of the ecosystem, which are known to mediate the energy and material flow within the entire system. Based on the principles and characteristics already mentioned, the following four proposed domains are relevant to the development of ecological engineering in terms of these two ecologies [19]:
1 Core system ecology theory
2 Ecological network analysis
3 Ecological modeling
4 System science
3.3 Practice and Implication of Ecological Engineering
A Newtonian approach alone may not be sufficient in formulating the design and principles of ecological engineering while framing a sustainable system. A balance between the domains of ecology, engineering, and design proposes a sustainable system model including an open living ecosystem that coexists with societal development. Traditional ecological knowledge3(TEK) and practices may prove to be revolutionary alternatives in generating thought‐provoking ideas for managing and restoring the environment by designing sustainable ecological engineering methods [2]. TEK has been practiced by indigenous and local populations to meet socioeconomic requirements since ancient times. With the integration of new techniques and concern about the environment, these practices have evolved over the years to ensure ecosystem sustainability and conservation. A World Commission on Environment and Development [62] report stated, “Local communities are the repositories of vast accumulations of traditional knowledge and experience that links humanity with its ancient origins. Their disappearance is a loss for the larger society, which could learn a great deal from their traditional skills in sustainably managing very complex ecological systems.” For more complex ecosystems with living and non‐living sections, a Newtonian worldview should embrace an organic approach to extend its boundaries. Traditional engineering, however, may not be successful in a natural system that depends on controlled distribution imposed on the environment and emergent behavior of the system during ecosystem management and design.
The practice of ecological engineering has been observed in various ecosystems with self‐design models and sustainability. Several large projects around the world have been designed based on these concepts: in the eastern part of the United States, restoration of salt marshes on Delaware Bay [45, 54]; river restoration in Jutland, Denmark, with farm and civilization protection [44]; reduction of nitrogen loading in the Gulf of Mexico [36]; restoration of Southeast Asian tropical mangroves [3]; and Mississippi River delta restoration [11, 12]. Mitsch [32] showed that well‐designed ecological engineering following oil spills in the Gulf of Mexico is more important than a traditional engineering approach that resulted only in wasting money and resulted in great harm to the ecosystem.
Practical approaches to ecological engineering are supported by programs and academic discussions. North American universities have developed several such programs: a separate environmental and ecological engineering department has been set up at Purdue University, Oregon State University has renamed its agricultural engineering department to biological and ecological engineering, and the University of Florida offers graduate‐level courses on ecological engineering. Other universities, such as the University of California Davis, Ohio State University, and McGill University, have special programs designed for students in this discipline.
3.4 Priority Areas for Ecological Engineering
The world population is growing rapidly and is expected to reach 10 billion by 2050 [5, 25]. With this accelerated population growth, exploitation of natural resources, fragmentation of land and water bodies, and extensive damage to ecosystems are inevitable consequences of urbanization and infrastructure development as a part of modern civilization. The prevailing processes of using non‐renewable natural resources and allochthonous energy inputs for long periods of time impose a future threat to the environment as a consequence of the exhaustion of these resources. Such resources are considered successful providers of energy and services due to their high calorific value.4 Urbanization, on the other hand, is linked to artificial floods, drying up of water bodies, soil erosion, and pollution of all strata of the ecosystem; it ultimately leads to imbalances in the ecosystem, agricultural outputs, and ability to maintain the biodiversity of the planet. A balance between the natural ecosystem and ecosystem engineering services must be retained for the vitality of mankind. It is vital to identify key areas of conservation priorities and meticulously design ecological engineering services with ecological principles and rules to develop and manage structures that effectively enhance industrialization with a reduced impact on the environment.
Xiao and Xiao [63] mathematically identified potential areas and hotspots/coldspots based on the amount of change in ecosystem services (i.e. provisioning, regulating, cultural and supporting services to human obtained from aquatic ecosystems, forest ecosystems, grassland ecosystems and agro ecosystems), assuming 100% conversion of all non‐forest land into forest. The ecological engineers, planners, and managers establish a monitoring program that objectifies decisions, ensures target fulfillment, and addresses social needs. For any restoration project to be successful, there are three primary stages of an effective adaptive management plan: (i) a clear vision and goal statement, (ii) a conceptualized design or model, and (iii) a definite framework [55]. The target or goal statement is a means to evaluate the system's practical applicability that can be assessed with the project's performance criteria. A properly designed model helps in devising a target‐oriented project based on ecological science. A project framework is based on a system‐development matrix by incorporating the knowledge gained through the previous two ingredients required for a project. During the process of implementing ecological engineering models and then developing and restoring a particular region, plausible outcomes must be foreseen and required measures undertaken to correct problems.
The term restoration is defined as any process that focuses on returning a system to its original, pre‐existing situation. The Society for Ecological Restoration has defined ecological restoration as “the process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed” [48]. The aim of ecological restoration is to replicate structures with reference to natural ecosystems as a basic model, maintaining biodiversity, functionality, and other parameters. Ecological engineering involves creating and then restoring sustainable ecosystems, thus benefiting both humans and Nature. Some of the major areas that require the attention of ecological engineering projects for development and restoration are discussed next.
3.4.1 Coastal Ecosystem Restoration
Protection and preservation of coastal regions were traditionally meant to safeguard against flooding. However, incomplete knowledge about the state of the system with this traditional approach often impacted the local ecology negatively and caused unpredicted outcomes that eventually affected the ecosystem more significantly. Incorporating ecological services into coastal ecosystem protection and restoration, due to the need for novel, cost‐effective, sustainable designs for solving problems like rising sea levels due to climate change and minimizing the anthropogenic impacts on these ecosystems, has attracted the attention of many researchers [13].
To fulfill the objectives of coastal ecology restoration, the methods used should be selected based on the paradigm of a few species (such as mussel beds, oyster beds, and vegetation) that can participate in the enhancements with their ability to modify/save the physical structure of the environment; the construction of dams or dikes also enhances ecosystem' biodiversity. In addition, the unique ability of these species to trap and stabilize sediments in intertidal areas leads to soil elevation and attenuation of tides; they are also suitable for construction of low‐cost, sustainable dams. For example, marram grass (Ammophilaarenaria) can trap sand, hence building protective sand dunes that invigorate dikes in sandy coastal regions. Dams or dikes constructed with reef‐forming shellfish species,
