Holism states that the whole is more than the sum of their parts. It provides a new way to analyze landscapes, and argues that landscape elements receive their meaning or significance by their context, or their position within the whole [47]. An ecosystem’s external “linkages” with the landscape are as important to proper functioning as the internal ecosystem environment [23]. Some even argue that context is more important that content [42]. This recognition of the importance of context emerges from systems thinking [42]. Besides landscape elements per se it is important to account for the (spatial) relationships between the elements that make up a landscape. All landscape elements, regardless of their specific land cover type, influence landscape functions through their spatial characteristics. This is a fundamental inter-relationship applicable to any landscape type, urban, rural, or natural. Thus, looking at landscapes holistically provides a common way of thinking about functions and processes, and how structure affects, and is affected by them [24].

The different systems that comprise our global habitat are highly interdependent. Indeed little is completely isolated from its surroundings, including people and cities. Urban landscapes are formed by a series of landscape elements such as houses and buildings, roads and highways, gardens and parks, etc. These elements are not isolated. They establish a number of relationships between each other. For example, housing is more expensive near urban parks because these generally provide for several urban functions, services, or amenities that are looked for by urbanites, e.g., urban climate is more amenable nearby parks which has a significant influence in bio-comfort, they provide for recreation opportunities, and a close contact between people and nature. Additionally cities are not isolated, and establish relationships with the surrounding rural landscapes and other cities.

According to Capra “(…) to understand things systematically literally means to put them into a context, to establish the nature of their relationships (…); the root meaning of the word “system” derives from the Greek “synhistanai”—to place together” [42]. “Systems thinking is a method of scientific enquiry that allows one to understand and investigate complex realities” such as landscapes [82], and can be characterized as an attempt to find common principles that apply at different levels of scale and across different types of phenomena [83]. The systems approach is hierarchical and views landscapes nested within larger systems (supersystems) and themselves composed of lower order systems (subsystems). A useful analogy can be made with the human body. Consider human cells as building blocks, which are organized as tissues, organs, organs systems (circulatory, respiratory, etc.) and ultimately as an organism. The human body is comprised of a group of systems. Similarly, individuals are part of communities that together form towns, states, and so on. Landscapes can be understood as groups of ecosystems, and regions as groups of landscapes [24]. The concept of networks introduced by early ecology enriched the systemic worldview where ecosystems are understood as networks of individual organisms [42]. Landscapes can also be viewed as networks of interacting ecosystems [46], cities as networks of urban elements (neighborhoods, buildings, infrastructures, etc.) [52], polycentric urban structures as networks of cities [19,60], and so forth. In the above context it is most important to acknowledge that when the notion of hierarchy (between levels) was introduced into ecological systems theory, it was not originally intended to portray a top-down, rigid structure involving a vertical authority and control, as tends to dominate in its everyday definition; the dynamic, adaptive nature of nested structures tended to be lost [45]. The latter introduced a new term to emphasize the latter interpretation: “Panarchy captures the adaptive and punctuated evolutionary nature of adaptive cycles that are nested one within the other across space and time scales” [45]. Here, the lesson to take home is that although living systems do present an organizational structure in hierarchies, it does not implies a top-down, vertical, and rigid but rather an adaptive, dynamic, network structure, whose elements work in complement with one another (see next section on autopoeisis).

In general, different systems levels have different levels of complexity, and each exhibits systemic properties that do not exist at lower levels—the so-called emergent properties, since they emerge at that particular level. Most important in contextual thinking is that the properties of the parts can only be understood within the context of the larger whole. This reverses the Cartesian paradigm where the dominant belief is that in systems the behavior of the whole can be understood entirely from the properties of its parts, leading to the Descartes’s analytic method, an essential characteristic of modern scientific thought, in contrast with the ideas synthetized hereby on holism and system thinking. A crucial point in systems thinking is the ability to shift from one system level to another back and forth [42]. In some instances, is useful to perceive the larger context of a specific locale, or of a specific issue of concern (the forest; the “big picture”) in order to recognize, understand and integrate the relationships between that place with its surroundings—the flows of energy and matter that crosses through and influence decisively its functioning. Complementarily we focus on the place in itself, in its parts (e.g., the trees of a forest) and most important in the intra-relationships between the parts (interaction between different trees); often we need to go even deeper and approach the specifics of each component (the functioning of a tree, its root system, the canopy, etc.), which in turn are systems by themselves.

Systems thinking is an emerging field. It was in the 50s and 60s that Ludwig von Bertalanffy, a biologist from Vienna, established his general systems theory or GST [84]. According to Steiner “(…) in GST control is maintained through the feedback received by what is dubbed the “control mechanism.” The control works like a homeostat (…), and the result is a regulatory action (…) that keeps the system in a dynamic equilibrium” [85]. Since then it has developed over the last 40 years in many different disciplines and through a range of applications [83]. According to these authors “(…) the report The Law of Sustainable Development, produced by the European Commission, states: ‘‘Today, no serious study and application of the principles of sustainable development is possible without the help of systems science’’. (…) Concepts emerging from systems thinking have had a profound influence (…) in helping to understand ‘‘the complexity of ecological and organizational systems” [83]. Based on a comparative review of existing participatory and ecological planning methodologies the latter realized that “(…) the ecological planning methodologies have been developed in a whole within the last three decades reflect an increasing interest in the insights of systems thinking methodologies. Several of the key thinkers in these areas cite systems thinking and living systems biology as an inspiration in the development of the methodologies” [83].

System thinking appeals also to city planning theorists [85], and cities can be seen as systems. Inspired by Urban et al., Grove et al. adopt a hierarchical approach where households are a part of larger systems—neighborhoods, which in turn are part of a larger system—the city [86]. Cities can also be a part of larger systems, e.g., metropolitan areas [33] or other type of urban agglomerations worldwide, e.g., polycentric urban regions and network cities [19,60]. Closely linked with holism and systems thinking are the concepts of self-organization and autopoeisis presented below.

Self-organization is a most important and distinguishing characteristic of living systems that explicitly or implicitly incorporates in itself several important concepts to understand complex systems, such as socio-ecological systems (SESs) that constitute cities and metropolitan systems. “Self-organization is a process in which pattern at the global level of a system emerges solely from numerous interactions among the lower-level components of the system. Moreover, the rules specifying interactions among the system’s components are executed using only local information, without reference to the global pattern. In short, the pattern is an emergent property of the system, rather than a property imposed on the system by an external ordering influence. (…) Critical to understanding our definition of self-organization is the meaning of the term pattern. As used here, pattern is a particular, organized arrangement of objects in space or time. (…) Emergent properties (…) are features of a system that arise unexpectedly from interactions among the system’s components. An emergent property cannot be understood simply by examining in isolation the properties of the system’s components, but requires a consideration of the interactions among the system’s components. (…) Systems are complex not because they involve many behavioral rules and large numbers of different components but because of the nature of the system’s global response. Complexity and complex systems, on the other hand, generally refer to a system of interacting units that displays global properties not present at the lower level. (…) Complexity in a system does not require complicated components or numerous complicated rules of interaction” [87].

Some diverse phenomena have been described as self-organizing in biology, such as homeostasis (property of a system that regulates its internal environment and tends to maintain a stable, constant condition of properties like temperature or pH, in a dynamic equilibrium), and flocking behavior (such as the formation of flocks by birds, schools of fish, etc.) [45,87]. “Prigogine and Stengers (1987) showed that the evolution of settlement patterns and urban networks behave like complex systems out of equilibrium and that self-reorganisation of the spatial structure to adapt to the changing functional needs is characteristic.” [47]

Poiesis is a Greek term that means making or production. Autopoiesis means self-making or self-production. Under this concept living beings are seen as systems that produce themselves in a ceaseless way through a network of interactions or production processes (the system’s metabolism). The function of each component is to participate in the production or transformation of other components in the network through the relationships that specify the system. An autopoietic system is at the same time the producer and the product, in a circular organization (e.g., the nervous system) [26,41,42]. Notably the organization of a living system is always a network pattern [42].

Autopoeisis is a general organization pattern common to all living systems, whichever the nature of its components, i.e. the organization is independent of the properties of its components. The system´s structure is the physical embodiment of its organization, comprising both the system´s components and the functional relationships between components. Capra uses a bicycle to illustrate this concept: the systems’ components are the frame, pedals, handlebars, wheels, chair, etc., which have a set of functional relationships between them; the complete configuration of the functional relationships constitutes the bicycle’s organization pattern (all of these relationships must be present to give the system the essential characteristics of a bicycle). Additionally to organization (pattern) and structure, this author argues for a third criterion when describing the nature of life. Process, as the link between organization and structure, regards to the activity involved in the continued embodiment of the system’s organization pattern. Using a designer’s metaphor, organization is the design sketches that are used to build the bicycle; the structure is a specific physical bicycle; and process, the mind of the designer [42].

Recently it was proposed to substantially expand long term ecological research (LTER) by including the human dimension focused on coupled socioecological systems (SESs). Long-term socioecological research (LTSER) regards society-nature interaction as a dynamic process in which two autopoietic systems, society, and nature interact, an approach particularly relevant to understand the relationships typical of complex urban environments [55].

Note that, from a self-sufficiency perspective, there is no such thing as sustainable cities [88]. Cities by themselves are not autopoietic since they are highly interdependent on the surrounding landscapes [38] continuously importing energy, food, materials, etc. and exporting the products of its metabolism, e.g., waste [22] (see section below on urban metabolism).

The capacity of a system to maintain its self-organization is closely related to the concept of adaptation (see above), and of resilience. Resilience comes from the Latin resilire, which means to rebound or recoil. This concept was first introduced to ecology and the environment in 1973 by Crawford (Buzz) Holling, who promoted, among others, the use of systems theory [43]. Resilience is the ability to absorb disturbances and reorganize while undergoing change, while retaining the same function, structure, identity, and feedbacks, the capacity for self-organization, and the capacity to adapt to stress and change [89]. Adaptive capacity resides in aspects of memory, creativity, innovation, flexibility, and diversity of ecological components and human capabilities [90]. It is important to distinguish two paradigms where resilience emerges that may be labeled equilibrium and non-equilibrium [51]. The first is focused on stable equilibrium conditions and is presently applied only to very particular situations; the second is more inclusive and deemed useful for urban planning and design, focusing on systems’ dynamic and evolutionary capacity to adapt and adjust to internal or external change. Hereafter this second meaning is adopted.

The concept and theory of resilience have a growing appeal in the disciplines of ecology and planning [80], and one can identify an increasing dialog between these two disciplines in addressing urban environments. In this context an urban planner and an ecologist proposed a new metaphor, “cities of resilience”, that both disciplines can share [91]. Ahern argues for an adaptive approach to planning and design, including monitoring and “learning-by-doing” [56,57,78,79], much attuned to the proposals of “designed experiments” [54]. Resilience capacity together with innovation can play an important role via “responsible experimentation, developing a culture of monitoring, and learning from modest failures” [79]. According to this author “resilience capacity can be strengthened by biodiversity, modularity, tight feedbacks, social capital, acknowledging slow variables and thresholds, and innovation “[79]. Resilience is at the core questions to be approached by the emerging science of sustainability [81], including also self-organizing complexity, inertia, thresholds, complex responses to multiple interacting stresses, adaptive management, and social learning [27]. There is common agreement in the literature that systems, organizations and people who are able and willing to adapt tend to be more resilient [43].

““Redundancy” is defined by the Oxford English Dictionary (OED) as “the state or quality of being redundant; superfluity, superabundance;” (…) “redundant” is further defined as “excessive, abounding too much.” [92]. The word, paradoxically, has substantially different meanings in the fields we survey, yet most, like the definition from the OED, carry a negative connotation. In their work these authors refer to redundancy of multiple units (building blocks) within some larger system and provide a thorough discussion of different kinds of redundancy, ranging from genetic to engineering systems. This review includes ecological systems where “redundancy is typically of the “multiple non identical copies” sort within ecosystems, or across ecosystems” and is associated with biodiversity, ecosystem function, and resilience [92].

Functional ecological redundancy is basically the degree to which organisms have evolved to do similar things [93]. Several species fill similar ecological roles increasing the number of potential community organizations that can uphold similar ecosystem functions. By maintaining the distribution of redundant species across multiple time and space scales it is possible to maintain key-functions of the ecosystem in the face of change, which makes the system resilient [53,88]. On a different note Rosenfeld argues that in terms of practica1 conservation issues, the concept of functional redundancy is a double-edged sword. For example, it is important to prioritize species protection, but at the same time it postulates that certain species perform similar roles in ecosystems and thus redundant species can be expendable [92]. He recognizes, however, that this interpretation was not intended by its original proponent, where redundant species were seen as necessary to ensure ecosystem resilience in face of perturbation [94].

In the context of landscape ecological urban planning and design, Ahern argues for the advantages of redundancy (and modularization), and distributed or decentralized systems as opposed to concentrated. Here redundant elements or components provide for the same or similar urban functions, which help spreading risks, and thus constitute “strategies to avoid putting all your eggs in one basket,” and for preparing and pre-planning for when (not if) a system fails [79]. It represents a “humble” design tactic where one acknowledges that it is not possible (and desirable) to exert total control over socio-ecological processes, and just try to mediate indeterminacy: “(…) since we can never be completely certain of how water flows and other ecologies work, one needs to build in redundant systems to make sure it works (…)”[95].

Urban metabolism is a metaphor that looks at the city as a system, which requires inputs and outputs; if we look at it as an organism, it requires food and other resources, e.g., water, energy, materials, etc. and releases the byproducts of its metabolism to the environment, i.e. waste. This metaphor was developed earlier in the 20s and 30s by the human ecological approach of the so-called “Chicago School” where the city was conceived as a closed and functional system that could be treated as an organism or “superorganism” [96]. Later, in the 60s, a few academics also adopted this perspective but rarely if ever used it in policy development in city planning: “by looking at the city as a whole and by analyzing the pathways along which energy and materials including pollutants move, it is possible to begin to conceive of management systems and technologies which allow for the reintegration of natural processes, increasing the efficiency of resource use, the recycling of wastes as valuable materials and the conservation (and even production) of energy” [63]. Since this metaphor was essentially biological in nature, the latter extended the original idea to “include the dynamics of settlements (transportation, economic and cultural priorities) and livability in these settlements (health, employment, income, leisure, etc.), which he called the “Extended Metabolism Model of the City”.

This emergent notion has been very useful in quantifying the horizontal (chorological) relationships and trends in consumption and waste generation of expanding cities. Over two decades several studies have shown large increases in the output of materials of cities, e.g., food and building materials, and outputs such as food wastes, paper and plastics. As an example, in Beijing “total carbon emitted from solid-waste treatment increased by a factor of 2.8 from 1990 to 2003.” [5]. Additionally the metabolism approach provides a way to integrate biophysical and socioeconomic processes [55]. Analyses of urban metabolism include the analysis of the pathways along which material and energy [22,63], and more recently information flow [55]. Urban metabolism is consistent with the holistic and systemic approaches to cities, and new city planning approaches that consider the relationships established between the built environment and its wider landscape (spatial) ecological context, as in the ecological footprint approach [33].

Capra argues for a change in the XXI century that brings new thinking and values, shifting from self-assertion to integration [42]. The author points out that neither tendency is good or bad and both are essential aspects of all living systems. However the Western industrial culture overemphasized the former and neglected the latter. For example, the competition paradigm, a self-assertive value, needs to be replaced, or better, complemented by cooperation in order to enable sustainable human ecological systems. In order to provide support for the above stated argument we can look at living systems and its organization once more to provide insight and analogies that arguably could be useful for the core theme of this paper—sustainable city planning and design.

An important concept in the context of autopoeisis is structural coupling [98], which is closely related with the notion of interdependence. It occurs whenever there is a history of recurrent interactions leading to the structural congruence or compatibility between two (or more) systems (e.g., between two organisms) or between a system and its containing environment. Note that in this context the structure of the organism will not change as specified or instructed by the environment’s structure, and vice versa—these interactions only “triggers” structural changes in one another. As long as a set of nondestructive, compatible or congruent interactions exist between a system (e.g., a city) and its environment (e.g., the surrounding landscapes, and or the hinterland) these two act as mutual sources of perturbation, triggering changes of state [98]. These authors provide an example in the context of cities: “Thus for example, in the history of structural coupling between the lineages of automobiles and cities there are dramatic changes on both sides, which have taken place in each one as an expression of its own structural dynamics under selective interactions with the other” [99]. In sum, structural coupling is always mutual; both organism and environment undergo transformations, and for example changes in cities trigger influences in its “region of influence” (see below) in multiple ways, and vice versa. Expanding on the example above mentioned on structural coupling and the influence of cars in cities, the urban form of the “diffuse city” (or sprawl) was facilitated by an increased urban mobility provided by individual transportation. A similar effect can be seen in the star-shaped urban form of post-industrial cities that expanded along the main axis of transportation infrastructure—railways, roads and highways, or both. Reciprocally cities congestion, partially due also to urban form, induced also the appearance of smaller cars—city cars. Both phenomena are intrinsically connected, reflecting a strong interdependence. The corollary is that sectorial approaches (in this case the city, for one side, and the car industry for the other) are bound to influence each other, significantly. Thus the need to look at the several dimensions of cities as a whole, where systems interact with other systems, at different levels, rather than from a reductionist perspective, focusing on one single dimension or on particular places as isolated features.

Maturana and Varela explained above how organisms interact to each other and with the surrounding environment [41]. The notion of structured coupling is useful to provide for insights on how organisms adapt to the environment. Below the authors continue this explanation by shedding light to “competition” and “natural selection” as the mechanisms that are traditionally related to “survival” of some species over others, and thus to species evolution. “The maintenance of the organisms as dynamic systems in their environment is centered on a compatibility of the organism with their environment which we call adaptation. The adaptation of a unity to an environment (…) is a necessary consequence of that system’s structural coupling with that environment. (…) Conservation of autopoeisis and conservation of adaptation are necessary conditions of the existence of living beings”. Important to the concept of cooperation (versus competition) is the above mentioned authors’ observations on how Darwin supposedly proposed the process of “natural selection”: “We often hear that what Darwin proposed has to do with the law of the jungle where each one looks out for himself, at the expense of others in unmitigated competition. (…) This view of animal life as selfish is doubly wrong: (a) instances of behavior which can be described as altruistic are almost universal in natural history; (b) living organisms existence is not geared to competition but to conservation of adaptation, in an individual encounter with the environment that result in the survival of the fittest” [100]. At this point it is important to clarify the distinctions between the three basic types of interactions between species: competition “leads to negative outcomes for both groups involved”, whereas symbiosis “benefits both participants”, and predation, or parasitism “benefits one and is detrimental to the other” [101]. Complementarily it is important to note that “(…) in nature there is no competition. What exists is competence”. As noted by Maturana, when two animals meet before the same piece of food and only one eats, this happens because in that specific moment one of them was the most competent to do so. But this does not mean that the animal that was unable to eat is doomed to be, from that moment on, forever forbidden to eat until death arrives. This does not happen in nature. However, when circumstances involve competition in human culture, the individual who succeeds to eat does not satisfy himself with this fact: he or she needs to make sure that the one who was not able to eat must cease forever to be a threat. In other words, competitive men usually do not feel sure of their competence, so they have the need to get rid of whoever could jeopardize them. In other words, when men cannot trust in themselves as living beings, their peers must be eliminated as soon as possible. But even so—let us insist on this point—this cannot be ascribed to the cultural dimension in itself: it plays such a role in a culture like ours, which does not know how to deal with aleatority and ceaseless change. And these conditions, as we know, constitute the very essence of life. In other words, we do not know how to deal with autopoiesis—that is why we feel ourselves in need to aggress it and to deny its reality” [102]. As part of the paradigm shift in sciences presented in earlier sections the “neo-Darwinian conception of evolution” is challenged by the notion of co-evolution, “(…) that emphasizes cooperation as the creative play of an entire evolving universe” [103].

Autopoesis, self-organization, adaptation, complex systems and the above discussed concepts have been increasingly integrated in the last decade in social sciences research. “In the literature on complexity theory applied to social systems, ‘self-organization’ has a more specific meaning, for example, ‘a process in which the components of a system in effect spontaneously communicate with each other and abruptly cooperate in co-ordinated and concerted common behaviour” [104].

As an example in spatial planning, cooperation between urban areas is at the very core of the polycentric regions paradigm adopted in the European Union. Here cooperation is viewed as a competiveness factor for the intervening cities: “Promoting complementarity between cities and regions means simultaneously building on the advantages and overcoming the disadvantages of economic competition between them” [19]. In the spatial planning policy framework for the European Union the polycentric paradigm plays a pivotal role. Complementarity is approached from a broad perspective and should focus not merely on economic issues but together with other urban functions such as environmental quality and social well-being. As an example, when one considers the emergence of polycentric communities foreseen to result from the implementation of this spatial planning approach, if we are to assure those to be socially viable, then co-operation should be fostered and built on common interests of all participants, as to re-integrate the n cities of the urban ensemble into one single community [65].

Another dimension of cooperation is the most needed collaboration between ecologists and social scientists, and planners and designers in inter- and transdisciplinarity studies focusing on urban environments, which are found critical to the emerging sustainability science [32]. Arguing for a stronger emphasis in the human dimension of sustainability and for both inter- and transdisciplinarity studies in planning Botequilha-Leitão emphasized the need for a symbiosis, within the SLP framework, between natural sciences (e.g., landscape ecology), social sciences (e.g., collaborative methods), and humanities (e.g., landscape history) as they all hold much value to an integrated, transdisciplinary planning approach [38]. It also argued for bridging the gap across a (too often) fragmented and divorced science (and knowledge as a whole). This holds true also between science and planning. In a world still dominated by reductionist thinking different areas of knowledge are reluctant to knowledge sharing and cooperation. It does not facilitate a proper, efficient, and true multidisciplinary integration much needed when planning for sustainability. In similar terms Musacchio argues to link sustainable design to sustainability science and calls for an expanded definition of translational research “[The process medical researchers use to bring scientific discoveries from research into clinical practice] (…) directed toward environmental professionals: a collaborative learning process between scientists, designers, planners, and engineers who seek to solve complex environmental problems by connecting scientific theory, concepts, and principles to the design and planning of the built environment. This definition of translational research assumes that such approaches and methods are transdisciplinary—not only are interactions among scientists, designers, and planners important, but public participation is a vital part of the process that should include practitioners, elected officials, local residents, and others” [105].

In the above context it is most important to develop collaborative ecological planning. As argued before public participation in the planning process is essential to successful planning [38,39]. Failure of former planning approaches led to the increasing recognition that collaborative methods are crucial in order to promote more and better citizen participation. Research has shown that people are more likely to accept an issue resolved when they have had a voice in the decision-making process [106]. Landscape planning and design professions have acknowledged this fact and incorporated participation in most methodologies. Meaningful and informed stakeholder and public participation is viewed as a most important dimension in a sustainable land planning process. Bottom-up approaches are needed and citizen participation is a key issue for successful planning, design and implementation of sustainable landscapes. Collaborative methods, e.g., collaborative design, are most useful to understand the cultural dimension and its interface with natural processes [38,107]. Public participation increases acceptance and the implementation success of plans, by increasing plan’s legitimacy. It empowers citizens, decreases the participation deficit, and thus contributes for a better democracy, and promotes social connectivity. It also increases citizens’ self-esteem and confidence. Finally it helps in accounting for uncertainty in planning by sharing responsibility and involving citizens that will be affected by decisions in the decision-making process, which contributes also for sharing power and thus increases decentralization and shortens the distance between decision fora and the receivers of policies [38].

I finish this section by stating “Axelrod’s (1984) principles of cooperation (…)—co-operation can get started by even a small cluster of players who are prepared to reciprocate, can thrive even in a world where no one else will cooperate and can protect itself once established—so long as the co-operation is based on reciprocity and the shadow of the future is important enough to make this reciprocity stable” [108].

More than half of the world’s population is urban and this phenomenon will continue to grow, with an emphasis on coastal areas where natural resources, e.g., biodiversity, are particularly concentrated; it is in cities that most of the environmental problems concentrate; moreover cities constitute highly vulnerable situations to the effects of global climate change [5]. Cities are highly vulnerable also due to the almost total reliance on external inputs: some commodities and manufactured goods travel thousands of kilometers between the point of production and the point of consumption [22], which is arguably made possible by an oil-based economy. Industrial societies in general and cities in particular, are the product of petroleum and may implode without it [109]. Not surprisingly “(…) most, if not all, our cities are unsustainable” [31]. However urban spatial planning is primary concerned with the degree of segregation or aggregation of different economic and social functions, efficiency of transportation and delivery of utilities, and efficient filling of undeveloped space [110]. The environmental dimension is usually a secondary consideration (if considered at all). Urban regions’ planning targets are traditionally focused on the several dimensions of socio-economical systems such as economics, transportation, housing, industry and so forth and not so much on climate, water, biodiversity, and other ecological systems dimensions [46]. Therefore we need a novel approach in city planning and design to lead us into the path of sustainability.

I argue that one of the key-challenges to Man today is to envision human habitat from a broader perspective (both thematically and spatially) than just the built-up space, i.e. urban areas, particularly when considering large urban agglomerations. Planners should mesh both socio-economic and ecological dimensions, and acknowledge the horizontal relationships of both processes with its context, into a unified approach. When planning and designing the cities of the future one should include all of the other landscape functions and processes that sustain them. These include those landscapes that provide for the necessary inputs needed for urbanites not only to survive but to live fully, namely the landscapes of production (and recycling) and recreation, and those that provide for the essential services that forms the ecological backbone that sustain all of the other functions [38] together in regional, cohesive, multifunctional, and resilient landscapes [22,61,73]. It is a shift from the parts to the whole, i.e. from the city, the economic-financial dimension, and mostly sectorial-based policies, to considering the city and its “region of influence” (see Section 3.3), and the three dimensions of sustainability—economic, social and ecological—supported by truly integrated policies, and governance institutions.

In a recent past the dominant conservation paradigm was focused on ex situ solutions such as zoos to preserve endangered species, and segregation-based, museum-like approaches for preserving the last natural ecosystems from Man’s negative influence. Today a paradigm shift in conservation biology is undergoing from single-species management to ecosystem management and from isolated reserves to managing the entire landscape [15,111]. The implementation of wide range ecological networks can be seen in Europe, i.e. the ecological network “NATURA 2000” at continental level [19,29,38], at the national level in some European countries such as in the Netherlands [29], among others, at the regional level, e.g., the Regional Ecological network for the Algarve, Portugal [34], or at the metropolitan level, e.g., in the Metropolitan Area of Lisbon [38]. As conservation is broadening its objectives to encompass the entire landscape as a whole so should humans consider the entire globe as their habitat. The former, narrow perspective of human habitat is rooted in the 17th Century Western culture that viewed Nature, not as its home (habitat) as the ancient Greek did, but solely as a reservoir of natural resources for Man’s own benefit, as implicit in Bacon (1624) and Descartes (1636) writings [112]. A legacy of the Enlightenment, this “Cartesian dualism” that maintains the psychoseparation of humans from their natural roots where human enterprise is somehow seen as separate from and above the world. In this period of “transition to sustainability” [81] it must be counteracted and overcome.

To cope with such complex, multidimensional issues that cities are facing entering the XXI century, the cities of the future need novel planning perspectives informed by holistic and systemic thinking. “The major problems of our time cannot be understood in isolation, since they are systemic, meaning they are interconnected and interdependent and must be seen as different aspect of one single crisis—a crisis of perception. This results from an outdated worldview—a perception of reality inadequate to deal with these problems” [42]. The new logic introduced by the information society with its high rates of change and the emergence of new, complex environmental issues calls also for a long-term planning vision that ought to frame everyday decisions. These broad visions would contribute to counteract those small, piece-meals, non-concerted actions decisions that have a particularly high impact in urban and suburban landscapes [111]. Part of the problem is that science has become so reductionist that society is victimized by a “tyranny of small technologies” (deriving from small decisions). “Piece-meal” or “quick-fix” approaches often work well in the short term of economic and political worlds, and when done independently as they often are, the central problem is not properly addressed [47]. According to T. Kuhn we have been experiencing in the turn of the XX century a paradigm shift, both scientific and social [49,113]. “Such a scientific revolution has occurred in the last 20±30 years with the emergence of the new field of what could be called `complexity science'. It has been enabled by the major paradigm shift from parts to wholes, leading from entirely reductionistic and mechanistic toward more holistic and organismic approaches, (…) and systemic thinking” [49].

In the former section I have explored several useful metaphors, concepts, and paradigms for sustainable city planning and design. These are emerging as a response to the challenges for urban planning of the new century, in the context of the abovementioned paradigm shift. Below I will elaborate on the role of the science of landscape ecology for a regional approach to city planning, focusing on some key-concepts and how those new emergent ideas described above can together contribute for better planning the cities of the future.

Landscape ecology, the scientific pillar of the sustainable land planning framework (SLP) [24,38,39], is increasingly relevant to sustainability in general and urban development in particular [31,46]. In order to promote more sustainable approaches to planning in the last decades of the 20th century we observed a transformation of the landscape planning paradigm to incorporate an explicit ecological approach, namely in Europe and in the USA [38,39]. More recently landscape planning begun to adopt landscape ecological principles and tools [24,25,38,39,40,56,114,115] and extending its principles more or less explicitly to urban planning and design [24,31,32,33,34,35,36,37,38,39,40,46,51,53,54,57,74,75,76,77,78,80,85] inter alia.

In earlier works I proposed and explored a framework for sustainable land planning (SLP) [24,38,39]. The SLP framework is a strategic landscape planning approach, based on the science of landscape ecology and several associated key-principles derived from holism, systems theory, and complexity theory described in earlier sections. SLP is proposed as both an art and a science by promoting the integration of the ecological, social, and cultural dimensions into design, planning and management of sustainable landscapes; it thrives for ecological and social equity and for the involvement of citizens and stakeholders at large across the entire planning (circular, iterative, continuous, learning) process (see PROBIO case-study below); and it adopts an adaptive planning approach under a “learning-by-doing” attitude which includes a continuous cycle of implementation-monitoring-evaluation [44] “(…) by treating the adopted planning solution as a working hypothesis rather than a 100% full proof solution (as done traditionally), that should be tested and closely monitored for its consequences” [38]. “Sustainability is a goal that no one as yet knows how to achieve. The act of sustainable planning and design is a heuristic process; that is, one in which we learn by doing, observing, and recording the changing conditions and consequences of our actions” [117]. Together with scenario techniques, and public participation this adaptive approach also contributes to deal with uncertainty both in science and planning [48,57], and thus to increase system’s resilience [44,83]. It integrates ecological with social and cultural processes, e.g., by promoting a participated process and by incorporating landscape history, which both contribute to formulate landscape visions. Finally SLP encourages intuitive and creative thinking by incorporating the development of shared planning visions, and the design of spatial planning concepts. The latter are useful to explore possible future directions, and to support the discussion of a broader range of ideas, the development of scenarios and the engagement of both decision-makers and the public at large into the planning process. SLP is arguably appropriate to all planning realms, e.g., waterresources [24,40], conservation planning [24,38,39], and urban planning [24,33,38,39].

The research project “Decision Support System for Planning and Management of Biodiversity in Protected Areas (acronym PROBIO, Ref. no. POCTI/MGS/36580/99)” (1999-2003) is an example of the application of the SLP framework [38]. The following description of PROBIO will focus on the integration of the social component via the process of collaborative planning and design implemented.

The major goal of PROBIO was to develop a Decision Support System (DSS) for Planning and Management of Biodiversity in Protected Areas. The DSS integrated landscape metrics, scenarios, and a Multi-Agent System (MAS) in a GIS environment, supported by collaborative planning and design. The study area was the Natural Park of Sintra-Cascais (PNSC), located in the Lisbon Metropolitan Area, in Portugal. The PROBIO project used alternative future planning scenarios in order to anticipate and prevent or minimize environmental impacts on protected areas, and to attract stakeholders’ participation, and the public in general to the planning process. Biodiversity indicators based on landscape metrics were useful to evaluate the different planning scenarios or management alternatives. The MAS was developed to model the socio-economic component and to help multi-purpose negotiations between the several (social and economic) agents in the Park, forming the central core for scenario generation. The assumption was that agents modeling could help the PNSC staff enhance its relationships with the social-economic agents involved in the park area. A series of workshops were promoted as to involve public and stakeholders participation. Before the workshops individual meetings were conducted with more than 40 stakeholders (individuals and groups) who supplied important information about the activity and vision of each participant. This information allowed identifying the main strategic vectors for the development of the region, which were translated into the scenario themes. The first workshop aimed at a pre-diagnosis using a SWOT procedure. At the end a questionnaire was distributed that allowed us to evaluate stakeholders’ opinion about the workshop. They thought it to have been relevant, stimulating, informative, and efficient. They mentioned they learned about the issues that were debated and about the other stakeholder’ opinions. The goal of the second workshop was to translate the planning issues identified by the stakeholders into a more spatial and detailed form, i.e. to reference geographically (present and potential) land use conflicts. This method is referred to as collaborative design. We produced a set of maps in transparencies that allowed to overlap them as in the McHarg method, e.g., natural resources, cultural heritage, zoning plans, etc. In the last workshop we presented the results to the stakeholders, in a nontechnical language. Previously we sent to the stakeholders a list of criteria (social, economic and ecological) asking them to rank these according to a dual goal: allow urban development, and protect wildlife. We discussed these criteria with them and produced a new ranking, as a product of a group decision. For this session we divided the stakeholders in groups as done in the other workshops. Then we aggregated the individual rankings (surveys were anonymous) and debated a final ranking with them. These criteria served as input for the MAS, to define rules for the simulation of urban growth in the PNSC. According to both the PNSC director at the time (O. Knoblich, pers. com), and the one that followed a few years later (C. Albuquerque, pers. com.), the experience was highly useful to the ongoing process of the PNSC new zoning plan, and to establish a strong linkage with the stakeholders and the public in general in this protected area. The integration of social sciences with landscape ecology, history, and planning, and computer modeling was crucial to approach the management of protected areas more sustainably by integrating the social-economic with the ecological dimension.