original ecosystem, and the conditions of water, soil, air or climate (Walz and Stein
2014).
Even before the Neolithic period, some species may have followed human traces.
In the following millennia their numbers increased slowly (e.g. Di Castri 1989). In
the post-Columbian period, the pace of human-induced spreading of species
increased (Kowarik 2003; Meyerson and Mooney 2007; Seebens et al. 2018).
Since most urban areas have existed for less than 100–200 years, it follows that a
large number, both of species and specimens, have only recently been confronted
with urban habitats (e.g. Hulme 2009; Humphries et al. 2019). The question arises
how quickly and widely flora, vegetation and fauna have been able to adapt to the
new circumstances. This question is important, as cities might play a major role in
contemporary evolution by accelerating phenotypic changes in wildlife, including
animals, plants, fungi, and other organisms (Alberti et al. 2017; Rivkin et al. 2019).
The flora and fauna of a region or city is represented by taxonomic lists of the
plant and animal species that occur in that area. Preliminary lists of plants and
animals date back at least to the time of the Greeks and are from Theophrastus and
Aristotle respectively. It can be assumed that prehistoric hunters and gatherers
already knew much about species and the ecological conditions in their surroundings. The first extensive floras of urban areas emerged in the course of the seventeenth and eighteenth centuries, such as those of London, Paris and Berlin (Sukopp
2002). Wildlife knowledge and technological development enhanced and intensified
human interaction with nature (Costanza et al. 2007).
The classification of European synanthropic vegetation distinguishes 10 groups
of vegetation classes dominated by higher vascular plants, and in addition, a series of
assemblages that consist of dominating bryophytes and lichens (Mucina et al. 2016).
Vegetation classes typical for urban areas include the class of subcosmopolitan
therophyte-rich dwarf-herb vegetation of trampled habitats (Polygono-Poetea
annuae) and the class of anthropogenic vegetation in human-disturbed habitats in
the subarctic and Arctic zones of Russia, Siberia and North America (MatricarioPoetea arcticae). Other anthropogenic vegetation classes include Perennial (sub)xerophilous ruderal vegetation of the temperate and sub-mediterranean regions of
Europe (Artemisietea); tall-herb semi-natural perennial vegetation on disturbed
forest edges, nutrient-rich riparian fringes and in forest clearings in the temperate
and boreal zones of Eurasia (Epilobietea angustifolii); and annual weed segetal
vegetation of arable crops, gardens and vineyards in the cool-temperate and boreal
zones of Eurasia (Papaveretea rhoeadis). Also at lower rank (alliance, association)
there are a number of plant communities which have their centre of gravity in urban
areas. This also applies to a number of bryophyte and lichen assemblies. In addition,
vegetation units which are assigned to other vegetation groups can also populate
typical biotopes of urban origin. There are, for instance, a number of species which
frequently grow on walls. This class is described as thermophilous chasmophytic
vegetation of walls of the Mediterranean and the winter-mild atlantic to subcontinental regions of temperate Europe, Middle East and North Africa (CymbalarioParietarietea). Such urban wall vegetation comes in part from natural habitats of rock
crevices and screes. Where construction is taking place and parts of the soil surface
432
J. Jansen and C. Hobohm
2014).
Even before the Neolithic period, some species may have followed human traces.
In the following millennia their numbers increased slowly (e.g. Di Castri 1989). In
the post-Columbian period, the pace of human-induced spreading of species
increased (Kowarik 2003; Meyerson and Mooney 2007; Seebens et al. 2018).
Since most urban areas have existed for less than 100–200 years, it follows that a
large number, both of species and specimens, have only recently been confronted
with urban habitats (e.g. Hulme 2009; Humphries et al. 2019). The question arises
how quickly and widely flora, vegetation and fauna have been able to adapt to the
new circumstances. This question is important, as cities might play a major role in
contemporary evolution by accelerating phenotypic changes in wildlife, including
animals, plants, fungi, and other organisms (Alberti et al. 2017; Rivkin et al. 2019).
The flora and fauna of a region or city is represented by taxonomic lists of the
plant and animal species that occur in that area. Preliminary lists of plants and
animals date back at least to the time of the Greeks and are from Theophrastus and
Aristotle respectively. It can be assumed that prehistoric hunters and gatherers
already knew much about species and the ecological conditions in their surroundings. The first extensive floras of urban areas emerged in the course of the seventeenth and eighteenth centuries, such as those of London, Paris and Berlin (Sukopp
2002). Wildlife knowledge and technological development enhanced and intensified
human interaction with nature (Costanza et al. 2007).
The classification of European synanthropic vegetation distinguishes 10 groups
of vegetation classes dominated by higher vascular plants, and in addition, a series of
assemblages that consist of dominating bryophytes and lichens (Mucina et al. 2016).
Vegetation classes typical for urban areas include the class of subcosmopolitan
therophyte-rich dwarf-herb vegetation of trampled habitats (Polygono-Poetea
annuae) and the class of anthropogenic vegetation in human-disturbed habitats in
the subarctic and Arctic zones of Russia, Siberia and North America (MatricarioPoetea arcticae). Other anthropogenic vegetation classes include Perennial (sub)xerophilous ruderal vegetation of the temperate and sub-mediterranean regions of
Europe (Artemisietea); tall-herb semi-natural perennial vegetation on disturbed
forest edges, nutrient-rich riparian fringes and in forest clearings in the temperate
and boreal zones of Eurasia (Epilobietea angustifolii); and annual weed segetal
vegetation of arable crops, gardens and vineyards in the cool-temperate and boreal
zones of Eurasia (Papaveretea rhoeadis). Also at lower rank (alliance, association)
there are a number of plant communities which have their centre of gravity in urban
areas. This also applies to a number of bryophyte and lichen assemblies. In addition,
vegetation units which are assigned to other vegetation groups can also populate
typical biotopes of urban origin. There are, for instance, a number of species which
frequently grow on walls. This class is described as thermophilous chasmophytic
vegetation of walls of the Mediterranean and the winter-mild atlantic to subcontinental regions of temperate Europe, Middle East and North Africa (CymbalarioParietarietea). Such urban wall vegetation comes in part from natural habitats of rock
crevices and screes. Where construction is taking place and parts of the soil surface
432
J. Jansen and C. Hobohm