Temporal patterns

Beginning in the Far East over 2000 years ago the discussion in this chapter charts the movement of species found in contemporary urban environments around the globe. A city is dependent on trade for the resources required by the inhabitants to live and work. Some items of trade are plants and animals, and over time, many species have been introduced intentionally, and many others unintentionally (perhaps as a result of hitching a lift in or on items being traded between countries and continents) to become part of the urban flora and fauna. All the time that such global dispersal has been occurring, some floral and faunal species originally present in an urban area have become locally extinct. These processes of invasion and extinction are controlled by filters and process, and there are certain traits, the possession of which is seemingly beneficial to organisms in urban environments.