Landscape Ecology Within an Urban Context
On Patches, Edges, and Corridors….
Ecology is generally defined as the study of interactions among organisms and their environment, and Landscape as an expansive mosaic (kilometers wide) over which many local environments and ecosystems occur. These mosaics are generally organized through the elements of :
- Patches – which withhold the local environments or ecosystems
- Edges – which enclose the patches and provide a buffer between its interior and its neighboring contrasting environment
- Corridors – which create means of circulation of organisms between different patches
This is a a diagram of patches and edges alone. However, corridors would connect multiple patches like these and frame a connected network. When a patch is fragmented or fractured one patch becomes two separate patches with distinct but larger boundaries, and remarkably reduced interior patch space
Throughout the late 20th century many principles emerged regarding how to govern and promote healthy landscapes. According to Landscape Ecology Principles in Landscape Architecture and Land Use Planning (Dramstad, Olson, and Forman), all landscape ecology principles can apply to all types of systems — pastural, urban, desert tundra, etc. In other words, these principles, which at first may seem only applicable to rural or untouched environments, can actually inform our design decisions across a broad range of geographical contexts to create healther environments. They can guide urban planners when deciding where to place a new suburban development with the smallest risk to ecological integrity, or where it may be appropriate to establish a wildlife conservation park. As bureaucratic and tedious as they seem, these issues are consequential to all citizens, as they correlate to our economy, lifestyle, and well-being.
The Urban Context….
To provide a relatable example, consider Washington, D.C. It is a very thorough and explicit landscape system built on these organizing principles. The city itself — a 10 mile x 10 mile rhombus can be considered a large but distinct urban landscape. Within it major neighborhoods form large patches. Georgetown, Adams Morgan, Spring Valley, or Dupont Circle, are all bordered patches differentiated through the type of architecture present, the density and size of its recursive streets, or even urban and environmental material changes. Major avenues like Connecticut, Georgia, or 16th St run the length or width of the city and form corridors of circulation that establish a network of connectivity between these different neighborhoods or “patches.”
Consider Georgetown and Rock Creek Park. Georgetown is a rich historical area with original cobblestone streets and renovated houses, not to mention the very old Georgetown University. It sits along the waterfront of the Potomac River with a dense system of one-way streets that access its low-elevation buildings. Its inherent organisms — residents and visitors — are often busy shopping along its commercially developed areas or enjoying its entertaining plazas. However, Rock Creek Park, another preserved landscape, is surrounded on all sides by urban context, while it remains minimally developed with only jogging paths and rest stops. Its access to water is mostly dependent on small creeks, and its inherent organisms are largely animals, although park police and joggers often patrol the area. Both self-contained environments, equally part of the fabric of the Washington, D.C., are situated along the Rock Creek/Potomac Parkway. This corridor guides vehicular circulation in and out of the city while connecting several patches of neighborhoods along the way.
We can further understand, and evaluate the he success and health of Washington, D.C. as an urban landscape by investigating the three main characteristics of landscapes: structure, function, and change. It’s comprehensive spatial organization as a large mosaic becomes clear as we consider its patches and corridors. How are these neighborhoods places? Are they spaced equally? Do they meet right at each other’s boundaries providing little room for expansion?
We can also consider its functioning through its connectivity. How do people circulate between the different neighborhood patches of D.C.? Are there multiple ways to arrive at your destination? Do these streets create a lot of traffic or is it efficient and easy to navigate? Are there other means of transportation besides streets? These questions help us conclude whether D.C. is an effective landscape for its human inhabitants.
Finally, there is the element change. Has there been radical development or changes to the internal organization of this system? Considering that it has not experienced critical change since the McMillan Plan in 1901, and that it still largely maintains its original layout as it was designed by Pierre Charles L’enfant in 1791, Washington, D.C. seems hold a largely satisfying and successful sort of “urban ecology” for its inhabitants. I do not possess enough data or knowledge to know how these characteristics stand when applied to the strict landscape ecology of the capital.
On a closing note….
“What are the natural features which make a township handsome? A river, with its waterfalls and meadows, a lake, a hill, a cliff or individual rocks, a forest, and ancient trees standing singly. Such things are beautiful; they have a high use which dollars and cents never represent. If the inhabitants of a town were wise, they would seek to preserve these things, though at a considerable expense; for such things educate far more than any hired teachers or preachers, or any present recognized system of school education. I do not think him [or HER] fit to be the founder of a state or even a town who does not foresee the use of these things…”
— Henry David Thoreau, Journal, 1861
Unfortunately, due to the advent of modern urbanism, ecology and culture have diverged within the urban landscapes of many countries. Meaning that ecological health has lost its priority in landscape planning and design within urban contexts due to changes in what our cultures deem as valuable — economics, aesthetics, and politics. Designers and planners must return to the conceptual foresight that shaped the design of great American cities, and development of national parks during the 20th century — successful harmonies of distinct landscapes. Their splendor and success lie in there ability to merge ecology and culture, land and people, human and nature.
CONTRAhabit 