Ecological network indicators of ecosystem status and change in the Baltic Sea

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1 Ecological network indicators of ecosystem status and change in the Baltic Sea Maciej T. Tomczak(1), Johanna J. Heymans (2), Johanna Yletyinen (3,4), Susa Niiranen (4), Saskia A. Otto (4) and Thorsten Blenckner (4) 1) Baltic Sea Centre, Stockholm University, Sweden 2) Scottish Association for Marine Science, Scottish Marine Institute, Dunbeg, Oban, United Kingdom 3) Nordic Centre for Research on Marine Ecosystems and Resources under Climate Change (NorMER), Stockholm Resilience Centre, Stockholm, Sweden 4) Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden

2 Baltic Sea

3 Characteris*cs large semi- enclosed brackish water body low diversity high produc9vity eutrophica9on high fishing pressure climate influences through temperature and salinity irregular inflows from North Sea stra9fied

4 Concept: Regime Shifts Ecosystem state Drivers over 9me Folke et al 2004 hap://ocean9ppingpoints.org

5 Ecosystem dynamics regime shi Food- web reorganisa*on

6 Casini M et al. PNAS 2009;106:

7 Regime Shift at the Baltic Sea Cod Herring Pseudocalanus sp. Sprat mean weight Acartia sp. Temora sp. Sprat Variables (sorted by their loading on the 1st PC-Axis) HERSSB CODSSB HERWC3 CODR2 SPRWC3 Pseudo_Sum Pseudo_Spr HERR1 cyano_bb_sum dia_gb_spr Chla_BBSum Temora_Sum cyano_gb_sum dino_bb_sum dia_gb_sum Acartia_Sum dino_gb_sum Cod_F46 dia_bb_sum cyano_bb_spr CODWC4 Chla_BBSpr Chla_GBSpr cyano_gb_spr SPRR1 dia_bb_spr Chla_GBSum dino_gb_spr Her_F36 Spr_F35 dino_bb_spr Temora_Spr SPRSSB Traffic Light Plot Acartia_Spr < 0.2 quintile < 0.4 quintile < 0.6 quintile < 0.8 quintile > 0.8 quintile missing value Years ICES/HECLOM WGIAB 2013

8 Ecological regime shifts in the Baltic Sea - due to overexploitation and climate change PC2 (12.4%) > Möllmann et al PC1 (24.0 %)

9 F F F fishing climate climate+nutrients cod F herring F Seals sprat F August T 1.2 RV cod RV cod RV Cod adult 2,3 yrs 0,1 yrs larvae Herring adult 0,1,2 yrs Sprat adult 0,1 yrs T (anomaly) salinity (anomaly) salinity hypoxia Mysids area (inverse) Macro- zoobenthos Micro ZP Acar9a spp. Temora sp. Other ZP Pseudocal sp. Meio- zoobenthos T (anomaly) spring T production (anomaly) primary production primary prod Detritus(s) Cyano- bacteria Phytoplankton Detritus(w) Tomczak et al. 2012

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11 Adult cod - diet composition changes (model) 100% % 4.2 Diet composi*on of Ad. Cod 80% 70% 60% 50% 40% 30% 20% 10% TL of Ad. Cod 0% Herring Sprat Macrobenthos Canibalism Mysids TL of Ad. Cod

12 Indices and ENA ( ) 1. Total System Throupout (TST) 2. Relative Ascendance (A/C) Network Indices 3. Average Mutual Information (AMI) 4. Entropy (H) 5. Finn Cycling Index (FCI) 6. Predatory Cycling Index (PCI) 7. Mean Path Length (MPL) 8. Proportional Flow to Detritus (PFD) 9. Total biomass per Total Production ratio (ToTB/ToTP) Recycle and Structure 10. The Total Production per Total respiration ratio (ToTP/ ToTR) 11. Total catches (TC) 12. Primary Production Required per PP (PPR/PP) 13. Mean Trophic Level of Catch (mtlc) Fisheries effect 14. Kempston Q

13 Ecological Network Analysis The overhead (Ø) is the fraction of a system s capacity and it indicates the system s energy in reserve (Monaco and Ulanowicz, 1997) Proposed Redundancy (R=internal Ø) as an index of system resilience R = n n i= 1 j= 1 ( T ij ) log n j= 1 T T ij 2 ij n i= 1 T ij

14 Pressures - PC1 model forcing Late 1980s Late 1990s State - PC1 model responce - biomass Late 1980s

15 Biomass Pressures

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17 Regime shift Resilience

18 Regime shift Resilience and presures 52 R [% of Capacity] Overall forcing index

19 Regime shift Resilience and presures 52 R [% of Capacity] Overall forcing index

20 Conclusios Adrupt changes at system (Low resilience) Food-web reorganization and redirection of energy flow pathways Ecosystem topology also changed from a web-like structure to a linearized food-web ENA indices - very informative but: not operational indicators model dependent reference points

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22 Thank you Thank you for prof Chris9an Möllmann and ICES/HELCOM Working Group on Integrated Ecosystem Assessment of the Bal9c Sea