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Long-term patch dynamics in the community shaped by bivalves, barnacles, ascidians and red algae: multiple foundation species in the White Sea shallow.

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Presentation on theme: "Long-term patch dynamics in the community shaped by bivalves, barnacles, ascidians and red algae: multiple foundation species in the White Sea shallow."— Presentation transcript:

1 Long-term patch dynamics in the community shaped by bivalves, barnacles, ascidians and red algae: multiple foundation species in the White Sea shallow subtidal

2 Eugene Yakovis Anna Artemieva Michael Fokin Marina Varfolomeeva Natalia Shunatova Eugene Yakovis Anna Artemieva Michael Fokin Marina Varfolomeeva Natalia Shunatova St.-Petersburg State University, Russia

3 Facilitation by foundation species shapes many terrestrial and benthic communities Communities with multiple functionally different foundation species are poorly studied

4 Locations: 12 m deep Site 1 and 15 m deep Site 2 Site 1 65° 01.2N 35° 39.7E The White Sea Site 2 65° 00.7N 35° 41.7E

5 Epibenthic patches (EPs) on the unstructured sediment

6 Mean density of EPs Mean density of EPs (m –2 ): 21±2 (Site 1), 6±1 (Site 2)

7 Species diversity in and around EPs epibenthic patches H = 2.28±0.04 (24±1 cm 2 patches) 119 mobile species (72 polychaetes) 111 sessile species (64 bryozans) unstructured sediment H=2.62±0.02 (55 cm 2 cores) 101 mobile species (78 polychaetes)

8 Biomass in and around EPs epibenthic patches wet weight of macrobenthic organisms 745 g/m 2 unstructured sediment wet weight of macrobenthic organisms 91 g/m 2

9 Overall species diversity H = 3.36±0.06 250 species in total (16 x 1 m 2 frame) 117±7 species per 1 m 2 frame

10 Epibenthic patches by primary substrate type

11 Primary substrate types by total area

12 Total weight of epibenthic organisms within the patches based on different substrate type

13 Live Serripes groenlandicus stays under the sediment surface and never has sessile organisms attached

14 Sessile organisms can utilize a shell only Sessile organisms can utilize a shell only when a clam dies

15 Sessile organisms can utilize a shell only Sessile organisms can utilize a shell only when a clam dies Site 1: 6.7±2.9 live individuals of Serripes groenlandicus per m 2 Site 1: 1.8±0.4 unfouled valves of Serripes groenlandicus per m 2 on the sediment surface

16 Most sessile organisms live on secondary biogenic Most sessile organisms live on secondary biogenic substrates (% individuals)

17 Principal secondary space providers are barnacles and Principal secondary space providers are barnacles and their empty shells, ascidians and red algae

18 These are 15 top frequent associations between sessile These are 15 top frequent associations between sessile organisms and substrates …

19 … and these are top 50

20 Most live barnacles Balanus crenatus are found on Most live barnacles Balanus crenatus are found on primary substrate and conspecifics

21 Most ascidians Styela spp. are found on barnacles and Most ascidians Styela spp. are found on barnacles and their empty shells

22 As a result, epibenthic patches with following structure As a result, epibenthic patches with following structure types are frequent:

23 Some of them look like this Some of them look like this

24 The observed variation in structure of epibenthic patches: (i) results from patch dynamics or (ii) is just a product of spatial heterogeneity and variable recruitment ? predictions from (ii): > the structure of patches would not depend much on their age > the age-dependent variation of structure would not match one observed in EPs

25 Number of initially empty Serripes shells exposed S = 34.4 ± 0.8 cm 2

26 1-2 yrs

27 3-4 yrs

28 5-6 yrs

29 7-8 yrs

30 9-10 yrs

31 Relative areas of principal substrates: shells, live barnacles, dead barnacles, ascidians and red algae by exposure term (shell area as 1) 1-2 yrs 3-4 yrs 5-6 yrs 7-8 yrs 9-10 yrs

32 Relative abundance of sessile organisms (% ind.) on shells, live barnacles, dead barnacles, ascidians, red algae and other substrates by exposure term 1-2 yrs 3-4 yrs 5-6 yrs 7-8 yrs 9-10 yrs

33 Mean LogE Shannon diversity of epibenthic assemblages on shells, live barnacles, dead barnacles, ascidians, red algae and other substrates by exposure term 1-2 yrs 3-4 yrs 5-6 yrs 7-8 yrs 9-10 yrs

34 nMDS of natural and experimental EPs on weights of ascidians, live and dead barnacles, red algae and Shannon diversity (stress=0.08) w/o substrate on Serripes shells on other substrates on live snails

35 nMDS of natural and experimental EPs on weights of ascidians, live and dead barnacles, red algae and Shannon diversity 1-2 yrs

36 nMDS of natural and experimental EPs on weights of ascidians, live and dead barnacles, red algae and Shannon diversity 3-4 yrs

37 nMDS of natural and experimental EPs on weights of ascidians, live and dead barnacles, red algae and Shannon diversity 5-6 yrs

38 nMDS of natural and experimental EPs on weights of ascidians, live and dead barnacles, red algae and Shannon diversity 7-8 yrs

39 nMDS of natural and experimental EPs on weights of ascidians, live and dead barnacles, red algae and Shannon diversity 9-10 yrs

40 nMDS of natural and experimental EPs on weights of ascidians, live and dead barnacles, red algae and Shannon diversity 1-10 yrs 1-23-45-67-89-10

41 The observed variation in structure of epibenthic patches: (i) results from patch dynamics or (ii) is just a product of spatial heterogeneity and variable recruitment ? predictions from (ii): > the structure of patches would not depend much on their age > the age-dependent variation of structure would not match one observed in EPs

42 The observed variation in structure of epibenthic patches: (i) results from patch dynamics or (ii) is just a product of spatial heterogeneity and variable recruitment ? predictions from (ii): > the structure of patches would not depend much on their age > the age-dependent variation of structure would not match one observed in EPs

43 The observed variation in structure of epibenthic patches: (i) results from patch dynamics or (ii) is just a product of spatial heterogeneity and variable recruitment ? predictions from (ii): > the structure of patches would not depend much on their age > the age-dependent variation of structure would not match one observed in EPs

44 The observed variation in structure of epibenthic patches: (i) results from patch dynamics or (ii) is just a product of spatial heterogeneity and variable recruitment ? predictions from (ii): > the structure of patches would not depend much on their age > the age-dependent variation of structure would not match one observed in EPs

45 CreditsCreditsCreditsCredits Funding: RFBR grants 02-04-50020-a, 05-04-48927-a, 05-04- 63041-k, 06-04-63077-k, 06-04-58536-z, 06-04-58537-z, 07- 04-10075-k, 07-04-08366-z, 08-04-01373-a, 08-04-10109-k, 09-04-10092-k, 10-04-08011-z Alexander Tcherenkov Nadezhda Tcherenkova Alexey Grishankov Alexandra Yakovis Dmitry Tomanovsky

46 Bonus trackBonus trackBonus trackBonus track

47 a shell exposed for 9 yrs


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