| 1. |
- Berkström, Charlotte, et al.
(författare)
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Assessing connectivity in a tropical embayment : Fish migrations and seascape ecology
- 2013
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Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207 .- 1873-2917. ; 166, s. 43-53
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Tidskriftsartikel (refereegranskat)abstract
- Seascape connectivity and configuration of multiple habitats are important features to include in marine spatial planning, and protecting seascapes with high connectivity is recommended. The present study examines the potential connectivity of reef fish assemblages in a shallow-water conservation area in Zanzibar (Tanzania) by analysing relationships between a set of habitat variables and fish diversity and density for different functional groups (based on diet) and life stages of fish using PLS-analysis. We combined spatial pattern metrics (habitat type, patch size, distance to patch) and dispersal abilities of a number of fish species using buffer radius to answer the questions; (i) do coral reefs with high connectivity to seagrass habitats have higher abundances and higher species richness of fish that undertake routine migrations during their life-history? and (ii) do coral reefs closer to mangrove forest support higher abundances of nursery species (i.e., fish species that use mangrove and seagrass beds as juvenile habitat)? Habitat mosaics surrounding fish survey sites and within-patch measurements inside fish survey sites were quantified at multiple scales (meters to kilometers) using aerial photography and scuba. Fish data was collected using a standardized point census method. We found that both fine- and broad-scale variables were important in structuring fish communities and connectivity with surrounding habitats, where predominantly seagrass beds within a 750 m radius had a positive influence on fish abundances of invertebrate feeders/piscivores (especially for lutjanids and lethrinids). Additionally, fine-scale seagrass cover had a positive influence on nursery species. Depth also had a positive influence on total species richness and the abundance of invertebrate feeders/piscivores. This study highlights the importance of combining connectivity and habitat configuration at different scales to fully understand and manage the tropical seascape.
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| 2. |
- Berkström, Charlotte, 1978-, et al.
(författare)
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Seascape configuration influences connectivity of reef fish assemblages
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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| 3. |
- Bodin, Örjan, et al.
(författare)
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Conservation Success as a Function of Good Alignment of Social and Ecological Structures and Processes
- 2014
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Ingår i: Conservation Biology. - : Wiley. - 0888-8892 .- 1523-1739. ; 28:5, s. 1371-1379
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Tidskriftsartikel (refereegranskat)abstract
- How to create and adjust governing institutions so that they align (fit) with complex ecosystem processes and structures across scales is an issue of increasing concern in conservation. It is argued that lack of such social-ecological fit makes governance and conservation difficult, yet progress in explicitly defining and rigorously testing what constitutes a good fit has been limited. We used a novel modeling approach and data from case studies of fishery and forest conservation to empirically test presumed relationships between conservation outcomes and certain patterns of alignment of social-ecological interdependences. Our approach made it possible to analyze conservation outcome on a systems level while also providing information on how individual actors are positioned in the complex web of social-ecological interdependencies. We found that when actors who shared resources were also socially linked, conservation at the level of the whole social-ecological system was positively affected. When the scales at which individual actors used resources and the scale at which ecological resources were interconnected to other ecological resources were aligned through tightened feedback loops, conservation outcome was better than when they were not aligned. The analysis of individual actors' positions in the web of social-ecological interdependencies was helpful in understanding why a system has a certain level of social-ecological fit. Results of analysis of positions showed that different actors contributed in very different ways to achieve a certain fit and revealed some underlying difference between the actors, for example in terms of actors' varying rights to access and use different ecological resources.
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| 4. |
- Crona, Beatrice I., et al.
(författare)
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Masked, diluted and drowned out : how global seafood trade weakens signals from marine ecosystems
- 2016
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Ingår i: Fish and Fisheries. - : Wiley. - 1467-2960 .- 1467-2979. ; 17:4, s. 1175-1182
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Tidskriftsartikel (refereegranskat)abstract
- Nearly 40% of seafood is traded internationally and an even bigger proportion is affected by international trade, yet scholarship on marine fisheries has focused on global trends in stocks and catches, or on dynamics of individual fisheries, with limited attention to the link between individual fisheries, global trade and distant consumers. This paper examines the usefulness of fish price as a feedback signal to consumers about the state of fisheries and marine ecosystems. We suggest that the current nature of fisheries systems and global markets prevent transmission of such price signals from source fisheries to consumers. We propose several mechanisms that combine to weaken price signals, and present one example - the North Sea cod - to show how these mechanisms can be tested. The lack of a reliable price feedback to consumers represents a challenge for sustainable fisheries governance. We therefore propose three complimentary approaches to address the missing feedback: (i) strengthening information flow through improved traceability and visibility of individual fishers to consumers, (ii) capitalizing on the changing seafood trade structures and (iii) bypassing and complementing market mechanisms by directly targeting citizens and political actors regarding marine environmental issues through publicity and information campaigns. These strategies each havelimitations and thus need to be pursued together to address the challenge of sustainability in global marine fisheries.
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| 5. |
- Galafassi, Diego, et al.
(författare)
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Stories in social-ecological knowledge co-creation
- 2018
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Ingår i: Ecology and Society. - 1708-3087. ; 23:1
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Tidskriftsartikel (refereegranskat)abstract
- Transformations in social-ecological systems to overturn poverty and ecosystem degradation require approaches to knowledge synthesis that are inclusive and open to creative innovation. In this paper we draw on interviews with participants and in-depth process observation of an iterative knowledge co-creation process in Kenya and Mozambique that brought together scientists, community representatives, government representatives and practitioners with expertise or experience of poverty and/or coastal natural resource use and management. We analyze the communicative spaces opened by techniques of system diagrams and future scenarios and provide a rich account of the emergent process of developing a “shared conceptual repertoire” as a basis for effective communication and knowledge synthesis. Our results highlight the difficulties of challenging dominant narratives and the creative potential that exists in reflecting on their underpinning assumptions. In our analysis stories and lived experiences emerged as key means shaping the construction of shared concepts and ideas. We conclude by outlining the implications for designing knowledge co-creation processes that support the task of devising systemic interventions robust to a range of future scenarios. This includes embracing the role of stories in generating shared meanings and opening up spaces for exploration of knowledge assumptions embedded in intervention narratives.
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| 6. |
- Lokrantz, Jerker, et al.
(författare)
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The non-linear relationship between body size and function in parrotfihes
- 2008
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Ingår i: Coral reefs (Print). - : Springer Science and Business Media LLC. - 0722-4028 .- 1432-0975. ; 27:4, s. 967-974
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Tidskriftsartikel (refereegranskat)abstract
- Parrotfishes are a group of herbivores that play an important functional role in structuring benthic communities on coral reefs. Increasingly, these fish are being targeted by fishermen, and resultant declines in biomass and abundance may have severe consequences for the dynamics and regeneration of coral reefs. However, the impact of overfishing extends beyond declining fish stocks. It can also lead to demographic changes within species populations where mean body size is reduced. The effect of reduced mean body size on population dynamics is well described in literature but virtually no information exists on how this may influence important ecological functions. The study investigated how one important function, scraping (i.e., the capacity to remove algae and open up bare substratum for coral larval settlement), by three common species of parrotfishes (Scarus niger, Chlorurus sordidus, and Chlorurus strongylocephalus) on coral reefs at Zanzibar (Tanzania) was influenced by the size of individual fishes. There was a non-linear relationship between body size and scraping function for all species examined, and impact through scraping was also found to increase markedly when fish reached a size of 15-20 cm. Thus, coral reefs which have a high abundance and biomass of parrotfish may nonetheless be functionally impaired if dominated by small-sized individuals. Reductions in mean body size within parrotfish populations could, therefore, have functional impacts on coral reefs that previously have been overlooked.
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| 7. |
- Nyström, Magnus, et al.
(författare)
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Confronting Feedbacks of Degraded Marine Ecosystems
- 2012
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Ingår i: Ecosystems. - : Springer Science and Business Media LLC. - 1432-9840 .- 1435-0629. ; 15:5, s. 695-710
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Tidskriftsartikel (refereegranskat)abstract
- In many coastal areas, marine ecosystems have shifted into contrasting states having reduced ecosystem services (hereafter called degraded). Such degraded ecosystems may be slow to revert to their original state due to new ecological feedbacks that reinforce the degraded state. A better understanding of the way human actions influence the strength and direction of feedbacks, how different feedbacks could interact, and at what scales they operate, may be necessary in some cases for successful management of marine ecosystems. Here we synthesize interactions of critical feedbacks of the degraded states from six globally distinct biomes: coral reefs, kelp forests, seagrass beds, shallow soft sediments, oyster reefs, and coastal pelagic food webs. We explore to what extent current management captures these feedbacks and propose strategies for how and when (that is, windows of opportunity) to influence feedbacks in ways to break the resilience of the degraded ecosystem states. We conclude by proposing some challenges for future research that could improve our understanding of these issues and emphasize that management of degraded marine states will require a broad social-ecological approach to succeed.
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| 8. |
- Nyström, Magnus, et al.
(författare)
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Steering feedbacks toward healthier marine ecosystems
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Marine ecosystem decline is accelerating. At some point degradation may pass a tipping point beyond which ecosystems become trapped in alternative degraded states, as a result of changes in critical feedbacks. Self-reinforcing feedbacks pose a major challenge for managers and policy-makers seeking remedial actions to curb the marine crisis. Here we synthesize the dynamics of critical feedbacks of the degraded states in five socio-economically important marine ecosystems; coral reefs, kelp forests, seagrass beds, shallow unvegetated soft-bottom habitats, and coastal pelagic food webs. A better understanding of the way human actions influence the strength and direction of feedbacks, how different feedbacks interact and at what scales they operate, is crucial for successful implementation of marine ecosystem management. We advocate a critical-feedback management approach that ventures beyond traditionally discipline boundaries, as an essential element of marine ecosystem management.
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| 9. |
- Oteros-Rozas, Elisa, et al.
(författare)
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Participatory scenario planning in place-based social-ecological research : insights and experiences from 23 case studies
- 2015
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Ingår i: Ecology and Society. - 1708-3087. ; 20:4
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Tidskriftsartikel (refereegranskat)abstract
- Participatory scenario planning (PSP) is an increasingly popular tool in place-based environmental research for evaluating alternative futures of social-ecological systems. Although a range of guidelines on PSP methods are available in the scientific and grey literature, there is a need to reflect on existing practices and their appropriate application for different objectives and contexts at the local scale, as well as on their potential perceived outcomes. We contribute to theoretical and empirical frameworks by analyzing how and why researchers assess social-ecological systems using place-based PSP, hence facilitating the appropriate uptake of such scenario tools in the future. We analyzed 23 PSP case studies conducted by the authors in a wide range of social-ecological settings by exploring seven aspects: (1) the context; (2) the original motivations and objectives; (3) the methodological approach; (4) the process; (5) the content of the scenarios; (6) the outputs of the research; and (7) the monitoring and evaluation of the PSP process. This was complemented by a reflection on strengths and weaknesses of using PSP for the place-based social-ecological research. We conclude that the application of PSP, particularly when tailored to shared objectives between local people and researchers, has enriched environmental management and scientific research through building common understanding and fostering learning about future planning of social-ecological systems. However, PSP still requires greater systematic monitoring and evaluation to assess its impact on the promotion of collective action for transitions to sustainability and the adaptation to global environmental change and its challenges.
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| 10. |
- Thyresson, Matilda, 1981-
(författare)
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Fish for Food and Ecosystem Function : Fisheries, Trade and Key Ecosystem Processes in Coral Reefs
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Fish is a key source of food and income to millions of people living along tropical coastlines. They also play essential roles underpinning key ecosystem processes in coral reefs. For example, herbivorous fish keep algae in check that otherwise may outcompete corals, reducing the reef’s social-ecological values. New fishing methods and globalization have turned fish into global commodities, threatening the ecological resilience of many reefs. This thesis addresses the delicate balance between social and ecological aspects associated with fisheries and trade with reef fish in Zanzibar, Tanzania. Paper I examines how parrotfish contribute to keeping reefs free from algae and shows a non-linear relationship between fish body size and function, hence illustrating that maintaining large fish individuals on coral reefs is particularly important. Gear-based management (GBM) has been suggested as an alternative to no-take marine protected areas (MPAs) to sustain ecosystem processes without threatening fishers’ livelihood. Paper II investigates fishers’ use of different gears and how these gears select different functional groups of fish. Results indicate that gear restrictions could be used to reduce fishing pressure on particularly important groups of fish, but also that such an approach is far from simple. MPAs and GBM are both restrictions targeting fishers, but with increasing global demand for reef fish, it is neither realistic nor fair to place the sole burden of sustainable fisheries on them. Papers III & IV analyze the value chain of fish, from fishers to traders and consumers. Results show that the Zanzibar fishery targets a wide range of fish species and sizes, intended for different markets. The thesis concludes that a sound understanding of the functional properties of fish and more nuanced approaches to regulate fishing may contribute to the management of reef fisheries, but that sustainable solutions will require that measures are taken far beyond the oceans.
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