31 January 2008

Taxonomy of Urban Ecosystems

Ladies'-tresses orchids, the Port Lands, Toronto

There are some easily definable remnant native landscapes in Toronto:

  • Fresh Water Dunes
  • Beach Bars
  • Oak Savannah and Tallgrass prairie
  • Upland and lowland deciduous and mixed forests and swamps
  • Ravines
  • Bluffs
  • Freshwater wetlands
  • Watershed valleys corridors, riparian river and stream banks
But after that, I often see many of our urban natural areas described, rather non-descriptively, as “Cultural Meadow” / CUM1-1. This doesn’t exactly tease the character out of a place and into my heart. Worse, I feel that when we don't accurately describe a natural area we diminish or even dismiss it. That concerns me because, I feel that each of our identities are in part the products of where we live, including the natural areas we authentically inhabit; that nature is not something you find somewhere else – at the cottage, in the country, on the other side of an admission gate, or in the past, instead, for each of us, nature is exactly where we live our everydays, and 1/2 of us live in cities, and our lives are better when we have the words and skills to recognize and describe our/the nature we live in -- it helps us to see, understand, interpret, nurture, steward, love, discourse about and even defend (show some one else the ecological value of) our lands.

So of course I’m so stoked to have come across the E*vue site (Emergent Vegetation of The Urban Ecosystem
) developed for Harvard's Graduate School of Design course Plants in Design. Here's my favourite part:
A Simple Taxonomy of Urban Ecosystems in the Northeast
Peter Del Tredici

Managed Urban Habitats

Well Maintained Landscapes (weeds controlled):

Mowed grass (lawns and ball fields)
Mowed grass with scattered trees and shrubs (savannahs)
Public parks and open space

Planted woodlands with understory shrubs
Residential landscapes
Commercial and institutional landscapes

[somewhere around here I would add: managed but wild post-industrial eco-restoration and habitat enhancement sites e.g. Brick Works, Leslie Spit]

Minimally Maintained Landscapes (weeds abundant):

Trampled grass in public parks
Planting islands in paved areas
Neglected public parks and open space
Neglected residential and commercial landscapes

Derelict (Ruderal*) Urban Habitats

Abandoned or Neglected Open Space:

Vacant lots and waste dumps (primary succession)
Abandoned lawns and ball fields
Woodlands on abandoned land
Freshwater wetland and stream corridors

Inner City Infrastructure:

Small-scale pavement openings (tree pits), edges, and cracks
Chain-link fence lines and stone walls
Roadway and highway banks, edges and median strips (salt applications)

Railroad tracks (gravel substrate and herbicide applications)
[I would also specify hydro corridors]

* Ruderal is defined by the American Heritage Dictionary as "growing in rubbish, poor land, or waste places. From Latin rudera , ruins, rubbish, plural of rudus , broken stone."

Cool, yes? I mean, in a Leonard Cohen "Suzanne takes your hand, and she leads you to the river… and she shows you where to look, among the garbage and the flowers ...they are leaning out for love, they’ll lean that way forever" kind-of-way: how it illuminates unarticulated land we already all privately know into something beautiful (potentially or currently) worth directing our own and some one else's eyes toward.

It also brought this Alex Wilson quote to mind:
"My own sense is that the immediate work that lies ahead has to do with fixing landscape, repairing its ruptures, reconnecting its parts. Restoring landscape is not about 'preserving' lands -- "saving what's left," as it's often put. Restoration recognizes that once lands have been "disturbed" -- worked, lived on, meddled with, developed -- they require human intervention and care. We must build landscapes that heal, connect and empower, that make intelligible our relations with each other and with the natural world: places that welcome and enclose, whose breaks and edges are never without meaning."

BTW: The E*vue site also has some info about several of our typical urban weeds species, and, where possible, their ecological functions and preferences: this is not lost on a girl who can madly dig out DSV or pull Garlic Mustard by the garbage bag full, but still find the odd Tree-of-Heaven to defend in situations where I can’t realistically imagine any native tree being able to survive (e.g. a sq foot of compacted dust, gravel and slag on the margin of an asphalted post-industrial heavy-metals contaminated alleyway) and perform as many services (keeps dust and noise down; shades / cools asphalt & buildings; CO2->O2; stabilizes soil; decreases run-off) ...I've learned there are times to be pragmatic, and it helps that I believe that Tree-of-Heaven will inevitably be a co-dominant tree, not a dominant like perhaps Norway Maple.


Anonymous said...

I am slowly changing my city property from trampled lawn to various definable native landscapes. Thanks for the list, I read through the list slowly, whispering... "Need 'em, got 'em, got 'em, need 'em...

Lonnie said...

Here in our area (central Virginia) one of our rarest ecosystems are the granite rock outcrop communities. One of the things that facinate me is how much these communities have in common with roof tops, thus it's quite possible that many of these rare plants could find a suitable home on green roofs. While it is vital to protect existing habitat, it may be that the only way we'll be able to save some species is also by finding new ways to fit them into urban and suburban ecosystems.

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