BSEP116B Biodiversity in the Baltic Sea - Helcom

More documents

Recommendations

Info

the other hand, is not selected by herring or sprat and, in fact, has a very effective escape reaction (Viitasalo et al. 1998). Temora longicornis, which increased during the period, is also strongly selected by clupeids (cf. references given above). However, T. longicornis is not as sensitive to salinity changes as Pseudocalanus and the species is furthermore a thermophile and may possibly have been stimulated by the increasing summer temperatures during the period (Figure 3.3.4c) (Hernroth & Ackefors 1979). The increasing trend in biomass concentrations of T. longicornis and partly Acartia spp. may also have other complex reasons. It could be the result of a potential carrying capacity for calanoids. In addition, decreasing eutrophication may affect the smallest calanoids in the Baltic Sea, the Acartia spp. (Figure 3.3.3c), as the biomass concentrations of the Acartia spp. follow a decadal course of the winter concentrations of nitrate in the upper 10 m of the central Bornholm Basin (Figure 3.3.4d). The causal mechanisms are unclear at the moment but are probably related to food web interactions. During the observation period the Baltic Proper, with the exception of the Åland Sea, has suffered from severe oxygen depletion periods in deep basins. This has significantly decreased the water volume available for species that thrive in the deep saline water under the halocline. As discussed above, this affects Pseudocalanus spp., perhaps the most important zooplanktonic prey item for Baltic herring. Hence, it may well be that human-induced Figure 3.3.4. (a) Salinity in the upper 3 m, (b) salinity in the layer between 70 m and 80 m, (c) temperature in the upper 3 m in July–August, and (d) winter nitrate concentrations (February, March) in the upper 10 m in the central Bornholm Basin between 1976 and 2007 (from IOW database) after Postel, in prep. (a) Salinity (psu) 8.5 8.0 7.5 7.0 R 2 = 0.3418 r = 0.5846 p< 0.001 6.5 6.0 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 (b) 20 19 18 R 2 = 0.2407 r = 0.4906 p< 0.001 17 Salinity (psu) 16 15 14 13 12 11 10 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 46
eutrophication and subsequent oxygen deficiency have a role in regulating zooplankton in the Baltic Proper as well. 3.3.3 Conclusions During the past 20–30 years, the copepod communities in the Baltic Sea have undergone considerable changes. The causes behind the changes, as well as their eventual effects, are at present difficult to define and distinguish. Climate variability with subsequent influence on salinity and temperature can likely explain some of the observed changes, while human pressures such as eutrophication also may have contributed. The observed changes in zooplankton communities have had cascading trophic effects which can be observed as reduced weight at age, general condition, and reproduction of Baltic herring and sprat. Furthermore, these changes combined with subsequent effects on planktivorous fish stocks have affected the growth, condition and reproduction of Baltic salmonids (e.g., Ikonen 2006), emphasizing the socio-economic impact of changes in Baltic zooplankton communities. 3.3.4 Recommendations Abiotic factors, such as decreasing salinity and increasing temperature, can substantially change the Baltic Sea zooplankton communities. Furthermore, anthropogenic eutrophication and subsequent deep-water oxygen deficiency have altered the species composition of zooplankton communities, often towards a state less favorable to their grazers, clupeid fish. The complex interactions that (c) 24 Temperature (°C) 22 20 18 16 14 12 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 (d) Nitrate (μmol/dm 3 ) 6.0 5.0 4.0 3.0 2.0 R 2 = 0.5158 r = 0.7182 p < 0.001 1.0 0.0 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 47
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 50 and 51: iomass can be used to assess enviro
Page 52 and 53: Average number of species 20 15 10
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
Page 104 and 105:
NOx emissions and sewage Macrophyte
Page 106 and 107:
Communication links There are a num
Page 108 and 109:
Figure 6.3.3. Left: concrete-stone
Page 110 and 111:
ecommendations would contribute to
Page 112 and 113:
Tourist fishing 110 cial fishery fo
Page 114 and 115:
112 Figure 6.5.1. Integrated classi
Page 116 and 117:
can be considered as having been a
Page 118 and 119:
Although no direct, dramatic mass m
Page 120 and 121:
Bearing in mind the complex hydrogr
Page 122 and 123:
Box 6.7.1. Invasion status of the B
Page 124 and 125:
Table 6.7.1. Examples of ecological
Page 126 and 127:
munities that formerly consisted of
Page 128 and 129:
6.8.2 Activities generating noise i
Page 130 and 131:
128 and fish in the Baltic Sea area
Page 132 and 133:
800 700 600 bag of the two German B
Page 134 and 135:
Fish swarm on kelp (Laminaria sp.)
Page 136 and 137:
tion of ice cover, either through r
Page 138 and 139:
7 STATUS OF THE NETWORK OF MARINE A
Page 140 and 141:
Box 7.1. Natura 2000 network of pro
Page 142 and 143:
25 20 on how the criteria on ecolog
Page 144 and 145:
estrial, nearshore marine, and offs
Page 146 and 147:
144 >30 psu 18-30 psu 11-18 psu 7.5
Page 148 and 149:
Permission needed Restricted Forbid
Page 150 and 151:
Figure 7.8.a. MARXAN ’best portfo
Page 152 and 153:
The BSPA network is relatively well
Page 154 and 155:
Mammals. Among the mammals, the pop
Page 156 and 157:
154 taxonomic groups and communitie
Page 158 and 159:
156 provided by an ecosystem. Use o
Page 160 and 161:
158 Reduction of human pressures Wh
Page 162 and 163:
160 fishing on fish population dyna
Page 164 and 165:
162 Baden, S., Boström, C. (2001).
Page 166 and 167:
164 Season 2001-2002. Acta Zoologic
Page 168 and 169:
166 Gasiūnaitė, Z.R., Cardoso, A.
Page 170 and 171:
168 HELCOM & OSPAR (2003): Joint HE
Page 172 and 173:
170 ICES (2008c). Report of the Bal
Page 174 and 175:
172 area: density-dependent effects
Page 176 and 177:
174 Noer, H., Clausager, I., Asferg
Page 178 and 179:
176 Scheffer M., Carpenter S.R., Fo
Page 180 and 181:
178 by passive acoustic monitoring.
Page 182 and 183:
180 Warzaw, Poland Vilhunen, Jarmo,
Page 184 and 185:
182 6.7 Alien speices Authors: Lepp
Page 186 and 187:
ANNEX III: CONSERVATION STATUS OF T
Page 188 and 189:
ANNEX IV: HABITAT OR SPECIES DISTRI
Page 190:
ANNEX V: STATUS OF BREEDING AND WIN
show all

BSEP116B Biodiversity in the Baltic Sea - Helcom

Create successful ePaper yourself

Delete template?

Save as template?