URBAN ECOLOGYThe study of the interconnected ecological

relationship between cities and nature.

● How have humans impacted the natural world?

● How can humans use the natural world for their benefit?

● How can the natural world benefit from humans?

Rebecca VeilleuxUrban Ecology Teacher-Lawrence High School

Definition of an Urban Environment:For our purposes, “urban” means an area of high population density where the dominant landform is built and where the majority of natural processes are mediated through, or influenced by human structures, social, economic, cultural and political activity.

Competing definitions of “urban” in published literature:

McIntyre, Knowles & Hope (2000) recognized that a multi-disciplinary approach could provide the most useful definition for Urban Ecology.

Characteristics include:

Population density, urban morphology, land use and cover, housing type and density, traffic patterns, vegetative cover, hydrology and biophysical

Pickett, S. T. A., M. L. Cadenasso, D. L. Childers, M. J. McDonnell, and W. Zhou. 2016. Evolution and future of urban ecological science: ecology in, of, and for the city. Ecosystem Health and Sustainability 2(7):e01229. doi:10.1002/ehs2.1229

Ecology “IN” vs. “Ecology OF”● Interdisciplinary Approach: Looks at the

unique nature of and discrete habitats within urban areas as distinct areas driven by the interplay of physical, economic and cultural forces.

● Examples: ○ soil composition,○ the adaptation of some species to the

built environment (Starlings and House Sparrows)

○ actively managed hydrology in many cities - all elements with no analog in “natural” habitats.

● Seeks to find analogs to natural habitats in urban communities in terrestrial and aquatic patches.

● Vacant lots become prairies.● Wooded parks become forests.● Downtown districts with tall

buildings become canyons.

Why are cities important to study?

Historically, cities dwell along the river because of the easy access to water

Hydrology• The hydrological cycle in

urban areas is dominated by human structures and activity.

• Impervious surfaces are prevalent in urban communities--stormwater needs to be actively managed by built structures.

Shawsheen River Outfall (2007)

Man-made structures dictate where water falls

The Old vs. The New

Average Household Income:

$14,819

Lawrence is one big flood plain...

This neighborhood: Average Household Income: $14,819

The Baltimore Study• An ongoing, long term study of urban

ecosystems.

• The most significant findings was the unique nature of urban soils.

• The study documented the direct impact of human social and economic activity on the most basic nature of urban ecosystems.

Urban Soils• Tend to contain high concentrations of carbon

due to fossil fuel combust.• Human activity has altered virtually every

aspect of soil functions and biotic activity. • Leaf litter decomposes more slowly, microbial

populations are different and exotic earthworms have been found in urban soils. – However, there is a higher concentration of

soluble Nitrogen that’s advantageous for plants.

Urban vs. “Natural” Soil Samples

“NATURAL”

● Nutrient-rich● Thick Organic (O) layer● “Balanced Microbial

Ecosystem”.

“Urban”

Urban Fill: ● Sediment, heavily

contaminated, soil material used for development.

● Usually contains waste products such as coal and wood ash.

● Heavily compacted

URBAN PATCHES Offer Unique Environments

• Urban habitats are often compared to “islands” – pockets of unique habitats isolated from neighboring “natural” habitats.

BIODIVERSITY?

Arrested Succession Arrested Succession refers to the human managed interruption of natural processes of succession.

• Normally, succession happens gradually-where different plant and tree species will gradually move into an area and become dominant.

• Constant, ongoing change is a normal condition. Nature is rarely “stable” or unchanging.

INVASIVE SPECIES• By maintaining a parkland in a fixed state, the natural

process of succession interrupted.

• This stasis can actually promote the presence of non-native invasive species and leave habitats vulnerable to disease and damage

Are Immigrants Really Threatening?• Non-native flora and fauna

are ubiquitous in the built environment.

• They are part of the biodiversity.

• Current research indicates that mixing native and non-native plants in a designed landscape increases pollinator habitat (which increases the biodiversity).

Community Gardens Throughout the City Contributes to Stormwater management and Biodiversity.

Spicket River Greenway

“[T]he values to which people cling most stubbornly under inappropriate conditions are those values that were previously the source of their greatest triumphs.” ― Jared Diamond, Collapse: How Societies Choose to Fail or Succeed

Why Study Urban Ecology?

We must think about the sustainability of our future world and generations to come…

The City is the Solution“We are at a turning point in history. Our planetary environment is severely damaged. Desertification is spreading, the globe is warming. Entire ecosystems are under threat. And the City is at the center of the storm of destruction.

But that is the key! We must cease seeing the City as a problem. We must see the City as the solution. For the City is our home. It is what we make it to be. It is where we live.”

– Charter of Calcutta