A post on Gardenvisit discusses the historical idea of creating artificial landscapes, in this case the Serpentine Lake in Hyde Park, to appear 'natural'.
"In 1730 Queen Charlotte ordered the damming of the Westbourne River as part of a general redevelopment of Hyde Park and Kennsington Gardens by Charles Bridgeman. The Serpentine Lake in Hyde Park is the remnant of the Westbourne River which since 1850 has been diverted into a culvert and runs into the Thames near Chelsea. “The Serpentine Lake was one of the earliest artificial lakes designed to appear natural” and was widely imitated. The Long Water because of its relatively undisturbed nature is a significant wildlife habitat."
:: images via Wikipedia
While there are probably hundreds of examples similar to this, and the fact that the site is mostly contained with a park (with a purely formal goal, versus ecological) - keeps it some distance from an engagement in the urban form and a viable idea of landscape or ecological urbanism.
It did remind me of what I think is a very good example of 19th Century work/precedent of landscape urbanism, Olmsted's restoration and naturalization of Boston's Back Bay Fens - a landscape that, as part of the Emerald Necklace, as a historically engineered construct, is today considered a natural and ecologically functioning natural area that the City was built around. In fact the inverse is true, as the space was massively designed and engineered, with the subsequent urban areas building up around the space. As seen from the pattern of Olmsted's plan in 1887, the Back Bay fens is a naturalistic work of landscape architecture, but also a feat of engineering that mitigated flooding in the area.
:: image via Wikipedia
And the current urban pattern, showing the infilling of urban areas around the 'open space' in the subsequent 130 years (yet remaining remarkably intact). Building up of the urban density around this 'constructed landscape' is striking, especially in contrast to the bucolic beginnings.
:: image via Google Earth
And some additional information and text from an MIT architecture class site 'The Site Through Time' - showing the historical evolution of the park - emerging from the marshy landfill that constituted the majority of the Boston area (see more on the urban expansion through landfilling here).
:: images via MIT
While it is easy to consider this an 'extension of nature' it is clear this is a constructed urban landscape, and that after time it is hard to see this historical ecology without some digging - as it is perceived as nature. A great site as part of the David Rumsey collection overlays a number of historical maps (there should be one of these for every city), which show the Back Bay area in different configurations (but the same scale and view) prior to and after 1887, which show the marsh, early landfill, evolution, and eventual implementation of the Olmsted plan (years 1856, 1874, and 1897)
:: images from David Rumsey
More on this one soon (in particular proto-landscape urbanism qualities of this historical work in providing a landscape framework for urbanism). It is telling that most people consider this 'nature', similarly to the very constructed Central Park and other naturalistic parks of the 19th Century. It is more specifically artificial ecologies as urban infrastructure - a novel concept well over a century removed.
:: Back Bay Fens - 1892 - image via The Olmsted Legacy
I've used this example before, in an article from a few years back (Winter 2006) called 'Creating Nature' (links to a PDF published in the ASLA Oregon journal ORegonland - article starts on pg. 4). For anyone interested in more detail, check out one of the essays in William Cronon's sporadicallyengaging 'Uncommon Ground: Rethinking the Human Place in Nature', specifically Anne Whiston Spirn's great essay 'Constructing Nature' which mentions this project and others by Olmsted using similar naturalistic tendencies. But for it's picturesque aesthetics of a century ago, it sounds a lot like landscape (or ecological) urbanism to me:
"Boston's Fens and Riverway were built over nearly two decades, (1880s - 1890s) as an urban 'wilderness,' the first attempt anywhere, so far as I know, to construct a wetland. These projects, built on the site of tidal flats and floodplains fouled by sewage and industrial effluent, were designed to purify water and protect adjacent land from flooding. They also incorporated an interceptor sewer, a parkway, and Boston's first streetcar line; together, they formed a landscape system designed to accommodate the movement of people, the flow of water, and the removal of wastes. This skeleton of park, road, sewer, and public transit structured the growing city and its suburbs." (Spirn quoted in Cronon, 1996, p.104)