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Topology and robustness of the Barents Sea food webs

Topology and robustness of the Barents Sea food webs. PhD Project. Susanne Kortsch 10.02.2012. The Barents Sea (BS). The Barents Sea. Oil riggs. Maritim transport. Climate warming. Fisheries. Modified from IMR. BarEcoRe. Spatial Distributions. Community Structure. PhD project.

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Topology and robustness of the Barents Sea food webs

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  1. Topology and robustness of the Barents Sea food webs PhD Project Susanne Kortsch 10.02.2012

  2. The Barents Sea (BS) The Barents Sea Oil riggs Maritim transport Climate warming Fisheries Modified from IMR

  3. BarEcoRe Spatial Distributions Community Structure PhD project Robustness Resilience Early warning signals Trophic Interactions

  4. Overall Goal To evaluatetherobustnessofthe Barents Sea food web throughnetworkanalysis

  5. Overall Goal Why? Food web robustness influences the magnitude of environmental impact on the ecosystem

  6. Subprojects - within the PhD projects 1. Topologyofthe BS food webs 2. Compartmentalizationofthe BS food webs 3. Secondarylocalextinctions 4. FutureProjectionsofthe BS food web topologyrelated to climatechange and fisheries

  7. Subproject 1 Topologyofthefood webs

  8. The food web can be defined as a network of trophic (feeding) interactions (Dunne J. 2002) Topology of the food web Links (L) Fundamental Properties Species (S) Connectance (C) = L/S^2 - Fraction of all possible links that are realized Luczkovich et al. 2003

  9. The topological properties have dynamical implications Influence the stability, resilience and robustness of the food web Properties to be calculated Topology of the food web

  10. Food web topology Compilation of food web data BarEcoRe Trophic-species > 220 Trophic links > 1150

  11. The database Topology of the food web List of taxa in the matrix

  12. The database Topology of the food web Consumer The matrix Prey First thingthatneeds to be finished !!!

  13. 88 nodes 305 links Examples (fish) Barents Sea food web 35 nodes 77 links Bodini et al. 2009 BarEcoRe 2011

  14. The Barents sea will be divided into regions Food Web topology Example R2 R4 R1 R3

  15. Finalizationofthefood web matrix Contribution to the Planque et al. Database paper Subproject 1: Outcome Paper 1 Spatial and temporal variation in the food web topology of the Barents Sea

  16. Subproject 2 Compartmentalisation

  17. Compartmentalisation Compartmentalisation • is a measureofthedegreeofconnectionsbetween species • In highlycompartmentalizedfood webs subgroupsof species interact more witheachotherwithinthecompartmentthanwith species in othercompartments

  18. Example of compartmentalisation Compartmentalisation Rezende et al. 2009. Ecology Letters

  19. Compartmentalisation Map of stations

  20. Compartmentalisation The degreeofcompartmentalisation has consequences for therobustnessofthefoodweb • Highercompartmentalisationreducesthepropagationof a pertubationthroughthefoodweb (Krause et al. 2003)

  21. Compartmentalisationcan be furthercharacterized by looking at phylogeny, habitat use and body sizeoftrophospecies Subproject 2: Outcome Rezende et al. 2009. Ecology Letters

  22. Subproject 2: Outcome A mapoffood web compartmentalisation for the BS sampling stations Estimatesofrobustness  consequences for cascadingeffects Paper 2 Degreeofcompartmentalisation and robustnesofthe Barents Sea

  23. Subproject 3 Secondaryextinctions

  24. Secondary extinctions • Triggering species loss willinducesecondaryextinctions • Secondaryextinctions ocurrwhen a consumer loses all ofitsresources • On the basis ofsecondaryextinctions a vulnerable species list can be generated

  25. Subproject 3: Outcome Identificationofsecondaryextinctionsthroughthe loss of species How willthisaffectcompartmentalisation and robustness? Paper 3 Secondaryextinctions and robustness

  26. Subproject 4 Future scenarios of food web topology

  27. Future scenarios the food web • Will thedegreeofcompartmentalisationchange in thefuture due to climatechange? • Scenarios offuturecommunitycompositionsbasedonforecasted spatial destributions under climatechange (WP3) • ”New” species or invasion scenarios

  28. Subproject 4: Outcome Identificationoffishcompositionofthe BS in collaborationwith WP3 How willthisaffectcompartmentalisation and robustness? Paper 3 Future scenarios offishcomposition and robustness in the BS related to climatechange

  29. Outcome Deliverables Paper 1 Spatial and temporal comparisons of the food web topology in the Barents Sea Paper 2 Compartmentalisation of the BS food web Paper 3 Secondary extinctions and robustness Paper 4 Futureprojectionsoffood web compartmentalisation in the BS

  30. Time line

  31. Potential collaborations with other research groups ??? • Bascompte group on compartmentalisation and mechanisms behind the struture • Bodini group on secondary extinctions • Santa fe group on food web properties in general

  32. Thank you..... for now Questions ???

  33. Constraints or critical questions Is the data representative? - Are the attributes of the foodweb artifacts of the species selection How to measure the sensitivity of the food web metric estimates to the selection criteria? How reliable are the conclusions?

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