Effects of shore-level displacement on the ecology of Baltic Sea bays

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Åsa Sandberg
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1 Joakim Hansen Effects of shore-level displacement on the ecology of Baltic Sea bays

2 Ecology; Aquatic plants; Invertebrates; Soft-bottom; Lagoons; Monitoring; Indicators Effects of shore-level displacement on the ecology of Baltic Sea bays

3 Aquatic plants; Invertebrates; Ecology; Soft-bottom; Lagoons; Monitoring; Indicators Effects of shore-level displacement on the ecology of Baltic Sea bays

5 Munsterhjelm 1997

6 Juvenile flad Glo flad Flad Glo Photos: Johan Persson

7 Appelgren & Mattila 2005 Hansen et al. 2008, 2011, 2012 Hansen 2012, 2013, unpubl. Mattila J, unpubl. Persson J, unpubl. Scheinin & Mattila 2010 Snickars et al Wallström & Persson 1997, 1999 Wallström et al. 2000

8 8 mm/yr.

9 Algae & Plants Bladderwrack (Blåstång) Filamentous algae/epiphytes (Trådformiga alger/påväxtalger) Stoneworts (Kransalger) Pondweeds (Natar & natingar) Milfoils (Slingor) Water Crowfoots (Möjor) Hornwort (Hornsärv) Naids (Najas) Starworts (Lånkar) Photos: Joakim Hansen, Inge Lennmark

10 Fucus vesiculosus (Blåstång) Potamogeton perfoliatus (Ålnate) Potamogeton pectinatus (Borstnate) Myriophyllum spicatum (Axslinga) Chara baltica (Grönsträfse) Chara tomentosa (Rödsträfse) Najas marina (Havsnajas) Munsterhjelm 1997

16 Macrophyte biomass Biomass (g DW sample 1 ) 12 8 4 0-1.5-1 -0.5 0 0.5 1 1.5 Epiphyte:macrophyte biomass 0.4 0.3 0.

11 16 Macrophyte biomass Biomass (g DW sample 1 ) Epiphyte:macrophyte biomass Proportion epiphytes Bay isolation JF F Hansen 2010; 2012 GF per sample per bay

12 Invertebrates Mussels (Musslor) Snails (Snäckor) Crustaceans (Kräftdjur) Insects (Insekter) Hydrozoans (Hydror) Bryozoans (Mossdjur) Water mites (Vattenkvalster) Leeches (Iglar) Polychaetes (Havsborstmaskar) Other worms (Övriga maskar) Photos J. Hansen & I. Lennmark

13 JF F GF JF F GF Hansen et al. 2008; 2012

14 200 Zooplankton abundance Abundance (Ind. l 1 ) Bay isolation Scheinin & Mattila 2010, Hansen et al. 2012

15 Fish *************************************** Perch (Abborre) Pike (Gädda) Roch (Mört) Rudd (Sarv) Breams (Björkna/Braxen) Tench (Sutare) Sticklebacks (Spigg) Minnow (Elritsa) Gobies (Stubb) ***************************************

16 15 Juvenile fish abundance Abundance (CPUE) Bay isolation Bay isolation Snickars et al. 2009, Hansen et al. 2012

18 Glo flad Juv. Flad Glo Flad Outside < >500 yrs.

20 0.0

22 Hansen et al Topographic openness Macroflora Macrofauna

24 Hansen 2013 Wave exposure Latitude Distance to freshwater?

25 Hansen 2013 Most important gradient Wave exposure Latitude Distance to freshwater?

26 Food web?

27 Food web δ 15 N, δ 13 C Hansen et al. 2012

28 Does the influence of allochtonous (terrestrial) carbon increase? H 1 Hansen et al Topographic openness No!

Biomass of macroflora and fauna decrease Increased proportion of disturbance tolerant sp.

29 Conclusions Decreased openness Decreasing water exchange Altered water proper es &bottom substrate characteristics Transition from stable to more variable abiotic conditions Increase in barriers hampering re colonization Clear effect on the ecological structure Biomass of macroflora and fauna decrease Increased proportion of disturbance tolerant sp. and fast colonizers From autotrophic fed to a more heterotrophic system Biomass of zooplankton and juvenile fish increase (High temperature & increased food availability) joakim.hansen@su.se;

30 Questions? Thank you for your attention!

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