The Environment in the City 135
Furthermore, the existence in the city of natural formations such as
steep rocks, lakes, etc. or even the presence of artificial formations
that can play an ecological role (e.g. birds nesting in high buildings)
contribute to the variety of the urban ecosystem.
• Abundance of food and water. All sorts of waste and by-products of
human activities, stored foodstuffs, etc. are the most important sources
of food for many animals, which in turn serve as food for carnivores.
One particular and rather important source of food for certain animals
in the city and the surrounding area is the dead bodies of animals killed
on roads. Water is usually available in cities in sufficient quantities for
most wild species. The existence of a high water table constitutes an
additional favourable factor for many species of plants.
• Less human-induced disturbance. Wildlife thrives better in cities
where people are familiar with nature, and when people tolerate
and/or assist it. A positive role is also played by the existence of protected spaces such as parks or other (archaeological sites, cemeteries,
tion or the presence of waste in general in urban areas are not substantial obstacles to the development of wildlife in the city, although
they may injure many organisms. However, the structure and functioning of the city create other negative factors, such as motorways,
construction works, the use of toxic or poisonous substances, etc.
Automobile accidents are the main cause of death for many species of
animals. Thus an urban ecosystem’s state also relates to the amount
of dangers in each city, as well as with the ways the animals have of
protecting themselves.
The status of an urban ecosystem, like that of every natural ecosystem,
may be assessed on the basis of fundamental ecological criteria, such as:
• The functioning of trophic levels, and the presence of higher carnivores in particular
• The natural regeneration of vegetation, the normal reproduction of
animals, the existence of stages of ecological succession in ecosystems
• The variety of biological species and the stability of populations
• The reduced presence of foreign species of the flora and fauna
Urban ecosystems are a reality in all cities and the areas surrounding
them. Wildlife establishes itself in public green spaces and private gardens,
as well as various other spots in built-up areas. Urban ecosystems develop
to some extent spontaneously in the city, but they can be “fabricated” to a
much greater extent. The transformation of the natural or rural environment into an urban environment has important impacts on the functioning
of ecosystems. Some of these impacts, however, may be restricted up to a
Furthermore, the existence in the city of natural formations such as
steep rocks, lakes, etc. or even the presence of artificial formations
that can play an ecological role (e.g. birds nesting in high buildings)
contribute to the variety of the urban ecosystem.
• Abundance of food and water. All sorts of waste and by-products of
human activities, stored foodstuffs, etc. are the most important sources
of food for many animals, which in turn serve as food for carnivores.
One particular and rather important source of food for certain animals
in the city and the surrounding area is the dead bodies of animals killed
on roads. Water is usually available in cities in sufficient quantities for
most wild species. The existence of a high water table constitutes an
additional favourable factor for many species of plants.
• Less human-induced disturbance. Wildlife thrives better in cities
where people are familiar with nature, and when people tolerate
and/or assist it. A positive role is also played by the existence of protected spaces such as parks or other (archaeological sites, cemeteries,
tion or the presence of waste in general in urban areas are not substantial obstacles to the development of wildlife in the city, although
they may injure many organisms. However, the structure and functioning of the city create other negative factors, such as motorways,
construction works, the use of toxic or poisonous substances, etc.
Automobile accidents are the main cause of death for many species of
animals. Thus an urban ecosystem’s state also relates to the amount
of dangers in each city, as well as with the ways the animals have of
protecting themselves.
The status of an urban ecosystem, like that of every natural ecosystem,
may be assessed on the basis of fundamental ecological criteria, such as:
• The functioning of trophic levels, and the presence of higher carnivores in particular
• The natural regeneration of vegetation, the normal reproduction of
animals, the existence of stages of ecological succession in ecosystems
• The variety of biological species and the stability of populations
• The reduced presence of foreign species of the flora and fauna
Urban ecosystems are a reality in all cities and the areas surrounding
them. Wildlife establishes itself in public green spaces and private gardens,
as well as various other spots in built-up areas. Urban ecosystems develop
to some extent spontaneously in the city, but they can be “fabricated” to a
much greater extent. The transformation of the natural or rural environment into an urban environment has important impacts on the functioning
of ecosystems. Some of these impacts, however, may be restricted up to a