Patch Atlas: Integrating Design Practices and Ecological Knowledge for Cities as Complex Systems

Modern urban planning treats cities as orderly composites of homogenous land uses, however, like a rich quilt, the urban landscape is an amalgam of different social, ecological and material areas or ‘patches’, a term used in urban ecology. Urban designers, landscape architects and architects may be familiar with urban and landscape analysis systems such as McHarg’s ‘layer cake’, the figure-ground, typology and urban morphological studies, however Patch Atlas offers a novel way of representing the social and ecological complexity of the urban realm, which is called ‘heterogeneity’ by landscape ecologists. The particular backgrounds of the authors of Patch Atlas_two urban ecologists and two designers_frame the intention of the book: Victoria Marshall is a landscape architect, founder of Till Design and at the National University of Singapore, Mary Cadenasso is a landscape and urban ecologist at the College of Agricultural and Environmental Sciences at UC Davis, Steward Pickett is a plant and urban ecologist at the Cary Institute of Ecosystem Studies at Arizona State University and Brian McGrath is an urban designer at the Parsons School of Design and founder of Urban-Interface. Correspondingly, the Patch Atlas originates from an inquiry that attempts to conceptualize the totality of the urban system from the perspective of ecology, and urban ecology in particular, providing an opportunity for designers to engage with an ecologically rigorous framing of urban heterogeneity as a system for design. This system is where places that were treated as homogeneous by land use are revealed_to varying degrees, which is the subject of the book_as actually heterogeneous when considered in terms of land cover. The book has three parts: the motivation and description of the system, the application in the form of a case study and a conclusion speculating on the nature of the integration of ecology and design. As a book, Patch Atlas is a handsome slim volume of 128 pages with a graphic nature, with brief chapters explaining their system, and maps, graphs and zoomed patches floating in white space, and a single photograph per chapter typifying each. In essence, Patch Atlas consists of two components. First, the Gwynns Falls watershed in Baltimore is extensively mapped as a set of patches (which are delineations of areas based on relative abundance of specific urban cover elements such as buildings, vegetation and surface materials) combined and represented to reveal patterns in their organization. Then these patterns are analysed and interpreted in the text to address a fundamental question the authors identify about cities as ‘complex hybrid socio-ecological systems’ (p. 2): ‘What are the links between the amount and distribution of various elements of urban form and ecological and social processes?’ (p. 2). The authors propose a new land cover classification tool they call HERCULES, which stands for ‘High Ecological Resolution Classification for Urban Landscapes and Environmental Systems’. They argue that HERCULES can be used ‘as a new conceptual approach appropriate for describing and envisioning change in any complex, urban place’ (p. vii). In addition, they specifically propose that the Patch Atlas extends HERCULES into a system for design, a noble claim that we nonetheless question in this review. Four themes for the book are succinctly articulated in the book’s preface, orientating the reader to the book’s central characteristics that underlie the logic that unfolds: • The atlas is co-produced by urban designers and urban ecologists working together. • It contributes to a long engagement with the relationship of nature and culture that is explicit in the built environment. Particularly, ‘Patch Atlas contrasts starkly with the predominant practice of starting urban classification by separating human-constructed covers from covers that emerge from predominantly biological and geological processes’ (p. viii). • It encourages speculative design. • It can be relevant to disciplines and practices beyond those professed by the authors.