BSEP116B Biodiversity in the Baltic Sea - Helcom

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Average number of species 20 15 10 5 0 Arkona Basin strains species distributions (Figure 3.4.1). In this broad-scale assessment, eight basins were evaluated and reference conditions, i.e., the average number of species that should be found, varied between 18.3 in the Arkona Basin and 2.0 in the Bothnian Bay. For the years 2000–2006, benthic invertebrate status varied considerably between sub-basins and was related to the widespread occurrence of hypoxia and anoxia in the Baltic Proper and the Gulf of Finland (Figure 3.4.1). None of the sub-basins can be regarded as pristine, even though the Gulf of Bothnia and the Arkona Basin are in a reasonable condition (as defined by the good-moderate border set by acceptable deviation; Bornholm Basin SE Gotland Basin N&CE Gotland Basin Northern Baltic Proper Reference value G/M border Assessment 2000-2006 Gulf of Finland Bothnian Sea Bothnian Bay Figure 3.4.1. Reference values and the border between good and moderate (G/M) ecological status in the different subbasins of the open-sea areas in the Baltic Sea depicted as Ecological Quality Ratio (EQR) and the average number of species. Benthic invertebrate status is described as an average for the period (2000–2006). see HELCOM 2009a). The entire Baltic Proper, from the Bornholm Basin to the northern Baltic Proper, and the Gulf of Finland are in a severely disturbed state (Figure 3.4.1). Some univariate measures of biodiversity were calculated for selected representative stations in each sea area, which highlight the nature of the overall diversity gradient in the Baltic Sea (Table 3.4.1). The total number of species recorded for the assessment period 2000–2006 ranged from 27 in the Arkona Basin (BY2) to only 3 in the Bothnian Bay (BO3), while average species diversity ranged from 13.7 to 1.4. Correspondingly, the Shannon-Wiener diversity index ranged from 2.4 to 0.02 (Table 3.4.1). In the low-diversity Baltic Sea, these traditional measures, such as Shannon-Wiener, are not very informative (Magurran 2008). Several stations, in particular, the Bornholm Basin (BY5) and the northern Baltic Proper (IBSV9), demonstrate the degraded state of macrobenthic communities over the assessment period. Interestingly, Cody’s measure of species turnover (β c ; beta diversity) provides useful insights into the transient and dynamic nature of the benthic communities in the southern Baltic Sea (Table 3.4.1). In the Arkona Basin (BY2), Cody’s measure reached 4.4 (which translates into an average actual species turnover of 8.8 between the years 2000–2006). In contrast, species turnover in the Bothnian Bay (BO3) gave an index value of 0.5. This obviously reflects the large differences in available species pools as well as the overall difference in biodiversity along the gradient. In addition, the dynamic nature of the southern Baltic is intimately linked to the periodic salt-water inflows. Table 3.4.1. Stations from each sea area provide examples of the benthic communities during the assessment period 2000–2006. Diversity is measured as the total and average number of species ± std (standard deviation) and Cody’s measure (β) represents the average species turnover ± std. Diversity is also calculated as the Shannon & Wiener (H’ (log 2 )) index (Shannon & Weaver 1963). 50 Sea area Station Depth Total nr Average nr of species Shannon-Wiener H' (log 2 ) Cody's measure ß C m of species x std x std x std Bothnian Bay BO3 110 3 1,43 0,53 0,02 0,03 0,50 0,32 Bothnian Sea, north US6B 82 3 2,14 0,69 0,07 0,06 0,25 0,42 Bothnian Sea, south SR5 125 5 3,86 0,90 0,88 0,37 0,17 0,26 Gulf of Finland LL11 67 7 3,14 1,21 0,34 0,16 0,83 0,93 Gulf of Finland LL4A 58 10 5,86 1,86 1,46 0,39 1,33 0,68 N Baltic Proper IBSV9 88 0 0,00 0,00 0,00 0,00 0,00 0,00 NE Gotland basin LF1 67 7 3,43 1,27 0,57 0,22 0,75 0,52 SE Gotland basin BCSIII10 90 3 1,71 0,76 0,33 0,47 0,42 0,38 Bornholm basin BY5 89 0 0,00 0,00 0,00 0,00 0,00 0,00 Bornholm basin HBP216 53 13 10,00 1,63 2,16 0,40 1,33 0,58 Arkona basin BY2 48 27 13,67 3,01 2,37 0,24 4,40 0,74
Long-term trends in biodiversity Long-term trends in benthic community composition from the mid-1960s to 2006 for four of the selected stations are illustrated in Figure 3.4.2. The patterns in these long-term trends exemplify the ‘shifting baseline’ of macrobenthic communities, especially in the southern Baltic (BCSIII10) and at the entrance to the Gulf of Finland (LL11), Bothnian Bay (BO3) 3000 100 % Individuals per m 2 2500 2000 1500 1000 500 80 % 60 % 40 % 20 % Marenzelleria spp. P. mobilata S. entomon M. affinis 0 0 % 1964 1968 1973 1980 1984 1988 1992 1996 2000 2004 1964 1968 1973 1980 1984 1988 1992 1996 2000 2004 Bothnian Sea (SR5) 7500 100 % Individuals per m 2 6000 4500 3000 1500 80 % 60 % 40 % 20 % Marenzelleria spp. P. f emorata H. sarsi M. balthica S. entomon M. affinis 0 0 % 1965 1968 1972 1977 1982 1986 1990 1994 1998 2002 2006 1965 1968 1972 1977 1982 1986 1990 1994 1998 2002 2006 Gulf of Finland (LL11) 7500 100 % Marenzelleria spp. Individuals per m 2 6000 4500 3000 1500 80 % 60 % 40 % 20 % Insecta P. elegans T. stroemi H. spinulosus P. f emorata H. sarsi M. balthica 0 1966 1970 1974 1980 1984 1988 1993 1997 2001 2005 0 % 1966 1970 1974 1980 1984 1988 1993 1997 2001 2005 S. entomon M. affinis SE Gotland Basin (BCSIII10) 2500 100 % T. stroemi Individuals per m 2 2000 1500 1000 500 0 1965 1969 1973 1980 1985 1990 1996 2000 2004 80 % 60 % 40 % 20 % 0 % 1965 1969 1973 1980 1985 1990 1996 2000 2004 S. armiger P. caudatus H. spinulosus D. rathkei A. jeffreysii P. f emorata H. sarsi M. balthica S. entomon Figure 3.4.2. Long-term changes in benthic community abundance (individuals per m 2 ) and composition (illustrating species turnover) are depicted for stations BO3 (Bothnian Bay), SR5 (Bothnian Sea), LL11 (at the entrance to the Gulf of Finland) and BCSIII10 (SE Gotland Basin). Note the different x- and y-axes. 51
Page 1: Baltic Sea Environment Proceedings
Page 4 and 5: Published by: Helsinki Commission K
Page 6 and 7: TABLE OF CONTENTS PREFACE . . . . .
Page 8 and 9: 6.6 Hazardous substances . . . . .
Page 10 and 11: 1 INTRODUCTION 8 1.1 An integrated
Page 12 and 13: Box 1.1. Biodiversity The term biod
Page 14 and 15: of saline water from the North Sea
Page 16 and 17: 14 On a global scale, marine ecosys
Page 18 and 19: Box 1.2. Regime shifts in the Balti
Page 20 and 21: 2 MARINE LANDSCAPES AND HABITATS 18
Page 22 and 23: From an ecological point of view, a
Page 24 and 25: Box 2.1.2. The Baltic marine landsc
Page 26 and 27: • A coherent data set on benthic
Page 28 and 29: Denmark Estonia Finland Germany Lat
Page 30 and 31: Mud-sandflat, Greifswald Lagoon, Ge
Page 32 and 33: 3 COMMUNITIES Communities are assem
Page 34 and 35: 32 Spring bloom index 1200 1000 800
Page 36 and 37: 34 Unusual events and new species i
Page 38 and 39: 36 Depth limit (m) the Gulf of Both
Page 40 and 41: Number of species 16 14 12 10 8 6 4
Page 42 and 43: Figure 3.2.7. Left panel shows pred
Page 44 and 45: Implications for the Baltic Sea Act
Page 46 and 47: Biomass (wet weight, mg per m 2 ) B
Page 48 and 49: the other hand, is not selected by
Page 50 and 51: iomass can be used to assess enviro
Page 54 and 55: 52 Macoma baltica where the influen
Page 56 and 57: the total BT identified for each ma
Page 58 and 59: Recruitment (thousands) 8000000 700
Page 60 and 61: Alien species Several alien fish sp
Page 62 and 63: 4 SPECIES The number of species in
Page 64 and 65: Table 4.1.1. Results of dedicated a
Page 66 and 67: Number of stranded porpoises 180 16
Page 68 and 69: is recommended to survey harbour po
Page 70 and 71: Number of individuals 12000 10000 8
Page 72 and 73: Mean blubber thickness (mm) 40 35 3
Page 74 and 75: Breeding pairs 60000 50000 40000 30
Page 76 and 77: predation on nests and nesting adul
Page 78 and 79: sites outside the Baltic, decreased
Page 80 and 81: Table 4.3.1. Development of the pop
Page 82 and 83: 80 Number of breeding pairs 3000 25
Page 84 and 85: The strategic goal of the BSAP to h
Page 86 and 87: for a given site or area. The secon
Page 88 and 89: Mussel bed reef community, Jasmund,
Page 90 and 91: Table 5.3. Assessment results of th
Page 92 and 93: Aerial photo of harbours seals (Pho
Page 94 and 95: 6 HUMAN PRESSURES ON BIODIVERSITY A
Page 96 and 97: Table 6.1.1. Catch range during the
Page 98 and 99: Baltic herring trawling, Bothnian B
Page 100 and 101: 6.1.3 Major international framework
Page 102 and 103:
100 Oil turnover (millions of tonne
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NOx emissions and sewage Macrophyte
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Communication links There are a num
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Figure 6.3.3. Left: concrete-stone
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ecommendations would contribute to
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Tourist fishing 110 cial fishery fo
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112 Figure 6.5.1. Integrated classi
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can be considered as having been a
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Although no direct, dramatic mass m
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Bearing in mind the complex hydrogr
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Box 6.7.1. Invasion status of the B
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Table 6.7.1. Examples of ecological
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munities that formerly consisted of
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6.8.2 Activities generating noise i
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128 and fish in the Baltic Sea area
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800 700 600 bag of the two German B
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Fish swarm on kelp (Laminaria sp.)
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tion of ice cover, either through r
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7 STATUS OF THE NETWORK OF MARINE A
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Box 7.1. Natura 2000 network of pro
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25 20 on how the criteria on ecolog
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estrial, nearshore marine, and offs
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144 >30 psu 18-30 psu 11-18 psu 7.5
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Permission needed Restricted Forbid
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Figure 7.8.a. MARXAN ’best portfo
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The BSPA network is relatively well
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Mammals. Among the mammals, the pop
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154 taxonomic groups and communitie
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156 provided by an ecosystem. Use o
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158 Reduction of human pressures Wh
Page 162 and 163:
160 fishing on fish population dyna
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162 Baden, S., Boström, C. (2001).
Page 166 and 167:
164 Season 2001-2002. Acta Zoologic
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166 Gasiūnaitė, Z.R., Cardoso, A.
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168 HELCOM & OSPAR (2003): Joint HE
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170 ICES (2008c). Report of the Bal
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172 area: density-dependent effects
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174 Noer, H., Clausager, I., Asferg
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176 Scheffer M., Carpenter S.R., Fo
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178 by passive acoustic monitoring.
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180 Warzaw, Poland Vilhunen, Jarmo,
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182 6.7 Alien speices Authors: Lepp
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ANNEX III: CONSERVATION STATUS OF T
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ANNEX IV: HABITAT OR SPECIES DISTRI
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ANNEX V: STATUS OF BREEDING AND WIN
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BSEP116B Biodiversity in the Baltic Sea - Helcom

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