Adaptability and sustainability

Urban landscape is as dynamic as urban life. It constantly changes. The design product is never finished due to both ever changing structure of urban realm and the living materials used in urban landscape design. Modern urban environments grow and expand so fast that efficient use of land becomes a necessity. Thus, any design should be capable of adaptation to changes through the time and space while maintaining identity. Adaptability and flexibility degree of a design product determines its lifetime. Therefore designing urban landscape requires a far-sighted approach. In landscape design adaptability can be achieved through selecting appropriate design elements (e. g. plants, water elements and construction material) that fit for site conditions (e. g. climate, soil and water resources) and creating multiuse or flexible outdoor facilities for activities for different groups in the community. On the other hand, if everything is designed to be flexible in order to achieve adaptability, then the design will fall apart without any sense of meaning or character. Hence some parts should be left permanent to provide a backbone for the design. Creating large open spaces is the easiest way to create flexibility in landscape design.

Adaptability is one of the key elements in achieving sustainability as it is about longevity. The concept of sustainability has been briefly explained in previous sections. Besides its strong relationship with life quality, ecological sustainability is fundamental to survival of all living organisms on the earth. Urban ecology, a relatively very new area of ecology, seeks to understand and explain ecological mechanisms within an urban environment. Embracing urban ecology in urban design and management is necessary to create sustainable environments. McHarg’s outstanding work "Design with Nature" (1969) has triggered ecological perspective in landscape planning and design. His overlay method of site

analysis (suitability analysis) aims to define potentials and constraints of an environment for land use planning. Although he has been criticized for neglecting cities and social dimensions, he promoted integration of the natural processes into planning and design. The suitability analysis of McHarg still constitutes a basis for contemporary landscape planning and design. Assessing the relationships between each component of an environment enables designers and planners to recognize the true potential of a site for various land uses. Neglecting natural values in design causes high costs of construction and maintenance (Memluk, 2009).

Ecological sustainability is a tough yet crucial challenge in landscape design. It is often hard for the designer to integrate his artistic desires with the ecological facts. Yet, ecological mechanisms can help and guide the landscape architect through the design, because landscape design mostly depends on natural resources. In their study, Cadenasso and Pickett (2008) presented and discussed five urban ecology principles in context of urban landscape design. Table 1 shows the summary of their work.

Principle

Principle basics

Design and practice implications

Cities are ecosystems

Cities are ecosystems by virtue of having interacting biological and physical complexes.

Urban ecosystems include four components: organisms, a physical setting and conditions, social structures, and the built environment.

Design affects all four components of human ecosystems.

Cities are heterogeneous

Heterogeneity in urban landscapes can be

caused by both biophysical and social Design should enhance structures and processes. In turn, biophysical heterogeneity, and its and social processes respond to urban spatial ecological functions. heterogeneity.

Cities are dynamic

Change in the structures and flows within cities, and between cities and other ecosystems lend a dynamic element to urban form and morphology (Decker et al. 2000; Kaika 2005; Shane 2005)

Design must accommodate internal and external changes projects can experience.

Human and natural

All landscape designs and management schemes should be judged for their ability to contribute to both social and ecological

Design should recognize and plan for feedbacks

processes interact in cities

goods and services, and to reduce both social and ecological risks and vulnerabilities (Steiner 2002; Grove et al. 2007).

between social and natural processes.

Ecological processes remain important in cities

Concepts and approaches basic to ecological research can be applied to urban areas in an effort to understand how the city itself functions as an ecosystem (Alberti et al. 2003).

Remnant ecological processes yielding ecological services should be maintained or restored.

Some strategies for ecologically sensitive urban landscape design are:

• Support and preserve biotic diversity and create habitat corridors.

• Minimize energy use and promote use of renewable energy resources. Reduce energy costs by using solar and wind energy systems.

• Protect and improve quality of water resources.

• Reduce water and fertilizer use by selecting native and drought tolerant plant species.

• Reduce water runoff by decreasing the amount of hard surfaces and proper drainage design.

• Conserve aquifer recharge zones.

• Provide collection and storage of rainwater in order to use it for maintenance of green spaces.

• Support pedestrian and bicycle circulation within the city. People should move easily and freely within a city. Cities should not be designed for vehicle traffic. Connected urban open and green space systems could create a environmentally and people friendly transportation routes.

• Choose plants suitable for local climate and site conditions. Selecting right plant species will increase the survival chance of plants in harsh urban environment, success of design and decrease maintenance costs.