ESS 8.2 Urban Ecosystems

Urban ecosystem

An ecosystem in an urban area made up of biotic (living) and abiotic (non-living) components, heavily shaped by human activity

Biotic components of urban ecosystems

Plants, animals, humans, microorganisms (decomposers)

Abiotic components of urban ecosystems

Soil, water, air, climate, topography

Urban heat island effect

Cities absorb and retain more heat than rural areas due to concrete and asphalt; raises local temperatures

Urban area

Built-up region with high population density, dense infrastructure, and concentrated economic and social activity

Urban vs rural

Urban = high density, modern infrastructure, industry/services; Rural = low density, basic infrastructure, agriculture

Urban system

Interconnected stores (buildings, population, water reservoirs) and flows (energy, transport, water, waste) that sustain city life

Urbanisation

The population shift from rural to urban areas; driven by push (rural disadvantages) and pull (urban opportunities) factors

Push factors for urbanisation

Lack of jobs, poor healthcare/education, natural disasters, conflict, climate change

Pull factors for urbanisation

Better jobs, improved infrastructure, quality healthcare/education, modern lifestyle

Rural-urban migration

Movement of people from rural to urban areas in search of better opportunities; mostly internal migration

Suburbanisation

Movement of people from dense city centres to lower-density suburban areas on the outskirts; also called urban sprawl

Causes of suburbanisation

Affordable housing, desire for space, improved transport, car ownership, remote work, decentralisation of jobs

Deurbanisation

Movement of people from cities back to rural areas; caused by high living costs, remote work, ageing populations

Environmental impacts of urban expansion

Loss of agricultural land and biodiversity, water pollution, altered river flows, increased air pollution, urban heat island

Eutrophication (urban)

Fertiliser and chemical runoff from urban/suburban areas → algal blooms → oxygen depletion → aquatic die-off

Urban planning

Process of designing and managing land use in cities to meet population needs while promoting sustainable development

Land use zoning

Dividing urban land into residential, commercial, industrial, and mixed-use zones for organised development

Compact city

Dense, mixed-use urban design that reduces sprawl, preserves nature, and minimises car dependency

Transit-oriented development (TOD)

High-density development around public transport hubs to reduce traffic and encourage public transit use

Smart city

Uses technology and data to optimise urban systems like waste, traffic, and energy

Green urbanism

Urban design prioritising green spaces, energy efficiency, water conservation, and low-carbon technologies

Ecological urban planning

Designing cities as living systems; integrates nature with the built environment to enhance sustainability, biodiversity, and resilience

Urban ecology

Designing urban spaces with green areas, wildlife habitats, water features, and biodiversity in mind

Urban farming

Growing food within cities; includes beekeeping, community gardens, vertical farms, aquaculture; supports food security and biodiversity

Biophilic design

Incorporating nature into buildings — green walls, roofs, water features, natural light; improves human wellbeing and biodiversity

Resilience planning

Preparing cities for climate change, floods, and resource scarcity; e.g. vertical farming, flood-resistant buildings, fail-safe power grids

Regenerative architecture

Buildings that actively improve the environment — air-scrubbing surfaces, rainwater harvesting, solar panels, biogas; goes beyond sustainability

High Line, New York

Elevated park on a former railway; native plants; habitat for birds and insects; promotes biodiversity and recreation

Bosco Verticale, Milan

Two residential towers covered in 9,000+ trees and 13,000 plants; reduces heat island, improves air quality, absorbs CO₂

The Edge, Amsterdam

Office building with green roof, solar panels, rainwater harvesting, and energy-efficient systems; one of the world's most sustainable buildings

Cerdà Plan, Barcelona (1860)

Grid layout with wide streets, mixed-use development, and green spaces; early model of sustainable urban planning

Copenhagen

Extensive cycling infrastructure and public transport; significantly reduced car dependency

Detroit urban farms

Vacant lots converted to farms; provides fresh food, reduces food deserts, promotes environmental education

Singapore vertical farming

Sky Greens vertical farm; grows vegetables in stacked layers; addresses food security and reduces transport emissions