Urban Ecosystems
Urban Ecosystems:
We must consider some ecosystems in a stronger context of human intervention. Certain factors influence the structure of local ecosystems. For example:
· Impermeable surfaces interfere with geomorphological and hydrological processes.
· Use of energy gives out heat and pollution, which is stored and emitted.
· Buildings upset air flow.
Humans are a dominant component:
· Urban areas develop from interaction of agents and people.
· These produce patterns of development, land use and an infrastructure.
· Results in changes in ecosystem: inner city, suburbs, open parkland.
· Far less likely that stability is reached due to constant alterations – leads to introduction and removal of species.
· We redistribute organisms and alter the flow of energy and material.
Estimation of how urban ecosystems differ from rural surroundings:
. Atmospheric Pollution: 10-25 times more.
. Solar Radiation: 15-20% less.
. Mean Air Temperature: 0.5-1.5°C higher.
. Clear Day Air Temperature: 2-6°C higher.
. Winter Relative Humidity: 2% less.
. Summer Relative Humidity: 8-10% less.
. Total Rainfall: 5-10% more.
. Periods of Overcast Sky: 5-10% more.
We must consider some ecosystems in a stronger context of human intervention. Certain factors influence the structure of local ecosystems. For example:
· Impermeable surfaces interfere with geomorphological and hydrological processes.
· Use of energy gives out heat and pollution, which is stored and emitted.
· Buildings upset air flow.
Humans are a dominant component:
· Urban areas develop from interaction of agents and people.
· These produce patterns of development, land use and an infrastructure.
· Results in changes in ecosystem: inner city, suburbs, open parkland.
· Far less likely that stability is reached due to constant alterations – leads to introduction and removal of species.
· We redistribute organisms and alter the flow of energy and material.
Estimation of how urban ecosystems differ from rural surroundings:
. Atmospheric Pollution: 10-25 times more.
. Solar Radiation: 15-20% less.
. Mean Air Temperature: 0.5-1.5°C higher.
. Clear Day Air Temperature: 2-6°C higher.
. Winter Relative Humidity: 2% less.
. Summer Relative Humidity: 8-10% less.
. Total Rainfall: 5-10% more.
. Periods of Overcast Sky: 5-10% more.
Oxford Ragwort:
Imported from Sicily in 1700s to the Oxford Botanical Gardens. However, it escaped into the outdoor environment in 1720 and colonised in and around Oxford. One niche was alongside railway tracks. As the railway networks expanded throughout the 18th and 19th centuries, so did Oxford Ragwort.
Imported from Sicily in 1700s to the Oxford Botanical Gardens. However, it escaped into the outdoor environment in 1720 and colonised in and around Oxford. One niche was alongside railway tracks. As the railway networks expanded throughout the 18th and 19th centuries, so did Oxford Ragwort.