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  • 151.
    Eriksson, Hampus
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Managing sea cucumber fisheries and aquaculture: Studies of social-ecological systems in the Western Indian Ocean2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Collecting sea cucumbers to supply the high value Chinese dried seafood market is a livelihood activity available to many people in the Western Indian Ocean (WIO), making it an important part of local economies. These fisheries are generally not successfully managed and tropical sea cucumber fisheries show continuing signs of decline. This thesis takes a social-ecological systems approach to guide better management of sea cucumber fisheries and aquaculture in the WIO. Papers 1 and 2 analyse the fishery situation in Zanzibar and find that in the absence of effective management institutions and income alternatives among fishers, leading to dependence, there are unsustainable expanding processes. Paper 3 compares the unmanaged fishery in Zanzibar to the highly controlled situation in Mayotte. In Mayotte, a protection effect is evident and the commercial value of stocks is significantly higher than in Zanzibar. The analysis of the situation in Mayotte demonstrates the importance of matching the fishery – management temporal scales through prepared and adaptive management to avoid processes that reinforce unsustainable expansion. Paper 4 analyses sea cucumber community spatial distribution patterns at a coastal seascape-scale in Mayotte establishing baseline patterns of habitat utilization and abundance, which can be used as reference in management. Paper 5 reviews the potential for sea cucumber aquaculture in the WIO. The review illustrates that this activity, which is currently gaining momentum, does so based on inflated promises and with significant social-ecological risks. Emphasis for improvements is, in this thesis, placed on the importance of prepared and adaptive institutions to govern and control expanding processes of the fishery. These institutional features may be achieved by increasing the level of knowledge and participation in governance and by integration of sea cucumber resources management into higher-level policy initiatives.

  • 152.
    Eriksson, Hampus
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Byrne, Maria
    de la Torre-Castro, Maricela
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Sea cucumber (Aspidochirotida) community, distribution and habitat utilization on the reefs of Mayotte, Western Indian Ocean2012In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 452, p. 159-170Article in journal (Refereed)
    Abstract [en]

    The tropical sea cucumber (Aspidochirotida) fishery for the lucrative Asian dried-seafood trade is a multi-species fishery with little ecological knowledge. To improve ecological understanding of the targeted species, the reefs of Mayotte, Western Indian Ocean, were surveyed to document the distribution, species assemblage and habitat utilization of commercial sea cucumbers. This is one of the few reef areas in the region protected from fishing, thus providing an important and unique opportunity to investigate sea cucumber ecology. Twenty-two species were observed. The medium-value Bohadschia atra and the high-value Holothuria nobilis were the most abundant species. Species distribution varied but the density was generally similar across areas and habitats. Multivariate analysis (ANOSIM) indicated that the community was similar between surveyed areas and reef habitats. Diversity was lower in one of the surveyed areas and in the ocean-facing barrier reef habitat. Habitat complexity was not a significant driver of diversity or abundance. A principal component analysis showed that the 6 most common species (B. atra, Holothuria atra, H. fuscopunctata, H. nobilis and Thelenota ananas) were associated with different substrate types. Clustering these species according to substrate variables indicated both habitat utilization overlap and segregation among species, valuable information for spatial planning of fisheries management and conservation. Although unique species were observed in some areas, the present study shows that, at a large spatial scale, the unfished reefs in Mayotte consist of similar commercial sea cucumber communities, an important baseline finding.

  • 153.
    Eriksson, Hampus
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    de la Torre-Castro, Maricela
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Eklöf, Johan
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Jiddawi, Narriman
    Institute of Marine Science, University of Dar es Salaam, Mizingani Rd., PO Box 668, Zanzibar .
    Resource degradation of the sea cucumber fishery in Zanzibar, Tanzania: a need for management reform2010In: Aquatic Living Resources, ISSN 0990-7440, E-ISSN 1765-2952, Vol. 23, p. 387-398Article in journal (Refereed)
    Abstract [en]

    This study assessed the Zanzibar sea cucumber fishery using a multidisciplinary approach. Data was collected by (i) interviewing various groups of actors in the fishery and reviewing management documentation and legislation, (ii) by monitoring catches and (iii) through a visual census of coastal sea cucumber populations in areas open and closed to fishing. The fishery showed clear signs of being unsustainable with high fishing effort, and weak formal and informal management institutions. The fishery operation was characterised by an intricate cross-scale structure with both fishers and sea cucumber products being transported across national borders. The visual census of commercial sea cucumber stocks at three sites open to fishing around Zanzibar showed low densities across the range of sea cucumber value groups including low value species. Furthermore, the diversity of commercial sea cucumber species was lower in fished reefs than on a protected reef. The poor status of the sea cucumber populations was confirmed by the perception of an overfished resource by the interviewed actors active in the fishery. This was also depicted by the paucity of high value species, and high representation of low value and newly commercialised species in fishers catch. We conclude that the current state of Zanzibar’s sea cucumber populations is compromising the fisheries self-replenishment and existence and that the fishery is in urgent need of a complete management reform. 

  • 154.
    Eriksson, Hampus
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    de la Torre-Castro, Maricela
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Olsson, Per
    Stockholm University, Stockholm Resilience Centre.
    Breaking degradation of sea cucumber resources: a social-ecological analysis of the fisheries in Zanzibar and Mayotte Islands in the Western Indian OceanManuscript (preprint) (Other academic)
    Abstract [en]

    Despite increasing research and management attention to tropical sea cucumber fisheries no apparent successes have been documented. To broaden the perspective of recent advances in management tools this study analyses the social-ecological processes in two contrasting sea cucumber fisheries situations, Zanzibar (Tanzania) and Mayotte (France) in the Western Indian Ocean. Zanzibar has an on-going fishery while the fishery in Mayotte operated approximately 10 years before it was closed in 2004. The study compares how different management strategies in Mayotte and Zanzibar were taken to address increasing fishing effort and a declining sea cucumber population. The comparison provide an opportunity learning and reflection. A visual census of stocks shows that the commercial value is nearly 30 times higher in Mayotte than Zanzibar owing to different fishery and management practices. In Mayotte less than 100 people were engaged in the fishery when it was active and the fishery was a comparatively small enterprise. In contrast, over 1000 people collect sea cucumbers as part of an expansive trade network that has developed in Zanzibar. In addition, in this site fishers are dependent on the resource for livelihood and expanding fishery processes have therefore occurred as a response to declines in catch abundance and value. These responses have taken place in the context of insufficient management and reinforce an unsustainable fishery situation difficult to break – referred to as a social-ecological trap. In contrast, management in Mayotte was receptive and adaptive to changes. The closure of the fishery illustrates the importance and positive outcome of matching the fishery – management temporal scales to avoid reinforcing fishery processes and to maintain ecosystem integrity. The multiple fisheries targeting sea cucumbers documented in this study captures how different management approaches and management plans are required, building on an understanding of the social-ecological context of the fishery. In addition, the comparison illustrates the importance of management systems with adequate resources (e.g. human and economic) and functioning information flows for positive management outcomes.  

  • 155.
    Eriksson, Hampus
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    de la Torre-Castro, Maricela
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Olsson, Per
    Stockholm University, Stockholm Resilience Centre.
    Mobility, Expansion and Management of a Multi-Species Scuba Diving Fishery in East Africa2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 4, p. e35504-Article in journal (Refereed)
    Abstract [en]

    Background: Scuba diving fishing, predominantly targeting sea cucumbers, has been documented to occur in an uncontrolled manner in the Western Indian Ocean and in other tropical regions. Although this type of fishing generally indicates a destructive activity, little attention has been directed towards this category of fishery, a major knowledge gap and barrier to management. 

    Methodology and Principal Findings: With the aim to capture geographic scales, fishing processes and social aspects the scuba diving fishery that operate out of Zanzibar was studied using interviews, discussions, participant observations and catch monitoring. The diving fishery was resilient to resource declines and had expanded to new species, new depths and new fishing grounds, sometimes operating approximately 250 km away from Zanzibar at depths down to 50 meters, as a result of depleted easy-access stock. The diving operations were embedded in a regional and global trade network, and its actors operated in a roving manner on multiple spatial levels, taking advantage of unfair patron-client relationships and of the insufficient management in Zanzibar. Conclusions and

    Significance: This study illustrates that roving dynamics in fisheries, which have been predominantly addressed on a global scale, also take place at a considerably smaller spatial scale. Importantly, while proposed management of the sea cucumber fishery is often generic to a simplified fishery situation, this study illustrates a multifaceted fishery with diverse management requirements. The documented spatial scales and processes in the scuba diving fishery emphasize the need for increased regional governance partnerships to implement management that fit the spatial scales and processes of the operation. 

  • 156.
    Eriksson, Hampus
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Robinson, Georgina
    Slater, Matthew
    Troell, Max
    Stockholm University, Stockholm Resilience Centre.
    Sea Cucumber Aquaculture in the Western Indian Ocean:  Challenges for Sustainable Livelihood and Stock Improvement2012In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 41, no 2, p. 109-121Article in journal (Refereed)
    Abstract [en]

    The decline in sea cucumber fisheries that serve the Asian dried seafood market has prompted an increase in global sea cucumber aquaculture. The tropical sandfish (Holothuria scabra) has in this context been reared and produced with mixed success. In the Western Indian Ocean, villagers often participate in the export fishery for sea cucumbers as a source of income. However, with a growing concern of depleted stocks introduction of hatcheries to farm sandfish as a community livelihood and to replenish wild stocks is being promoted. This review identifies and discusses a number of aspects that constitute constraints or implications with regard to development of sandfish farming in the region. The conclusion is that for sandfish farming to live up to its expectations the possible impacts need to be further studied, and that improved evaluation of ongoing projects is required. In the interim a precautionary approach towards new enterprise activities is suggested. 

  • 157.
    Eriksson, Hampus
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Thorne, Benjamin V.
    Byrne, Maria
    Population metrics in protected commercial sea cucumber populations (curryfish: Stichopus herrmanni) on one tree reef, great barrier reef2013In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 473, p. 225-234Article in journal (Refereed)
    Abstract [en]

    The population ecology of the tropical beche-de-mer sea cucumber Stichopus herrmanni (curryfish) was investigated on One Tree Reef, a no-take protected area in the Great Barrier Reef Marine Park. The size class frequency and density of this species at several sites were determined over 2 years: 2009 and 2011. There was a spatial separation of populations that differed in size and density, but these parameters did not change over the 2 yr of the study, indicating stable population metrics. The spatially heterogeneous population pattern has relevance for fisheries management, as current size limits protect animals with low fecundity that occur in shallow habitat, but make it legal to remove 85% of large, fecund animals in deeper areas. Data for 4 S. herrmanni populations were used to address 2 theories on the potential drivers of population structure: (1) adult migration and (2) phenotypic plasticity in growth with respect to habitat conditions. While connectivity through adult migration appears possible, the size structure and location of some populations indicate that population features are determined by post-recruitment growth in the habitat. The latter likely plays a major role in population dynamics and terminal growth of S. herrmanni. There was no day-night difference in density at fixed transects, indicating that data obtained in daytime surveys was representative. A frequency distribution profile of density data from manta tows is presented as an alternative to using mean density as an assessment indicator in sea cucumber fisheries. S. herrmanni showed a noticeable affinity for reef features, an important finding for improved resolution of spatial planning in management.

  • 158.
    Eriksson Hägg, Hanna
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Humborg, Christoph
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM). Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Mörth, Carl-Magnus
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Medina, Miguel Rodriguez
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Wulff, Fredrik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Scenario Analysis on Protein Consumption and Climate Change Effects on Riverine N Export to the Baltic Sea2010In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 44, no 7, p. 2379-2385Article in journal (Refereed)
    Abstract [en]

    This paper evaluates possible future nitrogen loadings from 105 catchments surrounding the Baltic Sea. Multiple regressions are used to model total nitrogen (TN) flux as a function of specific runoff (0), atmospheric nitrogen deposition, and primary emissions (PE) from humans and livestock. On average cattle contributed with 63%, humans with 20%, and pigs with 17% of the total nitrogen PE to land. Compared to the reference period (1992-1996) we then evaluated two types of scenarios for year 2070. i) An increased protein consumption scenario that led to 16% to 39% increased mean TN flux (kg per km(-2)). ii) Four climate scenarios addressing effects of changes in river discharge. These scenarios showed increased mean TN flux from the northern catchments draining into the Gulf of Bothnia (34%) and the Gulfs of Finland and Riga (14%), while the mean TN flux decreased (-27%) for catchments draining to the Baltic Proper. However, the net effect of the scenarios showed a possible increase in TN flux ranging from 3-72%. Overall an increased demand for animal protein will be instrumental for the Baltic Sea ecosystem and may be a major holdback to fulfill the environmental goals of the Baltic Sea Action Plan.

  • 159.
    Eriksson, Klemens Britas
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology. Marin ekologi.
    Rubach, A
    Hillebrand, H
    Dominance by a canopy forming seaweed modifies resource and consumer control of bloom-forming macroalgae2007In: Oikos, Vol. 116, p. 1211-1219Article in journal (Refereed)
  • 160.
    Eriksson Wiklund, Ann-Kristin
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Oskarsson, Hanna
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Thorsen, Gunnar
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Kumblad, Linda
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Behavioural and physiological responses to pharmaceutical exposure in macroalgae and grazers from a Baltic Sea littoral community2011In: Aquatic Biology, ISSN 1864-7782, E-ISSN 1864-7790, Vol. 14, no 1, p. 29-39Article in journal (Refereed)
    Abstract [en]

    Gammarus spp. and Fucus vesiculosus from the Baltic Sea littoral community were exposed to 3 concentrations of the pharmaceuticals ibuprofen and propranolol. Both physiological and behavioural parameters were measured to examine potential effects in the organisms. For Gammarus spp., respiration, feeding rate and activity with and without predator cues were measured, and gross production to respiration ratio (GP/R) and chlorophyll fluorescence were measured for F. vesiculosus. The results showed that propranolol decreased the activity related to movement, and Gammarus spp. could not compensate for the reduced movement when subjected to predator cues. The feeding rates of Gammarus spp. exposed to propranolol were more than 2 times higher at all concentrations compared to the control. Ibuprofen did not significantly affect any of the measured parameters of Gammarus spp. The GP/R was lower in algae exposed to propranolol. The effects of propranolol on both behaviour and physiology of Gammarus spp., in combination with the stress responses in the algae, might cause unexpected indirect and cascade effects which eventually could have implications at both community and ecosystem scales.

  • 161. Erlandsson, Johan
    et al.
    McQuaid, Christopher D.
    Stanczak, Sara
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Recruit/algal interaction prevents recovery of overexploited mussel beds: Indirect evidence that post-settlement mortality structures mussel populations2011In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 92, no 1, p. 132-139Article in journal (Refereed)
    Abstract [en]

    The mechanisms maintaining community structure following an ecosystem shift are poorly understood and we propose that they must inherently be biological. Over-exploitation can provide a natural experiment with man as a predator driving a change in community structure, possibly an ecosystem shift. We examined a possible mechanism that maintains algal beds as an alternative state on the east coast of South Africa where the mussel Perna perna has been overexploited. Even on unexploited shores, about 50% of mussel larvae settle onto algae, but it is unclear whether they later recruit into adult beds. On such shores we used two indirect field approaches to understand the fate of recruits, testing whether inhibition of mussel recruitment by macroalgae could constitute a biological mechanism preventing reversion from the algal to the pre-disturbance mussel-dominated state. First, we examined possible ontogenetic migration of recruits from algae to adult mussels, testing the prediction that the ratio large:small recruits in adult beds is greater where algae are liberally interspersed with mussels. Second, we examined whether, like adults, recruits show spatial structure that is related to the distribution of topographic depressions, testing the hypothesis that large and small recruits show different co-variation with depressions, microhabitats where algae commonly occur. We found no evidence that recruits on algae actively move to nearby mussel beds as neither the ratio large:small recruits nor the abundances of small or large recruits showed any relationship with algal cover/variability. Small and large recruits showed different co-variation with topographic depressions on spatially structured transects. Like adults, large recruits commonly exhibited negative relationships with depressions. Thus, large recruits neither occur on algae nor migrate from algae to the primary substratum or onto adult beds. Consequently our results (a) highlight the importance of post-settlement mortality in structuring these mussel populations, and (b) suggest that the interception of larvae by algae forms a biological mechanism that can maintain macroalgal beds that develop following exploitative disturbance by man, thus preventing or at least drastically delaying the natural recovery of mussel beds.

  • 162.
    Erlandsson, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Porri, F.
    McQuaid, C.D.
    Ontogenetic changes in small-scale movement by recruits of an exploited mussel: implications for the fate of larvae settling on algae.2008In: MARINE BIOLOGY, ISSN 0025-3162, Vol. 153, no 3, p. 365-373Article in journal (Refereed)
    Abstract [en]

    Many South African populations of the brown mussel Perna perna have been depleted through over-exploitation by subsistence harvesters. This is problematic because recovery after disturbance is very slow, partly because recruits are largely associated with adult mussels. However, unlike large recruits of 3.5-10 mm that exhibit spatial structure related to that of adults, a very high proportion of settlers and small recruits (0-3.5 mm) occur on foliose algae. We tested the hypothesis that recruits on algae move to adult mussel beds after a period of growth, with the null hypothesis that they die at a certain size. We conducted an indirect field study comparing the ratios of large to small recruits in 100% cover mussel patches at locations with high and low algal cover. A second laboratory experiment analysed whether the size of recruits on algae affects their active movement behaviour in response to nearby mussel patches. Large/small recruit ratios were slightly, but not significantly greater in high than low algal cover locations. Both small (2-2.5 mm) and medium (4.5-5.5 mm) recruits remained on algae and moved very short distances throughout the laboratory experiment, while larger recruits (9-10 mm) moved significantly further distances and more often into mussel patches. The results suggest that very large recruits are able to migrate actively to nearby mussel patches, indicating ontogenetic shifts in this behaviour. However, the absence of a significant difference in ratios between field locations with high and low algal cover suggests many large recruits are accidentally dislodged from the algae and presumably die. Thus settlement of P. perna onto algae is likely to be wasted, with consequences for sustainable management of the mussel resource.

  • 163. Ernstson, H.
    et al.
    Barthel, S.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Andersson, E.
    Borgström, S.
    Ecological scales and social network structure in urban landscapes: management and governance of urban ecosystem services in Stockholm, SwedenManuscript (Other academic)
  • 164.
    Ernstson, Henrik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    In Rhizomia: Actors, Networks and Resilience in Urban Landscapes2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    With accelerating urbanization it is crucial to understand how urban ecosystems play a part in generating ecosystem services for urban dwellers, such as clean water, spaces for recreation, stress relief and improved air quality. An equally important question relate to who gets to enjoy these benefits, i.e. the distribution of ecosystem services, and how issues of power and equity influence the management of ecosystems. Through case studies from the urban landscape of Stockholm, this doctoral thesis engages with these perspectives through combining ecological theory with social theory, including social network analysis, actor-network theory and social movement theory. Strategies for how to improve urban ecosystem management are presented along with frameworks for how to analyze issues of power and equity in relation to natural resource management.

    Paper I shows that ecosystem management can be studied through analyzing the structure of social networks, i.e. the patterns of relations between agencies, stake-holders and user groups. Paper II and Paper III analyze, based on a network survey of 62 civil society organizations and in-depth interviews, a transformational process of how an urban local movement managed to protect a large urban green area from exploitation (The Stockholm National Urban Park). Paper IV discusses, based on several case studies from Stockholm, a conducive network structure for linking managers and user groups (e.g. allotment gardens, cemetery managers, and urban planners) across spatial ecological scales so as to improve urban green area management. Paper V presents a framework to analyze the social-ecological dynamics behind the generation and distribution of ecosystem services in urban landscapes.

    The thesis points towards the notion of "a social production of ecosystem services" and argues for deeper engagement with urban political ecology and critical geography to inform governance and collective action in relation to urban ecosystems.

  • 165.
    Ernstson, Henrik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    The social production of ecosystem services: lessons from urban resilience researchManuscript (Other academic)
  • 166.
    Ernstson, Henrik
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Barthel, Stephan
    Andersson, Erik
    Borgström, Sara
    Ecological scales and social network structure: management and governance of urban ecosystem services in Stockholm, SwedenManuscript (Other academic)
  • 167.
    Ernstson, Henrik
    et al.
    Stockholm University, Stockholm Resilience Centre. Stockholm University, Faculty of Science, Department of Systems Ecology.
    Barthel, Stephan
    Stockholm University, Stockholm Resilience Centre.
    Andersson, Erik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Borgström, Sara
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Scale-Crossing Brokers and Network Governance of Urban Ecosystem Services: The Case of Stockholm2010In: Ecology & society, ISSN 1708-3087, E-ISSN 1708-3087, Vol. 15, no 4, p. 28-Article in journal (Refereed)
    Abstract [en]

    Urban ecosystem services are crucial for human well-being and the livability of cities. A central challenge for sustaining ecosystem services lies in addressing scale mismatches between ecological processes on one hand, and social processes of governance on the other. This article synthesizes a set of case studies from urban green areas in Stockholm, Sweden—allotment gardens, urban parks, cemeteries and protected areas—and discusses how governmental agencies and civil society groups engaged in urban green area management can be linked through social networks so as to better match spatial scales of ecosystem processes. The article develops a framework that combines ecological scales with social network structure, with the latter being taken as the patterns of interaction between actor groups. Based on this framework, the article (1) assesses current ecosystem governance, and (2) develops a theoretical understanding of how social network structure influences ecosystem governance and how certain actors can work as agents to promote beneficial network structures. The main results show that the mesoscale of what is conceptualized as city scale green networks (i.e., functionally interconnected local green areas) is not addressed by any actor in Stockholm, and that the management practices of civil society groups engaged in local ecosystem management play a crucial but neglected role in upholding ecosystem services. The article proposes an alternative network structure and discusses the role of midscale managers (for improving ecological functioning) and scale-crossing brokers (engaged in practices to connect actors across ecological scales). Dilemmas, strategies, and practices for establishing this governance system are discussed.

  • 168.
    Ernstson, Henrik
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Sörlin, Sverker
    Stockholm University, Stockholm Resilience Centre.
    Weaving protective stories:  connective practices to articulate holistic values in Stockholm National Urban Park2009In: Environment and planning A, ISSN 0308-518X, E-ISSN 1472-3409, Vol. 41, no 6, p. 1460-1479Article in journal (Refereed)
    Abstract [en]

    With rapid worldwide urbanization it is urgent that we understand processes leading to the protection of urban green areas and ecosystems. Although natural reserves are often seen as preserving 'higher valued' rather than 'lower valued' nature, it is more adequate to describe them as outcomes of selective social articulation processes. This is illustrated in the Stockholm National Urban Park. Despite strong exploitation pressure, a diverse urban movement of civil society organizations has managed to provide narratives able to explain and legitimize the need for protection-a 'protective story'. On the basis of qualitative data and building on theories of value articulation, social movements, and actor-networks, we show how activists, by interlacing artefacts and discourses from cultural history and conservation biology, managed to simultaneously link spatially separated green areas previously seen as disconnected, while also articulating the interrelatedness between the cultural and the natural history of the area. This connective practice constructed holistic values articulating a unified park, which heavily influenced the official framing of the park's values and which now help to explain the success of the movement. In contrast to historically top-down-led designation of natural reserves, we argue that the involvement of civil society in protecting nature (and culture) is on the rise. This nonetheless begs the question of who can participate in these value-creating processes, and we also strive to uncover constraining and facilitating factors for popular participation. Four such factors are suggested: (i) the number and type of artefacts linked to an area; (ii) the capabilities and numbers of activists involved; (iii) the access to social arenas; and (iv) the social network position of actors.

  • 169.
    Ernstson, Henrik
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Sörlin, Sverker
    Elmqvist, Thomas
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Social movements and ecosystem services: the role of social network structure in protecting and managing urban green areas in Stockholm2008In: Ecology & society, ISSN 1708-3087, E-ISSN 1708-3087, Vol. 13, no 2Article in journal (Refereed)
    Abstract [en]

    Exploitation and degradation of urban green areas reduce their capacity to sustain ecosystem services. In protecting and managing these areas, research has increasingly focused on actors in civil society. Here, we analyzed an urban movement of 62 civil-society organizations—from user groups, such as boating clubs and allotment gardens, to culture and nature conservation groups—that have protected the Stockholm National Urban Park. We particularly focused on the social network structure of the movement, i.e., the patterns of interaction between movement organizations. The results reveal a core-periphery structure where core and semi-core organizations have deliberately built political connections to authorities, whereas the periphery gathers all user groups involved in day-to-day activities in the park. We show how the core-periphery structure has facilitated collective action to protect the park, but we also suggest that the same social network structure might simultaneously have constrained collaborative ecosystem management. In particular, user groups with valuable local ecological knowledge have not been included in collaborative arenas. Our case points out the inherent double-nature of all social networks as they facilitate some collective actions, yet constrain others. The paper argues for incorporating social network structure in theories and applications of adaptive governance and co-management.

  • 170.
    Ernstson, Henrik
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    van der Leeuw, Sander E.
    Arizona State University.
    Redman, Charles L
    Arizona State University.
    Meffert, Douglas J.
    Tulane University.
    Davis, George
    SANBI, Urban Conservat Programme.
    Alfsen, Christine
    Columbia University.
    Elmqvist, Thomas
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Urban Transitions: On Urban Resilience and Human-Dominated Ecosystems2010In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 39, no 8, p. 531-545Article in journal (Refereed)
    Abstract [en]

    Urbanization is a global multidimensional process paired with increasing uncertainty due to climate change, migration of people, and changes in the capacity to sustain ecosystem services. This article lays a foundation for discussing transitions in urban governance, which enable cities to navigate change, build capacity to withstand shocks, and use experimentation and innovation in face of uncertainty. Using the three concrete case cities-New Orleans, Cape Town, and Phoenix-the article analyzes thresholds and cross-scale interactions, and expands the scale at which urban resilience has been discussed by integrating the idea from geography that cities form part of "system of cities" (i.e., they cannot be seen as single entities). Based on this, the article argues that urban governance need to harness social networks of urban innovation to sustain ecosystem services, while nurturing discourses that situate the city as part of regional ecosystems. The article broadens the discussion on urban resilience while challenging resilience theory when addressing human-dominated ecosystems. Practical examples of harnessing urban innovation are presented, paired with an agenda for research and policy.

  • 171.
    Ernstsson, Henrik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    The drama of urban greens and regimes: Social movement and ecosystem services in Stockholm National Urban Park2007Licentiate thesis, monograph (Other academic)
  • 172. Fabricius, C
    et al.
    Folke, Carl
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Cundhill, G
    Schultz, Lisen
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Powerless spectators, coping actors, and adaptive co-managers: a synthesis of the role of communities in ecosystem management2007In: Ecology and Society, ISSN 1708-3087, Vol. 12, no 1, p. 29-Article in journal (Refereed)
    Abstract [en]

    We provide a synthesis of the papers in the Special Issue, the Communities Ecosystems and Livelihoods component of the Millennium Ecosystem Assessment (MA), and other recent publications on the adaptive capacity of communities and their role in ecosystem management. Communities adapt because they face enormous challenges due to policies, conflicts, demographic factors, ecological change, and changes in their livelihood options, but the appropriateness of their responses varies. Based on our synthesis, three broad categories of adaptive communities are identified. “Powerless spectator” communities have a low adaptive capacity and weak capacity to govern, do not have financial or technological options, and lack natural resources, skills, institutions, and networks. “Coping actor” communities have the capacity to adapt, but are not managing social–ecological systems. They lack the capacity for governance because of lack of leadership, of vision, and of motivation, and their responses are typically short term. “Adaptive manager” communities have both adaptive capacity and governance capacity to sustain and internalize this adaptation. They invest in the long-term management of ecosystem services. Such communities are not only aware of the threats, but also take appropriate action for long-term sustainability. Adaptive co-management becomes possible through leadership and vision, the formation of knowledge networks, the existence or development of polycentric institutions, the establishment and maintenance of links between culture and management, the existence of enabling policies, and high levels of motivation in all role players. Adaptive co-managers are empowered, but empowerment is a consequence of the capacity for governance and the capacity to adapt, rather than a starting point. Communities that are able to enhance their adaptive capacity can deal with challenges such as conflicts, make difficult trade-offs between their short- and long-term well-being, and implement rules for ecosystem management. This improves the capacity of the ecosystem to continue providing services.

  • 173.
    Faxneld, Suzanne
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Coral reefs in the Anthropocene: The effects of stress on coral metabolism and symbiont composition2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Coral reefs constitute some of the most prolific and diverse ecosystems on our planet, but also among the most threatened.

    This thesis investigates the effects of environmental stressors on corals’ metabolism and symbiont diversity. Paper I shows that the coral Turbinaria mesenterina withstood a single stressor while a combination of two stressors (decreased salinity and increased seawater temperature) lead to decreased metabolism. Increased seawater temperature in combination with two stressors (enhanced nutrients and decreased salinity) lead to rapid mortality of all specimens. Paper II shows that chronic stress in combination with increased seawater temperature affects coral species differently. Porites lutea did not show any difference in response to temperature increase, regardless of environmental disturbance history, while Galaxea fascicularis’ metabolism was negatively affected in chronically disturbed corals but not in corals from less disturbed areas. The main explanation for the difference in response between the two species is different compositions of endosymbionts as found in paper III. P. lutea only harboured the symbiont C15, regardless of environment, whilst D1a dominated the nearshore G. fascicularis and C1 dominated offshore corals. In paper IV there was a clear inshore-offshore pattern of D1a along the whole coast of Vietnam, where D1a dominated inshore. In contrast, the five symbionts belonging to group C displayed a strong latitudinal gradient, with diversity increasing from north to south. The coral host showed higher diversity offshore than inshore.

    The thesis emphasizes the importance of improving water quality (paper I and II) and protecting marginal areas since tolerant coral hosts and symbionts can be found there (paper III and IV), as well as safeguarding areas with high symbiont diversity (paper IV) to increase the ability of corals to withstand future environmental changes.

  • 174.
    Faxneld, Suzanne
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Hellström, Micaela
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Symbiodinium spp. composition in nearshore and offshore Porites lutea and Galaxea fascicularis in northern VietnamManuscript (preprint) (Other academic)
  • 175.
    Faxneld, Suzanne
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Jörgensen, Tove L.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Effects of elevated water temperature, reduced salinity and nutrient enrichment on the metabolism of the coral Turbinaria mesenterina2010In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 88, no 4, p. 482-487Article in journal (Refereed)
    Abstract [en]

    Water quality is declining in many coastal areas, which has caused coral degradation worldwide. In addition, reduced water quality may aggravate the impacts of seawater temperature. In this study the effects of increased temperature (31 degrees C), nitrate enrichment (+5 mu M NO3-), low salinity (20) and combinations of these stressors were investigated compared to ambient water (25 degrees C, 30, 0.3 mu M NO3-) on the metabolism and survival of the coral Turbinaria mesenterina from the Tonkin Gulf, Vietnam. The results showed that all specimens exposed to a combination of all three stressors (i.e. high temperature + high nitrate + low salinity) died after 24 h exposure, while those that had been exposed to high nitrate + low salinity at ambient temperature did not show any effects on the metabolism or survival. Furthermore, corals exposed to low salinity + high temperature displayed a decrease in gross primary production/respiration (GP/R) ratio and the mortality rate was 50%. In addition, all corals exposed to increased temperature, alone or in combination with another stressor, displayed a GP/R-24h ratio below 1.0, suggesting that they depend on stored energy to cover their metabolic requirements. The results showed that corals may tolerate short-term exposure to stressors such as low salinity + high nitrate concentration in ambient temperature, while additional increased temperature lead to rapid mortality, hence suggesting a synergistic effect. Thus, the effect of climate change might be more severe in nearshore coastal areas where corals already are exposed to several disturbances.

  • 176.
    Faxneld, Suzanne
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Lund Jörgensen, Tove
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Nguyen, Ngai D.
    Nyström, Magnus
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Differences in physiological response to increased seawater temperature in nearshore and offshore corals in northern Vietnam2011In: Marine Environmental Research, ISSN 0141-1136, E-ISSN 1879-0291, Vol. 71, no 3, p. 225-233Article in journal (Refereed)
    Abstract [en]

    Effects of elevated seawater temperature show high spatial heterogeneity and variation within and among coral species. The objective of this study was to investigate how two coral species, Porites lutea and Galaxea fascicularis, from two high latitude reefs differently exposed to chronic disturbance, respond to elevated seawater temperatures. Corals were collected from reefs nearshore (i.e. subjected to high sediment load, higher chlorophyll α concentrations, turbidity etc.) and offshore (i.e. less exposed). The corals were exposed in the lab to gradually increasing temperatures (25.5–33.5 °C) for 72 h after which they were allowed to recover to ambient temperature (25.5 °C) for 24 h. Production and respiration were measured after 24, 48, 72 and 96 h. The results show that P. lutea from nearshore reefs suffered an initial decrease in gross primary production/respiration (GP/R) ratio after 24 h, after only a moderate temperature increase (+2 °C, from 25.5 to 27.5 °C), while there was no difference in GP/R ratio between heat-exposed and controls the other days, indicating that the chronic disturbance in the nearshore reef had no effect on their thermotolerance. Furthermore, P. lutea from the offshore reef showed a decrease in GP/R ratio both after 24 h and 72 h (33.5 °C) of exposure.

    In comparison, G. fascicularis showed a decrease in GP/R ratio after 48 h, 72 h and 96 h of exposure for the nearshore corals. Also, after 72 h these corals had withdrawn their polyps. There were no differences between heat-treated and controls for the offshore G. fascicularis. This implies that the chronically disturbed G. fascicularis had lower thermotolerance when exposed to a temperature increase.

    This study, hence, shows that the response of corals to elevated seawater temperature varies with species and environmental background history.

  • 177. Fazey,
    et al.
    Schultz, Lisen
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Adaptive people for adaptive management.2009In: Adaptive Environmental Management. A Practitioner's Guide. / [ed] Allan C., Stankey GH., Springer , 2009, p. 323-340Chapter in book (Other academic)
  • 178. Florin, Ann-Britt
    et al.
    Lavados, Gaston
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Feeding habits of juvenile flatfish in relation to habitat characteristics in the Baltic Sea2010In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 86, no 4, p. 607-612Article in journal (Refereed)
    Abstract [en]

    To investigate feeding habits of juvenile flounder (Platichthys flesus) and turbot (Psetta maxima) in relation to habitat characteristics a field survey with push net sampling was conducted in nursery areas with different ecological characteristics in the northern Baltic proper. Sampling sites were stratified to cover several different habitat types defined by substrate and wave exposure. Apart from flatfishes and epifauna, samples of macrofauna, meiofauna and hyperbenthic planktons were collected from each site together with data on vegetation, depth, salinity, temperature and turbidity. The diet differed between species where flounder diet was dominated by chironomids, copepods and oligochaetes while turbot apart from chironomids had a high incidence of amphipods, gobies and mysids. In both species there was a shift in diet with size, although this shift was influenced by the habitat. Among the environmental variables investigated, wave exposure was found to significantly influence flounder diet. Food preference in the most exposed areas was dominated by oligochaetes and copepods instead of chironomids, which dominated in sheltered areas. This study shows that habitat characteristics can have a major influence on feeding habits of juvenile flatfish.

  • 179.
    Folke, Carl
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Social-ecological systems and adaptive governance of the commons2007In: Ecological Research, Vol. 22, no 1, p. 14-15Article in journal (Refereed)
  • 180.
    Folke, Carl
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Gunderson, L
    Facing global change through social-ecological research2006In: Ecology and Society, Vol. 11, no 2, p. no. 43-Article in journal (Other academic)
  • 181.
    Folke, Carl
    et al.
    Stockholm University, Stockholm Resilience Centre. The Beijer Institute, Royal Swedish Academy of Sciences, Sweden.
    Jansson, Åsa
    Stockholm University, Stockholm Resilience Centre. The Beijer Institute, Royal Swedish Academy of Sciences, Sweden.
    Rockström, Johan
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Olsson, Per
    Stockholm University, Stockholm Resilience Centre.
    Crépin, Anne-Sophie
    Stockholm University, Stockholm Resilience Centre. The Beijer Institute, Royal Swedish Academy of Sciences, Sweden.
    Ebbesson, Jonas
    Stockholm University, Stockholm Resilience Centre. Stockholm University, Faculty of Law, Department of Law, Stockholm Environmental Law and Policy Centre.
    Elmqvist, Thomas
    Stockholm University, Stockholm Resilience Centre. Stockholm University, Faculty of Science, Department of Systems Ecology.
    Galaz, Victor
    Stockholm University, Stockholm Resilience Centre.
    Moberg, Fredrik
    Stockholm University, Stockholm Resilience Centre. Albaeco, Stockholm, Sweden .
    Nilsson, Måns
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Österblom, Henrik
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Persson, Åsa
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Peterson, Garry
    Stockholm University, Stockholm Resilience Centre.
    Steffen, Will
    Stockholm University, Stockholm Resilience Centre.
    Walker, Brian
    Stockholm University, Stockholm Resilience Centre. The Beijer Institute, Royal Swedish Academy of Sciences, Sweden; CSIRO Sustainable Ecosystems, Canberra, ACT, Australia .
    Reconnecting to the biosphere2011In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 40, no 7, p. 719-738Article in journal (Refereed)
    Abstract [en]

    Humanity has emerged as a major force in the operation of the biosphere, with a significant imprint on the Earth System, challenging social-ecological resilience. This new situation calls for a fundamental shift in perspectives, world views, and institutions. Human development and progress must be reconnected to the capacity of the biosphere and essential ecosystem services to be sustained. Governance challenges include a highly interconnected and faster world, cascading social-ecological interactions and planetary boundaries that create vulnerabilities but also opportunities for social-ecological change and transformation. Tipping points and thresholds highlight the importance of understanding and managing resilience. New modes of flexible governance are emerging. A central challenge is to reconnect these efforts to the changing preconditions for societal development as active stewards of the Earth System. We suggest that the Millennium Development Goals need to be reframed in such a planetary stewardship context combined with a call for a new social contract on global sustainability. The ongoing mind shift in human relations with Earth and its boundaries provides exciting opportunities for societal development in collaboration with the biosphere-a global sustainability agenda for humanity.

  • 182.
    Folke, Carl
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Pritchard, L
    Berkes, F
    Colding, Johan
    Svedin, U
    The problem of fit between ecosystems and institutions: ten years later2007In: Ecology and Society, Vol. 12, no 1, p. nr. 30-Article in journal (Refereed)
  • 183.
    Forslund, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Wikström, Sofia A.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Pavia, Henrik
    Higher resistance to herbivory in introduced compared to native populations of a seaweed2010In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 164, no 3, p. 833-840Article in journal (Refereed)
    Abstract [en]

    Non-indigenous species (NIS) are important components of global change, and in order to manage such species it is important to understand which factors affect their success. Interactions with enemies in the new range have been shown to be important for the outcome of introductions, but thus far most studies on NIS-enemy interactions have considered only specialist herbivores in terrestrial systems. Here we present the results from the first biogeographic study that compares herbivore resistance between populations in the native and new region of a non-indigenous seaweed. We show that low consumption of the non-indigenous seaweed by a generalist herbivore is caused by higher chemical defence levels and herbivore resistance in the new range-and not by the failure of the herbivore to recognise the non-indigenous seaweed as a suitable host. Since most seaweed-herbivore interactions are dominated by generalist herbivores, this pattern could be common in marine communities. Our results also reveal that traits used to predict the invasive potential of species, such as their resistance to enemies, can change during the invasion process, but not always in the way predicted by dominant theories.

  • 184. Franzen, Frida
    et al.
    Kinell, Gerda
    Walve, Jakob
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Elmgren, Ragnar
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Soderqvist, Tore
    Participatory Social-Ecological Modeling in Eutrophication Management: the Case of Himmerfjarden, Sweden2011In: Ecology & society, ISSN 1708-3087, E-ISSN 1708-3087, Vol. 16, no 4, p. 27-Article in journal (Refereed)
    Abstract [en]

    Stakeholder participation is increasingly seen as central in natural resource management. It is also required by the European Union Water Framework Directive, which identifies three levels of participation; information, consultation, and active involvement. In this paper we discuss the active involvement of stakeholders, using our experience from a case study in the Himmerfjarden region, which is a coastal area southwest of Stockholm, Sweden. Our study used the systems approach proposed by the European Union research project called Science and Policy Integration for Coastal System Assessment (SPICOSA), in which local stakeholders and a study site team constructed an integrated simulation model of a crucial coastal management issue. In this case the issue was nitrogen enrichment. We showed how stakeholder participation in the modeling process helped identify interesting and currently relevant management scenarios, and how the modeling process facilitated communication of the likely ecological, economic, and social effects of these scenarios to the stakeholders. In addition, stakeholders also reported social gains in terms of network building. We managed to actively involve local stakeholders in water issues, and the research process clearly strengthened the social capital in the Himmerfjarden region, and created a basis for future collaboration regarding water management. Our experience indicates that the approach we tried is a useful tool for promoting active stakeholder involvement in water management projects. Also, the results of our science and policy integration approach indicated that the study site team assumed a leadership role, which is a commonly recognized factor in successful natural resource management.

  • 185. Friedman, Kim
    et al.
    Eriksson, Hampus
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Tardy, Emmanuel
    Pakoa, Kalo
    Management of sea cucumber stocks: patterns of vulnerability and recovery of sea cucumber stocks impacted by fishing2011In: Fish and Fisheries, ISSN 1467-2960, E-ISSN 1467-2979, Vol. 12, no 1, p. 75-93Article in journal (Refereed)
    Abstract [en]

    Identifying rates of change in the abundance of sea cucumbers under differing management regimes is fundamental to estimating commercial yields, identifying ecological interactions and facilitating management. Here, we review the status of sea cucumber stocks from a range of Pacific Island countries (Samoa, Tonga, Palau, Fiji and Papua New Guinea), some of which have had a moratorium on exports for up to a decade. We use a time-series approach to look at variation in sea cucumber presence, coverage and density from survey and re-survey data. Results give an appreciation of variation between 'high' status (less impacted) and depleted stocks. Survey data show marked declines in coverage and abundance as a result of artisanal fishing activity, and although species groups were not lost at a country level, local extirpation and range restriction was noted. Resilience and 'recovery' following cessation of fishing varied greatly, both among locations and among the species targeted. Worryingly, even after extended periods of moratorium, the density of some species was markedly low. In many cases, the densities were too low for commercial fishing, and may be at a level where the effective population size is constrained due to 'Allee' affects. From these results, we suggest that management regimes presently employed are generally not well aligned with the level of response to fishing mortality that can be expected from sea cucumber stocks. New adaptive, precautionary approaches to management are suggested, which would allow more timely interventions to be made, while refined information on stock dynamics is sought.

  • 186.
    Friis Møller, Eva
    et al.
    National Environmental Research Institute,.
    Andersen Borg, Christian Marc
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Jonasdottir, Sigrun H.
    National Institute of Aquatic Resources.
    Satapoomin, Suree
    Phuket Marine Biological Center.
    Jaspers, Cornelia
    National Institute of Aquatic Resources.
    Nielsen, Torkel Gissel
    National Institute of Aquatic Resources.
    Production and fate of copepod fecal pellets acrossthe Southern Indian Ocean2011In: Marine Biology, ISSN 0025-3162, E-ISSN 1432-1793, Vol. 158, no 3, p. 677-688Article in journal (Refereed)
    Abstract [en]

    The vertical distribution of copepods, fecal pellets and the fecal pellet production of copepods were measured at seven stations across the Southern Indian Ocean from productive areas off South Africa to oligotrophic waters off Northern Australia during October/November 2006. We quantified export of copepod fecal pellet from surface waters and how much was retained. Furthermore, the potential impact of Oncaea spp. and harpacticoid copepods on fecal pellets degradation was evaluated and found to be regional substantial. The highest copepod abundance and fecal pellet production was found in the western nutrient-rich stations close to South Africa and the lowest at the central oligotrophic stations. The in situ copepod fecal pellet production varied between 1 and 1,000 mu g C m(-3) day(-1). At all stations, the retention of fecal pellets in the upper 400 m of the water column was more than 99% and the vertical export of fecal pellets was low (< 0.02 mg m(-2) day(-1)).

  • 187.
    Fröcklin, Sara
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    de la Torre-Castro, Maricela
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Lindström, Lars
    Stockholm University, Faculty of Social Sciences, Department of Political Science.
    Jiddawi, Narriman S.
    Msuya, Flower E.
    Seaweed mariculture as a development project in Zanzibar, East Africa: A price too high to pay?2012In: Aquaculture, ISSN 0044-8486, E-ISSN 1873-5622, Vol. 356, p. 30-39Article in journal (Refereed)
    Abstract [en]

    Seaweed mariculture has been promoted as a development project in tropical countries and Zanzibar, Tanzania, is commonly presented as a successful story. However, the results of the present research provide a nuanced picture of the activity identifying serious health problems among farmers. Semi-structured interviews were conducted with female seaweed farmers (n=140) and non-seaweed farmers (n=140) in Zanzibar to evaluate health and working conditions. In-depth interviews with additional 28 female seaweed farmers were performed to deepen the understanding of the working conditions and related problems. The research was undertaken at seven different locations to cover areas where seaweed is extensively executed during August to September 2009 and May to June 2010. Seaweed farmers considered their health significantly poorer than non-seaweed farmers with fatigue, musculoskeletal pain, hunger, respiratory problems, eye related problems, injuries from hazardous animals and sharp shells in the water and allergies as the most serious issues (p<0.05). Income was further reported below the extreme poverty line. Since seaweed farming affects thousands of households in the tropics these results should encourage changes towards better working conditions and sustainability.

  • 188.
    Galaz, Victor
    et al.
    Stockholm University, Stockholm Resilience Centre.
    Crona, Beatrice
    Stockholm University, Stockholm Resilience Centre.
    Daw, T
    Bodin, Örjan
    Stockholm University, Stockholm Resilience Centre.
    Nyström, Magnus
    Stockholm University, Stockholm Resilience Centre. Stockholm University, Faculty of Science, Department of Systems Ecology.
    Olsson, Per
    Stockholm University, Stockholm Resilience Centre.
    Can web crawlers revolutionize ecological monitoring?2010In: Frontiers in ecology and the environment, ISSN 1540-9295, Vol. 8, no 2, p. 99-104Article in journal (Refereed)
    Abstract [en]

    Despite recent advances, ecosystem service monitoring is limited by insufficient data, the complexity of social–ecological systems, and poor integration of information that tracks changes in ecosystems and economic activities. However, new information and communication technologies are revolutionizing the generation of, and access to, such data. Can researchers who are interested in ecological monitoring tap into these increased flows of information by “mining” the internet to detect “early-warning” signs that may signal abrupt ecological changes? Here, we explore the possibility of using web crawlers and internet-based information to complement conventional ecological monitoring, with a special emphasis on the prospects for avoiding “late warnings”, that is, when ecosystems have already shifted to less desirable states. Using examples from coral reef ecosystems, we explore the untapped potential, as well as the limitations, of relying on web-based information to monitor ecosystem services and forewarn us of negative ecological shifts.

  • 189.
    Gardeström, Johanna
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Coping with environmental stress: from the individual and population perspective2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Natural stress and disturbances are important factors affecting the structure and function of ecosystems. However the magnitude of stress has escalated due to anthropogenic activities. Environmental monitoring and toxicity assessments try to protect ecosystems from unwanted human alterations. The aim of this Doctoral thesis was to increase the understanding of the complex effects that environmental stress has on individuals and invertebrate populations. The low saline environment in the Baltic Sea is perceived as stressful for most organisms living there. In Paper I, it was found that Baltic blue mussels living in the less saline northern Baltic Proper (~5 psu) had lower basal metabolism and were more susceptible to toxic exposure than the mussels in the south (~7 psu). There was no genetic differentiation between the mussels from the northern and southern areas while there were genetic differences between mussels from sites within the respective areas (Paper III), indicating that there is not a simple relationship between the health of the mussels and genetic diversity in the microsatellite loci studied. In Paper IV it was found that the heat tolerance of the intertidal dogwhelk Nucella lapillus is oxygen dependent. Increased oxygen levels resulted in higher survival rate. Protein expression profiles also became more similar to those of the controls, compared to the whelks exposed to high temperature and normal oxygen levels. In Paper V and VI it was found that exposure to a single toxicant for more than one generation decreased the genetic diversity in exposed copepod populations even though abundances remained unaltered. In Paper VI, exposure to naturally contaminated sediments, which contained of a mixture of toxicants, did not decrease genetic diversity. However the genetic divergence (FST) within the treatments was very high, probably due to small effective population sizes in the replicates. Likewise in Paper III, the very low blue mussel abundance in the north together with the stressful environment suggests a small effective population in the northern Baltic Proper. In conclusion, my studies show that, measuring effects on several levels, including both functional and structural endpoints will both increase the sensitivity of the tests and increase their ecological relevance.

  • 190.
    Gardeström, Johanna
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Dahl, Ulrika
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Kotsalainen, Ola
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Maxson, Anders
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Elwing, Tina
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Grahn, Mats
    Bengtsson, Bengt-Erik
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Breitholtz, Magnus
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Evidence of population genetic effects of long-term exposure to contaminated sediments: A multi-endpoint study with copepods2008In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 86, no 3, p. 426-436Article in journal (Refereed)
    Abstract [en]

    In the environment, pollution generally acts over long time scales and exerts exposure of multiple toxicants on the organisms living there. Recent findings show that pollution can alter the genetics of populations. However, few of these studies have focused on long-term exposure of mixtures of substances. The relatively short generation time (ca. 4–5 weeks in sediments) of the harpacticoid copepod Attheyella crassa makes it suitable for multigenerational exposure studies. Here, A. crassa copepods were exposed for 60 and 120 days to naturally contaminated sediments (i.e., Svindersviken and Trosa; each in a concentration series including 50% contaminated sediment mixed with 50% control sediment and 100% contaminated sediment), and for 120 days to control sediment spiked with copper. We assayed changes in FST (fixation index), which indicates if there is any population subdivision (i.e., structure) between the samples, expected heterozygosity, percent polymorphic loci, as well as abundance. There was a significant decrease in total abundance after 60 days in both of the 100% naturally contaminated sediments. This abundance bottleneck recovered in the Trosa treatment after 120 days but not in the Svindersviken treatment. After 120 days, there were fewer males in the 100% naturally contaminated sediments compared to the control, possibly caused by smaller size of males resulting in higher surface: body volume ratio in contact with toxic chemicals. In the copper treatment there was a significant decrease in genetic diversity after 120 days, although abundance remained unchanged. Neither of the naturally contaminated sediments (50 and 100%) affected genetic diversity after 120 days but they all had high within treatment FST values, with highest FST in both 100% treatments. This indicates differentiation between the replicates and seems to be a consequence of multi-toxicant exposure, which likely caused selective mortality against highly sensitive genotypes. We further assayed two growth-related measures, i.e., RNA content and cephalothorax length, but none of these endpoints differed between any of the treatments and the control. In conclusion, the results of the present study support the hypothesis that toxicant exposure can reduce genetic diversity and cause population differentiation. Loss of genetic diversity is of great concern since it implies reduced adaptive potential of populations in the face of future environmental change

  • 191.
    Gardeström, Johanna
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Elfwing, Tina
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Löf, Marie
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Davenport, Julia
    Davenport, John
    The effect of thermal stress on protein composition in dogwhelks (Nucella lapillus) under normoxic and hyperoxic conditions2007In: Comparative Biochemistry and Physiology A, ISSN 1095-6433, E-ISSN 1531-4332, Vol. 148, no 4, p. 869-875Article in journal (Refereed)
    Abstract [en]

    In this laboratory study, dogwhelks (Nucella lapillus) were collected from the intertidal zone and exposed to 16 °C (ambient), 26.5 °C and 30 °C under normal and hyperoxic conditions respectively. It was shown that there was no thermally induced mortality at 26.5 °C, but that the mortality rate was 40–50% in 30 °C. This mortality rate was reduced to 10% if extra oxygen was provided, indicating that oxygen supply was setting the limit for whole organism thermal tolerance. Tissue samples were then analysed for protein features using two-dimensional gel electrophoresis, and both up and down regulation of proteins were visualised by silver staining and crosswise comparisons of gels from control vs. treated animals. The results clearly show that the protein profiles from dogwhelks exposed to increased water temperatures differ from those of the control, but that increased oxygen availability alleviates these differences thus increasing the similarity between heat-shocked and control animal protein pattern. This implies a more stable protein metabolism and might explain the increased survival of heat-shocked individuals when extra oxygen is supplied.

  • 192.
    Gardeström, Johanna
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Gorokhova, Elena
    Gilek, Mikael
    Grahn, Mats
    Bengtsson, Bengt-Erik
    Breitholtz, Magnus
    A multilevel approach to predict toxicity in copepod populations: Assessment of growth, genetics and population structure2006In: Aquatic Toxicology, Vol. 79, no 1, p. 41-48Article in journal (Refereed)
  • 193.
    Gardeström, Johanna
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Lilja, Karl
    Prevodnik, Andreas
    Elfwing, Tina
    Bollner, Tomas
    Tedengren, Michael
    No differences in neutral genetic loci between blue mussels from the northern and southern Baltic ProperManuscript (Other academic)
  • 194.
    Gardeström, Johanna
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Pereyra, Ricardo
    André, Carl
    Gardeström J., Pereyra R., André C. Characterization of six microsatellite loci in the Baltic Blue mussel Mytilus trossulus and cross-species amplification in North Sea Mytilus edulis2008In: Conservation Genetics, ISSN 1566-0621Article in journal (Refereed)
  • 195.
    Gorokhova, E.
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Hajdu, S.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Holmborn, T.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Kosinkova, L.
    Wikner, J.
    Djurplankton: En viktig länk i ekosystemet.2008In: Havet 2008: om miljötillståndet i svenska havsområdenArticle in journal (Other academic)
  • 196.
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    A single-step staining method to evaluate egg viability in zooplankton2010In: Limnology and Oceanography: Methods, ISSN 1541-5856, E-ISSN 1541-5856, Vol. 8, p. 414-423Article in journal (Refereed)
    Abstract [en]

    A simplified method for viability analysis of zooplankton eggs by staining of nonviable eggs with a fluorescent nucleic acid stain TO-PRO-1 iodide is proposed here as a further development of fluorescence-based egg viability assays. This is one-step analysis with no intermediate steps for chorion removal. The method was calibrated using predetermined mixtures of viable and nonviable eggs (rotifers and copepods), and validated using hatching experiments (copepods) and egg development assay (cladocerans) as reference measurements. In these tests, eggs of several zooplankton species, Brachionus plicatilis (Rotatoria), Daphnia magna (Cladocera), Nitocra spinipes (Harpacticoida), Acartia tonsa (Calanoida), were used. Moreover, staining efficiency was not affected by storage of samples for up to 1 month in -80 degrees C, making the assay suitable for egg viability assessment in field and laboratory studies. To illustrate usefulness of the method, it was applied to evaluate how absence of re-mating affects production of viable eggs in females of A. bifilosa (Calanoida). In females separated from males, proportion of sterile eggs increased in 3 d after the separation and no viable eggs were produced after 5 d. The effects of mating frequency on egg viability are important to understand when designing egg production experiments and interpreting field data on egg viability in populations with skewed sex ratios.

  • 197.
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Toxic cyanobacteria Nodularia spumigena in the diet of Baltic mysids: evidence from molecular diet analysis.2009In: Harmful Algae, ISSN 1568-9883, E-ISSN 1878-1470, Vol. 8, p. 264-272Article in journal (Refereed)
    Abstract [en]

    A PCR-based method was used to detect toxic cyanobacteria Nodularia spumigena in the diet of Baltic mysids, Mysis mixta and Mysis relicta. The decay in detectability of Nodularia DNA in mysid stomachs and feces following the cyanobacterium consumption was examined in laboratory with special references to (1) marker size (780 by vs. 200 bp), (2) mysid developmental stage (juveniles vs. subadults), and (3) feeding regime after consuming the cyanobacteria (continuous vs. interrupted feeding). The Nodularia DNA could be reliably detected in mysid stomachs and feces by PCR technique. In the mysid with interrupted feeding, the calculated half-lives of N. spumigena DNA in the mysid stomachs were 1.2 and 6.1 h for 780 and 200 by fragments, respectively. Continuous feeding, however, facilitated decay in the detectability, most likely due to increased gut evacuation rate. In stomachs of the field-collected mysids, the Nodularia DNA was detected with high frequencies, 60% in M. mixta and 51 % in M. relicta. Moreover, it was higher in immature mysids than in adults and correlated with stomach fullness in age-specific manner: in juveniles and subadults, stomachs containing Nodularia were significantly fuller, while in adults, the presence of the cyanobacteria was associated with empty stomachs. This suggests greater habitat overlap for juvenile mysids and N. spumigena and thus higher encounter and consumption rates. These findings contribute to a growing body of evidence that cyanobacteria in the Baltic Sea are important food for grazers.

  • 198.
    Gorokhova, Elena
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology. Marin ekologi.
    Edlund, Anna
    Hajdu, Susanna
    Stockholm University, Faculty of Science, Department of Systems Ecology. Marin ekologi.
    Zhivotova, E
    Nucleic acid levels in copepods: dynamic response to the phytoplankton bloom in the northern Baltic proper2007In: Marine Ecology Progress Series, Vol. 349, p. 213-225Article in journal (Refereed)
  • 199.
    Gorokhova, Elena
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Engström-Öst, Jonna
    Abo Akad Univ, Aronia Coastal Zone Res Team.
    Toxin concentration in Nodularia spumigena is modulated by mesozooplankton grazers2009In: Journal of Plankton Research, ISSN 0142-7873, E-ISSN 1464-3774, Vol. 31, no 10, p. 1235-1247Article in journal (Refereed)
    Abstract [en]

    The ecological role of nodularin in cyanobacterium Nodularia spumigena is still largely unknown, as are the conditions that promote toxin production. We report a modulating effect of mesozooplankton grazing on cellular nodularin content in N. spumigena expressed as a decrease in cell-bound toxin concentration in the presence of copepods compared with the cyanobacterium in similar assemblages without copepods. In our experiments, N. spumigena was incubated in an ambient plankton (< 90 mu m) assemblage (Expt I) or in 0.2-mu m filtered seawater (Expt II), with and without the copepod Eurytemora affinis. Following similar to 28-h incubation, we measured the changes in N. spumigena abundance and nodularin concentration, frequency of Nodularia DNA occurrence in copepods as a proxy for grazing pressure on the cyanobacterium and individual RNA content in E. affinis as a proxy for copepod growth response. In all copepod-free treatments, intracellular nodularin concentrations were up to four times higher than in the treatments containing copepods. In Experiment I, the copepods also has a positive effect on the cyanobacterium growth, presumably due to a selective removal of more edible algal species and thus decreased competition for nutrients. Nodularia DNA was detected with high frequencies, 18-80%, increase in treatments with no alternative food or high copepod densities. Simultaneously, no noxious effects of N. spumigena on the copepods were detected as indicated by higher RNA content in copepods exposed to N. spumigena with or without ambient plankton organisms compared with started controls. These findings stress the need to understand the importance of intra-specific interactions for nodularin production in relation to population dynamics of N. spumigena.

  • 200.
    Gorokhova, Elena
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Fagerberg, Towe
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Hansson, Sture
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Predation by herring (Clupea harengus) and sprat (Sprattus sprattus) on Cercopagis pengoi in a wastern Baltic Sea bay2004In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 61, no 6, p. 959-965Article in journal (Refereed)
1234567 151 - 200 of 548
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