term ecological engineering was coined by Howard T. Odum as early as the 1960s, and thus he is regarded as the father of the field [37]. He suggested ecological engineering for “those cases in which the energy supplied by man is small relative to the natural sources, but sufficient to produce large effects in the resulting patterns and processes” [37]. Since then, an array of definitions of ecological engineering has been proposed by many researchers. Odum has proposed several definitions, such as “the management of nature…, an endeavour with singular aspects supplementary to those of traditional engineering” in 1971 [38] and “the engineering of new ecosystem designs…that use systems that are mainly self‐organizing” in 1983 [39]. His contemporary, Ma Shijun, is famous as the “father of ecological engineering in China” for presenting his concept and ideology regarding ecological engineering [26, 27]. Teal also presented a definition of ecological engineering: “to use ecological processes within natural or constructed imitations of natural systems to achieve engineering goals” [53]. In another report, ecological engineering is defined as “the design of sustainable ecosystems that integrate human society with its natural environment for the benefit of both” [34]. “The practice of joining the economy of society to the environment symbiotically by fitting technological design with ecological self design” is another definition offered by Odum [40].
The basic idea of all these definitions is to create new designs to restore the ecosystem with sustainable development and help achieve harmony and integration of human society with Nature. The principles of ecological engineering combine the themes of basic and applied science to implement designing, contrasting, and restoring the ecosystem [49]. Engineering is a discipline that studies and solves technological problems. On the other hand, environmental engineering helps associate human society with the environment. This technology comprehends half of the interface while the other half is contributed by the self‐organizing ecosystem to complete the environment. Merging these two interfaces leads to ecological engineering, which uses natural resources with simultaneous economic growth for societal advancement. Figure 3.1 represents the exchange of materials and services in the ecological engineering domain.
The International Ecological Engineering Society (IEES) was founded in 1991 to conduct ecological engineering activities worldwide to promote the exchange of ecological engineering problems between scientific and educational organizations, private enterprises, non‐governmental and governmental organizations; and to facilitate cooperation among engineers, ecologists, and other scientists. Ecotechnology is used as a synonym for ecological engineering in the eastern part of Europe, defining it as a technological means to understand ecosystem management–based ecology with minimal cost and limited harm to the environment [50]. A number of sub‐disciplines, synonyms, and amalgamations of the two fields, as well as fields similar to ecological engineering are found in literature, such as industrial ecology, engineering ecology, agroecology, restoration ecology, reclamation ecology, synthetic ecology, bioengineering, ecotechnology, and nature engineering; aquatic, terrestrial, and wetland restoration; biomanipulation; habitat reconstruction and rehabilitation; and so on.
Figure 3.1 Sketches of the exchange of materials and services in the ecological engineering domain. (a) Unified system of environment and technology; (b) traditional boundary of environmental engineering design; (c) boundary of ecological engineering design.
Source: Odum and Odum [40]. © 2003, Elsevier.
The common aim of research by various groups with different backgrounds is to attain and promote the restoration1 and management of the ecosystem. Advances in engineering and environmental sciences during the twentieth century have made an immense contribution to ecological principles. A holistic approach toward the restoration and management of the biosphere with advanced engineering problem‐solving skills has led to the synergistic co‐existence of Nature and developed societies. In the 1960s, contradictory statements were raised in scientific communities on introducing a similar discipline, especially when environmental engineering was already well established. This new discipline integrates science and technology, deals with sustainability and self‐designed ecosystem; and serving the purpose of remediation and prevention of environmental issues and also addressing alarming global problems such as pollution and protecting the environment.
Ecological engineering envisages the practice of engineering methods and designs for ecological sciences, bridging these two disciplines with the interpretation of complex, uncertain, and variable natural systems. This approach can result in a unique archetype for designing engineering methods. Human beings are integral components of the ecosystem, providing the initial elements and composition and influencing the environment significantly. The self‐organizing ecosystem eventually takes over these changes and looks for the best route to adjust to artificial modulations imposed on it.
The approach of ecological engineering can be briefly summarized as (i) improvement of new or existing infrastructure with modern complex building models but using environmentally benign materials and ecofriendly designs, referred to as a “hard” approach2; (ii) incorporation of a “soft” approach, i.e. the replacement of buildings and infrastructure with natural habitats such as salt marshes, mangroves, or oyster reefs; (iii) designing hybrid ecological engineering where natural habitats or vegetation are made to coexist with built infrastructure[10]. The approach of ecological engineering may differ with the environment, geographic locations, resources, requirements etc., but the common goal of all the approaches is to restore the natural habitats with the best possible infrastructural design for the benefit of the environment with the progress of development.
The field of ecological engineering has developed immensely within the research and academic dimensions to achieve higher endeavors for environmental sustainability and mankind. Several essential steps are proposed by researchers as part of ecological engineering activities [2, 31, 33, 35, 50, 60]:
Propose principles.
Design processes and techniques.
Implement the techniques.
Organize research archives.
Create international societies.
Include ecological engineering in academic curricula.
Proposing principles is considered the most significant step as the foundation of ecological engineering will be established upon it. These principles must connect ecological theory with ecological practices on real ground, which has been a challenge to researchers for years. The primary principles of ecological engineering proposed by Ma [28] were designed to formulate species symbiosis, cycling, and regeneration, and harmonize the ecological structure with its function. Later, 12 commandants or guidelines were formulated as principles of ecological engineering [17]:
1 Ecosystem structure and functions are determined by the forcing functions of the system.
2 Homeostasis of ecosystems requires accordance between biological function and chemical composition.
3 It is necessary in environmental management to match recycling pathways and rates to ecosystems to reduce the effect of pollution.
4 Ecosystems are self‐designing systems. The more one works with the self‐designing ability of Nature, the lower the cost of the energy to maintain that system.
5 Processes of ecosystems have characteristic time and space scales that should be accounted for in environmental management.
6 Chemical