Ecosystems - Effects of urbanisation on ecosystems

How urbanisation creates ecosystems

• In between train lines 

 - No human activity
 - 2.5 million trees are around tracks in the UK

• Industrial sites

 - e.g. Battersea Power station
 - Peregrine falcons, black redstarts, bats and linnets can be found

• Urban gardens

 - 20% of London is gardens
 - Encourages more animals like bees

• Allotments

 - e.g. Southland road, Bromley
 - growing fruit and veg attracts toads, rabbits and hedgehogs

• Urban forests

 - e.g. Petts Wood, London
 - conservation work allows more species to be protected


Urban niches

Within an ecosystem all living organisms occupy a niche. Their niche is the place where they live (their habitat) and how they interact with other species (their role).

Human use means urban ecosystems are subject to more change and at a faster pace than other ecosystems.
Change such as drainage, composition of surface material, introduction of new species.

An example is the Kestrel, which likes to live in cities like London due to high rise buildings.

Colonisation of wasteland

The colonisation of most wastelands is a lithosphere type succession.

1. Lichens and mosses grow in cracks with moisture and nutrients.
2. A thin layer of soil is produced and herbs start to grow.
3. As the soil layer gets thicker taller grasses grow.
4. Next are small trees and shrubs like Buddleia.
5. Over many years this is replaced by scrub woodland.


Routeways

• In London, plane trees are commonly planted by the sides of roads as they are well adapted to urban environments.
• By roads, nitrogen rich exhaust fumes boost the growth of some wild flowers.
• Railways enable species to move around cities and through the country.
• Soil verges by motorways make a good seedbed for seeding due to chemicals from agricultural run off.
• Canals allows aquatic plants like the Yellow flag iris to spread along the canal system.
• The M4 corridor is home to Kestrels as they scavenge for road kill.
• Along train lines, tracks are fenced off so there is little human interference.
• Canals attract water loving insects like dragonflies.

Invasive species

An invasive species is a plant or an animal not native to an area.

e.g. Oxford ragwort

• Brought to Oxford from Sicily for research in a botanic garden.
• Seeds are air bound so can travel in the air for long distances.
• This allowed them to get on trains and travel along the rail network.
• This then allowed it to spread across the country.