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  • 301. Laliberte, Etienne
    et al.
    Wells, Jessie A.
    DeClerck, Fabrice
    Metcalfe, Daniel J.
    Catterall, Carla P.
    Queiroz, Cibele
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Aubin, Isabelle
    Bonser, Stephen P.
    Ding, Yi
    Fraterrigo, Jennifer M.
    McNamara, Sean
    Morgan, John W.
    Sanchez Merlos, Dalia
    Vesk, Peter A.
    Mayfield, Margaret M.
    Land-use intensification reduces functional redundancy and response diversity in plant communities2010In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 13, no 1, p. 76-86Article in journal (Refereed)
    Abstract [en]

    Ecosystem resilience depends on functional redundancy (the number of species contributing similarly to an ecosystem function) and response diversity (how functionally similar species respond differently to disturbance). Here, we explore how land-use change impacts these attributes in plant communities, using data from 18 land-use intensity gradients that represent five biomes and > 2800 species. We identify functional groups using multivariate analysis of plant traits which influence ecosystem processes. Functional redundancy is calculated as the species richness within each group, and response diversity as the multivariate within-group dispersion in response trait space, using traits that influence responses to disturbances. Meta-analysis across all datasets showed that land-use intensification significantly reduced both functional redundancy and response diversity, although specific relationships varied considerably among the different land-use gradients. These results indicate that intensified management of ecosystems for resource extraction can increase their vulnerability to future disturbances. Ecology Letters (2010) 13: 76-86.

  • 302. Larigauderie, Anne
    et al.
    Prieur-Richard, Anne-Helene
    Mace, Georgina M.
    Lonsdale, Mark
    Mooney, Harold A.
    Brussaard, Lijbert
    Cooper, David
    Cramer, Wolfgang
    Daszak, Peter
    Diaz, Sandra
    Duraiappah, Anantha
    Elmqvist, Thomas
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Faith, Daniel P.
    Jackson, Louise E.
    Krug, Cornelia
    Leadley, Paul W.
    Le Prestre, Philippe
    Matsuda, Hiroyuki
    Palmer, Margaret
    Perrings, Charles
    Pulleman, Mirjam
    Reyers, Belinda
    Rosa, Eugene A.
    Scholes, Robert J.
    Spehn, Eva
    Turner, B. L. , I I
    Yahara, Tetsukazu
    Biodiversity and ecosystem services science for a sustainable planet: the DIVERSITAS vision for 2012-202012In: Current Opinion in Environmental Sustainability, ISSN 1877-3435, E-ISSN 1877-3443, Vol. 4, no 1, p. 101-105Article in journal (Refereed)
    Abstract [en]

    DIVERSITAS, the international programme on biodiversity science, is releasing a strategic vision presenting scientific challenges for the next decade of research on biodiversity and ecosystem services: Biodiversity and Ecosystem Services Science for a Sustainable Planet. This new vision is a response of the biodiversity and ecosystem services scientific community to the accelerating loss of the components of biodiversity, as well as to changes in the biodiversity science-policy landscape (establishment of a Biodiversity Observing Network - GEO BON, of an Intergovernmental science-policy Platform on Biodiversity and Ecosystem Services - IPBES, of the new Future Earth initiative; and release of the Strategic Plan for Biodiversity 2011-2020). This article presents the vision and its core scientific challenges.

  • 303.
    Larsson, Ulf
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Sjösten, Anders
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Hajdu, Susanna
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Nyberg, Svante
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Himmerfjärden 2006: Rapport till SYVAB2006Report (Other academic)
  • 304. Lehtiniemi, M.
    et al.
    Gorokhova, E.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Predation of the introduced cladoceran Cercopagis pengoi on the calanoid copepod Eurytemora affinis in the Gulf of Finland, Baltic Sea.2008In: MARINE ECOLOGY-PROGRESS SERIES, ISSN 0171-8630, Vol. 362, p. 193-200Article in journal (Refereed)
    Abstract [en]

    We studied the potential of an introduced species, the predatory cladoceran Cercopagis pengoi, to influence native zooplankton populations in the Baltic Sea. Feeding rates (FRs) of different instars of C. pengoi on Eurytemora affinis, a dominant copepod species, were determined experimentally. The FRs of C. pengoi varied from 0.7 to 4.8 prey predator(-1) d(-1) and were significantly higher in older instars. Based on the experimental results and long-term zooplankton abundance data from the Gulf of Finland, we estimated the in situ predation rates. Our results imply that at maximum abundance, the C. pengoi population feeding in dense prey patches could consume as many as 10(5) E. affinis m(-3) d(-1). This could explain the observed drastic decrease in copepod abundances in the eastern Gulf of Finland, the region with the highest C. pengoi abundance after the expansion of this species. Such a decline may strengthen food competition between other zooplanktivores, i.e. planktivorous fish and mysids, feeding on the same copepod prey in regions where C, pengoi may reach high abundances. In the Gulf of Finland, especially in the eastern parts, a collapse of E. affinis, a key species in the pelagic system, would cause major changes in virtually all trophic levels, because the food web structure is simple with only a few species of zooplankton, planktivores, and piscivores.

  • 305. Lehtiniemi, M
    et al.
    Pääkkönen, J-P
    Flinkman, J
    Katajisto, T
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Karjalainen, M
    Viitasalo, S
    Björk, H
    Distribution and abundance of the American comb jelly (Mnemiopsis leidyi) – A rapid invasion to the northern Baltic Sea during 20072007In: Aquatic Invasions, Vol. 2, no 4, p. 445-449Article in journal (Refereed)
  • 306. Lehtiniemi, Maiju
    et al.
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM). Stockholm University, Faculty of Science, Department of Systems Ecology.
    Bolte, Sören
    Haslob, Holger
    Huwer, Bastian
    Katajisto, Tarja
    Lennuk, Lennart
    Majaneva, Sanna
    Pollumaee, Arno
    Schaber, Matthias
    Setala, Outi
    Reusch, Thorsten B. H.
    Viitasalo-Frosen, Satu
    Vuorinen, Ilppo
    Valipakka, Pentti
    Distribution and reproduction of the Arctic ctenophore Mertensia ovum in the Baltic Sea2013In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 491, p. 111-124Article in journal (Refereed)
    Abstract [en]

    Species identification based on morphological characteristics has caused misidentifications and led to twisted views of abundances and roles of ctenophores. Based on extensive field studies from 2007 to 2010, the occurrence of the arctic ctenophore Mertensia ovum was genetically verified in the southern, central and northern Baltic Sea, and its egg production, distribution and abundance were studied in relation to physical factors. Genetic analyses indicate that M. ovum is by far the most abundant small ctenophore in the Baltic Sea. Specimens from a 20 yr old ctenophore collection were also genetically identified as M. ovum, contrary to their previous morphological identification as another ctenophore species, Pleurobrachia pileus. Thus, earlier reports on P. pileus in the Baltic Sea may actually refer to M. ovum. The abundance of M. ovum was regulated by both salinity and temperature, with highest abundances found in sea areas and water layers at temperatures <7 degrees C, salinities >5.5 and oxygen levels >4 ml l(-1). During summer, the highest abundances of ctenophores and their eggs were found near the halocline, while the distribution was more uniform throughout the water column during winter. Only ctenophores >3.5 mm (oral-aboral length) produced eggs in the experiments, with an average rate of 2.2 eggs ind.(-1) d(-1). Finally, comparison with published data from the 1980s (assuming that those data refer to M. ovum) indicates that the present-day ctenophore abundance is similar to 80% lower in the north and similar to 55% higher in the southern parts of the Baltic Sea, due to reasons yet to be established.

  • 307. Lesutiene, J.
    et al.
    Gorokhova, E.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Gasiunaite, Z.R.
    Razinkovas, A.
    Role of mysid seasonal migrations in the organic matter transfer in the Curonian Lagoon, south-eastern Baltic Sea.2008In: ESTUARINE COASTAL AND SHELF SCIENCE, ISSN 0272-7714, Vol. 80, no 2, p. 225-234Article in journal (Refereed)
    Abstract [en]

    We investigated population dynamics, growth and feeding of an omnivorous mysid, Paramysis lacustris, performing seasonal horizontal migrations in the Curonian Lagoon. In autumn, increased predation pressure and deteriorated feeding conditions, due to zooplankton and phytoplankton decline in the open water, forces mysids to migrate to the shoreline, where large amounts of decaying submersed vegetation occur at the end of plant growth season. Using stable isotope analysis and mixing models, we evaluated relative importance of decaying submersed macrophytes, lagoon phytoplankton and mesozooplankton in the diet of mysids during this period. In September- November, mysids actively grew and produced three cohorts. Specific growth rates of adults (10.9 +/- 1.9 mm) and subadults (6 +/- 0.5 mm)were 3 and 9% DW d(-1), respectively, resulting in population somatic production of 36 g DW m(-2). Both delta N-15 and delta C-13 of mysids varied in concert with those in suspended and bottom particulate organic matter (POM) and mesozooplankton. The mixing models estimated that 45% of mysid diets were composed of bottom POM originated from the decaying macrophyte Potamogeton perfoliatus, 45% by suspended POM largely consisting of phytoplankton. while mesozooplankton contributed less than 10% of the diet. This diet composition differs from that in summer, when mysids rely mostly on zooplankton and phytoplankton. Therefore, mysid horizontal migrations and their ability to efficiently utilize littoral detritus improve the efficiency of macrophyte detritus transfer up the food chain and inshore/offshore habitat coupling in the Curonian Lagoon.

  • 308. Lesutiene, J
    et al.
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Systems Ecology. marin ekologi.
    Gasiunaite, ZR
    Razinkovas, A
    Isotopic evidence for zooplankton as an important food source for a coastal mysid Paramysis lacustris in the Curonian Lagoon, south-eastern Baltic Sea2007In: Estuarine, Coastal and Shelf Science, Vol. 73, p. 73-80Article in journal (Refereed)
  • 309.
    Lilja, Carl
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Prevodnik, Andreas
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Gardeström, Johanna
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Elfwing, Tina
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Bollner, Tomas
    Regional differences in mRNA responses in blue mussels within the Baltic proper2008In: Comparative Biochemistry and Physiology - Part C: Toxicology & Pharmacology, ISSN 1532-0456, E-ISSN 1878-1659, Vol. 148, no 2, p. 101-106Article in journal (Refereed)
    Abstract [en]

    Mussels (Mytilus sp.) from two regions along the permanent salinity gradient within the Baltic proper were exposed to copper (35 ppb) or petrol (0.3 mL/L) for 10 days and analyzed for mRNA expressions in gill tissue. Expression of mRNAs for the heat shock proteins HSP70 and HSP90 was significantly induced by copper, but not by petrol. For the metallothioneins MT10 and MT20, regional differences in mRNA expressions could be seen. In mussels from the northern Baltic proper, MT20 expression increased 2.8 and 3.4 times, after exposure to copper and petrol, respectively. In contrast, no change could be seen in MT20 expression for mussels from the southern Baltic proper. MT10 showed a peculiar expression not previously described. For some mussels, no expression at all was detected, some showed a weak expression and for some individuals a strong expression could be seen. For the mussels from the southern Baltic proper, the number of individuals with a strong expression of MT10 increased from 1 out of 18 (control), to 7 and 8, after exposure to copper and petrol, respectively. The results clearly show that responses vary between different regions within the Baltic proper, which emphasises the importance to study interactions between contaminants, populations and regions. 

  • 310.
    Lilja, Karl
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Regional differences in biomarker responses in Baltic Sea blue mussels (Mytilus sp.)2007Licentiate thesis, monograph (Other academic)
  • 311.
    Lilliesköld Sjöö, Gustaf
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Macroalgae in tropical seascapes: regulating factors and functions in the coastal ecosystem2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Although macroalgae usually are inconspicuous on pristine coral reefs, they often thrive on reefs that are subjected to various types of anthropogenic disturbance. This thesis consists of five papers and investigates how biomass and composition of macroalgal communities on coral reefs are affected by regulating factors, such as nutrient availability, herbivory, substrate availability and hydrodynamic forces. In addition, ecological functions and potential impacts of both wild and farmed macroalgal communities are evaluated. Paper I describes a method for using macroalgal tissue nutrient concentrations as bioindicator for nutrient availability, with the possibility to map nutrient loading from larger coastal cities. Papers II and III are manipulative studies comparing top-down and bottom-up regulation of macroalgal communities, where herbivore consumption seems to be the main regulator of biomass whereas nutrient availability mainly influences community composition. Exclosure of large-bodied herbivores had a positive influence on algal biomass in both studies, and during different climatic periods. Paper III also includes the influence of hydrodynamic forces on algal community biomass and structure by comparing a reef crest and a back reef-habitat. Alterations of top-down and bottom-up regulation generally had a stronger effect within the protected back reef-habitat, suggesting that such environments may be more sensitive to anthropogenic influence. Paper IV confirms the general conclusions from papers II and III by studying macroalgal biomass and composition on reef sites with different environmental prerequisites. This study also supports the notion that herbivorous fish can suppress accumulation of macroalgal biomass if substrate availability is low, but not where coral cover is reduced and plenty of substrate is open to macroalgal colonization. The study also found a large temporal variation of macroalgal standing stock and associated nutrients at sites with low top-down regulation. Paper V evaluates potential impacts of seaweed farming on coral reefs and nutrients in the seascape by experimentally studying growth, survival and nutrient binding capacity of Eucheuma denticulatum. This study showed that seaweed farms counteract eutrophication through nutrient extraction and that the risk of farmed algae colonizing local reefs seems to be small as they were rapidly consumed. In conclusion, the studies in this thesis contribute to the understanding of macroalgal regulation and function in tropical seascapes, thereby adding to the knowledge base for coastal management.

  • 312.
    Lilliesköld Sjöö, Gustaf
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Macroalgal content and community structure as indicators of anthropogenic disturbance – examples from the Eastern African coast.2008Licentiate thesis, monograph (Other academic)
  • 313.
    Lilliesköld Sjöö, Gustaf
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Andersson, Simon
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Troell, Max
    Stockholm University, Stockholm Resilience Centre.
    Seaweed farming in the tropical seascape – implications for coral reefs and nutrients in Chwaka Bay, TanzaniaManuscript (preprint) (Other academic)
  • 314.
    Lilliesköld Sjöö, Gustaf
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Mörk, Erik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Tissue Nutrient Content in Ulva spp. (Chlorophyceae) as Bioindicator for Nutrient Loading Along the Coast of East Africa2009In: The Open Environmental & Biological Monitoring Journal, ISSN 1875-0400, Vol. 2, p. 11-17Article in journal (Refereed)
    Abstract [en]

    Eutrophication is an increasingly occurring problem that causes degradation of coastal ecosystems worldwide.Traditional monitoring of dissolved nutrients in the water column can be complicated by short term fluctuations, especiallywhen levels of nutrients are low and turnover rapid. A proposed alternative method is the use of macroalgal tissuenutrient concentrations for indication of ambient nutrient availability, as they integrate nutrients over time. This studyevaluates the use of macroalgae within the genus Ulva (Chlorophyceae), regarding their ability to reflect nutrient gradientsoff the coast of East Africa (i.e. Kenya and Tanzania). Ulva was able to reflect nitrogen (N) gradients from all three outletsources, with up to 90% higher tissue N levels in vicinity of major cities compared to adjacent areas. Together with resultsfrom nutrient- uptake and fluctuation experiments, this study suggests that macroalgal tissue nutrient content has potentialas a complement to regular water nutrient sampling.

  • 315.
    Lilliesköld Sjöö, Gustaf
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Mörk, Erik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Andersson, Simon
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Melander, Inger
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Differences in top-down and bottom-up regulation of macroalgal communities between a reef crest and back reef habitat in Zanzibar2011In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 91, no 4, p. 511-518Article in journal (Refereed)
    Abstract [en]

    Coral reef ecosystems are subjected to intense pressure from growing coastal populations and subsequently increased nutrient loading and extraction of marine organisms. This development has altered top-down and bottom-up regulation of macroalgae in the reef system. The relative importance of these regulating forces is also influenced by environmental prerequisites, such as exposure to wave action and water motion. Thus, the present study tested the importance of top-down and bottom-up regulation, by manipulation of nutrient availability and grazer abundance, at one reef crest- and one back reef-site in Chwaka bay (Zanzibar, Tanzania). Wave action and water motion may regulate macroalgal communities by affecting the mobility of herbivores and availability of nutrients. The present study was conducted at the onset of the monsoon period, with a general decline of macroalgal cover and biomass in the region; positive effects on biomass development were therefore manifested in reduced decline and not in an actual increase. The experimental study showed that both caging and fertilization had significant impacts on macroalgal community composition but only caging showed any significant effects on biomass development. However, the influences of both these structuring forces were lower at the more exposed crest-site. This period was chosen as most similar studies have been conducted during growth season, often overlooking the studied period. Such previous studies have shown that herbivore exclusion increases macroalgal biomass, while the present study shows that it can also reduce biomass decline during the seasonal die-off by approx 50%. Together, these results suggest an overall larger macroalgal presence on the reef when herbivory is reduced. In general, our results propose that exposure to wave action and water motion functions as an important regulating factor, affecting macroalgal communities by influencing both top-down and bottom-up regulation. In turn, these results suggest that anthropogenic disturbances may have a greater impact on more sheltered coral reef habitats.

  • 316.
    Lilliesköld Sjöö, Gustaf
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Mörk, Erik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    McClanahan, Tim R.
    Marine Programs, Wildlife Conservation Society, Bronx, NY, USA.
    Regulation of macroalgal biomass accumulation and community structure by herbivory and nutrients on Kenyan coral reefsManuscript (preprint) (Other academic)
  • 317.
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Effects of land abandonment and restoration on plant species richness in Scandinavian rural landscapes2007In: IALE (International Association for Landscape Ecology) World Conference, Wagenegen, 2007, 2007Conference paper (Refereed)
  • 318.
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Evaluating the distribution of plant life-history traits in relation to current and historical landscape configurations2007In: Journal of Ecology, ISSN 0022-0477, Vol. 95, no 3, p. 555-564Article in journal (Refereed)
  • 319.
    Lindborg, Regina
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Bengtsson, Jan
    Berg, Åke
    Cousins, Sara A.O.
    Stockholm University, Faculty of Science, Department of Botany. Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    Gustafsson, Tomas
    Hasund, Knut Per
    Lenoir, Lisette
    Pihlgren, Aina
    Sjödin, Erik
    Stenseke, Marie
    A landscape perspective on conservation of semi-natural grasslands.2008In: AGRICULTURE ECOSYSTEMS & ENVIRONMENT, ISSN 0167-8809, Vol. 125, no 1-4, p. 213-222Article in journal (Refereed)
    Abstract [en]

    Current agri-environmental schemes and subsidies for conservation and restoration of semi-natural grasslands do not explicitly assess land use changes affecting whole landscapes, but have so far focused on single objects and small areas. In this paper, we discuss a landscape perspective versus a "single object" perspective when conserving semi-natural grassland in agricultural landscapes. The focus is on the values biodiversity, cultural heritage, a vital countryside, and effects on economy when land use changes. We conclude that when land use change in the landscape surrounding an object, important additional effects on the different values are found. For example, a countryside where animals graze former arable fields and where marginal habitats are managed will have a positive effect, not only on the biodiversity associated to semi-natural grasslands, but also for the image of a vital and dynamic landscape. An increased number of roads, on the other hand, may negatively affect cultural heritage and decrease biodiversity in grasslands, leading to negative effects on the value of common goods through isolation. Placing objects in a larger spatial context and combining several different aspects into a landscape perspective, will improve long-term preservation of values associated to semi-natural grasslands.

  • 320.
    Lindborg, Regina
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Eriksson, O.
    Department of Botany.
    Effects of grassland restoration on plant species richness in Swedish agricultural landscapes.2008In: Biodiversity and animal feed - future challenges for grassland production, EGF Conference, Uppsala 2008., 2008Conference paper (Refereed)
  • 321.
    Lindborg, Regina
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Stenseke, Marie
    Cousins, Sara A.O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Bengtsson, Jan
    Berg, Åke
    Gustafsson, Tomas
    Sjödin, N. Erik
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    Investigating biodiversity trajectories using scenarios – Lessons from two contrasting agricultural landscapes2009In: Journal of Environmental Management, ISSN 0301-4797, E-ISSN 1095-8630, Vol. 91, p. 499-508Article in journal (Refereed)
    Abstract [en]

    Agriculture is the major land use at a global scale. In addition to food production, multifunctionality of landscapes, including values and ecosystem services like biodiversity, recreation and culture, is now focus for management. This study explores how a scenario approach, involving different stakeholders, may help to improve landscape management for biodiversity conservation. Local farmers and executives at the County Administrative Board were invited to discuss rural development and conditions for farmland biodiversity in two Swedish landscapes. The potential biodiversity for three future land use scenarios for the two landscapes was discussed: nature conservation, outdoor recreation and energy production, and compared with current and historical landscapes in each region.

    Analyses of habitat areas, connectedness and landscape diversity suggested that the energy and recreation scenarios had a negative impact on farmland biodiversity, whereas the nature conservation scenario, the current and historically reconstructed landscapes had a higher potential for biodiversity. The farmers appreciated the nature conservation scenario, but also the energy production scenario and they highlighted the need of increased subsidies for management of biodiversity. The farmers in the high production area were less interested in nature quality per se. The executives had similar opinions as the farmers, but disagreed on the advantages with energy production, as this would be in conflict with the high biodiversity and recreational values. The local physical and socio-economical conditions differ between landscapes and potentially shaped the stakeholders emotional attachment to the local environment, their opinions and decisions on how to manage the land. We stress the importance of incorporating local knowledge, visions and regional prerequisites for different land uses in conservation, since site and landscape specific planning for biodiversity together with a flexible subsidy system are necessary to reach the conservation goals within EU.

  • 322. Lindborg, T
    et al.
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Löfgren, A
    Söderbäck, B
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Kautsky, Ulrik
    A strategy for describing the biosphere at candidate sites for repositories of nuclear waste: Linking ecosystem and landscape modeling2006In: Ambio, Vol. 35, no 8, p. 418-424Article in journal (Refereed)
  • 323. Liu, Bin-yang
    et al.
    Nie, Xiang-ping
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Liu, Wei-qiu
    Snoeijs, Pauline
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Guan, Chao
    Tsui, Martin T. K.
    Toxic effects of erythromycin, ciprofloxacin and sulfamethoxazole on photosynthetic apparatus in Selenastrum capricornutum2011In: Ecotoxicology and Environmental Safety, ISSN 0147-6513, E-ISSN 1090-2414, Vol. 74, no 4, p. 1027-1035Article in journal (Refereed)
    Abstract [en]

    The effects of three antibiotics (erythromycin, ciprofloxacin and sulfamethoxazole) on photosynthesis process of Selenastrum capricornutum were investigated by determining a battery of parameters including photosynthetic rate, chlorophyll fluorescence, Hill reaction, and ribulose-1.5-bisphosphate carboxylase activity, etc. The results indicated that three antibiotics could significantly inhibit the physiological progress including primary photochemistry, electron transport, photophosphorylation and carbon assimilation. Erythromycin could induce acute toxic effects at the concentration of 0.06 mg L(-1) while the same results were exhibited for ciprofloxacin and sulfamethoxazole at higher than 1.0 mg L(-1). Erythromycin was considerably more toxic than ciprofloxacin and sulfamethoxazole and may pose a higher potential risk to the aquatic ecosystem. Some indices like chlorophyll fluorescence, Mg(2+)-ATPase activity and RuBPCase activity showed a high specificity and sensitivity to the exposure of erythromycin, and may be potentially used as candidate biomarkers for the exposure of the macrolide antibiotics.

  • 324. Liu, J
    et al.
    Dietz, T
    Carpenter, SR
    Alberti, M
    Folke, Carl
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Moran, E
    Pell, AN
    Deadman, P
    Kratz, T
    Lubchenko, J
    Ostrom, E
    Ouyang, Z
    Provencher, W
    Redman, CL
    Scneider, SH
    Taylor, WW
    Complexity of coupled human and natural systems2007In: Science, Vol. 317, p. 1513-1516Article in journal (Refereed)
  • 325. Liu, J
    et al.
    Dietz, T
    Carpenter, SR
    Folke, Carl
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Alberti, M
    Redman, CL
    Schneider, SH
    Ostrom, E
    Pell, AN
    Lubchenco, J
    Taylor, WW
    Ouyang, Z
    Deadman, P
    Kratz, T
    Provencher, W
    Coupled human and natural systems2007In: Ambio, Vol. 36, no 8, p. 639-649Article in journal (Refereed)
  • 326.
    Lokrantz, Jerker
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Exploring the resilience in coral reefs2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Considering the unprecedented global decline of coral reefs concerns about their future existence are well-justified. Safeguarding ecological resilience (i.e. the capacity of ecosystems to absorb disturbance without changing their identity) has become a prime goal for management in order to combat further degradation of coral reefs. This thesis uses the concept of ecological resilience as the theoretical framework to analyze vulnerability of coral reefs exposed to human interventions. This thesis consists of four papers. Papers 1-3 are based on field data from Zanzibar Island, Tanzania, whereas Paper 4 is a synthesis that explores the use of the resilience concept in coral reefs, putting the first papers into a broader context.

    Paper 1 investigates the distribution and estimate the status of functional groups of coral, fish and sea urchins on five coral reefs outside the western coast of  Zanzibar Island. The study provides a first ecological “baseline” that may help detect future degradation and evaluate the effects of impending management interventions. The results show that reefs with high accessibility, i.e. close to shore and open to fisheries, have lower abundance and diversity of functional groups of both coral and fish compared to more remote or protected reefs. Paper 2 analyzes the impact of artisanal fishing on three key functional groups of herbivorous (grazers, scrapers and bioeroders). The study shows a negative correlation between fishing pressure and fish biomass, abundance, and diversity. The study also demonstrates a negative influence of fishing on the demographic structure of functional groups. Paper 3 focuses on the scraping function (i.e. the capacity of fish to remove algae and open up bare substratum for coral larval settlement) and investigates how body size of individual fishes influences the function. The results reveal a non-linear relationship between body size and scraping function and suggest that fishes start to have a significant impact on the function only after reaching a certain size. The results from Paper 1-3 suggest that human interventions (fishing in particular) can have profound impacts on the distribution and composition of functional groups which influence the vulnerability of coral reefs. Paper 4 provides an overview of the divergent uses of the resilience concept and proposes a range of empirical indicators which can be helpful when assessing coral reef resilience, such as functional groups, the ratio of “good” and “bad” colonizers of space, demographic skewness, discontinuities, the distribution of local phase shifts in the seascape and estimates of potential space availability against grazing capacity.

     

  • 327.
    Lokrantz, Jerker
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Norström, Albert
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Nyström, Magnus
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Öhman, Marcus
    Stockholm University, Faculty of Science, Department of Zoology.
    Muhando, Christopher
    Institute of Marine Sciences, University of Dar es Salaam.
    Jiddawi, Narriman
    Institute of Marine Sciences, University of Dar es Salaam.
    A comparison of functional groups in coral reefs around Zanzibar Island (Tanzania)Manuscript (Other academic)
    Abstract [en]

    Species’ traits determine how biodiversity interacts with ecosystem processes and influence the capacity of ecosystems to respond to and recover from disturbances. Classifying species with regards to their traits, i.e. functional groups, and analyzing their distribution provides a mechanistic approach to investigate the resilience in ecosystems. This study investigates the status of functional groups of coral, fish and sea urchins on reefs on the west coast of Zanzibar Island, Tanzania. The classification of functional groups is based on traits reflecting important community processes or properties which underpin ecosystem resilience. The results show that reefs with high accessibility, i.e. close to shore and open to fisheries, have lower abundance and diversity of functional groups of both coral and fish compared to more remote or protected reefs. More specifically, highly accessible reefs display lower abundances of herbivorous fish (macroalgae browsers in particular), large-bodied fish, structurally complex corals and corals with certain reproduction strategies. Based on these findings we speculate what this means in terms of ecosystem functioning and vulnerability. This study also provides a first “baseline” of functional group distribution and although it represents an already degraded state it may serve as an important comparison when evaluating further degradation and effects of impending management interventions.

  • 328.
    Lokrantz, Jerker
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Nyström, Magnus
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Norström, Albert
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Cinner, Joshua
    ARC Centre of Excellence for Coral Reef Studies, James Cook University.
    Assessing potential vulnerability of coral reefs through functional groups of herbivoresManuscript (Other academic)
    Abstract [en]

    Fishing can have major influences on ecological processes on coral reefs. Overfishing of herbivores is particularly detrimental, generating ecosystem-wide impacts where algae overgrow corals and become the dominant benthic organism. This can result in altered ecosystem functioning and subsequently, loss of important ecosystem services. Knowing when important processes, such as herbivory, are becoming fragile is important because it can provide an opportunity for managers to avoid such undesirable ecosystem changes. This study investigates the impact of artisanal fishing on three important functional groups of herbivores (grazers, scrapers and bioeroders) on five coral-dominated reefs outside Zanzibar, Tanzania. Fishing pressure was assessed through interviews with households and fishermen and compared with ecological data for each of the three focal functional groups. The ecological status of the groups were assessed through analysis of species richness, -abundance, -biomass and demographic structure; variables relating to functional performance and in a wider sense ecosystem resilience. The results showed a negative correlation between fishing pressure and fish biomass, -abundance, and diversity. Moreover, fishing had a negative influence on the demographic structure of functional groups, particularly for bioeroders, manifesting as a skewness towards smaller individuals within species populations. Fishing pressure also correlated positively with sea urchin abundances suggesting a compensatory response within the guild of herbivores, which could explain the low abundances of macro algae on all of the investigated reefs. This study shows that artisanal fishing can have significant impacts on herbivores which may erode the resilience on coral reefs. Moreover, it illustrates how functional groups may help to expose potential vulnerability of coral reefs by mechanistically linking the diversity and identity of species to ecosystem processes.

  • 329.
    Lokrantz, Jerker
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Nyström, Magnus
    Stockholm University, Stockholm Resilience Centre.
    Norström, Albert V.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Folke, Carl
    Stockholm University, Stockholm Resilience Centre.
    Cinner, Joshua E.
    ARC Centre of Excellence for Coral Reef Studies, James Cook University.
    Impacts of artisanal fishing on key functional groups and the potential vulnerability of coral reefs2010In: Environmental Conservation, ISSN 0376-8929, E-ISSN 1469-4387, Vol. 36, no 4, p. 327-337Article in journal (Refereed)
    Abstract [en]

    Fishing can have major impacts on the structure of coral reef ecosystems. Overfishing of herbivores is particularly detrimental, as it makes the coral system more likely to undergo shifts to macroalgal dominance in the event of coral mass mortality. Knowing when important processes, such as herbivory, are becoming brittle is important because it can provide an opportunity for managers to avoid undesirable ecosystem-level changes. This study investigates the impact of artisanal fishing on three important functional groups of herbivores (grazers, scrapers and excavators) on five coral-dominated reefs outside Zanzibar (Tanzania). There was a negative correlation between fishing pressure and fish biomass, abundance, diversity and species richness. Moreover, fishing had a negative influence on the demographic structure of functional groups, particularly excavators, manifesting itself as a skewness towards smaller individuals within populations. Artisanal fishing can have significant impacts on key functional groups of herbivorous reef fishes which may increase the vulnerability of coral reefs to undesirable ecosystem shifts.

  • 330.
    Lokrantz, Jerker
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Nyström, Magnus
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Thyresson, Matilda
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Johansson, C.
    The non-linear relationship between body size and function in parrotfihes2008In: Coral reefs (Print), ISSN 0722-4028, E-ISSN 1432-0975, Vol. 27, no 4, p. 967-974Article in journal (Refereed)
    Abstract [en]

    Parrotfishes are a group of herbivores that play an important functional role in structuring benthic communities on coral reefs. Increasingly, these fish are being targeted by fishermen, and resultant declines in biomass and abundance may have severe consequences for the dynamics and regeneration of coral reefs. However, the impact of overfishing extends beyond declining fish stocks. It can also lead to demographic changes within species populations where mean body size is reduced. The effect of reduced mean body size on population dynamics is well described in literature but virtually no information exists on how this may influence important ecological functions. The study investigated how one important function, scraping (i.e., the capacity to remove algae and open up bare substratum for coral larval settlement), by three common species of parrotfishes (Scarus niger, Chlorurus sordidus, and Chlorurus strongylocephalus) on coral reefs at Zanzibar (Tanzania) was influenced by the size of individual fishes. There was a non-linear relationship between body size and scraping function for all species examined, and impact through scraping was also found to increase markedly when fish reached a size of 15-20 cm. Thus, coral reefs which have a high abundance and biomass of parrotfish may nonetheless be functionally impaired if dominated by small-sized individuals. Reductions in mean body size within parrotfish populations could, therefore, have functional impacts on coral reefs that previously have been overlooked.

  • 331. Lopez, Jose L.
    et al.
    Golemba, Marcelo
    Hernandez, Edgardo
    Lozada, Mariana
    Dionisi, Hebe
    Jansson, Janet K.
    Carroll, Jolynn
    Lundgren, Leif
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Sjoling, Sara
    Mac Cormack, Walter P.
    Microbial and viral-like rhodopsins present in coastal marine sediments from four polar and subpolar regions2016In: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 93, no 1, article id fiw216Article in journal (Refereed)
    Abstract [en]

    Rhodopsins are broadly distributed. In this work, we analyzed 23 metagenomes corresponding to marine sediment samples from four regions that share cold climate conditions (Norway; Sweden; Argentina and Antarctica). In order to investigate the genes evolution of viral rhodopsins, an initial set of 6224 bacterial rhodopsin sequences according to COG5524 were retrieved from the 23 metagenomes. After selection by the presence of transmembrane domains and alignment, 123 viral (51) and non-viral (72) sequences (> 50 amino acids) were finally included in further analysis. Viral rhodopsin genes were homologs of Phaeocystis globosa virus and Organic lake Phycodnavirus. Non-viral microbial rhodopsin genes were ascribed to Bacteroidetes, Planctomycetes, Firmicutes, Actinobacteria, Cyanobacteria, Proteobacteria, Deinococcus-Thermus and Cryptophyta and Fungi. A rescreening using Blastp, using as queries the viral sequences previously described, retrieved 30 sequences (> 100 amino acids). Phylogeographic analysis revealed a geographical clustering of the sequences affiliated to the viral group. This clustering was not observed for the microbial non-viral sequences. The phylogenetic reconstruction allowed us to propose the existence of a putative ancestor of viral rhodopsin genes related to Actinobacteria and Chloroflexi. This is the first report about the existence of a phylogeographic association of the viral rhodopsin sequences from marine sediments.

  • 332. Ludford, Adam
    et al.
    Cole, Victoria J.
    Porri, Francesca
    McQuaid, Christopher D.
    Nakin, Motebang D. V.
    Erlandsson, Johan
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Testing source-sink theory: the spill-over of mussel recruits beyond marine protected areas2012In: Landscape Ecology, ISSN 0921-2973, E-ISSN 1572-9761, Vol. 27, no 6, p. 859-868Article in journal (Refereed)
    Abstract [en]

    Source-sink theory has contributed to our understanding of the function of protected areas, particularly due to their role as population sources. Marine reserves are a preferred management tool for the conservation of natural populations, creating areas of good quality habitat and thus improving population connectivity by enhancing larval supply and recruitment among shores. Despite recent advances in the study of protected areas in the context of the source-sink theory, rigorous and empirical testing of marine reserves as metapopulation sources for the adjacent areas remain largely unexplored. We investigated the role of marine reserves as population sources, whether there was spill-over beyond the reserve boundaries and if so, whether spill-over was directional. We measured percentage cover and recruitment of mussels (Perna perna) at two reserves and two comparably sized exploited control areas on the south-east coast of South Africa where unprotected populations are severely affected by artisanal exploitation. Adult abundances were enhanced within reserves, but decreased towards their edges. We predicted that recruitment would mirror adult abundances and show directionality, with northern shores having greater recruitment following the prevalent northward flow of near-shore currents. There were, however, no correlations between adult abundances and recruitment for any months or shores, and no clear spatial patterns in recruitment (i.e. similar patterns occurred at reserves and controls). The results emphasise that, while reserves may act as important refuges by protecting adult abundances, their influence on promoting recovery of near-by exploited shores through larval spill-over may be overestimated.

  • 333. Lundström, Karl
    et al.
    Hjerne, Olle
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Lunneryd, Sven-Gunnar
    Karlsson, Olle
    Understanding the diet composition of marine mammals: grey seals (Halichoerus grypus) in the Baltic Sea2010In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 67, no 6, p. 1230-1239Article in journal (Refereed)
    Abstract [en]

    Dietary studies are important in understanding the ecological role of marine mammals and in formulating appropriate management plans in terms of their interactions with fisheries. The validity of such studies has, however, often been compromised by unrepresentative sampling procedures, resulting in false weight being given to external factors seeming to influence diet composition. The bias caused by non-random sampling was examined, using canonical correspondence analysis to assess how the prey species composition in digestive tract samples of Baltic grey seals (Halichoerus grypus) was related to spatial, temporal, and demographic factors and to whether the samples were collected in association with fishing gear or not (“sampling condition”). Geographic region explained the largest fraction of the observed variation, followed by sampling condition, age group, and year. Season and gender were not statistically significant. Segregation of the two age categories “pups” and “juveniles–adults”, and the two geographic categories “Baltic proper” and “Gulf of Bothnia” are proposed to estimate the diet and fish consumption of the Baltic grey seal population as a whole. Atlantic herring was the most commonly recovered prey item in all areas and age groups, followed by European sprat in the south, and common whitefish in the north. Pups had eaten relatively more small non-commercial species than older seals.

  • 334.
    Lyimo, Thomas J.
    et al.
    Department of Molecular Biology and Biotechnology, University of Dar es Salaam.
    de la Torre-Castro, Maricela
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Shaghude, Yohanna W.
    Institute of Marine Sciences, University of Dar es Salaam.
    Jiddawi S., Narriman
    Institute of Marine Sciences, University of Dar es Salaam.
    Björk, Mats
    Stockholm University, Faculty of Science, Department of Botany.
    Lindström, Lars
    Stockholm University, Faculty of Social Sciences, Department of Political Science.
    Synthesis: Towards an integrative research approach on coastal ecosystems – The example of Chwaka Bay2012In: People, Nature and Research in Chwaka Bay, Zanzibar, Tanzania / [ed] de la Torre-Castro Maricela and Lyimo Thomas J., Zanzibar Town: Western Indian Ocean Marine Science Association , 2012, p. 17-22Chapter in book (Other academic)
  • 335. Majaneva, Markus
    et al.
    Rintala, Janne-Markus
    Hajdu, Susanna
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Hallfors, Seija
    Hallfors, Guy
    Skjevik, Ann-Turi
    Gromisz, Slawomira
    Kownacka, Janina
    Busch, Susanne
    Blomster, Jaanika
    The extensive bloom of alternate stage prymnesium polylepis (haptophyta) in the Baltic Sea during autumn spring 2007 20082012In: European journal of phycology, ISSN 0967-0262, E-ISSN 1469-4433, Vol. 47, no 3, p. 310-320Article in journal (Refereed)
    Abstract [en]

    During autumn 2007, an unusual increase in an algal species belonging to the order Prymnesiales was observed throughout the Baltic Sea Proper during routine national monitoring. Electron microscopical examination of the blooming species showed two types of flat scales - small and large - that resembled those of the alternate stage of Prymnesium polylepis. No spine-bearing scales were found. The 18S rDNA sequence data (n = 20, c. 1500 bp) verified the species identification as P. polylepis. There was up to 0.5% (7 bp) variability in the P. polylepis partial 18 S rDNA sequences from the Baltic Sea. These environmental sequences differed by 0-0.35% (0-4 bp) from cultured P. polylepis (isolate UIO036), and by 1.0-3.7% from other available Prymnesium sequences. The number of cells assumed to be P. polylepis began to increase in October 2007 coincidently with significantly calm and dry weather, and at their maximum the cells accounted for over 80% of the total phytoplankton biovolume in December-January. During February-April 2008, 95% of the Prymnesiales cells were in the size class of P. polylepis (>6 mu m). The species attained bloom concentrations (>1 x 10(6) cells l(-1)) from March to May 2008. The species was observed throughout the Baltic Sea, except the Bothnian Bay, Gulf of Riga and the Kattegat. No toxic effects of the bloom were observed.

  • 336. Majaneva, Sanna
    et al.
    Setala, Outi
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Lehtiniemi, Maiju
    Feeding of the Arctic ctenophore Mertensia ovum in the Baltic Sea: evidence of the use of microbial prey2014In: Journal of Plankton Research, ISSN 0142-7873, E-ISSN 1464-3774, Vol. 36, no 1, p. 91-103Article in journal (Refereed)
    Abstract [en]

    Since its first reported appearance in the Baltic Sea in 2007, there has been a little research on the role of the Arctic ctenophore Mertensia ovum in this ecosystem. We provide results from the first feeding experiments of M. ovum from the northern Baltic Sea. Experiments were conducted with various prey types; picocyanobacteria Synechococcus bacillaris, ciliates Mesodinium rubrum, nauplii of mixed copepod species and copepodites of Eurytemora affinis. Molecular gut content analyses were also used to measure in situ feeding of M. ovum on the picocyanobacteria. The observed clearance rates on M. rubrum (< 9.0 mL predator(-1) h(-1)), and S. bacillaris (<7.5 mL predator(-1) h(-1)) were lower than those reported for similar-sized ctenophore species feeding on similar prey. Similarly, clearance rates of M. ovum on copepodites and copepod nauplii were close to zero, implying significantly lower predation on crustacean prey compared with other ctenophores. Overall, M. ovum predation rates were relatively low with a maximum daily consumption of 0.95 mu g C ind.(-1) day(-1) (similar to 15.8% of estimated predator carbon content). In addition, we examined the vertical distribution of M. ovum in relation to that of micro- and mesozooplankton and found greater overlap with potential microplankton prey than with mesozooplankton. Taken together, these results imply that in the Baltic Sea, M. ovum feed mainly on bacterio-and microplankton, thus potentially contributing to the coupling between the microbial loop and higher consumers in the pelagic food web.

  • 337.
    Margonski, Piotr
    et al.
    Sea fisheries institute, Gdynia.
    Hansson, Sture
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Tomczak, Maciej T.
    Technical University of Denmark.
    Grzebielec, Ryszard
    Sea fisheries institute, Gdynia.
    Climate influence on Baltic cod, sprat, and herring stock–recruitment relationships2010In: Progress in Oceanography, ISSN 0079-6611, E-ISSN 1873-4472, Vol. 87, p. 277-288Article in journal (Refereed)
  • 338.
    Martinsson, Jesper
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Ecology of juvenile turbot and flounder in the Central Baltic Sea: Implications for recruitment2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Our understanding of turbot and flounder ecology in the Baltic Sea is insufficient for sound management decisions. This thesis aims to fill some gaps in current knowledge by providing information of the ecology of turbot and flounder within their juvenile habitat, and to relate these findings to issues assumed relevant for recruitment variation. Main focus is on turbot due to its relatively low abundance and high variability in recruitment. The distribution of both species was studied on different scales, as was environmental effects on food consumption in 0-group turbot. The 0-group turbot display a relatively restricted spatial distribution compared to flounder. This is possibly due to a more specialized diet, which may make them more vulnerable to habitat degradation, especially eutrophication as a strong negative correlation was found with the organic content in the sediment. The species show high temporal and spatial overlap when settling in July-September, with peak abundances in August, and at depths <1 m. Both species display sedentary behavior within the nursery ground. Compared to flounder, turbot was more mobile potentially due to its restricted diet calling for extended searches. For turbot, feeding conditions appear to vary between size groups, which potentially could cause variations in survival between years through size-selective mortality. But, the predation may be low in central Baltic Sea as the abundance of the main predator, brown shrimp are comparatively low during flatfish occupancy. A significant positive relationship was found between the recruitment of turbot and flounder, which suggests that no inter-specific interactions during the juvenile stage affect recruitment. This co-variation also suggests that the recruitment of the species is determined by the same phenomena, potentially by large scale abiotic factors during the egg- and larval stage. For turbot, additional variability is potentially generated during the juvenile stage due to its relatively restricted food and habitat requirements. The specific habitat demands of turbot revealed in this thesis may be used to protect and restore essentially nursery grounds.

  • 339.
    Martinsson, Jesper
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    The potential of Visible Implant Elastomer as a nursery role evaluation tool for 0-group turbot (Psetta maxima) and flounderArticle in journal (Refereed)
  • 340.
    Martinsson, Jesper
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Nissling, Anders
    Högskolan på Gotland.
    Nursery area utilization by 0-group turbot (Psetta maxima) and flounder (Platichthys flesus) at Gotland, Baltic Sea2011In: Boreal environment research, ISSN 1239-6095, E-ISSN 1797-2469, Vol. 16, no 1, p. 60-70Article in journal (Refereed)
  • 341.
    Martinsson, Jesper
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Nissling, Anders
    Högskolan på Gotland.
    Marie, Jacobsson
    Högskolan på Gotland.
    Rebecca, Retz
    Högskolan på Gotland.
    Potential food limitation of 0-group turbot: A bioenergetics approachArticle in journal (Refereed)
  • 342.
    Martinsson, Jesper
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Sällebrant, John
    Högskolan på Gotland.
    Habitat associations of 0-group turbot (Psetta maxima) and flounder (Platichthys flesus) at Gotland, Central Baltic SeaArticle in journal (Refereed)
  • 343. McQuatters-Gollop, Abigail
    et al.
    Gilbert, Alison J.
    Mee, Laurence D.
    Vermaat, Jan E.
    Artioli, Yuri
    Humborg, Christoph
    Stockholm University, Stockholm Resilience Centre. Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Wulff, Fredrik
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    How well do ecosystem indicators communicate the effects of anthropogenic eutrophication?2009In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 82, p. 583-596Article in journal (Refereed)
    Abstract [en]

    Anthropogenic eutrophication affects the Mediterranean, Black, North and Baltic Seas to various extents. Responses to nutrient loading and methods of monitoring relevant indicators vary regionally, hindering interpretation of ecosystem state changes and preventing a straightforward pan-European assessment of eutrophication symptoms. Here we summarize responses to nutrient enrichment in Europe's seas, comparing existing time-series of selected pelagic (phytoplankton biomass and community composition, turbidity, N:P ratio) and benthic (macro flora and faunal communities, bottom oxygen condition) indicators based on their effectiveness in assessing eutrophication effects. Our results suggest that the Black Sea and Northern Adriatic appear to be recovering from eutrophication due to economic reorganization in the Black Sea catchment and nutrient abatement measures in the case of the Northern Adriatic. The Baltic is most strongly impacted by eutrophication due to its limited exchange and the prevalence of nutrient recycling. Eutrophication in the North Sea is primarily a coastal problem, but may be exacerbated by climatic changes. Indicator interpretation is strongly dependent on sea-specific knowledge of ecosystem characteristics, and no single indicator can be employed to adequately compare eutrophication state between European seas. Communicating eutrophication-related information to policy-makers could be facilitated through the use of consistent indicator selection and monitoring methodologies across European seas. This work is discussed in the context of the European Commission's recently published Marine Strategy Directive.

  • 344. Mooij, Wolf M.
    et al.
    Brederveld, Robert J.
    de Klein, Jeroen J. M.
    DeAngelis, Don L.
    Downing, Andrea S.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Faber, Michiel
    Gerla, Daan J.
    Hipsey, Matthew R.
    't Hoen, Jochem
    Janse, Jan H.
    Janssen, Annette B. G.
    Jeuken, Michel
    Kooi, Bob W.
    Lischke, Betty
    Petzoldt, Thomas
    Postma, Leo
    Schep, Sebastiaan A.
    Scholten, Huub
    Teurlincx, Sven
    Thiange, Christophe
    Trolle, Dennis
    van Dam, Anne A.
    van Gerven, Luuk P. A.
    van Nes, Egbert H.
    Kuiper, Jan J.
    Serving many at once: How a database approach can create unity in dynamical ecosystem modelling2014In: Environmental Modelling & Software, ISSN 1364-8152, E-ISSN 1873-6726, Vol. 61, p. 266-273Article in journal (Refereed)
    Abstract [en]

    Simulation modelling in ecology is a field that is becoming increasingly compartmentalized. Here we propose a Database Approach To Modelling (DATM) to create unity in dynamical ecosystem modelling with differential equations. In this approach the storage of ecological knowledge is independent of the language and platform in which the model will be run. To create an instance of the model, the information in the database is translated and augmented with the language and platform specifics. This process is automated so that a new instance can be created each time the database is updated. We describe the approach using the simple Lotka-Volterra model and the complex ecosystem model for shallow lakes PCLake, which we automatically implement in the frameworks OSIRIS, GRIND for MATLAB, ACSL, R, DUFLOW and DELWAQ. A clear advantage of working in a database is the overview it provides. The simplicity of the approach only adds to its elegance.

  • 345.
    Motwani, Nisha
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Molecular evidence for metazooplankton feeding on filamentous cyanobacteria and picocyanobacteria in the Baltic Sea2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Interactions between zooplankton and cyanobacteria are complex and system-specific. They play an important role in mediating responses of phytoplankton to changes in nutrient regime and top-down manipulations. Negative consequences associated with these interactions include massive blooms of diazotrophic blue-green algae and declines in zooplankton and fish stocks. With regard to filamentous cyanobacteria, toxicity, morphology, and poor nutritional quality have commonly been implicated as mechanisms hampering efficient grazing, whereas picocyanobacteria are generally considered as inaccessible for mesozooplankton grazers due to their small size. The evidence for these assumptions are, however, contradictory, and there are studies showing that both picocyanobacteria and filamentous cyanobacteria can contribute substantially to zooplankton diets. Moreover, by supplying nitrogen to non-diazotrophic phytoplankton, these cyanobacterial blooms fuel production of edible phytoplankton and picoplankton, including picocyanobacteria. Thus, cyanobacteria could have a neutral or even positive effect on growth of mesozooplankton. As zooplankton is the main trophic link between primary producers and higher trophic levels, it is important to understand whether mesozooplankton can efficiently utilize cyanobacterial production by direct grazing. Here, I used molecular approach in the field and laboratory studies to determine (1) whether pico- and filamentous cyanobacteria are ingested by mesozooplankton grazers, (2) what species/groups are particularly efficient in grazing on picocyanobacteria, and (3) consequences of feeding on toxic filamentous cyanobacterium for copepod physiological status.

    In Paper I, we experimentally studied effects of direct ingestion of toxic filamentous cyanobacteria on oxidative status, reproduction, and juvenile development in the copepod Acartia bifilosa. Moreover, using short- and long-term field observations on the egg production in Acartia tonsa and growth of nauplii in the common Baltic copepods Acartia spp. and Eurytemora affinis in relation to cyanobacteria abundance, we showed overall positive effects of diazotrophic filamentous cyanobacteria on oxidative balance, viable egg production and nauplial growth. These findings suggest that cyanobacterial blooms in the Baltic Sea might contribute, both directly and indirectly, to zooplankton nutrition. The indirect effects are most likely mediated through the stimulation of picoplankton communities by filamentous cyanobacteria blooms thus enhancing nutrition of zooplankton capable of utilizing picoplankton component of the microbial food webs.

    In Paper II, we evaluated the extent of the direct grazing by mesozooplankton on picocyanobacteria in the field as hypothesized in Paper I. The picocyanobacteria in ambient plankton communities and zooplankton guts were quantified by molecular diet analysis. The method is based on quantitative PCR (qPCR) targeting ITS-1 sequence of the picocyanobacteria Synechococcus that allowed us to measure picocyanobacterial DNA in the guts of major Baltic mesozooplankton groups (cladocerans, rotifers and various developmental stages of copepods). Also, a feeding experiment with laboratory reared copepod Acartia tonsa fed a mixture of the picocyanobacterium Synechococcus bacillaris and the cryptophyte alga Rhodomonas salina was conducted to measure picocyanobacteria consumption in the presence of the alternative food. All field-collected and experimental animals were found to consume Synechococcus spp. In terms of Synechococcus quantity, the individual gut content was highest in the cladocerans, whereas biomass-specific gut content was highest in the rotifers and the copepod nauplii. The amount of Synechococcus DNA in the guts of the field-collected copepods was positively related to the picocyanobacteria abundance and negatively to the total phytoplankton (> 2 µm) stocks at the time of sampling. This indicates that increased availability of picocyanobacteria resulted in the increased intake of this prey and that copepods may rely more on this prey when preferred food declines. These findings suggest that if abundant, picoplankton is an important component of mesozooplankton diet, which needs to be accounted for in food web models and productivity assessments.

  • 346.
    Motwani, Nisha H.
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Mesozooplankton Grazing on Picocyanobacteria in the Baltic Sea as Inferred from Molecular Diet Analysis2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 11, article id e79230Article in journal (Refereed)
    Abstract [en]

    Our current knowledge on the microbial component of zooplankton diet is limited, and it is generally assumed that bacteria-sized prey is not directly consumed by most mesozooplankton grazers in the marine food webs. We questioned this assumption and conducted field and laboratory studies to examine picocyanobacteria contribution to the diets of Baltic Sea zooplankton, including copepods. First, qPCR targeting ITS-1 rDNA sequence of the picocyanobacteria Synechococcus spp. was used to examine picocyanobacterial DNA occurrence in the guts of Baltic zooplankton (copepods, cladocerans and rotifers). All field-collected zooplankton were found to consume picocyanobacteria in substantial quantities. In terms of Synechococcus quantity, the individual gut content was highest in cladocerans, whereas biomass-specific gut content was highest in rotifers and copepod nauplii. Moreover, the gut content in copepods was positively related to the picocyanobacteria abundance and negatively to the total phytoplankton abundance in the water column at the time of sampling. This indicates that increased availability of picocyanobacteria resulted in the increased intake of this prey and that copepods may rely more on picoplankton when food in the preferred size range declines. Second, a feeding experiments with a laboratory reared copepod Acartia tonsa fed a mixture of the picocyanobacterium Synechococcus bacillaris and microalga Rhodomonas salina confirmed that copepods ingested Synechococcus, even when the alternative food was plentiful. Finally, palatability of the picocyanobacteria for A. tonsa was demonstrated using uptake of C-13 by the copepods as a proxy for carbon uptake in feeding experiment with C-13-labeled S. bacillaris. These findings suggest that, if abundant, picoplankton may become an important component of mesozooplankton diet, which needs to be accounted for in food web models and productivity assessments.

  • 347.
    Mwandya, Augustine
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Gullström, Martin
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Science, Department of Systems Ecology.
    Andersson, Mathias H.
    Stockholm University, Faculty of Science, Department of Zoology.
    Öhman, Marcus C.
    Stockholm University, Faculty of Science, Department of Zoology.
    Mgaya, Yunus D.
    Ian, Bryceson
    Spatial and seasonal variation of fish assemblages in mangrove creek systems in Zanzibar (Tanzania)2010In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 89, no 4, p. 277-286Article in journal (Refereed)
    Abstract [en]

    Spatial and seasonal variations of fish assemblage composition were studied in three non-estuarine mangrove creeks of Zanzibar (Tanzania). Fish were collected monthly for one year at three sites (lower, intermediate and upper reaches) in each creek using a seine net (each haul covering 170 m(2)). Density, species number and diversity of fish were all higher at sites with dense cover of macrophytes (seagrass and macroalgae) than over unvegetated sandy sites. In general, fish assemblages mainly comprised juveniles of a few abundant taxa, e.g. Mugil cephalus, Mugilidae spp. and Leiognathus equulus at sites with mud substratum and Germs oyena, Lethrinus harak and Sillago sihama at sites dominated by macrophytes. Multivariate analyses revealed significant separations in fish assemblage composition within the two creeks where the bottom substratum differed among sites. Overall, season seemed to have little effect on density, species number, diversity index (H') and assemblage structure of fish. Water condition variables were also relatively stable across the season, although a short-term fluctuation primarily induced by decreased salinity, occurred during the heavy rains in April and May. Fish assemblage structure was not significantly affected by any of the abiotic factors tested. However, significant regressions were found between the other fish variables and environmental variables, but since these associations were mostly species-specific and generally inconsistent, we suggest that the overall distribution patterns of fish were mainly an effect of particular substrate preferences of fish species rather than contemporary water conditions.

  • 348.
    Mörk, Erik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Macroalgal community dynamics on coral reefs: Implications for management2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Although rather inconspicuous on healthy coral reefs, macroalgae form the basis of coral food webs. Today, macroalgae are generally increasing and many reefs undergo transitions from coral to macroalgal dominance resulting from e.g. enhanced nutrient loading or increased fishing.

    This thesis aims to investigate the relative importance of top-down and bottom-up regulation, and different herbivore types, on macroalgal distribution, fecundity and community composition on coral reefs. Papers I and II indicate that macroalgal abundance in a coral reef system is largely governed by top-down regulation through grazing by herbivores, while bottom-up regulation through enhanced nutrient availability rather influence algal species composition. Paper II also shows that these regulating effects are not as evident in an area with relatively strong water motion, suggesting that impacts of anthropogenic disturbance may be site-specific. Paper III shows that herbivory is an important factor influencing macroalgal growth and subsequent reproduction. Furthermore, Paper IV and V conclude that efficiency in removing macroalgal biomass is dependent on the type of dominant herbivore, where sea urchins seem to be more effective than fish. Paper IV indicates a seasonal variation in macroalgal biomass and distribution in a small geographic scale but with relatively high temporal resolution. Paper V on the other hand shows these same effects, but with a focus on geographic variation, including a large part of the East African region, as well as between year temporal variations in Kenya. Together, results from the two latter studies indicate that herbivory by fish may not be able to prevent a macroalgal bloom in a degraded system where substrate availability for algal colonization is high, but that it may still facilitate coral recovery over time. Thus, a large algal biomass may not necessarily indicate a reef beyond the possibility of recovery.

  • 349.
    Mörk, Erik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Top-down and bottom-up regulation of macroalgal communities – implications for coral reef management in Eastern Africa.2008Licentiate thesis, monograph (Other academic)
  • 350.
    Mörk, Erik
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Lilliesköld Sjöö, Gustaf
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Kautsky, Nils
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    McClanahan, Tim R.
    Marine Programs, Wildlife Conservation Society, Bronx, NY, USA.
    Top–down and bottom–up regulation of macroalgal community structure on a Kenyan reef2009In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 84, no 3, p. 331-336Article in journal (Refereed)
    Abstract [en]

    Top–down and bottom–up regulation in the form of grazing by herbivores and nutrient availability areimportant factors governing macroalgal communities in the coral reef ecosystem. Today, anthropogenicactivities, such as over-harvesting of herbivorous fish and sea urchins and increased nutrient loading, arealtering the interaction of these two structuring forces. The present study was conducted in Kenya andinvestigates the relative importance of herbivory and nutrient loading on macroalgal communitydynamics, by looking at alterations in macroalgal functional groups, species diversity (H0) and biomasswithin experimental quadrats. The experiment was conducted in situ for 42 days during the dry season.Cages excluding large herbivorous fish and sea urchins were used in the study and nutrient addition wasconducted using coated, slow-release fertilizer (nitrogen and phosphorous) at a site where herbivory isgenerally low and nutrient levels are relatively high for the region. Nutrient addition increased tissuenutrient content in the algae, and fertilized quadrats had 24% higher species diversity. Herbivoreexclusion resulted in a 77% increase in algal biomass, mainly attributable to a >1000% increase in corticatedforms. These results are in accordance with similar studies in other regions, but are unique in thatthey indicate that, even when prevailing nutrient levels are relatively high and herbivore pressure isrelatively low, continued anthropogenic disturbance results in further ecological responses and increasedreef degradation.

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