depth distribution, wave action and eutrophication level. This study has demonstrated that the less-investigated F. radicans may be as important as the larger F. vesiculosus for the associated faunal assemblages. At the same time, the limited extent of F. radicans at shallower depths makes F. radicans vegetation potentially more vulnerable to anthropogenic changes, as declines in fucoid vegetation are usually first manifested in populations at their lower depth limits, whereas shallow populations are less affected.

  • 28.
    Råberg, Sonja
    et al.
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Consumers affect prey biomass and diversity through resource partitioning2007In: Ecology: Reports, ISSN 0012-9658, Vol. 88, no 10, p. 2468-2473Article in journal (Refereed)
    Abstract [en]

    Consumer presence and nutrient availability can have contrasting and interactive effects on plant diversity. In a factorial experiment, we manipulated two levels of nutrient supply and the presence of two moderately specialized grazers in different combinations (no grazers, two species in monoculture, and both in combination). We tested how nutrients and grazers regulated the biomass of marine coastal epiphytes and the diversity of algal assemblages, based on the prediction that the effect of consumers on prey diversity depends on productivity and consumer specialization. Nutrient enrichment increased the epiphytic load while monocultures of single grazer species partly prevented epiphyte growth. However, only the presence of two species with complementary feeding preferences effectively prevented epiphyte overgrowth.

    The epiphytes comprised micro- and macroalgal species and the diversity of these algal assemblages differed depending on grazer identity. For the microalgae, diversity was reduced by nutrient addition when grazer control was inefficient, but not when specialist microalgal grazers were present. Macroalgal diversity was reduced in ambient water with specialist macroalgal grazers compared to the treatment with inefficient ones. These results indicate that grazer composition and productivity are crucial in determining whether consumer pressure will have a positive or negative effect on algal diversity.

  • 29.
    Schagerström, Ellen
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Forslund, Helena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Paernoja, Merli
    Kotta, Jonne
    Does thalli complexity and biomass affect the associated flora and fauna of two co-occurring Fucus species in the Baltic Sea?2014In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 149, p. 187-193Article in journal (Refereed)
    Abstract [en]

    On rocky shores, fucoids provide habitat, shelter and food for associated biota. In the northern parts of the Baltic, the Bothnian Sea, the new fucoid species Fucus radicans (Bergstrom et Kautsky) was recently described. This study compares the thallus complexity and size as well as quantified the abundance and biomass of epiphytic algae and invertebrate taxa of the two fucoid species F. radicans and Fucus vesiculosus L. from sympatric sites in the Bothnian Sea on the Swedish coast and around the Estonian island Saaremaa. We found that F. radicans was more complex than F. vesiculosus within the whole study range, but both species had a more complex thallus structure in the Bothnian Sea compared to Estonia. The complexity of host algae did not contribute to their associated flora and fauna taxon richness; instead, the size of thalli was a good proxy for associated communities. Specifically, on a biomass basis, F. vesiculosus displayed highest species richness and highest faunal abundance in the Bothnian Sea, whereas no such differences were found around Saaremaa, probably because both Focus species had similar height around Saaremaa whereas F. vesiculosus grew much taller and larger in the Bothnian Sea. There were some unique associated macroalgal and invertebrate species that were found only on either of the fucoids, indicating the importance of separating them as species in surveys and monitoring.

  • 30.
    Schagerström, Ellen
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Despite marine traits, the endemic Fucus radicans (Phaeophyceae) is restricted to the brackish Baltic Sea2016In: European journal of phycology, ISSN 0967-0262, E-ISSN 1469-4433, Vol. 51, no 4, p. 378-386Article in journal (Refereed)
    Abstract [en]

    Many of the marine species that were introduced to the Baltic Sea during the Littorina stage (c. 8500-3000 years BP), e.g. Fucus vesiculosus and F. serratus, have adapted to the present low salinity. These marine species have gone from marine conditions into lower salinity environments. In this paper we ask why the recently discovered endemic brown alga Fucus radicans shows the opposite pattern. Fucus radicans is only present in the northern parts of the Baltic Sea, the low salinity Bothnian Sea (4-6 psu). Potentially, the fitness of F. radicans might be reduced in higher salinities if it is better adapted to brackish conditions. We hypothesize, however, that the southern distribution limit of F. radicans is set by biotic factors, e.g. competition with F. vesiculosus and higher grazing pressure by Idotea balthica and not by salinity. Our results show that the reproductive output of F. radicans is limited by low salinity (4 psu) but increases in higher salinities. However, the southern distribution limit, i.e. the northern Baltic Proper, is regulated by biotic factors, where the additive effects from shading by taller F. vesiculosus thalli and grazing on F. radicans by the isopod I. balthica limit the biomass production of F. radicans. We suggest that F. radicans still maintains marine traits due to its ability to propagate clonally and is restricted to the Bothnian Sea by interactions with F. vesiculosus and I. balthica. We also propose that increased precipitation due to climate change might affect the northern range limit and that the distribution of F. radicans could be expected to shift further south into the Baltic Proper.

  • 31.
    Schagerström, Ellen
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Macroscopic sexual dimorphism in Fucus radicans (Phaeophyceae) with implications for its reproductive ecology2016In: Botanica Marina, ISSN 0006-8055, E-ISSN 1437-4323, Vol. 59, no 6, p. 485-490Article in journal (Refereed)
    Abstract [en]

    Sexual dimorphism on a macroscopic scale is unusual within the Phaeophyceae. We report for the first time macroscopic sexual dimorphism in Fucus radicans. A set of morphological characters was measured on three dioecious Fucus species, F. radicans, Fucus serratus and Fucus vesiculosus, to determine if sexual dimorphism occurs in the endemic F. radicans in the Baltic Sea and if it also is found in the other fucoids. F. radicans was sampled from highly clonal populations of the Bothnian Sea and from populations in the Vainameri Sea where no clones have been found. In both locations, sexual dimorphism was recorded in receptacle size and weight in F. radicans. Also, the receptacle dry weight to wet weight ratio was higher in males than in females, showing that male receptacles have a lower water content than females. The dimorphism was more pronounced in the Bothnian Sea populations, where further differences between the sexes in thallus width and fertility index also were present. This has not been shown for any member of the genus Fucus before, but seems to be a species-specific character in F. radicans, as there were no differences between the sexes in either F. serratus or F. vesiculosus.

  • 32. Viitasalo, Markku
    et al.
    Blenckner, Thorsten
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Gårdmark, Anna
    Kaartokallio, Hermanni
    Kautsky, Lena
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Kuosa, Harri
    Lindegren, Martin
    Norkko, Alf
    Olli, Kalle
    Wikner, Johan
    Environmental Impacts - Marine Ecosystems2015In: Second Assessment of Climate Change for the Baltic Sea Basin / [ed] The BACC II Author Team, Springer, 2015, p. 363-380Chapter in book (Refereed)
    Abstract [en]

    Increase in sea surface temperature is projected to change seasonal succession and induce dominance shifts in phytoplankton in spring and promote the growth of cyanobacteria in summer. In general, climate change is projected to worsen oxygen conditions and eutrophication in the Baltic Proper and the Gulf of Finland. In the Gulf of Bothnia, the increasing freshwater discharge may increase the amount of dissolved organic carbon (DOC) in the water and hence reduce phytoplankton productivity. In winter, reduced duration and spatial extent of sea ice will cause habitat loss for ice-dwelling organisms and probably induce changes in nutrient dynamics within and under the sea ice. The projected salinity decline will probably affect the functional diversity of the benthic communities and induce geographical shifts in the distribution limits of key species such as bladder wrack and blue mussel. In the pelagic ecosystem, the decrease in salinity together with poor oxygen conditions in the deep basins will negatively influence the main Baltic Sea piscivore, cod. This has been suggested to cause cascading effects on clupeids and zooplankton.

  • 33.
    Wennerström, Lovisa
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Laikre, Linda
    Stockholm University, Faculty of Science, Department of Zoology.
    Ryman, Nils
    Stockholm University, Faculty of Science, Department of Zoology.
    Utter, Fred M.
    Ab Ghani, Nurul Izza
    André, Carl
    DeFaveri, Jacquelin
    Johansson, Daniel
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Merilä, Juha
    Mikhailova, Natalia
    Pereyra, Ricardo
    Sandström, Annica
    Teacher, Amber G. F.
    Wenne, Roman
    Vasemägi, Anti
    Zbawicka, Malgorzata
    Johannesson, Kerstin
    Primmer, Craig R.
    Genetic biodiversity in the Baltic Sea: species-specific patterns challenge management2013In: Biodiversity and Conservation, ISSN 0960-3115, E-ISSN 1572-9710, Vol. 22, no 13-14, p. 3045-3065Article in journal (Refereed)
    Abstract [en]

    Information on spatial and temporal patterns of genetic diversity is a prerequisite to understanding the demography of populations, and is fundamental to successful management and conservation of species. In the sea, it has been observed that oceanographic and other physical forces can constitute barriers to gene flow that may result in similar population genetic structures in different species. Such similarities among species would greatly simplify management of genetic biodiversity. Here, we tested for shared genetic patterns in a complex marine area, the Baltic Sea. We assessed spatial patterns of intraspecific genetic diversity and differentiation in seven ecologically important species of the Baltic ecosystem-Atlantic herring (Clupea harengus), northern pike (Esox lucius), European whitefish (Coregonus lavaretus), three-spined stickleback (Gasterosteus aculeatus), nine-spined stickleback (Pungitius pungitius), blue mussel (Mytilus spp.), and bladderwrack (Fucus vesiculosus). We used nuclear genetic data of putatively neutral microsatellite and SNP loci from samples collected from seven regions throughout the Baltic Sea, and reference samples from North Atlantic areas. Overall, patterns of genetic diversity and differentiation among sampling regions were unique for each species, although all six species with Atlantic samples indicated strong resistence to Atlantic-Baltic gene-flow. Major genetic barriers were not shared among species within the Baltic Sea; most species show genetic heterogeneity, but significant isolation by distance was only detected in pike and whitefish. These species-specific patterns of genetic structure preclude generalizations and emphasize the need to undertake genetic surveys for species separately, and to design management plans taking into consideration the specific structures of each species.

  • 34.
    Wikström, Sofia A.
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Invasion of a habitat-forming seaweed: effects on associated biota2004In: Biological Invasions, ISSN 1387-3547, E-ISSN 1573-1464, Vol. 6, no 2, p. 141-150Article in journal (Refereed)
    Abstract [en]

    Fucus evanescens is a brown alga of arctic origin that has invaded European coasts. The epiphytic community of F. evanescens in southern Sweden was compared with that of the native Fucus vesiculosus, to examine to what extent an invading seaweed can modify local biodiversity. F. evanescens was much less fouled than F. vesiculosus, supporting both less biomass and fewer species of epiphytes. Multivariate analysis of the most common epiphyte taxa showed that the epiphytic community composition of F. evanescens was not entirely separated from that of F. vesiculosus, but host species contributed significantly to explain the variation in community composition. The biomass of free-living invertebrates was also lower on F. evanescens, although the pattern differed between taxonomic groups. While the biomass of amphipods was lower on F. evanescens, there was no significant difference in biomass of isopods or gastropods between the Fucus species. The good correlation between biomass of epiphytes and free-living animals suggests that the epiphytes play an important role in providing a suitable habitat for many species of free-living epifauna. The study shows that the invasion of F. evanescens affects the environmental conditions for many species associated with the Fucus community but that the direct effect on biodiversity is probably low.

  • 35.
    Wikström, Sofia A.
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    von Wachenfeldt, Torgny
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Establishment of the exotic species Fucus evanescens C. Ag. (Phaeophyceae) in Öresund, Southern Sweden2002In: Botanica Marina, ISSN 0006-8055, E-ISSN 1437-4323, Vol. 45, no 6, p. 510-517Article in journal (Refereed)
    Abstract [en]

    The spread and establishment of the exotic species Fucus evanescens in öresund, Southern Sweden was documented through inventories in 1966–72 and 2000. The species spread fast from the first known introduction in 1955, colonising harbours along the coast. After this expansion the further spread has been limited and the species is still largely confined to harbour areas, where it occurs in the same depth zone as its native relatives, F. vesiculosus, F. serratus and Ascophyllum nodosum. It is more common in the northern part of the area and has not expanded into the Baltic Sea proper. Tests of the attachment strength of F. evanescens plants suggest that the restriction to harbours is not due to the direct effects of wave exposure on adults. In the laboratory, reproductive success of F. evanescens decreased from 99% in 24 psu to 12% in 10 psu and at lower salinity reproduction failed. Growth of embryonic recruits was similarly affected by salinity. Hence, low salinity explains the limited success of F. evanescens in southern Öresund, where the salinity is low and fluctuating, and its failure to colonise the Baltic Sea proper.

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