BSEP116B Biodiversity in the Baltic Sea - Helcom

(2003–2007), the number of breeding pairs was
between 50 and 60. The total Baltic population
was estimated at about 1 110–1 360 bp in 2002
(Thorup 2006), and not more than 700–800 bp in
2007 (Table 4.3.2).
the dunlin population. It is very likely that the rapid
decline of the dunlin in the Baltic Sea area is not a
consequence of habitat loss, but rather is driven by
large-scale factors such as climate change.
Habitat loss by drainage and land reclamation
have been considered as reasons for the population
decline in the past (Holz 1986). An increase in
predators and management problems for coastal
meadows seem to be other important fac tors
affecting the population. However, the dramatic
long-term decline from probably far more than
100 000 bp at the beginning of the 20th century
to less than 1 000 one hundred years later cannot
be explained only by habitat loss and predation.
Even in areas where suitable habitats have been
conserved and properly managed, the dunlin is
declining or has even disappeared. In Germany,
Denmark, Sweden and Lithuania, restoration
projects for breeding habitats of dunlin, ruff
(Philomachus pugnax) and other waders have
recently been implemented or are currently under
implementation. Specific programmes and projects
aiming to restore breeding habitats are also being
implemented in Finland and Poland. However,
these efforts do not yet show positive effects for
Sandwich tern (Sterna sandvicensis)
At the beginning of the 20th century, the Baltic
Sea was not part of the breeding range of the
sandwich tern. However, during the first half of the
century, the species expanded its range gradually
to the northeast, colonizing Skåne in 1911 and the
Swedish east coast during the 1930s. Starting with
the formation of a colony on the island Heuwiese
(Germany, Mecklenburg-Western Pomerania) in
1957, the sandwich tern continued its range expansion
to the southern coasts of the western and
central Baltic, becoming a permanent breeding bird
first at the German Baltic coast and shortly after, in
1962, in Estonia. It bred in Poland from 1977–1991
and again since 2006.
The range expansion and positive population
development in the Baltic Sea area during the
1950s/1960s occurred at a time when the North
Sea population declined dramatically. This indicates
that the colonization of the Baltic Sea could have
Table 4.3.2. The dunlin population in the Baltic littoral countries.
Country
Current breeding
Remarks
Source of information
population
Denmark 350 2002 Thorup (2003)
Sweden 85–120 2006 M. Larsson, pers. com.
Estonia 200–250 2007 Elts et al. (2008)
Finland 50–60 2003–2007 Finnish working group on
Southern Dunlin, Ministry
of Environment Finland
Germany, Mecklenburg-
Western Pomerania
Germany,
Schleswig-Holstein
9 2007 Working Group for Coastal
Bird Protection Meckl.- W.
Pomerania
0 at the west coast (North Sea) W. Knief, pers. comm.
probably still 0–5 bp
Latvia 1–5 1989–1997 Thorup (2006)
Lithuania 25–30 1996–1998 Thorup (2006)
Poland 0–5 no breeding record in 2007,
but observation of some
individuals during the
breeding season
Sikora et al. (2008)
Russia,
St. Petersburg Region
Russia, Kaliningrad
Region
Total, Baltic Sea littoral
countries
1–5 sporadic breeder at the Gulf
of Finland, one nest found
in 2008
2 2001, no breeding record
after 2001
700–800
V. Fedorov, pers. comm.
Grishanov & Lykov (2008)
79