The diagram above, called a Muir Web, is a visualization of habitat relationships and ecological associations of the Manhattan island, circa 1609. The Black dots represent elements or groups of habitat elements, such as a particular species or habitat type. The lines indicate connections or affiliations between these elements. The visualization (by Chris Harrison) is part of the recently completed Mannahatta Project, which, after a decade of forensic ecological research, has mapped and identified 50+ ecological communities on Manhattan prior to its transformation by European influences. The diagram’s name is based on a quote from famed naturalist John Muir: “When we try to pick out anything by itself we find that it is bound fast by a thousand invisible cords that cannot be broken, to everything in the universe.”
Eric Sanderson, the author and lead landscape ecologist behind the Mannahatta project describes Muir webs as:
“a new grammar for describing habitat entities and their interconnections across taxa using an analogy to language. This grammar can be used to write “sentences” relating one ecosystem entity to a series of others, as in resource selection functions that predict the distribution of a “subject” with respect to other “elements”…
… We began compiling habitat descriptions for the 1001 likely species of Mannahatta into a database, using habitat information found in field guides. A tree species might grow best in “dry sandy soils” or a warbler may eat “tree insects, especially in open deciduous woods.” As we developed these lists, we added entries to include the definition of “openness” or of “woods” and eventually even “dry sandy soils.” We reconstructed the habitat relationships until eventually they reached the physical and ecological variables we had mapped, and then even further. At the base of the “Muir Web” of habitat relationships are fundamentals like space, time, geology and climate.”
(a detailed presentation of the Muir webs is available here)
Thus the ‘code’ for a Muir Web is derived from the habitat descriptions one finds in field guides, which is derived from the recorded accounts of countless hours of many naturalists’ observations. The Muir web is a recombinant splicing of borrowed (and de-authored) texts used to engender a sense of the functioning of the real from an unseen and unexperienced past. Both the (incidentally post modern) methodology and the representation of the web is intriguing. The minimal, abstract nature of the diagram is in sharp contrast to just about everything else encountered in the Mannahatta project.
Defining an ‘original’ or reference ecosystem in the effort to restore any landscape (either in concept or in actuality) is a nebulous and creative task requiring educated guesses and assumptions to be made about what was, based on variable types and amounts of evidence that can rarely be fully verified…fuzzy CSI for the landscape.
But what is most compelling about this approach is its emphasis on articulating relationships (over 8,000 mapped in the web above), its diagramming of the organizational complexity of a lost environment through the consideration of multiple variables, and the astute application of years of accumulated natural history and observation. The web attempts to reveal the importance of what is largely invisible in a world of things too often considered as discreet objects. They provide a glimpse (albeit a partial, abstract, non-spatial and provisional one) of the richness of the processes, networks and functional associations that are present in landscapes, and the possible implications of tinkering with them. How many threads can be pulled out until the overall structure changes? What happens when new components are intentionally or accidentally added? How best to design and implement restorative armatures?
The obvious next question is what would Manhattan’s Muir Map look like today? What if we were able to map the extensive anthropogenic hive and the species that have learned to co-exist and/or thrive within it: the likes of rats, starlings, crows, pigeons, squirrels, cats, dogs, oddly robust microbes, and an international collection of trees and horticulturally derived plants.