LOVELL, S.T.; JOHNSTON, D.M. 2009: Creating multifunctional landscapes

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TAYLOR LOVELL, Sarah; JOHNSTON, Douglas M. (2009): Creating multifunctional landscapes: How can the field of ecology inform the design of the landscape?, en Frontiers in Ecology and the Environment

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The publication of Ian McHarg’s Design with nature in 1969 challenged landscape designers to provide an ecological analysis of the landscape prior to recommending landscape changes (McHarg 1969). Since that time, landscape ecology has emerged as an applied field for studying the past, current, and future structure of the landscape, including the analysis of spatial metrics and the development of analytical models for assessing ecological, hydrological, and other impacts (…) represent major advances as analytical tools for studying spatial relationships, landscape change, land suitability for various functions, and social impacts.

(…) We suggest that opportunities exist for using ecological principles to influence the design of the landscape, from initiation through to completion, and that ecologists should be actively involved in this effort.

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Defining the project site and landscape context

Most designers and ecologists would agree that, for a landscape to function as part of a healthy ecosystem, the context of the site must be considered through a multiscale approach (Spirn 1985; Watzin and McIntosh 1999).

Nearly every site affects its surroundings through positive and negative interactions. The economic term “externalities” is used to refer to the costs and benefits of decisions that are not directly accounted for by the person making the decision – in this case, the land owner. Externalities result from lateral flows of water, air, soil, fire, substances, or organisms from one area of land to another and can be affected by landscape features that serve as barriers, filters, or corridors (van Noordwijk et al. 2004).

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Characterizing and analyzing landscape structures and functions

The development of a multifunctional landscape must include consideration of biophysical features important for conservation of biodiversity and ecological processes (Baschak and Brown 1995). Topography, hydrology, vegetation, soil type, and other features help to inform the design of landscapes by guiding decisions on the location of new landscape features, restoration of ecological functions, and production of food or other resources. Characterizing existing land uses, such as open green space, agricultural cropping systems, and built features, is critical to understanding the landscape and suitability for future functions. Socioeconomic features, including population density, household incomes, and land values, should also be considered in the design, to facilitate a better understanding of the cultural values of the site. The work of Ian McHarg demonstrates the specific contributions of ecology to the characterization of existing features through the comprehensive development of an “ecological inventory”, which includes climate, geology, hydrology, soils, vegetation, and wildlife. Today, these inventories are often developed as spatial data layers for use in GIS and help us to understand landscape conditions by providing a mechanism for characterizing existing landscape features and historical data (Watzin and McIntosh 1999).

Landscape analysis builds upon the inventory (characterization) by synthesizing complex data, aggregating values from established criteria, and modeling ecological processes (Baschak and Brown 1995). Classification systems to analyze ecological performance, based on heterogeneity in landscape spatial pattern, have been widely accepted (Gustafson 1998), but integrated approaches that include other metrics, such as plant community structure and landscape processes, are increasingly used to develop landscape associations (Baschak and Brown 1995; Makhzoumi 2000). Process models can be used to assess the existing and proposed conditions of the site, including hydrology, geomorphology, climatic conditions, habitat suitability, wildlife movement, risks to specific species, disturbance patterns, spread of invasive species, habitat fragmentation, and a range of ecological functions. These models can also be used to evaluate landscape modifications and compare design alternatives. The involvement of ecologists is critical during the stage of characterization and analysis of existing features, as they can identify key structure–function relationships within the existing site and recognize the importance of landscape pattern to the flows of resources and organisms.

Developing a master plan using an ecosystem approach

Using the ecosystem concept as a basis for master planning will provide a greater understanding of the landscape at multiple scales, while incorporating the needs of society and interactions between human activities and the environment (Spirn 1985). Ecosystem management can be defined as “the application of ecological and social information, options, and constraints to achieve desired social benefits within a defined geographic area and over a specified period” (Lackey 1998). With this approach, the framework for local landuse planning is the ecosystem and the ecological processes contained within it (Brody 2003); humans are considered a component of the ecosystem (Haeuber 1998). While ecosystem management plans have typically focused on natural and semi-natural areas, such as forests, prairies, and conservation lands, the same concepts could be applied to intensively managed urban and agricultural landscapes at the master planning stage (Spirn 1985). We suggest several design objectives, based on an ecosystem concept that would benefit from the input of ecologists, resulting in a greater likelihood of long-term success for the project as a healthy, functioning ecosystem.

The first objective is to improve landscape performance by developing designs that integrate multiple functions in the landscape. Ecosystem multifunctionality has been recognized as a condition for sustainability in natural systems (de Groot 2006), and recent interest has focused on

multifunctionality of intensively managed landscapes (Wiggering et al. 2003; Brandt and Vejre 2004). Within this context, we define multifunctionality as the provision of multiple environmental, social, and economic functions in a given area of land (Wiggering et al. 2003) (…)In contrast to the more abstract concept of “sustainability”, the goal in designing a multifunctional landscape is to consider ecological, production, and cultural functions within the same site. This approach encourages the designer to aim for multiple targeted performance standards, such as conserving and producing energy; providing food; managing water quality and quantity; reducing, reusing, and treating waste; conserving and increasing biodiversity; meeting visual quality expectations; and providing recreational opportunities.

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A second objective is to increase heterogeneity in the spatial pattern of the landscape. Recent studies suggest that increasing heterogeneity can improve ecosystem services in urban and agricultural landscapes by increasing function and resilience (Fischer et al. 2006). The addition of features such as woodlots, natural woody hedgerows, riparian buffers, greenways, and parks can all contribute to landscape heterogeneity, improving the quality of the landscape matrix and conserving biodiversity.

(…)“Ecological land-use complementation” (ELC) is a variation on the ecological network concept, emphasizing conservation of biodiversity and provision of ecosystem services through the clustering of complementary land uses. This spatial arrangement encourages movement between habitat patches, provides resources in close proximity to each other, and enlarges the area available in a habitat – all without changing the total area of each land-use type (Colding 2007).

(…)Conserving and promoting biodiversity is a third ecologically based design objective. Humans rely on a wide range of plants and animals to supply food, fiber, fuel, medicines, and many indirect services, such as nutrient cycling and waste decomposition. But global biodiversity is severely threatened by a number of human-related activities

(…)A fourth objective is to improve and manage water quality and quantity. Any transformation of the landscape involving a change in built structures, topography, vegetation, or soil structure will impact the hydrology of the site and areas well beyond. Development typically results in large areas of impervious or “sealed” surface, in the form of rooftops, roads, parking lots, and other built features.

Designing sites to highlight ecological functions

The development of key sites within the larger landscape can highlight ecological functions and bring them to the attention of the public. Plant selection and arrangement, choice of building materials, and development of hydrologic features can all have an important impact on the local ecology, while providing an opportunity to draw attention to ecological functions at the site scale. Guiding principles for designing a site might include: reduction in use of, and reuse of, building materials, protection and treatment of water, conservation of biodiversity, production of food and energy, and special consideration of cultural functions (Orr 1992; Nassauer 1997; Todd et al. 2003). “Eco-revelatory design” supports the concept of highlighting ecological functions, based on the assumptions that landscapes can reflect cultural values of nature and that they have the power to communicate those values (Brown 1998)

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Conclusions

(…) we are concerned that our research and education systems have not encouraged the interdisciplinary programs that might produce experts who understand both ecology and design. We feel that this problem needs to be addressed in the very early stages of the education process, by promoting the enrollment of ecology students in design studios, and encouraging design students to expand their coursework in the sciences. As McHarg appropriately stated in 1969, “There clearly is a desperate need for professionals who are conservationists by instinct, but who care not only to preserve but to create and manage” (McHarg 1969). If ecologists do not recognize the importance of the designed landscape to their field and become involved in the design process, they will not be prepared to meet the challenges of the future: human population growth, degradation of landscapes, and competition for limited natural resources.

Referencia

Lovell, S. T., & Johnston, D. M. (2009). Creating multifunctional landscapes: How can the field of ecology inform the design of the landscape? Frontiers in Ecology and the Environment, 7(4), 212–220. https://doi.org/10.1890/070178