Joakim Hansen www.su.se/ostersjocentrum Effects of shore-level displacement on the ecology of Baltic Sea bays
Ecology; Aquatic plants; Invertebrates; Soft-bottom; Lagoons; Monitoring; Indicators Effects of shore-level displacement on the ecology of Baltic Sea bays
Aquatic plants; Invertebrates; Ecology; Soft-bottom; Lagoons; Monitoring; Indicators Effects of shore-level displacement on the ecology of Baltic Sea bays
Munsterhjelm 1997
Juvenile flad Glo flad Flad Glo Photos: Johan Persson
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. 2009 Wallström & Persson 1997, 1999 Wallström et al. 2000
8 mm/yr.
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
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 0.2 0.1 Proportion epiphytes 0-1.5-1 -0.5 0 0.5 1 1.5 Bay isolation JF F Hansen 2010; 2012 GF per sample per bay
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
JF F GF JF F GF Hansen et al. 2008; 2012
200 Zooplankton abundance Abundance (Ind. l 1 ) 150 100 50 0-1.5-1 -0.5 0 0.5 1 1.5 Bay isolation Scheinin & Mattila 2010, Hansen et al. 2012
Fish *************************************** Perch (Abborre) Pike (Gädda) Roch (Mört) Rudd (Sarv) Breams (Björkna/Braxen) Tench (Sutare) Sticklebacks (Spigg) Minnow (Elritsa) Gobies (Stubb) ***************************************
15 Juvenile fish abundance Abundance (CPUE) 10 5 0-1.5-1 -0.5 0 0.5 1 1.5 Bay isolation Bay isolation Snickars et al. 2009, Hansen et al. 2012
Glo flad Juv. Flad Glo Flad Outside <50 100 200 300 400 >500 yrs.
0.0
Hansen et al. 2008 Topographic openness Macroflora Macrofauna
Hansen 2013 Wave exposure Latitude Distance to freshwater?
Hansen 2013 Most important gradient Wave exposure Latitude Distance to freshwater?
Food web?
Food web δ 15 N, δ 13 C Hansen et al. 2012
Does the influence of allochtonous (terrestrial) carbon increase? H 1 Hansen et al. 2012 Topographic openness No!
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;
Questions? Thank you for your attention! joakim.hansen@su.se;