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  • 1.
    Ahlbeck, Ida
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Living in a predation matrix: Studies on fish and their prey in a Baltic Sea coastal area2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis was written within the framework of a biomanipulation project where young-of-the-year (YOY) pikeperch (Sander lucioperca) were stocked to a Baltic Sea bay to improve water quality through a top-down trophic cascade. The aim of my doctorial studies was however focused on a broader ecological question, namely predation (the main driving force in a biomanipulation). Hence, this thesis consists of four papers where we study the interactions between predator and prey using fish and zooplankton and how these interactions can be measured.

    In paper I we evaluated the performance of different diet analysis methods by individual based modelling and found that when having a nutritional gain perspective, mass based methods described diets best. Paper II investigated how the explorative, foraging and anti-predator behaviour of the YOY pikeperch used for stocking were affected by their rearing environment (pond vs. tank rearing). The more complex and varied environment in the semi-natural ponds seemed to promote a more flexible and active behaviour, better equipping young fish for survival in the wild. For paper III we studied the diel vertical migration in the six copepodite stages of the zooplankton Acartia spp. and Eurytemora affinis in relation to fish biomass, phytoplankton abundance and temperature. Both species migrated and in addition showed increased migration range with size within species, indicating evasion from visual predators. Paper IV addressed the movement of littoral Eurasian perch (Perca fluviatilis) via stable isotope signatures (13C and 15N) and body condition. We found clear indications of sedentarity and intra-habitat dietary differences. Interactions between predators and prey are complex and affected by both physiological and environmental characteristics as well as behavioural traits. The results in this thesis suggest that different species and even different life stages pursue different strategies to survive.

  • 2.
    Ahlbeck, Ida
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Hansson, Sture
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Hjerne, Olle
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Evaluating fish diet analysis methods by individual-based modelling2012In: Canadian Journal of Fisheries and Aquatic Sciences, ISSN 0706-652X, E-ISSN 1205-7533, Vol. 69, no 7, 1184-1201 p.Article in journal (Refereed)
    Abstract [en]

    Knowledge of diet compositions is important in ecological research. There are many methods available and numerous aspects of diet composition. Here we used modelling to evaluate how well different diet analysis methods describe the true diet of fish, expressed in mass percentages. The methods studied were both basic methods (frequency of occurrence, dominance, numeric, mass, points) and composite indices (Index of Relative Importance, Comparative Feeding Index). Analyses were based on both averaged stomach content of individual fish and on pooled content from several fish. Prey preference, prey size, and evacuation rate influenced the performance of the diet analysis methods. The basic methods performed better than composite indices. Mass and points methods produced diet compositions most similar to the true diet and were also most robust, indicating that these methods should be used to describe energetic-nutritional sources of fish.

  • 3.
    Ahlbeck, Ida
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Hansson, Sture
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Hjerne, Olle
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Evaluation of diet analysis methods by individual based modellingIn: Canadian Journal of Fisheries and Aquatic Sciences, ISSN 0706-652X, E-ISSN 1205-7533Article in journal (Refereed)
  • 4.
    Ahlbeck, Ida
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Hansson, Sture
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Karlöf, Oliver
    Sedentarity in Eurasian perch (Perca fluviatilis) in a coastal Baltic Sea areaIn: Ecology of Freshwater Fish, ISSN 0906-6691, E-ISSN 1600-0633Article in journal (Refereed)
  • 5.
    Ahlbeck, Ida
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Holliland, Per B.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Rearing environment affect important life skills in pikeperch (Sander lucioperca)2012In: Boreal environment research, ISSN 1239-6095, E-ISSN 1797-2469, Vol. 17, no 3-4, 291-304 p.Article in journal (Refereed)
    Abstract [en]

    The effect of rearing environment on the behaviour of young-of-the-year pikeperch (Sander lucioperca) bred at three different production facilities was investigated. Two groups were reared in semi-natural ponds and one group in indoor tanks. Exploratory, foraging and anti-predator behaviours were studied in aquarium experiments. There were no significant differences between pond- and tank-reared fish in reluctance to explore their new environment, but pond-reared fish spent significantly more time in macro-vegetation. Pond-reared fish were significantly faster to start foraging on live prey (Neomysis integer) that they had not encountered before. As compared with tank-reared fish, pond-reared fish were also significantly more active in their anti-predator response. Rearing environment obviously influences the development of important life skills. These differences may impact the success rate when stocking young-of-the-year pikeperch into natural waters.

  • 6.
    Ahrné, Karin
    et al.
    Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Bengtsson, Jan
    Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Elmqvist, Thomas
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Bumble Bees (Bombus spp) along a Gradient of Increasing Urbanization2009In: PLoS ONE, Vol. 4, no 5Article in journal (Refereed)
  • 7. Allan, Ian J.
    et al.
    Nilsson, Hans C.
    Tjensvoll, Ingrid
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Naes, Kristoffer
    Mobile passive samplers: Concept for a novel mode of exposure2011In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 159, no 10, 2393-2397 p.Article in journal (Refereed)
    Abstract [en]

    Integrative passive sampling with devices such as semipermeable membrane devices generally relies on rigs for month-long static exposures in water. We evaluate here whether mobile exposures of passive samplers can provide reliable estimates of dissolved contaminant concentrations. Mobile exposures were obtained by towing samplers fastened to the end of a benthic trawl net. Significant and reproducible absorption of polycyclic aromatic hydrocarbons during 5 h-long deployments was made possible by high sampling rates resulting from high water turbulences during towing at 1.2-1.5 knots. Sampling rates (72-215 L d(-1)) estimated from the dissipation of performance reference compounds were supported by in situ calibration with samplers exposed for a 30 days in the vicinity of the test site. Higher fluoranthene and pyrene absorption in samplers exposed to the trawling-induced sediment plume could be attributed to desorption from re-suspended sediments. This mode of exposure has the potential to be used in monitoring programmes.

  • 8. Allan, Ian J.
    et al.
    Nilsson, Hans C.
    Tjensvoll, Ingrid
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Naes, Kristoffer
    PCDD/F release during benthic trawler-induced sediment resuspension2012In: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 31, no 12, 2780-2787 p.Article in journal (Refereed)
    Abstract [en]

    Benthic trawling can cause the resuspension of large amounts of sediments. Such regular practice in the Grenland fjord system in the south of Norway has the potential to affect the fate, movement, and bioavailability of sediment-associated polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). A novel mode of exposing passive sampling devices consisting of towing semipermeable membrane devices attached to the trawl net was used to gauge in situ changes in the freely dissolved concentration of PCDD/Fs on benthic trawlerinduced sediment resuspension. Significant accumulation of a number of PCDD/F congeners was observed despite the short (5?h) sampler exposure times. On average, a one order of magnitude increase in freely dissolved PCCD/F concentrations was seen within minutes of the sediment being resuspended. This observation was supported by similar changes in filtered PCDD/F concentrations measured by high-volume sampling prior to resuspension and in the sediment plume. Environ. Toxicol. Chem. 2012; 31: 27802787.

  • 9.
    Almesjö, Lisa
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Filamentous cyanobacteria in the Baltic Sea - spatiotemporal patterns and nitrogen fixation2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Summer blooms of filamentous, diazotrophic cyanobacteria are typical of the Baltic Sea Proper, and are dominated by Aphanizomenon sp. and the toxic Nodularia spumigena. Although occurring every summer, the blooms vary greatly in timing and spatial distribution, making monitoring difficult and imprecise. This thesis studies how the spatial variability of Baltic cyanobacterial blooms influences estimates of abundance, vertical and horizontal distribution and N2-fixation. Implications for sampling and monitoring of cyanobacterial blooms are also discussed.

    The results of the thesis confirm the importance of diazotrophic cyanobacteria in providing N for summer production in the Baltic Proper. It also highlights the large spatial and temporal variation in these blooms and argues that improved spatial coverage and replication could make monitoring data more useful for demonstrating time trends, and for identifying the factors regulating the blooms. The vertical distribution of Aphanizomenon and Nodularia was found to be spatially variable, probably as a combination of species-specific adaptations and ambient weather conditions. Vertical migration in Aphanizomenon was more important towards the end of summer, and is probably regulated by a trade-off between P-availability and light and temperature.

  • 10.
    Almesjö, Lisa
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Limén, Helene
    Fiskpopulationer i svenska vatten. Hur påverkas de av fiske, övergödning och miljögifter?2008Report (Other academic)
  • 11.
    Almesjö, Lisa
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Rolff, C.
    Automated measurements of filamentous cyanobacteria by digital image analysis2007In: Limnology and Oceanography: Methods, Vol. 5, 217-224 p.Article in journal (Refereed)
  • 12.
    Almesjö, Lisa
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Rolff, C.
    Experimental vertical migration in Aphanizomenon sp.: the influence on biovolume concentration and filament lengthManuscript (Other academic)
  • 13.
    Almesjö, Lisa
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Rolff, C.
    The effect of hose diameter on depth-integrated sampling of filamentous cyanobacteriaManuscript (Other academic)
  • 14.
    Almesjö, Lisa
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Rolff, C.
    Vertical and horizontal distribution of Aphanizomenon sp. and Nodularia spumigena in the Baltic SeaManuscript (Other academic)
  • 15.
    Almesjö, Lisa
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology. Marin ekologi.
    Rolff, Carl
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Automated measurements of filamentous cyanobacteria by digital image analysis2007In: Limnology and Oceanography: Methods, Vol. 5, 217-224 p.Article in journal (Refereed)
  • 16.
    Almqvist, G.
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Arciszewski, B.
    Appelberg, M.
    Annual Fecundity of Round Goby in the Gulf of Gdansk, Southern Baltic SeaManuscript (Other academic)
  • 17.
    Almqvist, G.
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Skóra, K. E.
    Appelberg, M.
    Life History Characteristics of the Invasive Round Goby in Different Habitats in the Southern Baltic SeaIn: Journal of the Great Lakes ResearchArticle in journal (Refereed)
  • 18.
    Almqvist, G.
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Strandmark, A.
    Appelberg, M.
    Has the invasive Round goby caused new links in Baltic food webs?Manuscript (Other academic)
  • 19.
    Almqvist, Gustaf
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Främmande arter2006In: Kustfiske och fiskevård. En bok om ekologisk fiskevård på kusten., Bokförlaget Settern, Örkelljunga , 2006, 89-94 p.Chapter in book (Other (popular science, discussion, etc.))
  • 20.
    Almqvist, Gustaf
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Invasion Biology: a Baltic Fish Experience2007Report (Other academic)
  • 21.
    Almqvist, Gustaf
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Round goby Neogobius melanostomus in the Baltic Sea – Invasion Biology in practice2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Human mediated transfer of non-indigenous species is considered to be a major threat to global biodiversity. The Ponto-Caspian round goby (Neogobius melanostomus), which has established populations in various regions in Eurasia and North-America, was first observed in Gulf of Gdańsk, Baltic Sea, in 1990. In this thesis the round goby is used as case study for assessing the invasion process of an alien species in to the Baltic Sea. Factors governing life history characteristics, traits that have enhanced the invasion, and ecological consequences for the Baltic Sea are assessed. Two diverging life history strategies of the round goby related to habitat were found: one to-wards early maturation and short population turnover time in sheltered areas, the other towards high growth rate and late maturation in exposed areas. Females produced two batches in average during the spawning season. Lengths of spawning season and annual fecundity of round gobies in Gulf of Gdańsk were in the same range as in the donor region. The species was found to compete with juvenile flounder for space and food resources, and probably also other native species are affected in coastal areas. Round goby comprised a main food source for cod and perch, forming a new energetic pathway between mussels and predatory fish. It is predicted that the species must produce more than one batch per season to sustain a viable population. Low temperature in the northern Baltic Sea is expected to hamper the devel-opment of new round goby populations, however, the global climate change might change this situation. In the southern Baltic Sea a shortage of optimal reproduction habitats is suggested to moderate the rate of spread. Although round goby in the Gulf of Gdańsk seems to have passed abundance maximum it is likely that the species will continue to be an important ecosystem component, at least in southern Baltic Sea, in the future.

  • 22.
    Almqvist, Gustaf
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Strandmark, Alma K.
    Appelberg, Magnus
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Has the invasive round goby caused new links in Baltic food webs?2010In: Environmental Biology of Fishes, ISSN 0378-1909, E-ISSN 1573-5133, Vol. 89, no 1, 79-93 p.Article in journal (Refereed)
    Abstract [en]

    The Ponto-Caspian round goby (Neogobius melanostomus, Pallas 1814) most probably was established in the Gulf of GdaA""sk, Baltic Sea, in the late 1980's and has since become one of the dominant species in the region. In this study we assess the role of round gobies as prey for two important fish species in the Gulf of GdaA""sk, cod (Gadus morhua) and perch (Perca fluviatilis). We compared their present diet with stomach analyses from the area prior the round goby establishment, as well as with diet analysis from Baltic regions where round gobies are absent. There were large differences in the diet between cods from the Gulf of GdaA""sk 2003-2006 compared to cods in earlier studies (1977-1981) from the Southern Baltic Sea. There were also large differences in cod and perch diets from areas with and without round goby. Presently, round goby constitutes the most important prey for medium sized cods in Gulf of GdaA""sk, and perch from the same area almost exclusively feed on gobiids. Stomach analysis, trophic level estimates, and stable isotope analyses all indicated that cod and perch in Gulf of GdaA""sk after the round goby establishment belonged to a similar trophic level. Beside round goby, no mussel feeding fish contributed much to the diet of cod or at all to the diet of perch. Thus, it is likely that round gobies constitute a new energetic pathway from mussels to top predators. However, due to the short time elapsed after round goby establishment, we can only speculate on the species future impacts on Baltic food webs.

  • 23. Anderies, John M.
    et al.
    Norberg, J.
    Stockholm University, Faculty of Science, Department of Systems Ecology. interfaculty units, Stockholm Resilience Centre.
    Theoretical challenges: Information processing and navigation in social-ecological systems.2008In: Complexity theory for a sustainable future, Columbia university press. NY , 2008Chapter in book (Refereed)
  • 24.
    Andersen Borg, C.M.
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Gorokhova, E.
    The feeding biology of invasive predatory cladoceransManuscript (Other academic)
  • 25.
    Andersen Borg, Marc
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Non-indigenous zooplankton: the role of predatory cladocerans and of copepods in trophic dynamics2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Human-mediated introductions of non-indigenous species now threaten to homogenize the biota of the Globe, causing huge economic and ecological damage. This thesis studies the ecological role of 3 invasive planktonic crustaceans, the omnivorous copepod Acartia tonsa (western Atlantic and Indo-Pacific) and the predatory cladocerans, Cercopagis pengoi (Ponto-Caspian) and Bythotrephes longimanus (Eurasian). B. longimanus invaded the North American Great Lakes in 1982, C. pengoi the Baltic in 1992 and the Great Lakes in 1999, while A. tonsa has an extensive invasion history that includes the Baltic.

    We review current knowledge on feeding biology of the predatory cladocerans. A study of stable C and N isotope ratios indicated mesozooplankton as the main food source of C. pengoi in the northern Baltic Sea proper, with young C. pengoi also eating microzooplankton, such as rotifers. Young-of-the-year herring did eat C. pengoi and herring trophic position shifted from 2.6 before the invasion to 3.4 after, indicating that C. pengoi had been “sandwiched” into the modified food web between mesozooplankton and fish.

    Salinity tolerance experiments on Acartia tonsa and co-occurring Acartia clausi showed the formers euryhaline character and high grazing potential. Energy partitioning between ingestion, production and respiration was rather constant over the tested salinity range of 2 to 33, with small differences in gross growth efficiency and cost of growth, but maximum ingestion at 10-20. Egg hatching in A. tonsa was only reduced at the lowest salinity. Extreme changes in salinity were needed to cause significant mortality of A. tonsa in the field, but its feeding activity could be severely reduced by salinity changes likely to occur in estuaries. A study of a hypertrophic estuary showed that A. tonsa can sustain a population despite very high mortality rates, caused by predation, high pH and low oxygen, helping explain the success of A. tonsa as an invader of estuaries.

  • 26. Andersson, E.
    et al.
    Barthel, S.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Ahrné, K.
    Measuring social-ecological dynamics behind the generation of ecosystem services2007In: Ecological Application, ISSN 1051-0761, Vol. 17, no 5, 1267-1278 p.Article in journal (Refereed)
  • 27.
    Andersson, Erik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Managing the Urban Greens: Maintaining ecological functions in human dominated landscapes2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    At the core of this thesis lie two realisations: First, like other ecosystems, those in urban landscapes provide humans with a number of ecosystem services, some recognized while others are not. Second, in cities just as in other intensively used social-ecological systems, management is of central importance. This thesis focuses on how we may manage green areas in cities in an ecologically sustainable way, and enjoy functioning ecosystems close to where most people live.

    The thesis has four specific objectives: 1) analyse methods for describing the urban landscape, 2) analyze methods for managing urban landscapes rather than single patches of urban green areas, 3) explore the effects of management on diversity patterns and its implications for ecological functions, and 4) investigate the motivations behind the use of different management practices.

    My results show that changes in urbanization were most distinct at a small scale and that the presence of different bird species depended mostly on access to habitat. They also show that groups of small habitat patches can maintain many of the values of larger patches as long as they are sufficiently close for the organism to move between them, and that matrix heterogeneity must be accounted for. To identify such connected patches and assess their ecological importance I have developed two modelling approaches, one to select suitable model organisms and one to analyse spatial configuration. Further, management is shown to create ecological differences even in areas that are superficially similar, and the roots to these differences are ascribed to the knowledge, institutions and sense of place among different groups of managers. Finally, I try to combine these objectives and sketch out how the organisation of management could be changed to overcome scale mismatches and rigidity. There is potential, both for protection and for management, at all scale levels and this potential should be tapped and nurtured to improve our ability to cope with changes.

  • 28.
    Andersson, Erik
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Ahrné, Karin
    Department of Ecology, Swedish University of Agricultural Sciences.
    Pyykönen, Markku
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Elmqvist, Thomas
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Patterns and scale relations among urbanization measures in Stockholm, Sweden2009In: Landscape Ecology, ISSN 0921-2973, E-ISSN 1572-9761, Vol. 24, 1331-1339 p.Article in journal (Refereed)
    Abstract [en]

    In this study we measure urbanization based on a diverse set of 21 variables ranging from landscape indices to demographic factors such as income and land ownership using data from Stockholm, Sweden. The primary aims were to test how the variables behaved in relation to each other and if these patterns were consistent across scales. The variables were mostly identified from the literature and limited to the kind of data that was readily accessible. We used GIS to sample the variables and then principal component analyses to search for patterns among them, repeating the sampling and analysis at four different scales (250 × 250, 750 × 750, 1,250 × 1,250 and 1,750 × 1,750, all in meters). At the smallest scale most variables seemed to be roughly structured along two axes, one with landscape indices and one mainly with demographic factors but also impervious surface and coniferous forest. The other land-cover types did not align very well with these two axes. When increasing the scale this pattern was not as obvious, instead the variables separated into several smaller bundles of highly correlated variables. Some pairs or bundles of variables were correlated on all scales and thus interchangeable while other associations changed with scale. This is important to keep in mind when one chooses measures of urbanization, especially if the measures are indices based on several variables. Comparing our results with the findings from other cities, we argue that universal gradients will be difficult to find since city shape and size, as well as available information, differ greatly. We also believe that a multivariate gradient is needed if you wish not only to compare cities but also ask questions about how urbanization influences the ecological character in different parts of a city.

  • 29.
    Andersson, Erik
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology. Naturresurshushållning.
    Barthel, Stephan
    Stockholm University, Faculty of Science, Department of Systems Ecology. Naturresurshushållning.
    Ahrné, K
    Measuring social-ecological dynamics behind the generation of ecosystem services2007In: Ecological Applications, Vol. 17, no 5, 1267-1278 p.Article in journal (Refereed)
  • 30.
    Andersson, Erik
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Bodin, Örjan
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Practical tool for landscape planning? An empirical investigation of network based models of habitat fragmentation.2009In: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 32, no 1, 123-132 p.Article in journal (Refereed)
    Abstract [en]

    This study presents a graph-theoretical modelling approach using daily movements and habitat demands of different target bird species in an urban context to assess: 1) habitable land cover types, 2) threshold distances between patches of habitat, 3) the required minimum accessible habitat areas and 4) the effects of barriers and stepping stones. The modelling approach is tested using empirical data from field surveys in the urban area of Stockholm, Sweden.

    The results show that groups of small habitat patches can house the same species as larger contiguous patches as long as they are perceived as functionally connected by the inhabitant organisms. Furthermore, we found that binary habitat/non-habitat representations of the landscape could roughly explain the variation in species occurrence, as long as habitat was properly defined. However, the explanatory power of the landscape models increased when features of matrix heterogeneity such as stepping stones and barriers were accounted for.

    Synthesis and application: in a world where forest ecosystems are becoming increasingly fragmented there is an urgent need to find comprehensive and scientifically relevant methods for managing and planning ecosystems. This study shows that: 1) groups of well placed small habitat patches can, together, be sufficient to attract birds in intensively developed areas, 2) the presented modelling approach can help identify such groups of patches, 3) matrix heterogeneity should preferably be accounted for, and 4) proper assessments of habitable land cover types are important. Finally, we argue that the modelling approach applied here may substantially improve landscape management and planning at scales ranging from whole landscapes down to neighbourhoods.

  • 31. Andrade, Carlos A. P.
    et al.
    Nascimento, Francisco
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Conceicao, Luis E. C.
    Linares, Fatima
    Lacuisse, Marc
    Dinis, Maria T.
    Red Porgy, Pagrus pagrus, Larvae Performance and Nutritional Condition in Response to Different Weaning Regimes2012In: Journal of the World Aquaculture Society, ISSN 0893-8849, E-ISSN 1749-7345, Vol. 43, no 3, 321-334 p.Article in journal (Refereed)
    Abstract [en]

    Red porgy, Pagrus pagrus, is a candidate species for aquaculture diversification. The aim of this work was to assess whether an early supply of enriched Artemia (D1) or a direct step to dry diets (D3) would be advantageous weaning strategies for red porgy larvae, compared to a later supply of Artemia followed by dry diets (D2). Direct weaning to dry diet resulted in significantly lower growth, survival, pancreatic (trypsin and lipase), and intestinal (alkaline phosphatase) enzyme-specific activity, with the exception of leucine-alanine peptidase. The direct weaning strategy presented severe nutritional restrictions from early weaning stages with an associated delay of the maturation of digestive system. The two-step strategy presented in D1 and D2 resulted in comparable results in most parameters, including survival. Weaning using enriched Artemia as an intermediate step is confirmed as the most adequate strategy for red porgy larvae. Digestive enzymes and selected fatty acids correlated well with performance responses to dietary regimes, thereby supporting the use of these parameters as sensitive and reliable indicators of red porgy nutritional or physiological status during larval stages.

  • 32. Andrade, Carlos A. P.
    et al.
    Nascimento, Francisco J. A.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Nogueira, Natacha
    Pimenta, Filomena
    Dinis, Maria T.
    Narciso, Luis
    Allometric Growth in Red Porgy Larvae: Developing Morphological Indices for Mesocosm Semi-Intensive Culture2013In: North American Journal of Aquaculture, ISSN 1522-2055, E-ISSN 1548-8454, Vol. 75, no 1, 42-49 p.Article in journal (Refereed)
    Abstract [en]

    We studied the morphological development, allometric growth, and cannibalistic behavior of Red Porgy Pagrus pagrus reared in mesocosm semi-intensive culture. The study was conducted from hatching to 32 d after hatching (DAH). Red porgy ontogeny was characterized by strong positive allometric growth of body depth at anus (BDA) to 6.7mm total length (TL) at about 2122 DAH. The BDA combined with standard length (SL) in a morphometric index was found to be better correlated with dry weight than TL and provided an improved method to estimate larval growth. Mouth size also exhibited strong positive allometric growth at early larval stages that, together with inflation of the swim bladder, may have contributed to improve feeding ability, in preparation for the high energy demands of metamorphosis. A predictive regression model developed for cannibalism underestimated prey size. Cannibalism coincided with the development of acidic digestion and was first evident at 27 DAH as larvae reached about 23% of their maximum size variation. We hypothesize that cannibalism is associated with larval size and condition, but is prompted by physiological and energetic factors. The bivariate morphometric index developed in this study can be used to mitigate cannibalism by controlling larval size variation and improving feed supply. The morphological measurements and morphometric indices that result from this study provide important tools for improving red porgy larvae culture. Received December 13, 2011; accepted July 12, 2012

  • 33.
    Andriam Parany, Rivolala
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    von Heland, Jacob
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Elmqvist, Thomas
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    The role of sacred forests in pollination of livelihoods crops in southern MadagascarIn: Ecological Economics, ISSN 0921-8009, E-ISSN 1873-6106Article in journal (Refereed)
  • 34.
    Angerbrandt, Henrik
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Political Science.
    Lindström, Lars
    Stockholm University, Faculty of Social Sciences, Department of Political Science.
    de la Torre-Castro, Maricela
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    What is this thing called 'community' good for?2011In: World Small-Scale Fisheries: Contemporary Visions / [ed] Ratana Chuengpagdee, Delft: Eburon Academic Publishers, 2011, 353-366 p.Chapter in book (Refereed)
  • 35. Artioli, Yuri
    et al.
    Friedeich, Jana
    Gilbert, Alison J.
    McQuatters-Gollop, Abigail
    Mee, Laurence D.
    Vermaat, Jan E.
    Wulff, Fredrik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Humborg, Christoph
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Palmeri, Luca
    Pollehne, Falk
    Nutrient budgets for European seas: A measure of the effectiveness of nutrient reduction policies.2008In: Marine Pollution Bulletin, ISSN 0025-326X, E-ISSN 1879-3363, Vol. 56, no 9, 1609-1617 p.Article in journal (Refereed)
    Abstract [en]

    Socio-economic development in Europe has exerted increasing pressure on the marine environment. Eutrophication, caused by nutrient enrichment, is evident in regions of all European seas. Its severity varies but has, in places, adversely impacted socio-economic activities. This paper aims to evaluate the effectiveness of recently adopted policies to reduce anthropogenic nutrient inputs to European seas. Nitrogen and phosphorus budgets were constructed for three different periods (prior to severe eutrophication, during severe eutrophication and contemporary) to capture changes in the relative importance of different nutrient sources in four European seas suffering from eutrophication (Baltic Proper, coastal North Sea, Northern Adriatic and North-Western Black Sea Shelf). Policy success is evident for point sources, notably for P in the Baltic and North Seas, but reduction of diffuse sources has been more problematic.

  • 36.
    Axenrot, Thomas
    et al.
    e of Freshwater Research, Swedish Board of Fisheries.
    Ogonowski, Martin
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Sandström, Alfred
    e of Freshwater Research, Swedish Board of Fisheries.
    Didrikas, Tomas
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Multifrequency discrimination of fish and mysids2009In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 66, no 6, 1106-1110 p.Article in journal (Refereed)
    Abstract [en]

    The opossumshrimp (Mysis relicta) is common in many lakes in the northernparts of Eurasia and North America. The shrimp is often an importantlink in the foodweb for fish, either throughout life or in earlylife stages. Generally, quantitative measurements of mysidsin large volumes of water are difficult to obtain with traditionalsampling methods. In this pilot study, measurements of volume-backscatteringstrength (Sv) at 38, 120, and 200 kHz were used to separatebackscattering from fish and mysids. Mysids were sampled withtrawls. Where mysids were caught, the correlations between mysidbiomass (dry weight) and mean Sv at 120 and 200 kHz were positive(r2 = 0.89 and 0.81, respectively). Where mysids were abundant,the Sv exhibited a characteristic frequency response. This wasnot found where mysids were scarce or absent. Therefore, areaswith great abundances of mysids can be identified, and theirbiomasses estimated from data collected during ecosystem monitoring.

  • 37.
    Barthel, S.
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Colding, J.
    Elmqvist, T.
    Folke, C.
    History and local management of a biodiversity rich, urban, cultural landscape2005In: Ecology and Society, ISSN 1708-3087, Vol. 10, no 2Article in journal (Refereed)
  • 38.
    Barthel, S.
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Folke, C.
    Colding, J.
    Social-ecological memory for management of ecosystem servicesManuscript (Other academic)
  • 39.
    Barthel, Stephan
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Recalling Urban Nature: Linking City People to Ecosystem Services2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Societal development is dependent on the generation of ecosystem services (ES) to sustain it; however, many ES are degrading. This thesis investigates how social-ecological features behind practices of actor groups shape the generation of ES. The empirical basis is case studies in the urban landscape of Stockholm, Sweden, and the methodological approach is interdisciplinary. Paper I shows that the urban landscape owes it current flow of ES to co-evolutionary processes and that governance with the aim of sustaining ES must take into account historical property rights and the involvement of a diversity of actor groups, as well as ecological processes of the larger landscape. Paper II studies allotment gardens, cemeteries and city parks in relation to the generation of pollination, seed dispersal and pest regulation. Differences in social features behind practice are reflected primary as higher abundance of pollinators in the informally managed allotment gardens and as differences in the compositions of seed dispersers and insectivores’ birds. Thus, voluntary and often ignored actor groups, motivated by sense-of-place, support the generation of some ES here. Paper III shows how practice, linked to ES generation, is retained and stored among allotment gardeners, and modified and transmitted through time, by means of social-ecological memory (SE-memory). SE-memory is an emergent property of a dual process of participation and reification and it facilitates monitoring of local change and links practice, often in habits, to place specific processes that underlie provisioning ES. Paper IV explores how spatial scale mismatches between ecological process and processes of management can be bridged by a spatially explicit and flexible social network structure of governance. Urban ES are a product of human driven co-evolution, consequently sustaining ES in urban landscapes is not about conservation without people, but shaped by and dependent on management practice by people. Practice that links to generation of ES are facilitated by SE-memory of local actors that holds long term management rights. Consequently, local communities of ecosystem practice, which contribute to the production of ES should explicitly be taken into account in urban green governance.

  • 40.
    Barthel, Stephan
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Folke, Carl
    Stockholm University, Stockholm Resilience Centre. Stockholm University, Faculty of Science, Department of Systems Ecology.
    Colding, Johan
    Stockholm University, Stockholm Resilience Centre.
    Social-ecological memory in urban gardens-Retaining the capacity for management of ecosystem services2010In: Global Environmental Change, ISSN 0959-3780, E-ISSN 1872-9495, Vol. 20, no 2, 255-265 p.Article in journal (Refereed)
    Abstract [en]

    Many ecosystem services are in decline. Local ecological knowledge and associated practice are essential to sustain and enhance ecosystem services on the ground. Here, we focus on social or collective memory in relation to management practice that sustains ecosystem services, and investigate where and how ecological practices, knowledge and experience are retained and transmitted. We analyze such social-ecological memory of allotment gardens in the Stockholm urban area, Sweden. Allotment gardens support ecosystem services such as pollination, seed dispersal and pest regulation in the broader urban landscape. Surveys and interviews were preformed over a four-year period with several hundreds of gardeners. We found that the allotment gardens function as communities-of-practice, where participation and reification interact and social-ecological memory is a shared source of resilience of the community by being both emergent and persistent. Ecological practices and knowledge in allotment gardens are retained and transmitted by imitation of practices, oral communication and collective rituals and habits, as well as by the physical gardens, artifacts, metaphors and rules-in-use (institutions). Finally, a wider social context provides external support through various forms of media, markets, social networks, collaborative organizations, and legal structures. We exemplify the role of urban gardens in generating ecosystem services in times of crisis and change and conclude that stewards of urban green areas and the social memory that they carry may help counteract further decline of critical ecosystem services. .

  • 41. Beilin, R.
    et al.
    Queiroz, Cibele
    Stockholm University, Stockholm Resilience Centre.
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Re-imagined and re-defined meanings: The complexity of land abandonment, identity and place in the quest for sustainable and biodivers rural and regional landscapes.2011In: Landscapes, Identities and Development / [ed] Zoran Roca, Paul Claval, John Agnew, Ashgate, 2011, 243-256 p.Chapter in book (Refereed)
    Abstract [en]

    Bringing together theoretical and empirical research from 22 countries in Europe, North America, Australia, South America and Japan, this book offers a state-of-the-art survey of conceptual and methodological research and planning issues relating to landscape, heritage, and development. It has 30 chapters grouped in four main thematic sections: landscapes as a constitutive dimension of territorial identities; landscape history and landscape heritage; landscapes as development assets and resources; and landscape research and development planning. The contributors are scholars from a wide range of cultural and professional backgrounds, experienced in fundamental and applied research, planning and policy design. They were invited by the co-editors to write chapters for this book on the basis of the theoretical frameworks, case-study research findings and related policy concerns they presented at the 23rd Session of PECSRL - The Permanent European Conference for the Study of the Rural Landscape, organized by TERCUD - Territory, Culture and Development Research Centre, Universidade Lusofona, in Lisbon and Obidos, Portugal, 1 - 5 September 2008. With such broad inter-disciplinary relevance and international scope, this book provides a valuable overview, highlighting recent findings and interpretations on historical, current and prospective linkages between changing landscapes and natural, economic, cultural and other identity features of places and regions; landscape-related identities as local and regional development assets and resources in the era of globalized economy and culture; the role of landscape history and heritage as platforms of landscape research and management in European contexts, including the implementation of The European Landscape Convention; and, the strengthening of the landscape perspective as a constitutive element of sustainable development.

  • 42. Beilin, Ruth
    et al.
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology. Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Stenseke, Marie
    Pereira, Henrique Miguel
    Llausas, Albert
    Slätmo, Elin
    Cerqueira, Yvonne
    Navarro, Laetitia
    Rodrigues, Patricia
    Reichelt, Nicole
    Munro, Nicola
    Queiroz, Cibele
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Faculty of Science, Stockholm Resilience Centre. Universidade de Lisboa, Portugal.
    Analysing how drivers of agricultural land abandonment affect biodiversity and cultural landscapes using case studies from Scandinavia, Iberia and Oceania2014In: Land use policy, ISSN 0264-8377, E-ISSN 1873-5754, Vol. 36, 60-72 p.Article in journal (Refereed)
    Abstract [en]

    Agricultural land abandonment (ALA) is widespread in many countries of the global north. It impacts rural communities, traditional landscapes, biodiversity and ecosystem services. It is an opportunity for ecosystem restoration or new landscape functions. We explored ALA in study areas in Australia, Portugal and Sweden. In each, we assessed plant species diversity, historical trajectories of land cover change; and the socioeconomic past, present and future in interviews with farmers. The ALA data was integrated and analysed by identifying the drivers of change. The relative importance of each driver and its scale of action was estimated, both in the past (1950-2010) and in the future (2010-2030). ALA has transformed rural landscapes in the study areas of Portugal and Sweden. It is at a much earlier stage with potential to increase in the Australian case. We identified a set of driving forces, classified into pressures, frictions and attractors that clarify why ALA, noting its temporal and spatial scale, occurs differently in each study area. The effect of the drivers is related to social and historical contexts. Pressures and attractors encouraging agricultural abandonment are strongest in Portugal and Sweden. Generally more (institutionalized) frictions are in place in these European sites, intended to prevent further change, based on the benefits assumed for biodiversity and aesthetics. In Australia, the stimulation of driving forces to promote a well-managed abandonment of some cleared areas could be highly beneficial for biodiversity, minimally disruptive for current dairy farming operations and would bring opportunities for alternative types of rural development.

  • 43.
    Bergsten, Arvid
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Fragmented landscapes: Assessment and communication of landscape connectivity in human-dominated landscapes2012Licentiate thesis, monograph (Other academic)
    Abstract [en]

    This licentiate thesis summarizes the first half of my PhD on the theme of management of fragmented landscapes. The thesis applies – and reflects on the use of – network analysis of connectivity in relation to landscape planning. Relevant theory on knowledge management and spatial ecology is summarized and discussed in connection with two papers.

    Paper I centers on municipal ecologists and environmental planners in the Stockholm region. They state that connectivity is rarely considered enough in planning and that assessment tools are lacking. Paper I studies the benefits and difficulties of using network analysis to manage connectivity in land-use planning. Among the main difficulties was the choice of model species and access to input data. The main strengths were the graphical and quantitative results, the potential for social learning, identification of critical sites and to relate local planning and ecology to the regional landscape.

    Paper II applies network methodology to quantify habitat availability of fragmented lichen-type forests in protected areas in northern Sweden. It studies a dynamic landscape that is continuously rearranged by forestry, with consequences that depend on species’ abilities to compete for resources in protected habitats, and to disperse through unprotected mature forest stands. We discuss the results with reference to the planning of forestry and protected areas, and to the resilience of species to patchy disturbance regimes.

    To end I propose a continuation of research, including a methodological development of network analysis; a sociological study of the acceptance of ecological advice in urban planning; and an integration of social and ecological network analysis to compare patterns of cross-municipal collaboration with landscape connectivity.

  • 44.
    Berkström, Charlotte
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Ecological connectivity in East African seascapes2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Coral reefs, seagrass beds and mangroves constitute a complex mosaic of habitats referred to as the tropical seascape. Great gaps exist in the knowledge of how these systems are interconnected. This thesis sets out to examine ecological connectivity, i.e. the connectedness of ecological processes across multiple scales, in Zanzibar and Mafia Island, Tanzania. Paper I examined the current knowledge of interlinkages and their effect on seascape functioning, revealing that there are surprisingly few studies on the influences of cross-habitat interactions and food-web ecology. Furthermore, 50% of all fish species use more than one habitat and 18% of all coral reef fish species use mangrove or seagrass beds as juvenile habitat in Zanzibar. Paper II examined the seascape of Menai Bay, Zanzibar using a landscape ecology approach and studied the relationship between fish and landscape variables. The amount of seagrass within 750m of a coral reef site was correlated with increased invertebrate feeder/piscivore fish abundance, especially Lethrinidae and Lutjanidae, which are known to perform ontogenetic and feeding migrations. Within patch seagrass cover was correlated with nursery species abundance. Paper III focused on a seagrass-dominated seascape in Chwaka Bay, Zanzibar and showed that small-scale habitat complexity (shoot height and density) as well as large-scale variables such as distance to coral reefs affected abundance and distribution of a common seagrass parrotfish Leptoscarus vaigiensis. Paper IV studied the connectivity and functional role of two snappers (Lutjanus fulviflamma and L. ehrenbergii) using stable isotopes (δ15N and δ13C) and found that connectivity between habitats was maintained by ontogenetic and foraging migrations by these species. The thesis concludes that ecological connectivity and multi-habitat usage by fish is a general and important characteristic in the Western Indian Ocean and should be considered in management planning.

  • 45.
    Berkström, Charlotte
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Gullström, Martin
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology. Stockholm University, Stockholm Resilience Centre.
    Mwandya, Augustine W.
    Stockholm University, Faculty of Science, Department of Zoology.
    Yahya, Saleh A. S.
    Stockholm University, Faculty of Science, Department of Zoology.
    Kautsky, Nils
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Nyström, Magnus
    Stockholm University, Stockholm Resilience Centre.
    Exploring 'knowns' and 'unknowns' in tropical seascape connectivity with insights from East African coral reefs2012In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 107, 1-21 p.Article in journal (Refereed)
    Abstract [en]

    Applying a broader landscape perspective to understand spatio-temporal changes in local populations and communities has been increasingly used in terrestrial systems to study effects of human impact and land use change. With today’s major declines in fishery stocks and rapid degradation of natural coastal habitats, the understanding of habitat configuration and connectivity over relevant temporal and spatial scales is critical for conservation and fisheries management of the seascape. Coral reefs, seagrass beds and mangroves are key-components of the tropical seascape. The spatial distribution of these habitat-types may have strong influences on cross-habitat migration and connectivity patterns among organisms. However, the consequences of seascape fragmentation and ecological connectivity are largely unknown. Here, we review the literature to provide an overview of current knowledge with regards to connectivity and food-web interactions within the tropical seascape. We show that information on fish acting as mobile links and being part of nutrient transfer and trophic interactions is scarce. We continue by making an in-depth analysis of the seascape around Zanzibar (Eastern Africa) to fill some of the knowledge gaps identified by the literature survey. Our analysis shows that (i) fifty percent of all fish species found within the Zanzibar seascape use two or multiple habitat-types, (ii) eighteen percent of all coral reef-associated fish species use mangrove and seagrass beds as juvenile habitat, and (iii) macrocarnivores and herbivores are highly represented among those coral reef fish species that use mangrove and seagrass beds as juvenile habitat. We argue that understanding the inter-linkages within and between habitat-types is essential for successful management of the tropical seascape.

  • 46.
    Berkström, Charlotte
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Jones, Geoffrey P.
    McCormick, Mark I.
    Srinivasan, Maya
    Ecological versatility and its importance for the distribution and abundance of coral reef wrasses2012In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 461, 151-163 p.Article in journal (Refereed)
    Abstract [en]

    Ecological versatility, the degree to which organisms fully exploit the available resources, is an important component of ecological and evolutionary theory. However, patterns and consequences of versatility in coral reef fish have received little attention. Using a comparative approach, this study tested the consequences of ecological versatility on the distribution and abundance of juvenile wrasses (family: Labridae) in Kimbe Bay, Papua New Guinea. Resource use was examined along 4 different resource axes (horizontal distribution or reef zone, vertical distribution or depth, microhabitat and diet). Stepwise multiple regressions were used to test for relationships between niche breadth and patterns of abundance and distribution. Most exhibited a degree of apparent specialisation on at least one resource, but none were specialised along all resource axes. In terms of juvenile diet, the majority of species exhibited a high reliance on harpacticoid copepods. Microhabitat specialisation was associated with low local abundance and narrow distribution among depth zones. However, diet and macrohabitat specialisation were poor predictors of local abundance, and no relationships between local abundance, and local and regional distribution were observed. We conclude that the relationship between versatility and abundance/distribution is dependent on the resource in question. A greater understanding of the degree of ecological versatility in relation to different resources is necessary to predict how reef fishes will respond to escalating human impacts on coral reefs.

  • 47.
    Berkström, Charlotte
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Thyresson, Matilda
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Gullström, Martin
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Seascape configuration influences connectivity of reef fish assemblagesManuscript (preprint) (Other academic)
    Abstract [en]

    Shallow-water habitats within tropical seascapes are intimately connected through ontogenetic and/or feeding migrations of fish. Knowledge on connectivity in the Indo-Pacific region is however sparse. Landscape ecology has been suggested as a useful approach when studying seascape connectivity. In this study, we examine the influence of habitat connectivity on reef fish assemblages in shallow-water habitats surrounding Zanzibar (Tanzania), using a seascape approach. We tested the relationships between a set of landscape and habitat variables and fish diversity and density for different functional groups and life stages. Habitat data was collected at scales ranging from 1m to >2km using aerial photography and ground-truthing. Fish data was collected using a standardised point census method. Furthermore, semi-structured interviews with 127 fishers in the bay were conducted to account for different fishing activity. We show that coral reefs in a complex seascape of Zanzibar are connected to seagrass beds through migration of fish. Habitat connectivity of seagrass and seagrass/coral mix within a 750m radius of coral reefs had a positive influence on fish abundances in the functional group of invertebrate feeders/piscivores, especially within the family Lutjanidae and Lethrinidae. Within-patch seagrass cover had a positive influence on nursery species. Depth also had a positive influence on fish assemblages, highlighting the importance of considering a third dimension, not accounted for in terrestrial studies. Generally, fishing activity between sites did neither influence species richness nor abundance, except for the abundance of juvenile parrotfish. We demonstrate that a landscape ecology approach, combining connectivity and habitat variables, is important for understanding and managing the tropical seascape, although it must be applied at relevant scales, habitat metrics and seascape configurations to fully capture ecological connectivity.

  • 48. Biggs, R
    et al.
    Raudsepp-Hearne, C
    Atkinson-Palombo, C
    Bohensky, E
    Boyd, E
    Cundhill, G
    Fox, H
    Ingram, S
    Kok, K
    Spehar, S
    Tengö, Maria
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Timmer, D
    Zurek, M
    Linking futures across scales: a dialog on multiscale scenarios2007In: Ecology and society, Vol. 12, no 1, no. 17- p.Article in journal (Refereed)
  • 49.
    Biggs, Reinette
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Crépin, Ann-Sophie
    Stockholm University, Stockholm Resilience Centre. The Beijer Institute of Ecological Economics, The Royal Swedish Academy of Sciences, Sweden.
    Engström, Gustav
    Stockholm University, Stockholm Resilience Centre. The Beijer Institute of Ecological Economics, The Royal Swedish Academy of Sciences, Sweden.
    Folke, Carl
    Stockholm University, Stockholm Resilience Centre. The Beijer Institute of Ecological Economics, The Royal Swedish Academy of Sciences, Sweden.
    Kautsky, Nils
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Walker, Brian
    Stockholm University, Stockholm Resilience Centre. Sustainable Ecosystems, Australia.
    General Resilience to Cope with Extreme Events2012In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 4, no 12, 3248-3259 p.Article in journal (Refereed)
    Abstract [en]

     Resilience to specified kinds of disasters is an active area of research and practice. However, rare or unprecedented disturbances that are unusually intense or extensive require a more broad-spectrum type of resilience. General resilience is the capacity of social-ecological systems to adapt or transform in response to unfamiliar, unexpected and extreme shocks. Conditions that enable general resilience include diversity, modularity, openness, reserves, feedbacks, nestedness, monitoring, leadership, and trust. Processes for building general resilience are an emerging and crucially important area of research.

  • 50.
    Bjorklund, M.
    et al.
    Department of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Norbyvägen, 18D, SE-752 36 Uppsala, Sweden.
    Almqvist, G.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Is it possible to infer the number of colonisation events from genetic data alone?2010In: Ecological informatics, ISSN 1574-9541, Vol. 5, no 3, 173-176 p.Article in journal (Refereed)
    Abstract [en]

    The current state of populations is to a large determined by events in the past that we have no information about Thus, we have to rely on indirect methods to infer likely scenarios of these events In this paper we describe a simple simulation approach to infer the minimum number of introductions of an invasive species, the round goby in the Baltic Sea The results show that several introductions are most likely to have occurred, possibly even a constant rate of immigration. This poses new threats to local fish populations that currently suffer from overfishing The method is very general and can be applied to other similar situations.

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