Zgryźliwość kojarzy mi się z radością, która źle skończyła.
Poznań
Bogdan Jackowiak
Fig. 1
Town hall of Poznań
Abstract
Poznań is a typical large central European city in terms of its spatial structure
and intensive urbanisation. It has been subject to systematic botanical research for
almost 200 years, consequently it is possible to follow changes in the city’s flora over
a long period. The floristic studies indicate, amongst other things, that cities are areas
where strong species selection takes place. The loss of indigenous elements and the
spread of cosmopolitan plants lead to the uniformity of urban flora, at least within the
Bogdan Jackowiak (
*
)
Department of Plant Taxonomy, Faculty of Biology, Adam Mickiewicz University,
Umultowska 89, 61-614 Poznań, Poland
e-mail: bogjack@amu.edu.pl
J.G. Kelcey and N. Müller (eds.),
Plants and Habitats of European Cities
,
DOI 10.1007/978-0-387-89684-7_11, © Springer Science+Business Media, LLC 2011
363
364
B. Jackowiak
same biogeographical region. Degradation of habitats and direct human impact on
isolated populations of plants are not the only causes of species extinction, a crucial
role is played by invasive alien species. Generally, there is weak competitiveness
in urban environment, which promotes the establishment and spread of invasive
species. As a consequence the city is a source of expansive species. This is evidenced
in the history of colonisation of several alien species that occur on a massive scale
in the Wielkopolski National Park, which is close to the city. Knowledge of the
mechanisms of changes in urban flora and its role in modifying the vegetation
cover outside the administrative boundaries of a city suggests that it is advisable to
undertake specific actions in terms of environmental management.
Natural Environment of the City
Poznań is located at the geographical co-ordinates 16°48′ to 17°06′ North longi-
tude and 52°18′ to 52°29′ east latitude. The city, which is within the Wielkopolska
Lakeland macro-region, contains three meso-regions: the Poznań Lakeland
(western part), the Gniezno Lakeland (the eastern districts) and the Poznań Ravine
of the Warta River, which is a narrow strip that divides the other two. The natural
relief was formed in the Poznań phase of the Baltic glaciation. It is lowland
that lies approximately 80–100 m a.s.l. Most of the city occupies flat moraine
upland (Fig.
2
).
Since the earliest times in its development, the axis of Poznań has been the
ravine of the Warta River, which connects two wide pro-glacial stream valleys, the
Warta-Odra and Toruń-Eberswald. The natural landscape of the town was signifi-
cantly influenced by glacial lakes that flowed into the Warta River.
The hydrographic network of the town includes two lakes: Lake Kierskie
(309.2 ha) and Lake Strzeszyńskie (32 ha). Additionally, Lake Swarzędzkie lies
adjacent to the north-western boundary of the city. Reservoirs also play an important
role, for example, the Malta reservoir (ca. 70 ha) in the valley of the Cybina river and
Rusałka (ca. 50 ha) located in the valley of the Bogdanka River. In addition, there is
an extensive complex of clay pits in the valley of the Strumień Junikowski (Fig.
2
).
About half of Poznań is situated mainly on Quaternary sands and gravels. The
lower moraine clay accounts for 34%, upper moraine clay for 14% and loams for
only 1%. These deposits overlie mottled clays of the Pliocene, which only outcrop
occasionally in the city (Bartkowski
1981
). The predominant soils are podsols,
pseudo-podsols and lixiviated brown earths which cover the moraine upland and
the outwash plain. Only a small area of the town is occupied by phaeozems and
degraded phaeozems. Alluvial soils and low peaty soils occur in the valleys of the
Warta River and the smaller rivers and streams.
In terms of the climatic regionalisation of Poland, Poznań belongs to the “middle
district”, which comprises the eastern part of the Wielkopolska region and the western
part of Mazovia. The significant feature of this district is that it has the lowest
annual rainfall in Poland, <550 mm (Fig.
3
). Poznań is situated in the zone of the
so-called western circulation with the influence of the continental climate.
Poznań
365
Fig. 2
Geomorphological and hydrographical layout of Poznań (After Bartkowski
1981
). Key: (l)
the bottom of the valley, (2) glacial troughs with a strongly levelled bottom, (3) glacial troughs
weakly transformed, (4) small valleys on the moraine upland, (5) non-flooded terraces, (6) the flat
moraine upland, (7) moraine undulating upland, (8) hilly moraine upland, (9) sandur, (10) kame
hill, (11) esker ridge
Fig. 3
Gaussen-Walter
climatic diagram for Poznań
(data from 1950–1980)
(After Jackowiak
1993
)
The dominant type of natural vegetation is the
Galio silvatici-Carpinetum
forest
(Bartkowski
1981
)
,
which formerly occupied the vast areas of the moraine upland
and non-inundated terraces of the Warta River valley (Fig.
4
).
A smaller area was covered by
Leucobryo-Pinetum
forest (on poor habitats of
the outwash plain) and
Pino-Quercetum
forest, which occurred on the podsol soils
366
B. Jackowiak
Fig. 4
Potential natural vegetation (After Wojterski et al.
1981
). Key: (1)
Fraxinus-Alnus
riparian
forest
(Circaeo-Alnetum),
(2)
Salix-Populus
wood
(Salicetum albae-fragilis),
(3)
Fraxinus
-
Ulmus
riparian forest
(Fraxino-Ulmetum),
(4)
Quercus
and
Carpinus
forest, a poor form
(Galio silvatici-
Carpinetum),
(5)
Quercus
and
Carpinus
forest, a rich form
(Galio silvatici-Carpinetum),
(6) mixed
coniferous forest, a dry form
(Pino-Quercetum),
(7) fresh coniferous forest
(Leucobryo-Pinetum),
(8) xerothermic
Quercus
wood
(Potentillo albae-Quercetum),
(9) watercourses and reservoirs
in the lowlands. The complex of Carr forests was associated with the valleys of the
Warta River and its many tributaries and streams. In the larger valleys, there were
mainly three riparian forests types (
Fraxino-Ulmetum, Salicetum albae-fragilis
and
Salici-Populetum
) while in the smaller ones the forests were primarily of the
Circaeo-Alnetum
type. As an addition to the forest communities, there were scat-
tered
Carici elongatae-Alnetum
and
Potentillo albae- Quercetum
forests. In the
geobotanical division of Poland, Poznań belongs to the Poznań-Gniezno district,
included in the Wielkopolska-Kujawy Lowland (Szafer
1972
); however, it is
outside the natural range of such important forest-forming trees as
Fagus sylvatica,
Picea abies, Abies alba, Taxus baccata
and
Larix polonica.
Poznań
367
Historical Development of the City
Poznań is one of the oldest and largest towns in Poland. Currently it is the
economic and cultural centre of Wielkopolska, a region located in western Poland.
At least four important periods of its history can be identified (Jackowiak
1990
).
AD 1253
The area of the present town was inhabited as early as the Middle Paleolithic Age
(10,000–7,000 years BC) when agriculture started to develop (Gąsiorowski
1973
).
The early form of the town was a fortified settlement, which was probably estab-
lished at the turn of the eighth and ninth century AD on Ostrów Tumski – a sandy
island formed at the confluence of Warta and Cybina rivers (Fig.
5
).
Fig. 5
Spatial development of Poznań (After Jackowiak
1993
). Key: (1) the borough of Ostrów
Tumski at the beginning of the eleventh century, (2) left-bank town (founded in 1253), (3–7) areas
incorporated into the city before: 1896 (3), 1900 (4), 1939 (5), 1945 (6), l980 (7)
zanotowane.pl doc.pisz.pl pdf.pisz.pl hannaeva.xlx.pl
Bogdan Jackowiak
Fig. 1
Town hall of Poznań
Abstract
Poznań is a typical large central European city in terms of its spatial structure
and intensive urbanisation. It has been subject to systematic botanical research for
almost 200 years, consequently it is possible to follow changes in the city’s flora over
a long period. The floristic studies indicate, amongst other things, that cities are areas
where strong species selection takes place. The loss of indigenous elements and the
spread of cosmopolitan plants lead to the uniformity of urban flora, at least within the
Bogdan Jackowiak (
*
)
Department of Plant Taxonomy, Faculty of Biology, Adam Mickiewicz University,
Umultowska 89, 61-614 Poznań, Poland
e-mail: bogjack@amu.edu.pl
J.G. Kelcey and N. Müller (eds.),
Plants and Habitats of European Cities
,
DOI 10.1007/978-0-387-89684-7_11, © Springer Science+Business Media, LLC 2011
363
364
B. Jackowiak
same biogeographical region. Degradation of habitats and direct human impact on
isolated populations of plants are not the only causes of species extinction, a crucial
role is played by invasive alien species. Generally, there is weak competitiveness
in urban environment, which promotes the establishment and spread of invasive
species. As a consequence the city is a source of expansive species. This is evidenced
in the history of colonisation of several alien species that occur on a massive scale
in the Wielkopolski National Park, which is close to the city. Knowledge of the
mechanisms of changes in urban flora and its role in modifying the vegetation
cover outside the administrative boundaries of a city suggests that it is advisable to
undertake specific actions in terms of environmental management.
Natural Environment of the City
Poznań is located at the geographical co-ordinates 16°48′ to 17°06′ North longi-
tude and 52°18′ to 52°29′ east latitude. The city, which is within the Wielkopolska
Lakeland macro-region, contains three meso-regions: the Poznań Lakeland
(western part), the Gniezno Lakeland (the eastern districts) and the Poznań Ravine
of the Warta River, which is a narrow strip that divides the other two. The natural
relief was formed in the Poznań phase of the Baltic glaciation. It is lowland
that lies approximately 80–100 m a.s.l. Most of the city occupies flat moraine
upland (Fig.
2
).
Since the earliest times in its development, the axis of Poznań has been the
ravine of the Warta River, which connects two wide pro-glacial stream valleys, the
Warta-Odra and Toruń-Eberswald. The natural landscape of the town was signifi-
cantly influenced by glacial lakes that flowed into the Warta River.
The hydrographic network of the town includes two lakes: Lake Kierskie
(309.2 ha) and Lake Strzeszyńskie (32 ha). Additionally, Lake Swarzędzkie lies
adjacent to the north-western boundary of the city. Reservoirs also play an important
role, for example, the Malta reservoir (ca. 70 ha) in the valley of the Cybina river and
Rusałka (ca. 50 ha) located in the valley of the Bogdanka River. In addition, there is
an extensive complex of clay pits in the valley of the Strumień Junikowski (Fig.
2
).
About half of Poznań is situated mainly on Quaternary sands and gravels. The
lower moraine clay accounts for 34%, upper moraine clay for 14% and loams for
only 1%. These deposits overlie mottled clays of the Pliocene, which only outcrop
occasionally in the city (Bartkowski
1981
). The predominant soils are podsols,
pseudo-podsols and lixiviated brown earths which cover the moraine upland and
the outwash plain. Only a small area of the town is occupied by phaeozems and
degraded phaeozems. Alluvial soils and low peaty soils occur in the valleys of the
Warta River and the smaller rivers and streams.
In terms of the climatic regionalisation of Poland, Poznań belongs to the “middle
district”, which comprises the eastern part of the Wielkopolska region and the western
part of Mazovia. The significant feature of this district is that it has the lowest
annual rainfall in Poland, <550 mm (Fig.
3
). Poznań is situated in the zone of the
so-called western circulation with the influence of the continental climate.
Poznań
365
Fig. 2
Geomorphological and hydrographical layout of Poznań (After Bartkowski
1981
). Key: (l)
the bottom of the valley, (2) glacial troughs with a strongly levelled bottom, (3) glacial troughs
weakly transformed, (4) small valleys on the moraine upland, (5) non-flooded terraces, (6) the flat
moraine upland, (7) moraine undulating upland, (8) hilly moraine upland, (9) sandur, (10) kame
hill, (11) esker ridge
Fig. 3
Gaussen-Walter
climatic diagram for Poznań
(data from 1950–1980)
(After Jackowiak
1993
)
The dominant type of natural vegetation is the
Galio silvatici-Carpinetum
forest
(Bartkowski
1981
)
,
which formerly occupied the vast areas of the moraine upland
and non-inundated terraces of the Warta River valley (Fig.
4
).
A smaller area was covered by
Leucobryo-Pinetum
forest (on poor habitats of
the outwash plain) and
Pino-Quercetum
forest, which occurred on the podsol soils
366
B. Jackowiak
Fig. 4
Potential natural vegetation (After Wojterski et al.
1981
). Key: (1)
Fraxinus-Alnus
riparian
forest
(Circaeo-Alnetum),
(2)
Salix-Populus
wood
(Salicetum albae-fragilis),
(3)
Fraxinus
-
Ulmus
riparian forest
(Fraxino-Ulmetum),
(4)
Quercus
and
Carpinus
forest, a poor form
(Galio silvatici-
Carpinetum),
(5)
Quercus
and
Carpinus
forest, a rich form
(Galio silvatici-Carpinetum),
(6) mixed
coniferous forest, a dry form
(Pino-Quercetum),
(7) fresh coniferous forest
(Leucobryo-Pinetum),
(8) xerothermic
Quercus
wood
(Potentillo albae-Quercetum),
(9) watercourses and reservoirs
in the lowlands. The complex of Carr forests was associated with the valleys of the
Warta River and its many tributaries and streams. In the larger valleys, there were
mainly three riparian forests types (
Fraxino-Ulmetum, Salicetum albae-fragilis
and
Salici-Populetum
) while in the smaller ones the forests were primarily of the
Circaeo-Alnetum
type. As an addition to the forest communities, there were scat-
tered
Carici elongatae-Alnetum
and
Potentillo albae- Quercetum
forests. In the
geobotanical division of Poland, Poznań belongs to the Poznań-Gniezno district,
included in the Wielkopolska-Kujawy Lowland (Szafer
1972
); however, it is
outside the natural range of such important forest-forming trees as
Fagus sylvatica,
Picea abies, Abies alba, Taxus baccata
and
Larix polonica.
Poznań
367
Historical Development of the City
Poznań is one of the oldest and largest towns in Poland. Currently it is the
economic and cultural centre of Wielkopolska, a region located in western Poland.
At least four important periods of its history can be identified (Jackowiak
1990
).
AD 1253
The area of the present town was inhabited as early as the Middle Paleolithic Age
(10,000–7,000 years BC) when agriculture started to develop (Gąsiorowski
1973
).
The early form of the town was a fortified settlement, which was probably estab-
lished at the turn of the eighth and ninth century AD on Ostrów Tumski – a sandy
island formed at the confluence of Warta and Cybina rivers (Fig.
5
).
Fig. 5
Spatial development of Poznań (After Jackowiak
1993
). Key: (1) the borough of Ostrów
Tumski at the beginning of the eleventh century, (2) left-bank town (founded in 1253), (3–7) areas
incorporated into the city before: 1896 (3), 1900 (4), 1939 (5), 1945 (6), l980 (7)