| 1. |
- Andersson, Magnus, et al.
(författare)
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Fiskbestånd och miljö i hav och sötvatten : Resurs- och miljööversikt 2012
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Detta är den nionde utgåvan av den samlade översikten över fisk- och kräftdjursbeståndens status i våra vatten. Kunskap om fiskbestånden och miljön är en förutsättning för att utnyttjandet av fiskresurserna skall bli bärkraftigt. För svenska vattenområden beskrivs miljöutvecklingen i ett ekosystemsperspektiv, dels för att tydliggöra fiskens ekologiska roll och beskriva yttre miljöfaktorer som påverkar fiskbestånden, dels för att belysa fiskets effekter på miljön.Fiskbestånd och miljö i hav och sötvatten är utarbetad av Sveriges lantbruksuniversitet (SLU), Institutionen för akvatiska resurser (SLU Aqua), på uppdrag av Havs- och vattenmyndigheten. Rapporten sammanfattar utveckling och beståndsstatus för de kommersiellt viktigaste fisk- och kräftdjursarterna i våra vatten. Bedömningar och förvaltningsråd är baserade på Internationella Havsforskningsrådets (ICES) rådgivning, SLU Aquas nationella och regionala provfiskedata, samt yrkesfiskets rapportering.
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| 2. |
- Belgrano, Andrea, et al.
(författare)
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Överfiske - en miljöfarlig aktivitet : orsaker till fiskbeståndens utarmning och dess konsekvenser i svenska hav
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Bestånden av marina fiskarter har minskat dramatiskt i både Västerhavet och i Östersjön under de senaste 100 åren. Flera olika faktorer påverkar fiskbeståndens storlek, men ett ökande antal studier tyder på att överfiske är en huvudorsak i de flesta fall. Fisket med trål anses också skada många bottenlevande organismer, men det är idag oklart hur omfattande denna miljöpåverkan är. Vidare tyder nya studier på att förlusten av stora rovfiskar kan ge negativa effekter på hela ekosystem genom trofiska kedjereaktioner. Sammantaget anser många forskare idag att fisket utgör ett av de allvarligaste miljöhoten mot svenska hav. Denna rapport sammanställer det vetenskapliga kunskapsläget över orsakerna till nedgången av svenska marina fiskbestånd, samt fiskets roll för minskning av biodiversitet och förändringar i svenska kust- och utsjöekosystem.
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| 3. |
- Bergström, Lena, et al.
(författare)
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Klimatförändringar och biologisk mångfald : Slutsatser från IPCC och IPBES i ett svenskt perspektiv.
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- De stora miljö- och samhällsproblemen kommer inte ensamma. De är sammankopplade på olika sätt. Detta innebär utmaningar men ger också möjligheter att utveckla åtgärder och lösningar. Det gäller både för klimatfrågan och frågan om att motverka förlusten av biologisk mångfald och ekosystem. Kunskapens betydelse för att hantera dessa och andra aspekter är ovärderlig, såväl kring specifika frågeställningar som kring omständigheter och förutsättningar för åtgärdsarbetet.Den här kunskapssammanställningen har gjorts av forskare från Lunds universitet och Sveriges lantbruksuniversitet på uppdrag av Naturvårdsverket och SMHI. Forskarna har tagit avstamp i de omfattande kunskapsutvärderingar som gjorts av den mellanstatliga klimatpanelen (IPCC) och den mellanstatliga plattformen för biologisk mångfald (IPBES). Slutsatserna från IPCC och IPBES sätts i ett svenskt perspektiv, bland annat genom utvalda exempel vilka fungerar som aktuella illustrationer av hur klimatförändringar påverkar biologisk mångfald och ekosystem i Sverige.
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| 4. |
- Bergström, Lena, et al.
(författare)
-
Report of the ICES/HELCOM Working Group on Integrated Assessments of the Baltic Sea (WGIAB)
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The ICES/HELCOM Working Group on Integrated Assessments of the Baltic Sea(WGIAB) was established in 2007 as a forum for developing and combining ecosystembasedmanagement efforts for the Baltic Sea. The group intends to serve as a scientificcounterpart and support for the ICES Baltic Fisheries Assessment Working Group(WGBFAS) as well as for efforts and projects related to Integrated Ecosystem Assessments(IEA) within ICES and HELCOM. The group works in cooperation with similargroups within the ACOM/SCICOM Steering Group on Integrated Ecosystem Assessments(SSGIEA).The 2015 WGIAB meeting was held in Cádiz, Spain, from 9–13 March, back-to-backwith the meeting of its counterpart in the Working Group on Ecosystem Assessmentof Western European Shelf Seas (WGEAWESS). The meetings had joint sessions as wellas WG specific work, and some participants effectively participated in both meetings.The WGIAB meeting was attended by 27 participants from nine countries. The meetingwas chaired by Christian Möllmann, Germany, Laura Uusitalo, Finland and Lena Bergström,Sweden.This was the last year of the ongoing three-year Terms of Reference (ToR) for WGIAB.The main working activities in 2015 were to i) conduct studies on Baltic Sea ecosystemfunctioning with the goal to publish case studies from different parts of the Baltic Seain peer-reviewed journals, ii) work on the demonstration exercise to develop ecosystem-based assessment and advice for Baltic fish stocks focusing on cod (DEMO) withmultiple approaches, iii) plan further how to integrate the social and economic aspectsmore tightly in the WGIAB work, and iv) discuss the future focus and format of theWGIAB work.The Baltic ecosystem functioning activity focused on identifying and exploring keytrends and linkages in the Baltic Sea foodweb. This was pursued by presentation andfurther discussion of ongoing intersessional work on foodweb modelling and integratedanalyses, and by exercises to develop conceptual models Baltic Sea foodwebsand the links to ecosystem function. Long-term monitoring datasets on the abiotic andbiotic parts of the Baltic Sea Proper ecosystem were updated for use in the continuedwork to develop environmental indicators for fisheries and marine management.The focus of the DEMO 3 (DEMOnstration exercise for Integrated Ecosystem Assessmentand Advice of Baltic Sea cod) was on finding a way to use the results from theDEMO1 and DEMO2 workshops in short and midterm projections/scenarios of Balticcod dynamics based on different types of modelling, as well as designing methodologyand modelling data for practical implementation of Integrated Advice for Baltic cod.The WGIAB was positively inclined towards including social and economic aspectsinto the integrated assessment. Openings to this path were provided by presentationon ongoing project work, and discussing their linkages to ecological aspects. It wasseen as crucial that experts on social and economic analysis should be included andtake an active part in the future work of the group.The group concluded that its upcoming work should focus more closely on functionaldiversity, which was identified as a recurring issue in the Baltic Sea. This approach wasalso identified as a useful connection point between scientific and management aspectsin order for the group to continue serving as a forum for developing ecosystem-basedmanagement efforts in the Baltic Sea. A focus on functional diversity was also seen as2 | ICES WGIAB REPORT 2015a potentially feasible way of bringing together management aspects for different sectors,by linking to ecosystem services concepts.The group proposed Saskia Otto, Germany and Martin Lindegren, Denmark as newincoming Chairs, together with Lena Bergström, Sweden and Laura Uusitalo, Finland.Having four Chairs is justified due to the wide scope of the group's work, as well asthe increased work load due to the planned new foci.
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| 5. |
- Griffiths, Jennifer R., et al.
(författare)
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The importance of benthic-pelagic coupling for marine ecosystem functioning in a changing world
- 2017
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 23:6, s. 2179-2196
-
Forskningsöversikt (refereegranskat)abstract
- Benthic-pelagic coupling is manifested as the exchange of energy, mass, or nutrients between benthic and pelagic habitats. It plays a prominent role in aquatic ecosystems, and it is crucial to functions from nutrient cycling to energy transfer in food webs. Coastal and estuarine ecosystem structure and function are strongly affected by anthropogenic pressures; however, there are large gaps in our understanding of the responses of inorganic nutrient and organic matter fluxes between benthic habitats and the water column. We illustrate the varied nature of physical and biological benthic-pelagic coupling processes and their potential sensitivity to three anthropogenic pressures - climate change, nutrient loading, and fishing - using the Baltic Sea as a case study and summarize current knowledge on the exchange of inorganic nutrients and organic material between habitats. Traditionally measured benthic-pelagic coupling processes (e.g., nutrient exchange and sedimentation of organic material) are to some extent quantifiable, but the magnitude and variability of biological processes are rarely assessed, preventing quantitative comparisons. Changing oxygen conditions will continue to have widespread effects on the processes that govern inorganic and organic matter exchange among habitats while climate change and nutrient load reductions may have large effects on organic matter sedimentation. Many biological processes (predation, bioturbation) are expected to be sensitive to anthropogenic drivers, but the outcomes for ecosystem function are largely unknown. We emphasize how improved empirical and experimental understanding of benthic-pelagic coupling processes and their variability are necessary to inform models that can quantify the feedbacks among processes and ecosystem responses to a changing world.
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| 6. |
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| 7. |
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| 8. |
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| 9. |
- Bergenius, Mikaela, et al.
(författare)
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Fishing or the environment - what regulates recruitment of an exploited marginal vendace (Coregonus albula (L.)) population?
- 2013
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Ingår i: Advances in Limnology. - 1612-166X. ; 64, s. 57-70
-
Konferensbidrag (refereegranskat)abstract
- Fish populations inhabiting marginal areas are generally highly susceptible to environmental variation and therefore show large fluctuations in recruitment. The commercially important, and usually freshwater, vendace (Coregonus albula (L.)) occupying the brackish waters of the Bothnian Bay forms one such marginal population and shows large annual variation in recruitment. Here, we investigate the relative importance of fishing (trawling time), hydro-climatic factors and species interactions in explaining the variability in vendace recruitment using three sets of models. A comparison of the best models in the hydro-climatic model set and the fishing model revealed that the hydro-climatic variables were overall superior to the anthropogenic model in describing recruitment variability. Trawling time and water temperature in winter combined with salinity explained 33 and 63.7% of the variation in recruitment, respectively. The importance of water temperature and salinity, in combination with the effects of trawling time, calls for catch levels to be set with caution in this vendace fishery.
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| 10. |
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| 11. |
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| 12. |
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| 13. |
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| 14. |
- Bergström, Lena, et al.
(författare)
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Kustfisk och Fiske : Analyser av tillståndet hos abborre, gädda, gös, piggvar, sik, siklöja och skrubbskädda år 2005
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I denna internrapport redovisas de analyser som utgjort underlag till Kustlaboratoriets bidragtill Fiskeriverkets gemensamma resurs- och miljööversikt år 2006. Analyserna häri byggerpå loggboksdata, provfi ske, journalföringsdata, samt i vissa fall även omgivningsdata, ochomfattar abborre, gädda, gös, piggvar, sik, siklöja och skrubbskädda. Syftet har varit attdokumentera analyserna för spridning inom laboratoriet, och de tillhörande texterna är därförkortfattade. Vidare information kan fås av Ann-Britt Florin, Kerstin Söderberg, Lena Bergströmeller Anna Gårdmark, som genomförde analyserna.
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| 15. |
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| 16. |
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| 17. |
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| 18. |
- Bernes, Claes, et al.
(författare)
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What is the influence of a reduction of planktivorous and benthivorous fish on water quality in temperate eutrophic lakes? : A systematic review
- 2015
-
Ingår i: Environmental Evidence. - : BioMed Central. - 2047-2382. ; 4:1
-
Tidskriftsartikel (refereegranskat)abstract
- BackgroundIn recent decades, many attempts have been made to restore eutrophic lakes through biomanipulation. Reducing the populations of planktivorous and benthivorous fish (either directly or through stocking of piscivorous fish) may induce ecosystem changes that increase water transparency and decrease the risk of algal blooms and fish kills, at least in the short term. However, the generality of biomanipulation effects on water quality across lake types and geographical regions is not known. Therefore, we have undertaken a systematic review of such effects in eutrophic lakes in temperate regions throughout the world.MethodsSearches for literature were made using online publication databases, search engines, specialist websites and bibliographies of literature reviews. Search terms were developed in English, Danish, Dutch and Swedish. Identified articles were screened for relevance using inclusion criteria set out in an a priori protocol. To reduce the risk of bias, we then critically appraised the combined evidence found on each biomanipulation. Data were extracted on outcomes such as Secchi depth and chlorophyll a concentration before, during and/or after manipulation, and on effect modifiers such as lake properties and amounts of fish removed or stocked.ResultsOur searches identified more than 14,500 articles. After screening for relevance, 233 of them remained. After exclusions based on critical appraisal, our evidence base included useful data on 128 biomanipulations in 123 lakes. Of these interventions, 85% had been made in Europe and 15% in North America. Meta-analysis showed that removal of planktivores and benthivores (with or without piscivore stocking) leads to increased Secchi depth and decreased chlorophyll a concentration during intervention and the first three years afterwards. Piscivore stocking alone has no significant effect. The response of chlorophyll a levels to biomanipulation is stronger in lakes where fish removal is intense, and in lakes which are small and/or have high pre-manipulation concentrations of total phosphorus.ConclusionsOur review improves on previous reviews of biomanipulation in that we identified a large number of case studies from many parts of the world and used a consistent, repeatable process to screen them for relevance and susceptibility to bias. Our results indicate that removal of planktivorous and benthivorous fish is a useful means of improving water quality in eutrophic lakes. Biomanipulation tends to be particularly successful in relatively small lakes with short retention times and high phosphorus levels. More thorough fish removal increases the efficacy of biomanipulation. Nonetheless successes and failures have occurred across a wide range of conditions.
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| 19. |
- Bernes, Claes, et al.
(författare)
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What is the influence on water quality in temperate eutrophic lakes of a reduction of planktivorous and benthivorous fish? : A systematic review protocol
- 2013
-
Ingår i: Environmental Evidence. - : BioMed Central (BMC). - 2047-2382. ; 2:1
-
Forskningsöversikt (refereegranskat)abstract
- Background: In lakes that have become eutrophic due to sewage discharges or nutrient runoff from land, problems such as algal blooms and oxygen deficiency often persist even when nutrient supplies have been reduced. One reason is that phosphorus stored in the sediments can exchange with the water. There are indications that the high abundance of phytoplankton, turbid water and lack of submerged vegetation seen in many eutrophic lakes may represent a semi-stable state. For that reason, a shift back to more natural clear-water conditions could be difficult to achieve. In some cases, though, temporary mitigation of eutrophication-related problems has been accomplished through biomanipulation: stocks of zooplanktivorous fish have been reduced by intensive fishing, leading to increased populations of phytoplankton-feeding zooplankton. Moreover, reduction of benthivorous fish may result in lower phosphorus fluxes from the sediments. An alternative to reducing the dominance of planktivores and benthivores by fishing is to stock lakes with piscivorous fish. These two approaches have often been used in combination. The implementation of the EU Water Framework Directive has recently led to more stringent demands for measures against eutrophication, and a systematic review could clarify whether biomanipulation is efficient as a measure of that kind. Methods: The review will examine primary field studies of how large-scale biomanipulation has affected water quality and community structure in eutrophic lakes or reservoirs in temperate regions. Such studies can be based on comparison between conditions before and after manipulation, on comparison between treated and nontreated water bodies, or both. Relevant outcomes include Secchi depth, concentrations of oxygen, nutrients, suspended solids and chlorophyll, abundance and composition of phytoplankton, zooplankton and fish, and coverage of submerged macrophytes.
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| 20. |
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| 21. |
- Bryhn, Andreas, et al.
(författare)
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Hur mycket strömming finns det?
- 2013
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Ingår i: Havsutsikt. - 1104-0513. ; , s. 20-21
-
Tidskriftsartikel (populärvet., debatt m.m.)
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| 22. |
- Casini, Michele, et al.
(författare)
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Hypoxic areas, density-dependence and food limitation drive the body condition of a heavily exploited marine fish predator
- 2016
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Ingår i: Royal Society Open Science. - : The Royal Society. - 2054-5703. ; 3
-
Tidskriftsartikel (refereegranskat)abstract
- Investigating the factors regulating fish condition is crucial in ecology and the management of exploited fish populations. The body condition of cod (Gadus morhua) in the Baltic Sea has dramatically decreased during the past two decades, with large implications for the fishery relying on this resource. Here, we statistically investigated the potential drivers of the Baltic cod condition during the past 40 years using newly compiled fishery-independent biological data and hydrological observations. We evidenced a combination of different factors operating before and after the ecological regime shift that occurred in the Baltic Sea in the early 1990s. The changes in cod condition related to feeding opportunities, driven either by density-dependence or food limitation, along the whole period investigated and to the fivefold increase in the extent of hypoxic areas in the most recent 20 years. Hypoxic areas can act on cod condition through different mechanisms related directly to species physiology, or indirectly to behaviour and trophic interactions. Our analyses found statistical evidence for an effect of the hypoxia-induced habitat compression on cod condition possibly operating via crowding and density-dependent processes. These results furnish novel insights into the population dynamics of Baltic Sea cod that can aid the management of this currently threatened population.
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| 23. |
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| 24. |
- Casini, Michele, et al.
(författare)
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Predator transitory spillover induces trophic cascades in ecological sinks
- 2012
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 109:21, s. 8185-8189
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding the effects of cross-system fluxes is fundamental in ecosystem ecology and biological conservation. Source-sink dynamics and spillover processes may link adjacent ecosystems by movement of organisms across system boundaries. However, effects of temporal variability in these cross-system fluxes on a whole marine ecosystem structure have not yet been presented. Here we show, using 35 y of multitrophic data series from the Baltic Sea, that transitory spillover of the top-predator cod from its main distribution area produces cascading effects in the whole food web of an adjacent and semi-isolated ecosystem. At varying population size, cod expand/contract their distribution range and invade/retreat from the neighboring Gulf of Riga, thereby affecting the local prey population of herring and, indirectly, zooplankton and phytoplankton via top-down control. The Gulf of Riga can be considered for cod a true sink habitat, where in the absence of immigration from the source areas of the central Baltic Sea the cod population goes extinct due to the absence of suitable spawning grounds. Our results add a metaecosystem perspective to the ongoing intense scientific debate on the key role of top predators in structuring natural systems. The integration of regional and local processes is central to predict species and ecosystem responses to future climate changes and ongoing anthropogenic disturbances.
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| 25. |
- Certain, Grégoire, et al.
(författare)
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How do MAR(1) models cope with hidden nonlinearities in ecological dynamics?
- 2018
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Ingår i: Methods in Ecology and Evolution. - 2041-210X. ; 9, s. 1975-1995
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Tidskriftsartikel (refereegranskat)abstract
- 1. Multivariate autoregressive (MAR) models are an increasingly popular technique to infer interaction strengths between species in a community and to predict the community response to environmental change. The most commonly employed MAR(1) models, with one time lag, can be viewed either as multispecies competition models with Gompertz density dependence or, more generally, as a linear approximation of more complex, nonlinear dynamics around stable equilibria. This latter interpretation allows for broader applicability, but may come at a cost in terms of interpretation of estimates and reliability of both short- and long-term predictions.2. We investigate what these costs might be by fitting MAR(1) models to simulated 2-species competition, consumer-resource and host-parasitoid systems, as well as a larger food web influenced by the environment. We review how MAR(1) coefficients can be interpreted and evaluate how reliable are estimates of interaction strength, rank, or sign; accuracy of short-term forecasts; as well as the ability of MAR(1) models to predict the long-term responses of communities submitted to environmental change such as PRESS perturbations.3. The net effects of species j on species i are usually (90%-95%) well recovered in terms of sign or rank, with the notable exception of overcompensatory dynamics. In actual values, net effects of species j on species i are not well recovered when the underlying dynamics are nonlinear. MAR(1) models are better at making short-term qualitative forecasts (next point going up or down) than at predicting long-term responses to environmental perturbations, which can be severely over- as well as underestimated.4. We conclude that when applying MAR(1) models to ecological data, inferences on net effects among species should be limited to signs, or the Gompertz assumption should be tested and discussed. This particular assumption on density-dependence (log-linearity) is also required for unbiased long-term predictions. Overall, we think that MAR(1) models are highly useful tools to resolve and characterize community dynamics, but we recommend to use them in conjunction with alternative, nonlinear models resembling the ecological context in order to improve their interpretation in specific applications.
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| 26. |
- Conversi, Alessandra, et al.
(författare)
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A holistic view of marine regime shifts
- 2015
-
Ingår i: Philosophical Transactions of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 370:1659
-
Forskningsöversikt (refereegranskat)abstract
- Understanding marine regime shifts is important not only for ecology but also for developing marine management that assures the provision of ecosystem services to humanity. While regime shift theory is well developed, there is still no common understanding on drivers, mechanisms and characteristic of abrupt changes in real marine ecosystems. Based on contributions to the present theme issue, we highlight some general issues that need to be overcome for developing a more comprehensive understanding of marine ecosystem regime shifts. We find a great divide between benthic reef and pelagic ocean systems in how regime shift theory is linked to observed abrupt changes. Furthermore, we suggest that the long-lasting discussion on the prevalence of top-down trophic or bottom-up physical drivers in inducing regime shifts may be overcome by taking into consideration the synergistic interactions of multiple stressors, and the special characteristics of different ecosystem types. We present a framework for the holistic investigation of marine regime shifts that considers multiple exogenous drivers that interact with endogenous mechanisms to cause abrupt, catastrophic change. This framework takes into account the time-delayed synergies of these stressors, which erode the resilience of the ecosystem and eventually enable the crossing of ecological thresholds. Finally, considering that increased pressures in the marine environment are predicted by the current climate change assessments, in order to avoid major losses of ecosystem services, we suggest that marine management approaches should incorporate knowledge on environmental thresholds and develop tools that consider regime shift dynamics and characteristics. This grand challenge can only be achieved through a holistic view of marine ecosystem dynamics as evidenced by this theme issue.
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| 27. |
- Dannewitz, Johan, et al.
(författare)
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Both predation and feeding opportunities may explain changes in survival of Baltic salmon post-smolts
- 2012
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Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 69, s. 1574-1579
-
Tidskriftsartikel (refereegranskat)abstract
- The survival of wild and hatchery-reared post-smolts of salmon (Salmo salar) in the Baltic Sea has declined since the 1990s. Direct observations of the processes affecting survival are, however, lacking. Here, the importance of food availability and predation in regulating post-smolt survival is analysed. Based on previous studies, the following explanatory variables were selected: (i) availability of herring (Clupea harengus membras) recruits in the Gulf of Bothnia (Bothnian Sea, Bothnian Bay) in the northern Baltic Sea; (ii) sprat (Sprattus sprattus balticus) and herring abundance in the southern Baltic Sea; and (iii) abundance of grey seal (Halichoerus grypus) along the post-smolt migration route. Bayesian analysis was used to estimate the relative probability of each of the 32 combinations of these variables and revealed that the model including grey seal abundance and herring recruits per post-smolt had the highest posterior probability and a high coefficient of determination. The results suggest that the declining trend in post-smolt survival is explained by the increased number of grey seals, whereas the annual variation in survival coincides with variation in the recruitment of Bothnian Sea herring. However, it remains uncertain whether the observed correlations arise from direct causalities or other mechanisms.
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| 28. |
- Ekström, Andreas, 1979, et al.
(författare)
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Cardiorespiratory adjustments to chronic environmental warming improve hypoxia tolerance in European perch (Perca fluviatilis).
- 2021
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Ingår i: The Journal of experimental biology. - : The Company of Biologists. - 1477-9145 .- 0022-0949. ; 224:6
-
Tidskriftsartikel (refereegranskat)abstract
- Aquatic hypoxia will become increasingly prevalent in the future as a result of eutrophication combined with climate warming. While short-term warming typically constrains fish hypoxia tolerance, many fishes cope with warming by adjusting physiological traits through thermal acclimation. Yet, little is known about how such adjustments affect tolerance to hypoxia. We examined European perch (Perca fluviatilis) from the Biotest enclosure (23°C, Biotest population), a unique ∼1km2 ecosystem artificially warmed by cooling water from a nuclear power plant, and an adjacent reference site (16-18°C, reference population). Specifically, we evaluated how acute and chronic warming affect routine oxygen consumption rate (ṀO2,routine) and cardiovascular performance in acute hypoxia, alongside assessment of the thermal acclimation of the aerobic contribution to hypoxia tolerance (critical O2 tension for ṀO2,routine: Pcrit) and absolute hypoxia tolerance (O2 tension at loss of equilibrium; PLOE). Chronic adjustments (possibly across lifetime or generations) alleviated energetic costs of warming in Biotest perch by depressing ṀO2,routine and cardiac output, and by increasing blood O2 carrying capacity relative to reference perch acutely warmed to 23°C. These adjustments were associated with improved maintenance of cardiovascular function and ṀO2,routine in hypoxia (i.e. reduced Pcrit). However, while Pcrit was only partially thermally compensated in Biotest perch, they had superior absolute hypoxia tolerance (i.e. lowest PLOE) relative to reference perch irrespective of temperature. We show that European perch can thermally adjust physiological traits to safeguard and even improve hypoxia tolerance during chronic environmental warming. This points to cautious optimism that eurythermal fish species may be resilient to the imposition of impaired hypoxia tolerance with climate warming.
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| 29. |
- Förlin, Lars, 1950, et al.
(författare)
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Fokus Kvädöfjärden - Varför mår kustfisken dåligt?
- 2014
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Ingår i: HAVET 2013/2014. - 1654-6741. ; år 2014, s. 26-30
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Forskningsöversikt (refereegranskat)abstract
- Abborre och tånglake längs kusten har länge visat tecken på att de inte mår bra. Inte ens i områden som förutsätts vara mer eller mindre opåverkade av miljögifter, som exempelvis Kvädöfjärden i Östergötland. Här samarbetar nu flera forskare i ett nytt stort projekt för att försöka ta reda på om det är just miljögifter som är orsaken till den dåliga fiskhälsan. I så fall vilka och var kommer de ifrån? Det är en stor uppgift med många utmaningar och jakten på orsaker har bara börjat.
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| 30. |
- Gårdmark, Anna, et al.
(författare)
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Biological ensemble modeling to evaluate potential futures of living marine resources
- 2013
-
Ingår i: Ecological Applications. - : Wiley. - 1051-0761 .- 1939-5582. ; 23:4, s. 742-754
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Tidskriftsartikel (refereegranskat)abstract
- Natural resource management requires approaches to understand and handle sources of uncertainty in future responses of complex systems to human activities. Here we present one such approach, the biological ensemble modeling approach,'' using the Eastern Baltic cod (Gadus morhua callarias) as an example. The core of the approach is to expose an ensemble of models with different ecological assumptions to climate forcing, using multiple realizations of each climate scenario. We simulated the long-term response of cod to future fishing and climate change in seven ecological models ranging from single-species to food web models. These models were analyzed using the biological ensemble modeling approach'' by which we (1) identified a key ecological mechanism explaining the differences in simulated cod responses between models, (2) disentangled the uncertainty caused by differences in ecological model assumptions from the statistical uncertainty of future climate, and (3) identified results common for the whole model ensemble. Species interactions greatly influenced the simulated response of cod to fishing and climate, as well as the degree to which the statistical uncertainty of climate trajectories carried through to uncertainty of cod responses. Models ignoring the feedback from prey on cod showed large interannual fluctuations in cod dynamics and were more sensitive to the underlying uncertainty of climate forcing than models accounting for such stabilizing predator-prey feedbacks. Yet in all models, intense fishing prevented recovery, and climate change further decreased the cod population. Our study demonstrates how the biological ensemble modeling approach makes it possible to evaluate the relative importance of different sources of uncertainty in future species responses, as well as to seek scientific conclusions and sustainable management solutions robust to uncertainty of food web processes in the face of climate change.
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| 31. |
- Gårdmark, Anna, et al.
(författare)
-
Density-dependent body growth reduces the potential of marine reserves to enhance yields
- 2006
-
Ingår i: Journal of Applied Ecology. - : Wiley. - 1365-2664 .- 0021-8901. ; 43:1, s. 61-69
-
Tidskriftsartikel (refereegranskat)abstract
- 1. Some models of marine no-take reserves predict that reserves can enhance fishery yield. However, empirical evidence of this remains inconclusive. One reason for this may be the disregard for density-dependent body growth in most models. Density-dependent body growth links the number and size of individuals, and thus could influence the biomass of fishery yield. 2. We developed an age- and size-structured model of an exploited population and analysed the effect of implementing a no-take reserve of varying size. 3. Protecting part of a population from exploitation in a no-take reserve results in a rapid build-up of biomass inside the reserve because of increased survival. However, when body growth is density-dependent it also results in reduced length at a given age within the no-take reserve because of crowding effects. This prediction is backed up by empirical observations. 4. If there is export of individuals (here larvae) from the no-take reserve, length at a given age will also decrease in the fished part of the population outside the reserve. An increase in the number of exploitable individuals thus results in decreased individual body mass. The positive effect of larval drift on fished population size and catch numbers will therefore rarely translate into an increase in equilibrium yield biomass. 5. Synthesis and applications. When body growth is density-dependent, implementation of no-take reserves affects the body size of both protected and exploitable individuals. Although reserves can have several benefits besides increasing yields, our study shows that, if density-dependent somatic effects are important, a general increase in yield biomass cannot be expected. In populations with density-dependent body growth, reserves are more likely to decrease yield biomass unless the population is severely overexploited. Analyses of the efficiency of marine reserves as a means of enhancing the yield of fisheries need to account for ecological processes, and density-dependent body growth is likely to be key.
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| 32. |
- Gårdmark, Anna, et al.
(författare)
-
Disparate maturation adaptations to size-dependent mortality
- 2006
-
Ingår i: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 273:1598, s. 2185-2192
-
Tidskriftsartikel (refereegranskat)abstract
- Body size is an important determinant of resource use, fecundity and mortality risk. Evolution of maturation size in response to size-dependent selection is thus a fundamental part of life-history theory. Increased mortality among small individuals has previously been predicted to cause larger maturation size, whereas increased mortality among large individuals is expected to have the opposite effect. Here we use a continuously size-structured model to demonstrate that, contrary to these widespread expectations, increased mortality among small individuals can have three alternative effects: maturation size may increase, decrease or become evolutionarily bistable. We show that such complex responses must be reckoned with whenever mortality is size-dependent, growth is indeterminate, reproduction impairs growth and fecundity increases with size. Predicting adaptive responses to altered size-dependent mortality is thus inherently difficult, since, as demonstrated here, such mortality cannot only reverse the direction of but also cause abrupt shifts in evolutionarily stable maturation sizes.
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| 33. |
- Gårdmark, Anna, et al.
(författare)
-
Does predation by grey seals (Halichoerus grypus) affect Bothnian Sea herring stock estimates?
- 2012
-
Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 69, s. 1448-1456
-
Tidskriftsartikel (refereegranskat)abstract
- Mortality of small pelagic fish due to marine mammals is generally considered to be low compared with other sources of mortality. With recent recoveries of marine mammal predators worldwide, this may no longer hold. The grey seal (Halichoerus grypus) population in the Bothnian Sea has increased fivefold since 1985. Its main prey, herring (Clupea harrengus), is a key species for fisheries in the region. Yet, current stock assessments assume constant natural mortality, leading to a risk of biased stock estimates with increasing predation and misleading analyses of herring population dynamics. We estimated grey seal predation from diet data and reanalysed herring spawning stock biomass (SSB) during 1973-2009. Accounting for predation increased the herring SSB 16% (maximum 19%), but this was within the confidence intervals when ignoring predation. Although mortality in older individuals was inflated when accounting for seal predation, this did not change the conclusions about drivers of herring dynamics. Accounting for grey seal predation is important for abundance estimates of old herring, but currently not for SSB estimates, given the great uncertainties in the standard assessment. The grey seal impact on Bothnian Sea herring will need to be reassessed if stock age composition, grey seal feeding preferences, or total stock development change.
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| 34. |
- Gårdmark, Anna
(författare)
-
Early Detection of Ecosystem Regime Shifts: A Multiple Method Evaluation for Management Application
- 2012
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7, s. 1-9
-
Tidskriftsartikel (refereegranskat)abstract
- Critical transitions between alternative stable states have been shown to occur across an array of complex systems. While our ability to identify abrupt regime shifts in natural ecosystems has improved, detection of potential early-warning signals previous to such shifts is still very limited. Using real monitoring data of a key ecosystem component, we here apply multiple early-warning indicators in order to assess their ability to forewarn a major ecosystem regime shift in the Central Baltic Sea. We show that some indicators and methods can result in clear early-warning signals, while other methods may have limited utility in ecosystem-based management as they show no or weak potential for early-warning. We therefore propose a multiple method approach for early detection of ecosystem regime shifts in monitoring data that may be useful in informing timely management actions in the face of ecosystem change.
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| 35. |
- Gårdmark, Anna
(författare)
-
Forage Fish Interactions: a symposium on "Creating the tools for ecosystem-based management of marine resources"
- 2014
-
Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 71, s. 1-4
-
Tidskriftsartikel (refereegranskat)abstract
- Forage fish (FF) have a unique position within marine foodwebs and the development of sustainable harvest strategies for FF will be a critical step in advancing and implementing the broader, ecosystem-based management of marine systems. In all, 70 scientists from 16 nations gathered for a symposium on 12-14 November 2012 that was designed to address three key questions regarding the effective management of FF and their ecosystems: (i) how do environmental factors and predator-prey interactions drive the productivity and distribution of FF stocks across ecosystems worldwide, (ii) what are the economic and ecological costs and benefits of different FF management strategies, and (iii) do commonalities exist across ecosystems in terms of the effective management of FF exploitation?
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| 36. |
- Gårdmark, Anna, et al.
(författare)
-
Individual variation and interactions explain food web responses to global warming
- 2020
-
Ingår i: Philosophical transactions of the Royal Society of London. Series B, Biological sciences. - : The Royal Society. - 0080-4622. ; 375
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding food web responses to global warming, and their consequences for conservation and management, requires knowledge on how responses vary both among and within species. Warming can reduce both species richness and biomass production. However, warming responses observed at different levels of biological organization may seem contradictory. For example, higher temperatures commonly lead to faster individual body growth but can decrease biomass production of fishes. Here we show that the key to resolve this contradiction is intraspecific variation, because (i) community dynamics emerge from interactions among individuals, and (ii) ecological interactions, physiological processes and warming effects often vary over life history. By combining insights from temperature-dependent dynamic models of simple food webs, observations over large temperature gradients and findings from short-term mesocosm and multi-decadal whole-ecosystem warming experiments, we resolve mechanisms by which warming waters can affect food webs via individual-level responses and review their empirical support. We identify a need for warming experiments on food webs manipulating population size structures to test these mechanisms. We stress that within-species variation in both body size, temperature responses and ecological interactions are key for accurate predictions and appropriate conservation efforts for fish production and food web function under a warming climate.
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| 37. |
- Gårdmark, Anna, et al.
(författare)
-
Life-history evolution in harvested populations: the role of natural predation
- 2003
-
Ingår i: Evolutionary Ecology Research. - 1522-0613. ; 5:2, s. 239-257
-
Tidskriftsartikel (refereegranskat)abstract
- Models and experiments of the evolution of age- and/or size-at-maturation in response to population harvesting have consistently shown that selective harvesting of older and larger individuals can cause earlier maturation. These predictions, however, are all based on single-species considerations and thus crucially neglect the selective forces caused or mediated by species interactions. Here we develop simple models of phenotypic evolution of age-at-first-reproduction in a prey population subject to different types of predation and harvesting. We show that, in the presence of natural predation, the potential evolutionary response of age-at-first-reproduction to population harvesting is ambiguous: harvesting can cause either earlier or later maturation depending on the type of predator interaction and its strength relative to the fishing pressure. The counterintuitive consequences of harvesting result from the indirect effects that harvesting of a prey population has on the selection pressure exerted by its natural predator, since this selection pressure itself typically depends on prey density. If harvest rates are high, the direct selection pressures considered in classical analyses prevail and harvesting decreases the age-at-first-reproduction, whereas at lower harvest rates the indirect, inter-specifically mediated effects of harvesting can qualitatively overturn predictions based on simpler single-species models.
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| 38. |
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| 39. |
- Gårdmark, Anna
(författare)
-
Modellering av fisklarvsspridning
- 2008
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Vi har modellerat transporten av skarpsillslarver och deras individuella tillväxt i subdivision 27 under åren 1996-2005 med en hydrodynamisk cirkulationsmodell (baserad på drivdata från SMHI) kopplad med en individ-baserad tillväxtmodell. Syftet var att identifiera (i) säsongs- och mellanårsvariation i skarspsillslarvers spridningsmönster, (ii) åldersspecifik (50 dgr) och längdspecifik (25 mm) utbredning av skarpsillslarver, (iii) potentiella uppväxtområden för skarspillslarver, samt (iv) analysera huruvida skarpsillslarvernas utbredning överlappar med rekryteringsområden av abborre och gädda. Dessutom har vi studerat torsklarvers spridning från lekområden i de tre djupbassängerna in till subdivision 27. Våra resultat visar att i genomsnitt 65-100 % av skarpsillslarverna som kläcks i djupvattnen (>40m) i subdivision 27 hålls kvar inom subdivisionen. Variationen är stor mellan år, men generellt driver larver som kläcks sent på säsongen i högre grad ut ur området jämfört med tidigt kläckta larver. Det finns en skillnad i utbredning av 50 dgr gamla larver och larver som är 25 mm stora (motsvarande 8-25 dgr gamla). När larverna är större än 25 mm antas de kunna simma aktivt, och predikterade transportmönster är därför mindre tillförlitliga för larver >25 mm. På grund av den kortare spridningsperioden är de yngre larverna, som är 25 mm stora, inte lika utspridda som de som är 50 dgr, och de är mer koncentrerade till de norra delarna av västra Gotlandsbassängen. Andelen skarpsillslarver som transporteras in till grundare vatten (< 30m) längs kusten varierar mindre mellan år. På grund av den kortare drifttiden så når en lägre andel av 25 mm-larver grundare vatten än 50 dgr gamla larver. Då tillväxten (och därmed perioden av passiv transport) beror av temperaturen varierar andelen larver som når grundare vatten med säsong. Tidigt kläckta larver, som växer långsamt pga låga temperaturer, transporteras i högre grad in till grundområden än sent kläckta individer. I genomsnitt når omkring 15 % av skarpsillslarverna som kläcks i subdivision 27 de grundare vattnen längs kusten. Våra resultat indikerar att hela kuststräckan i subdivision 27 kan utgöra uppväxtområde för skarpsill, med en viss tyngdpunkt mot de nordligare delarna. Den genomsnittliga utbredningen av 25 mm-larver under 1996-2005 korrelerar endast svagt med potentiella rekryteringsområden (<6m djup) för abborre och gädda. Minskad rekryteringsframgång hos dessa arter kan därför inte förklaras med passivt transporterade skarpsillslarver. Det bör dock påpekas att vår studie inte omfattar prediktioner av aktivt simmande larver, vilka har en stor möjlighet att sprida sig från de häri modellerade utbredningsområdena vidare in på grunda kustvatten. Våra prediktioner för transport och settling av torsklarver visar att endast mycket låga andelar av torsk som kläcks i Bornholmbassängen, och som potentiellt skulle kunna kläckas i Gdansk- och Gotlandsbassängen, når kustområdena i subdivision 27. På grund av avsaknad av zooplankton data har vi antagit att födointag (och därmed tillväxt) begränsas enbart av temperatur. Individerna i modellen har därför maximal tillväxthastighet, och perioderna av passiv transport för 25 mm stora skarpsillslarver är därför kortast möjliga. Vårt resultat att omkring 15 % av skarpsillslarverna som kläcks i subdivision 27 transporteras in till de grundare vattnen längs kusten är därmed en konservativ skattning. Vid längre transporttider på grund av lägre födotillgång kan potentiellt en större andel av skarpsillslarverna spridas in till kusten. Projektet har visat att modellen kan generera typiska utbredningsmönster av skarpsill för områden från tidigare studier, och därför kan användas för att studera kopplingen mellan kust och utsjö på grund av larvtransport. Projektet har vidare visat att prediktioner av transport och utbredning av absoluta larvtätheter kräver data på såväl zooplankton som ägg och larver av skarpsill, liksom studier av hur vertikala rörelsemönster hos skarpsill påverkar dess horisontella driftmönster.
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| 40. |
- Gårdmark, Anna, et al.
(författare)
-
Regime shifts in exploited marine food webs : detecting mechanisms underlying alternative stable states using size-structured community dynamics theory
- 2015
-
Ingår i: Philosophical Transactions of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 370:1659, s. 20130262-
-
Tidskriftsartikel (refereegranskat)abstract
- Many marine ecosystems have undergone 'regime shifts', i.e. abrupt reorganizations across trophic levels. Establishing whether these constitute shifts between alternative stable states is of key importance for the prospects of ecosystem recovery and for management. We show how mechanisms underlying alternative stable states caused by predator-prey interactions can be revealed in field data, using analyses guided by theory on size-structured community dynamics. This is done by combining data on individual performance (such as growth and fecundity) with information on population size and prey availability. We use Atlantic cod (Gadus morhua) and their prey in the Baltic Sea as an example to discuss and distinguish two types of mechanisms, 'cultivation-depensation' and 'overcompensation', that can cause alternative stable states preventing the recovery of overexploited piscivorous fish populations. Importantly, the type of mechanism can be inferred already from changes in the predators' body growth in different life stages. Our approach can thus be readily applied to monitored stocks of piscivorous fish species, for which this information often can be assembled. Using this tool can help resolve the causes of catastrophic collapses in marine predatory-prey systems and guide fisheries managers on how to successfully restore collapsed piscivorous fish stocks.
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| 41. |
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| 42. |
- Gårdmark, Anna
(författare)
-
Species interactions govern evolutionary and ecological effects of population harvesting
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Harvesting changes population abundance and can affect adaptation of several life-history traits. Harvesting can also have indirect effects ? effects on non-target species and secondary effects on target species ? because interactions between species in a community determine the relevant ecological and evolutionary feedback environment. Species interactions therefore influence the effect of harvesting on community structure and dynamics as well as on trait evolution. Yet, this problem has often been neglected. In this thesis I have studied how species interactions affect the response of target and non-target species to population harvesting, using multi-species models of population dynamics and trait evolution. I show that species? evolutionary and ecological responses to harvesting depend on the community context. Specifically, the direction and magnitude of harvest-induced evolutionary changes in a trait depend on (1) the type of species interactions, (2) the strength of species interactions, and (3) which individuals in the population that are affected by interspecific interactions. Harvest-induced changes in spatial abundance patterns depend on (1) traits that influence species interactions, (2) local species interactions in combination with migration, and (3) the interplay between migration and traits determining local population dynamics. This thesis shows that evolutionary responses to harvesting depend on multiple ecological processes, and, conversely, suggests that trait evolution influence how harvesting affects population abundance patterns. In conclusion, types of interspecific interactions that do not lead to a feedback between species can be disregarded when assessing qualitative harvesting effects on target species. In contrast, community feedback that results in indirect density-dependence or frequency-dependent selection needs to be accounted for in analyses of harvest-induced ecological and evolutionary effects on target and non-target species.
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| 43. |
- Gårdmark, Anna, et al.
(författare)
-
Temperature-Dependence Assumptions Drive Projected Responses of Diverse Size-Based Food Webs to Warming
- 2024
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Ingår i: Earth's Future. - 2328-4277. ; 12
-
Tidskriftsartikel (refereegranskat)abstract
- Food web projections are critical for evaluating potential risks to ecosystems and fisheries under global warming. The temperature dependence of biological processes and regional differences in food web structure are two important sources of uncertainty and variation in climate forced projections of fish communities, but we do not know their magnitude or relative contribution. Here we systematically evaluated a range of different assumptions about temperature-dependence on rates, including size-dependent effects, controlling food intake, metabolism, and non-predation mortality in fishes using species-resolved size spectrum food web models that link individual-level physiological processes to population and community dynamics. We simulated the physiological effect of warming in a range of size-structured food web models calibrated to different marine ecosystems and in simplified trait-based models. Higher food intake in warmed conditions increased total fish biomass, catches, and mean body weight, but these effects were offset by the negative effects of warming on metabolism and mortality, which combined resulted in lower total biomasses and catches for most food webs. These effects were enhanced when warming increased metabolic rates more than food intake, and the outcomes were also sensitive to size dependency of temperature responses. Importantly, these general patterns were not uniform across all food webs-individual functional groups and fish species within food webs responded to warming in different ways depending on their position in the food web and its structure. Hence, caution is warranted when generalizing food web or species outcomes to warming because they are mediated by community interactions. Uncertainty related to temperature dependence and ecological interactions will impact food web projections and should be represented in climate change projections.Multi-species models are often used to predict how climate change will affect marine ecosystems, fisheries yields and conservation. However, temperature can affect species in a variety of ways, making predictions challenging. Moreover, warming driven changes in a fish community will also depend on species interactions, potentially amplifying or dampening warmingdriven effects in individual species. We explored how 2 degrees C of warming may impact fish biomasses, yields and sizes using six models developed for different marine food webs and three theoretical models with different assumptions about species interactions. We found that, overall, warming tended to result in lower biomasses and fisheries yields, but slightly larger average fish sizes. Yet, results differed depending on how we modeled temperature effects on species food intake and energy expenditure. Moreover, even under the same assumptions about temperature impacts, models developed for different ecosystems behaved differently showing that species interactions will modify warming effects, making general predictions difficult. To make better predictions on warming impacts and more informed adaptation strategies we urgently need more work to understand how temperature affects individual species and communities. Meanwhile, models predicting ecosystems responses to warming should more clearly account for the uncertainty in temperature effects on fishes.Assumptions regarding how temperature drives biological rates strongly influence food web responses to warming Community interactions further modify outcomes to warming which complicate efforts to generalize warming responses across food webs Uncertainty in food web temperature dependences should be represented in climate change projections
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| 44. |
- Gårdmark, Anna
(författare)
-
Temperature variability alters the stability and thresholds for collapse of interacting species
- 2020
-
Ingår i: Philosophical Transactions B: Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 375
-
Tidskriftsartikel (refereegranskat)abstract
- Temperature variability and extremes can have profound impacts on populations and ecological communities. Predicting impacts of thermal variability poses a challenge, because it has both direct physiological effects and indirect effects through species interactions. In addition, differences in thermal performance between predators and prey and nonlinear averaging of temperature-dependent performance can result in complex and counterintuitive population dynamics in response to climate change. Yet the combined consequences of these effects remain underexplored. Here, modelling temperature-dependent predator-prey dynamics, we study how changes in temperature variability affect population size, collapse and stable coexistence of both predator and prey, relative to under constant environments or warming alone. We find that the effects of temperature variation on interacting species can lead to a diversity of outcomes, from predator collapse to stable coexistence, depending on interaction strengths and differences in species' thermal performance. Temperature variability also alters predictions about population collapse-in some cases allowing predators to persist for longer than predicted when considering warming alone, and in others accelerating collapse. To inform management responses that are robust to future climates with increasing temperature variability and extremes, we need to incorporate the consequences of temperature variation in complex ecosystems. This article is part of the theme issue 'Integrative research perspectives on marine conservation'.
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| 45. |
- Gårdmark, Anna, et al.
(författare)
-
The ecology of recovery
- 2003
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Ingår i: Annales Zoologici Fennici. - 0003-455X. ; 40:2, s. 131-144
-
Tidskriftsartikel (refereegranskat)abstract
- The current high rate of population declines and attempts to 'manage' their recovery, call for a better understanding of recovery dynamics of populations. In many cases, recovery of a population may primarily be determined by a single life history property or ecological interaction, allowing for straightforward management actions. For example, a generalist predator may prevent the recovery of its prey, and populations with sex-biased dispersal are particularly vulnerable to demographic stochasticity. However, linking life history with intra- and interspecific population dynamics is needed to assess the relative importance of these factors. A clear example is depensatory dynamics that can be caused either by e.g., mutual predation or cooperative breeding. Moreover, dynamics of a recovering population can alter both its physiological and behavioural traits, affecting its interspecific interactions. Here we review life histories (reproduction, resource use and dispersal) and species interactions affecting recovery processes, and discuss their implications for management.
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| 46. |
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| 47. |
- Gårdmark, Truls, et al.
(författare)
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Analysis of clinical characteristics, management and survival of patients with Ta T1 bladder tumours in Sweden between 1997 and 2001
- 2006
-
Ingår i: Scandinavian Journal of Urology and Nephrology. - : Informa UK Limited. - 0036-5599 .- 1651-2065. ; 40:4, s. 276-282
-
Tidskriftsartikel (refereegranskat)abstract
- Objective. To analyse the management and outcome of patients with Ta T1 urinary bladder cancer in a population-based national database. Material and methods. Between 1997 and 2001, 94% of all newly diagnosed cases of urinary bladder cancer were registered in the Swedish National Bladder Cancer Register. Data were analysed regarding gender, healthcare region, stage and grade for patients with Ta T1 tumours. The choice of initial treatment in different regions was reviewed. Survival was analysed by calculating relative survival. Results. Out of 9859 registered patients, there were 4442 Ta tumours and 2139 T1 tumours. The median age at diagnosis was 72 and 73 years for patients with Ta and T1 tumours, respectively. Seventy-six percent of the patients were men. The choice of treatment varied between different healthcare regions. A significant trend towards an increased use of intravesical therapy was seen over time. Significantly fewer older than younger patients received such therapy. There was also a tendency towards more intensive therapy in men. The bladder cancer relative 5-year survival rate was 93% for Ta and 75% for T1 tumours. Survival was similar for men and women. Conclusions. Our analysis revealed a regional variation in the treatment of bladder cancer. A large group of patients, even those at high risk, were still undertreated. However, the recent publication of guidelines may have contributed to an increased use of intravesical treatment. Urologists tended to treat TaG3 and T1G3 tumours more aggressively than T1G2 tumours. Therapeutic aggressiveness decreased as the age of the patients increased. The survival rate of patients with bladder cancer in Sweden seems to remain at the levels previously reported for the 1980s.
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| 48. |
- Hekim, Zeynep, et al.
(författare)
-
The role of climate and fisheries on the temporal changes in the Bothnian Bay foodweb
- 2016
-
Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 73:7, s. 1739-1749
-
Tidskriftsartikel (refereegranskat)abstract
- Climate change, eutrophication, and fishing are main pressures associated with changes in the abiotic and biotic environment in several sub-basins of the Baltic Sea. Identifying the nature of such changes is of relative importance for fisheries and environmental management. The Bothnian Bay is the northernmost sub-basin in the Baltic Sea and the responses of the foodweb to long-term changes in combined pressures have not been investigated. In this study, we explore long-term changes in the Bothnian Bay foodweb, represented by key species across all trophic levels over the past 34 years, and identify potential environmental and anthropogenic drivers. The results indicate that salinity is the most important driver to explain changes in the composition of the offshore biota in the Bothnian Bay. These changes are probably driven by indirect effects of salinity rather than bottom-up effects. A decline in the herring spawning-stock biomass was most plausibly attributed to an increased competition for food due to a parallel increase in vendace, which uses the same food resources (zooplankton and zoobenthos) and may benefit from declining salinity due to its limnic origin. A strong increase in the abundance of grey seal and ringed seal populations was seen in the late 2000s but was not related to any of the pressure variables analysed. Temperature and nutrients were not identified as important drivers of changes in the overall biota. Our study explores correlative relationships between variables and identifies potential interactions in the foodweb to generate hypotheses for further studies.
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| 49. |
- Hemdan, Tammer, et al.
(författare)
-
Stathmin-1 is a promising prognostic factor and potential therapeutic target in urinary bladder cancer
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Aim: The oncoprotein 18/stathmin 1 (STMN1), involved in cell cycle progression and cell migration, has been reported to be expressed in several types of cancer, and is associated with clinical outcome in e.g. breast and liver cancer. The aims in this study were to investigate the clinical significance of STMN1 and to examine if STMN1 might be a possible therapeutic target in urinary bladder cancer.Experimental design: Immunohistochemical analyses of STMN1 protein expression were performed in a wide-range tissue microarray (115 Ta-, 115 T1-, 112 T2-4-tumors) and in a metastatic primary tumor/matched metastasis-material (90 patients). In the T24 cell line, the effect of STMN1 on cell proliferation was evaluated by inhibiting the cellular expression of STMN using STMN1-siRNA.Results: Patients with T1- or muscle-invasive disease exhibiting high expression of the STMN1 protein had a poorer overall survival (OS) and disease specific survival (DSS). In a multivariate analysis adjusting for stage, age and gender the results were for T2-T4 patients: OS (HR=1.77 95% CI 1.02-3.07; p=0.04) and DSS (HR=2.04 95% CI 1.13-3.68; p=0.02); for T1-4 patients: DSS (HR=1.83 95% CI 1.09-3.08; p=0.02). In the metastatic bladder cancer material, the majority of the patients with one metastasis (69%) and with several matched metastases (70%) were STMN1-positive in both the primary tumor and the matched metastases. Moreover, the ability of the urinary bladder cancer cell line to grow was significantly reduced after 72 hours (p<0.0001) when transfecting the cells with a siRNA targeting STMN1.Conclusion: Our results suggest that STMN1 protein-expression has a potential both as a prognostic marker and a novel treatment target in urinary bladder cancer.
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| 50. |
- Huss, Magnus, et al.
(författare)
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Cohort Dynamics Give Rise to Alternative Stable Community States
- 2013
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Ingår i: American Naturalist. - : University of Chicago Press. - 0003-0147 .- 1537-5323. ; 182, s. 374-392
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Tidskriftsartikel (refereegranskat)abstract
- Many ecological systems can exhibit alternative stable states (ASS), which implies that ecological communities may diverge depending on their initial state, despite identical environmental conditions. Here we present a new mechanism that can cause ASS in competition systems. Using a physiologically structured model of competing populations, representing Baltic Sea sprat and herring and their resources, we show how cohort-driven population cycles may result in priority effects leading to ASS. Similar mechanisms could, depending on mortality level, also result in a resident strikes back phenomenon. We argue that the prerequisites for the occurrence of ASS in our model system, that is, communities with competing populations exhibiting cohort cycles and variation in size at maturation, may be common in ecological systems.
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