Exploring the Ecological Effectiveness of Taiwan’s Ecological Check and Identification Mechanism in Coastal Engineering

Abstract

Extreme weather events from climate change challenge infrastructure stability. While water-related engineering enhances disaster resilience, it also impacts ecosystems. Taiwan has implemented Ecological Check and Identification (ECI) since 2003, yet challenges remain in standards, resource allocation, and effectiveness. This study analyzes 35 coastal engineering cases and participated in two engineering projects from five key perspectives. The results show that there are regional differences in the types of projects implemented for ECI. Landscape engineering was the main type in northern Taiwan (31%), water resource engineering was the main type in southern Taiwan (43%), and no cases were found in eastern Taiwan. Most inspections occur in the proposal (24%), planning (22%), and design (22%) stages, with limited post-construction monitoring (14%). Furthermore, ecological assessments were lacking in 49% of cases, and aquatic ecosystems were underrepresented. Inconsistent inspection formats and low species documentation (57% of cases) reduce data comparability and conservation effectiveness. To address these gaps, some recommendations were made, including standardizing inspections, integrating Sustainable Development Goals (SDGs), promoting low-carbon approaches, strengthening public participation, and establishing long-term monitoring. The findings provide policy insights to enhance ECI, supporting sustainable coastal engineering while balancing infrastructure benefits and environmental conservation.

1. Introduction

Extreme weather events caused by global climate change, such as heavy rains and typhoons, pose severe challenges to the stability of infrastructure. In Taiwan, the increasing frequency and intensity of such events have placed significant pressure on water-related engineering systems, including reservoirs, rivers, and ports. These developments align with global trends noted by the Intergovernmental Panel on Climate Change, which highlights infrastructure vulnerability as a major concern in climate adaptation planning [1]. In response, the Taiwanese government has actively promoted post-disaster reconstruction and disaster prevention infrastructure through a series of national policies, including the Forward-Looking Infrastructure Development Program and the National Climate Change Adaptation Action Plan, Phase III (2023–2026) [2,3].

The institutional promotion of the Ecological Check and Identification (ECI) mechanism in Taiwan can be traced back to 2003 when the Public Construction Commission began conducting related studies and gradually established a standardized framework. One of the earliest legislative references to ecological conservation appeared in the Special Regulations on the Improvement of Shimen Reservoir and Its Reservoir Watershed, enacted in 2006, which incorporated ecological protection considerations into water-related engineering planning. This regulation explicitly addressed key issues such as environmental and ecological conservation, geomorphological maintenance, and comprehensive watershed restoration [4].

Although primarily focused on upstream watershed management, it reflected Taiwan’s early awareness of integrating ecological considerations into major water infrastructure projects. More importantly, the regulation introduced a form of integrated ecological assessment thinking that aligned with the core principles of the ECI mechanism later formalized. As such, it served as a foundational step that paved the way for the institutional development of ecological governance in public construction.

If water-related engineering projects are carried out without a proper ECI mechanism, they may cause significant and long-term impacts on ecosystems—such as habitat destruction, disruption of migration corridors, and species loss [5]. In response to these concerns, since 2003, the Public Construction Commission of Taiwan has promoted a series of ECI-related studies and gradually established a standardized and institutionalized mechanism. This mechanism has since been integrated into various stages of public construction and engineering governance [6]. While early applications of ECI in engineering projects can be traced back to 2008 [7], its implementation has significantly increased in recent years, especially in water-related engineering, including reservoirs, rivers, and, notably, coastal infrastructure [8].

As coastal engineering is one of the primary application domains for ECI, it is essential to understand the physical characteristics of Taiwan’s coastal zones. Taiwan’s coastlines are primarily categorized into three types: clastic coasts, rocky coasts, and biogenic reef coasts [9]. Clastic coasts, also referred to as sandy coasts, are formed through the weathering and fragmentation of rock masses. These fragments are transported downstream by rivers to estuaries and coastal areas. Rocky coasts consist of rock formations such as sedimentary, igneous, and metamorphic rocks. Biogenic reef coasts develop when solid substrates are present in tropical to subtropical climates, facilitating the growth of reef-building organisms such as hermatypic corals and crustose coralline algae. This growth leads to the formation of coral reefs and algal reefs [10,11,12]. The distribution of these coastal types in Taiwan is detailed in

Table 1. Distribution and types of Taiwan’s coast.

Coastal Type		Distribution Area in Taiwan
		North	West	South	East
Detrital	Sandy shore		V
Rock	Gravel-free beach	V
	Gravel beach			V	V
Biomass	Coral reefs			V
	Algae reef	V

Note: “V” indicates the presence of the characteristic.

. Each coast type necessitates different engineering approaches, and ecological considerations vary accordingly [13].

Taiwan’s coastline, characterized by clastic coasts, rocky coasts, and biogenic reef coasts [11,13], presents diverse geomorphological and ecological features. Each coast type necessitates distinct engineering strategies and ecological considerations. In response to the increasing awareness of marine environmental protection and sustainable development, coastal protection practices in Taiwan have evolved beyond traditional structural defenses to embrace integrated approaches.

Commonly used coastal protection methods can be categorized into hard engineering, soft engineering, and hybrid methods. Hard engineering, such as vertical seawalls and groins, focuses on robust structural stability but often disrupts natural coastal processes [14,15]. Conversely, soft engineering methods, including beach nourishment and vegetative stabilization, align more closely with natural dynamics and prioritize ecological preservation and landscape enhancement, although they offer comparatively less protection against extreme wave events [16]. Hybrid approaches seek to combine the advantages of both systems, effectively balancing safety with environmental sustainability [17]. The characteristics, advantages, and limitations of these coastal protection methods are summarized in

Table 2. Controlling factors and advantages/disadvantages of coastal protection methods.

Type of Construction Method	Control Target	Advantage	Shortcoming
Traditional seawall	Tide prevention, wave protection, linear defense	Easy construction and relatively low cost.	Wave reflection in front of the seawall tends to accelerate beach loss, causing beach erosion and reducing recreational accessibility.
Sloping seawall	Wave energy is reduced by increasing wave run-up distance through gentle slopes.	Weaker wave reflection reduces scouring at the toe of the seawall, providing better landscape aesthetics and recreational accessibility.	Requires extensive hinterland, has weaker control over littoral sediment transport, and offers limited protection against storm surges.
Groin	Reduces the velocity of longshore currents, traps littoral drift sediments, and prevents shoreline retreat.	Simple structure and easy construction.	Likely to cause scouring at the groin head and exacerbate beach erosion downstream.
Offshore breakwater	Reduces wave intensity, increases defensive depth, and promotes sediment deposition to form beaches.	Sand spits or tombolos are formed behind offshore breakwaters, effectively nourishing the beach.	Toe scouring frequently occurs, maintenance is difficult, and erosion often occurs on the downstream side, resulting in poor landscape aesthetics.
Submerged breakwater	Reduces wave energy and facilitates sediment accumulation to form beaches.	Restrains offshore sediment transport without adversely impacting landscape aesthetics.	Limited control over littoral sediment transport; unsuitable for areas with large tidal ranges; navigation safety must be considered.
Artificial headland bay	Provides localized protection by altering wave patterns to achieve beach stabilization.	Facilitates the formation of bays in static equilibrium.	Most effective when applied to coasts with smaller waves and consistent longshore sediment transport directions.
Artificial beach nourishment	Maintains beach presence to protect against tides and waves.	Forms natural beaches, maintains beach areas to absorb wave energy, enhancing recreational accessibility.	Requires continuous sand replenishment with high implementation costs; more effective when combined with other protection methods.
Artificial sand dune	Maintains coastal dunes to protect against tides and waves.	Excellent at absorbing wave energy and providing good recreational accessibility.	Requires extensive hinterland and continuous sand replenishment; performs better when combined with sand fences or vegetation stabilization methods.
Integrated coastal protection	Provides comprehensive area-wide protection, expanding defensive depth against wave and tidal attacks.	Offers high safety, excellent landscape aesthetics, and recreational accessibility.	Requires extensive hinterland and high implementation costs.

[14,17].

In practical applications, ecological considerations in coastal engineering have become increasingly critical. For example, in Taiwan’s Xiangshan Wetland, rapid mangrove expansion previously led to reduced benthic biodiversity and sediment accumulation. Subsequent moderate mangrove removal has significantly restored benthic biodiversity, notably increasing the abundance of key indicator species such as Mictyris brevidactylus, Macrophthalmus banzai, and Uca arcuata [18,19]. Internationally, similar ecological recoveries following mangrove management interventions have been observed in Mangawhai Harbor, New Zealand, and coastal regions of China [20,21].

Moreover, adjustments in mangrove ecosystems can influence wetland carbon cycling, with bioturbation by intertidal benthic organisms such as mud shrimp playing a significant role in enhancing carbon sequestration capacity [22]. Advances in monitoring technologies, particularly environmental DNA (eDNA) analysis, have further enhanced the precision and efficiency of marine biodiversity assessments, offering a promising complementary tool to traditional ecological surveys [21,23]. Integrating innovative monitoring techniques with conventional assessment methods can strengthen the ecological evaluation framework for coastal engineering projects and promote more sustainable environmental management.

The evolutionary process of ECI can be categorized into three distinct stages based on its development (Figure 1). The first phase is the early research stage, during which the foundational theories are constructed, and relevant domestic and international experiences are referenced, aiming to initially explore the relationship between engineering activities and ecological conservation [24,25,26].

The second phase is the operation and testing stage, during which the inspection process and standardized tools are designed, and operational tests are conducted using small-scale cases to adjust the applicability of the inspection mechanism and gradually implement it into practical applications [25,27].

The third phase is the empirical validation and confirmation stage, during which ECI is widely applied to various engineering cases, and its scientific validity and feasibility are verified through empirical research. Additionally, the accumulated implementation experience is utilized to improve cross-agency collaboration and data-sharing systems, further providing scientific evidence for the formulation of ecological conservation policies [5,28,29].

The ECI mechanism has been implemented for over 20 years, serving as a crucial tool for evaluating the environmental impacts of engineering [30]. Its scientific foundation has been utilized to support environmentally friendly development and ecological conservation. However, although the mechanism has been applied to public construction in Taiwan, challenges remain at both the institutional and implementation levels. The current system lacks unified standards and effective cross-agency coordination, making it difficult to compare application results and hindering evidence-based decision-making for ecological protection [31,32]. Moreover, the inspection process remains insufficient in terms of standardization, consistency across project stages, and the ability to evaluate ecological effectiveness. In addition, at the specific implementation level, the inspection standards and evaluation benchmarks of each unit are scattered, making it difficult to effectively evaluate the ecological impact of different engineering types, thus limiting the overall effectiveness of the inspection mechanism [5,30].

According to statistics from the Public Construction Commission, in September 2024, there were a total of 2468 public construction projects, and only 747 cases required ECI, accounting for only 30.3%. Some of the unimplemented projects are exempted mainly because of “maintenance and management related engineering” or “non-centrally subsidized engineering” [33]. In engineering design and planning, ecological conservation was not adequately emphasized in past professional training, resulting in ecological impacts not being fully considered and further limiting the depth of ECI implementation in engineering [5]. How to enhance the scientific rigor and operational feasibility of the inspection mechanism—and promote a better balance between engineering benefits and ecological conservation—remains a central issue to be explored in this study.

This study evaluates the effectiveness and challenges of Taiwan’s ECI mechanism for coastal engineering. A total of thirty-five collected cases and two executed cases were analyzed to assess the distribution characteristics and implementation efficiency of ECI across different regions and engineering types. Special attention was given to the enforcement of the inspection mechanism at various engineering stages.

2. Literature Review

2.1. Environmental and Ecological Assessment Frameworks

This study summarizes common past regulations related to environmental protection, impact assessment, ecosystem management, and other fields. A comparative overview of these regulations is presented in

Table 3. Summary of differences between previous ecological-related work and ECI.

Regulation	Environmental Impact Assessment	Ecological Impact Assessment	Habitat Assessment	Ecological Risk Assessment	Environmental Management Plan	Ecological Check and Identification
Announcement time	1970	1980–1990	1970	1980	1970–1980	2017
Execution purpose	Assess the overall environmental impact of development engineering	Reduce damage to ecosystems	Evaluate the habitat suitability of a specific area for a species	Quantify and assess potential harm to ecosystems from risk sources	Develop specific measures to manage and reduce the environmental impact of the engineering	Reduce the negative ecological impacts of engineering and promote eco-friendly engineering methods
Execution scope	Broad coverage of the natural and social environment, including air, water quality, soil, and noise	For ecosystems and associated biological groups, focusing on species and habitat impacts	Focused on a particular habitat	Target sources of risks that may cause ecological damage	Covering the entire engineering cycle, from design to environmental management, during construction and operations phases	Cover the engineering construction area and its surrounding ecologically sensitive areas and dynamically monitor ecological impacts
Ecological conservation methods	Mitigation, compensation, alternative strategies	Ecological engineering method	Targeting habitat protection and restoration	Risk mitigation strategies	Mitigation measures	Avoid, reduce, mitigate, and compensate
Citizen participation	Mandatory public participation	Rely mainly on experts for assessment	Rely mainly on experts for assessment	Rely mainly on experts for assessment	Ask for public participation	Emphasis on the participation of citizen groups, stakeholders, and civil society
Information disclosure	Public	May be made public or restricted to internal use	Usually not public	May be made public or restricted to internal use	Public	Public
Implementation Region	International, applied in Taiwan	International, applied in Taiwan	International, referenced in Taiwan	International, referenced in Taiwan	International, applied in Taiwan	Taiwan

.

• Environmental Impact Assessment (EIA)

EIA was first introduced in the 1970s and initiated under the National Environmental Policy Act (NEPA) in the United States [34,35]. It was subsequently adopted worldwide and has since become a standard tool for the pre-assessment of development projects [35,36]. EIA is one of the earliest and most widely applied frameworks to evaluate the potential impacts of human activities on the environment, including ecosystems [35,37]. It typically covers environmental domains such as air, water, soil, and biodiversity and emphasizes the proposal of mitigation measures to reduce negative effects [37,38]. This regulation has been adopted in Taiwan and forms the foundation of the Environmental Impact Assessment Act.

2.

Ecological Impact Assessment (EcIA)

EcIA emerged in the 1980s and 1990s as awareness of environmental protection increased. As an extension of EIA, EcIA has been widely adopted to assess ecosystems specifically and has become a common tool in environmental protection regulations in many countries [39,40]. This is a branch of EIA that is specifically focused on ecosystem assessment. EcIA mainly focuses on the impacts on biodiversity, species habitats, and ecological connections and provides specific protection and remediation plans in the assessment [40,41,42]. This assessment framework is not formally institutionalized in Taiwan but is partially referenced in ecological-related evaluations.

3.

Habitat Assessment (HA)

HA has been applied to the management of protected areas and natural habitats since the 1970s, particularly in North America and Europe [43,44]. This concept was initially developed to support wildlife conservation and habitat restoration and was later incorporated into various environmental protection programs as conservation policies strengthened [45]. This concept focuses on assessing the habitat status of an area and its suitability for local species. This type of assessment is typically used for conservation plans or pre-development environmental reviews [43,46]. This assessment approach is mainly applied internationally and referenced in Taiwan for specific ecological conservation projects.

4.

Ecological Risk Assessment (ERA)

ERA emerged in the 1980s as concerns over industrial pollution and chemical risks increased [47,48]. It was developed as a tool to quantify the impacts of risks on ecosystems and has been utilized to identify and mitigate potential ecological risks [47,49]. This is an assessment of substances (e.g., pollutants and chemicals) that may pose risks to ecosystems. The purpose of ERA is to quantify the extent of risk and propose response strategies to reduce potential harm to organisms and the environment [47,50]. ERA is internationally adopted and has been referenced in Taiwan’s pollution control and ecological impact studies, though not widely institutionalized.

5.

Environmental Management Plan (EMP)

EMP was introduced in the 1970s and 1980s and was typically integrated with EIA to ensure that environmental protection measures were implemented throughout project operations [35,51]. It encompassed environmental management and monitoring from construction to operation. Although EMP has a broad scope, it is often used in early engineering to ensure that environmental protection measures can be implemented during the development process [51,52]. EMP includes monitoring and mitigation measures for engineering impacts and sometimes involves ecological protection [51,53]. EMP is a globally used tool that is incorporated into EIA practices in Taiwan, particularly in large-scale infrastructure and industrial development.

6.

Ecological Check and Identification (ECI)

ECI was established in 2003 by the Public Construction Commission to mitigate the negative environmental impacts of public construction [5,6]. It was developed based on the principles of ecological conservation, public participation, and information transparency, aiming to create a high-quality environment proactively, and corresponding guidelines were formulated accordingly [6,28,29]. This mechanism is currently implemented in Taiwan and serves as a national standard for ecological consideration in public construction.

As can be seen from Table 3, in terms of environmental investigation and protection, various regulations have similar concepts in terms of purpose, scope, and method design. The larger differences are mainly reflected in the levels of public participation and information disclosure. Early investigation methods mostly relied on experts for evaluation, with relatively little public participation. In terms of data disclosure, some regulations favored internal use and failed to fully allow the public to access engineering and environmental information related to themselves. In comparison, Taiwan’s ECI regulations place greater emphasis on the participation of civic groups, stakeholders, and non-governmental organizations (NGOs) [5,6,30]. Additionally, data disclosure is required to enhance transparency and increase public awareness [5,6,28].

2.2. Taiwan SDGs (T-SDGs)

T-SDGs were proposed in 2019 by the National Development Council to align with the global SDGs while addressing Taiwan’s unique environmental and social development priorities [54]. The concept of sustainable development originated in 1987 when the United Nations World Commission on Environment and Development published the Brundtland Report, which defined sustainable development as a strategy to “meet the needs of the present without compromising the ability of future generations to meet their own needs” [55]. This report marked the beginning of global awareness of sustainability issues.

Subsequent international initiatives reinforced this direction, including Agenda 21, launched at the 1992 Earth Summit, and the Millennium Development Goals introduced in 2000 [56,57]. In 2015, the United Nations adopted Transforming Our World: The 2030 Agenda for Sustainable Development, establishing 17 SDGs and 169 specific targets [58]. These were followed in 2017 by the development of 232 indicators for global progress measurement.

Taiwan began referencing the SDG framework in 2016 and, by 2018, had formulated 18 core goals, 143 targets, and 336 indicators tailored to national circumstances. These goals were revised and updated in 2019, and as of the 2022 rolling review, Taiwan had finalized 337 corresponding indicators to track and promote domestic and international sustainable development [54].

Recent studies have explored how ECI mechanisms can align with the SDGs. For instance, Shih [59] examined aquatic environmental construction in the Crescent Bay Marine Tourism Area using SDG 13 (Climate Action) and SDG 14 (Life Below Water) as the assessment framework. By monitoring the diversity and abundance of macrobenthos, the study found an increase in biodiversity post-construction and proposed recommendations for integrating ECI principles into water engineering, including carbon reduction techniques, use of local materials, and incorporation of ecosystem service values to support both economic development and ecological protection.

2.3. Taiwan ECI Promotion

Various agencies in Taiwan, such as the Public Construction Commission, the Water Resources Agency (WRA), the Forestry and Nature Conservation Agency, and the Institute of Transportation, have developed practical inspection systems based on the types of engineering under their jurisdiction and ecological conditions. These agencies have established different regulations for ECI, covering the scope of application, operational stages, ecological assessment methods, and professional background requirements. The guidelines for implementation and operational procedures were initially proposed by the WRA and were formally promulgated by the Public Construction Commission in 2017 as the Guidelines for ECI in Public Construction [6,32]. The compiled information is presented in

Table 4. Summary of ECI regulations by various agencies in Taiwan.

Government Agency	A 1	B 2		C 3	D 4	E 5	F 6	G 7	H 8
Agency-Specific Guidelines	Y	Y	Y	Y	N	N	N	N	Y
Release time	2013/12	2016/11	2017/02	2017/04	2017/04	2017/04	2017/04	2017/04	2017/08
Scope of application	Y	Y	Y	Y	Y	Y	Y	Y	Y
Operation stage	3	4	3	5	5	5	5	5	5
Ecological assessment	Y	Y	Y	Y	Y	Y	Y	Y	Y
Ecological checkup form	12	14	1	1	1	1	1	1	19
Grading system	N	N	N	N	N	N	N	N	1, 2
Ecological professional background requirements	N	Y	N	Y	Y	Y	Y	Y	Y
Government Agency	I 9	J 10	K 11	L 12	M 13	N 14	O 15	P 16	Q 17
Agency-Specific Guidelines	Y	N	Y	Y	Y	Y	Y	Y	Y
Release time	2019/05	2019/05	2019/07	2019/12	2019/12	2020/12	2021/01	2021/11	2023/11
Scope of application	Y	Y	Y	Y	Y	Y	Y	Y	Y
Operation stage	4	5	3	4	5	5	5	5	5
Ecological assessment	Y	Y	Y	Y	Y	Y	Y	Y	Y
Ecological checkup form	14	1	5	11	8	2	1	5	1
Grading system	1, 2, 3	N	N	1, 2	N	N	N	N	N
Ecological professional background requirements	N	Y	Y	Y	Y	Y	Y	Y	Y

Notes: ¹ Water Resources Planning Branch. ² Water Resources Agency. ³ Public Construction Commission. ⁴ Maritime and Port Bureau. ⁵ Railway Bureau. ⁶ Taoyuan International Airport Corporation. ⁷ Freeway Bureau. ⁸ Highway Bureau. ⁹ Forestry and Nature Conservation Agency. ¹⁰ Civil Aviation Administration. ¹¹ Tourism Administration. ¹² Agency of Rural Development and Soil and Water Conservation. ¹³ Taiwan International Ports Corporation. ¹⁴ State-owned Taiwan Railway Corporation, Ltd. ¹⁵ Chunghwa Post Co., Ltd. ¹⁶ Institute of Transportation. ¹⁷ Central Weather Administration.

.

Regarding the operation stage, in most cases, the engineering life cycle is divided into five key stages: proposal, planning and design, construction, completion acceptance, and maintenance and management. Each stage represents a checkpoint for integrating ecological considerations. However, whether ECI is implemented at a given stage depends on project characteristics.

For example, large-scale or ecologically sensitive projects are typically required to initiate ecological checks from the proposal or planning stage to ensure early integration of mitigation strategies. In contrast, maintenance projects or low-impact urban works may only perform checks at the construction or completion stage if deemed necessary. The applicability across stages is often determined by project scale, funding source, and whether the site intersects with ecological conservation zones [7,57].

In terms of the ecological checkup form, The Engineering Council initially provided a standardized form template for conducting ecological checks. Over time, this form was customized by different agencies into multiple formats—ranging from 2 to 19 variations—depending on the ecological sensitivity and complexity of specific project types [6,7]. These forms typically include fields for project location, ecological type, engineering phase, adjacent sensitive habitats, indicator species presence, ecological connectivity, and proposed mitigation measures.

For the grading system: Certain agencies, such as the Highway Bureau and Soil and Water Conservation Agency, adopt a two-tier inspection system to distinguish between general and sensitive projects. Others, such as the Forestry and Nature Conservation Agency, implement a three-tier classification system that includes additional ecological criteria for projects in highly sensitive habitats [4,28].

For example, in the two-tier systems, Level 1 typically refers to projects involving ecologically sensitive areas, species habitats, or high public concern, requiring the involvement of ecological professionals or external teams. Level 2 applies to projects of lower ecological risk, which may be reviewed internally by the project team based on simplified forms and existing ecological data. The Soil and Water Conservation Agency and Highway Bureau both follow this two-level approach, with the Highway Bureau defining Level 1 as projects located in ecologically sensitive areas, involving key species habitats, or extending more than one kilometer in length.

In the three-tier system adopted by the Forestry and Nature Conservation Agency, Level 1 applies to highly sensitive or controversial ecological issues, Level 2 covers general projects with no major ecological concern, and Level 3 includes post-disaster emergency repairs or maintenance works in non-critical ecological zones.

As for the ecological professional background requirements, while some agencies, such as the WRA, do not mandate specific ecological expertise for project teams, other agencies adhere to baseline standards established by the Engineering Council. These standards typically require the involvement of personnel with training or degrees in environmental science, ecology, or related fields or compliance with one or more of the following: holding a professional engineering license relevant to the content, having more than two years of relevant ecological or EIA experience, possessing certifications from accredited ecology-related training, or having graduated from programs in ecology, biology, or environmental science [6,32].

3. Materials and Methods

3.1. Research Information and Background

Data analyzed in this study mainly come from Water Environments cases in the implementation of “The Forward-looking Infrastructure Development Program” by county and city governments in Taiwan, focusing on coastal engineering with public ECI results. The criteria for selecting cases include:

• Time frame: Plans implemented in recent years (2019–2024);
• Environmental conditions: Select engineering cases located in coastal areas;
• Data disclosure: Screen cases with public ECI results for current status collection and analysis.

This study collected 35 coastal engineering cases from the Forward-looking Infrastructure Development Program, which was launched to address Taiwan’s long-term challenges in flood prevention, water resource management, and ecological sustainability. Originating from the National Water Forum in 2016, the program emphasizes “Smart Water Management, Happy Water Taiwan” and promotes integrated water resource strategies focused on development, safety, and environmental protection. These cases serve as a basis for analyzing the current implementation and effectiveness of ECI mechanisms in coastal engineering. In addition, two actively implemented projects were included to supplement the analysis [3].

In addition to the 35 cases collected, this study also analyzed two projects that were actually implemented, Case A and B. Case A is a port project, and Case B is a park landscape facility project in the estuary area. This study explores the ecological impact assessment and conservation strategy formulation in the design stage of these two cases.

3.2. Multilevel Research

Multilevel research has been recognized as an emerging and widely adopted paradigm in the field of organization and management [60,61]. Multilevel analysis is a statistical method that has been designed specifically to handle data with hierarchical structures, such as individuals nested within groups or students nested within classes. This method allows researchers to analyze variations across different levels simultaneously, enabling a more accurate estimation of relationships between variables. Methodologically, it is composed of three main components: model development, parameter estimation, and model evaluation.

First, the Hierarchical Linear Model can be chosen to analyze continuous outcome variables, while the Generalized Hierarchical Linear Model can be used to handle non-continuous outcome variables, such as binary or count data. Second, in parameter estimation, common methods include Maximum Likelihood Estimation and Bayesian Estimation, which are used to compute the optimal values of model parameters. Finally, the model evaluation uses the intraclass correlation coefficient to quantify the proportion of variation at different levels and uses the likelihood ratio test (Likelihood Ratio Test) or information criteria (such as AIC and BIC) to compare the fit of the model. For example, in the study by Wen and Shih [62], the application of multilevel models in organizational and management research was thoroughly examined, and solutions to challenges related to technology, measurement, and methodology were proposed.

This study began by collecting case data, which were categorized based on area, engineering type, ECI execution stage, and inspection form to establish a comprehensive data structure. Subsequently, using area, engineering type, and inspection stage as the primary analytical levels, SPSS version 20.0 was employed to perform data cleaning and multilevel qualitative and quantitative analyses. The results were compared with case characteristics to verify patterns and explore potential influencing factors.

4. Results

4.1. Overview of ECI Implementation

Based on the literature review and institutional documents, Taiwan’s promotion of ECI aligns with international standards in ecological survey and environmental assessment. Since the official implementation of the mechanism in 2017, agencies have developed context-specific inspection guidelines tailored to different engineering types and ecological conditions [5,6,7,32].

Furthermore, in light of global attention to climate change, some researchers have begun incorporating SDGs into ecological check frameworks, particularly SDG13 (Climate Action) and SDG14 (Life Below Water) [55,59]. This indicates that Taiwan’s ECI system has the potential to become a strategic reference for integrating ecological assessment with sustainable infrastructure planning.

Nevertheless, the promotion and practice of ecological checks in Taiwan remain largely decentralized. Each agency conducts its own adaptations, leading to challenges in standardization and experience sharing. A more integrated, cross-agency collaboration mechanism is needed to enhance the operability and scalability of the system [30,31].

This study collected 35 cases, mainly distributed in the northern (11 cases), central (3 cases), southern (15 cases), and outlying island areas (6 cases), as shown in Figure 2 and Appendix A. Since the eastern area mostly focuses on river inland engineering, there are no engineering cases in coastal areas. The southern region has the highest number of cases, most of which are classified as hydraulic engineering. This indicates that because of its geographical characteristics, there is a high demand for flood control and coastal protection engineering in this area. In the northern region, the majority of cases involve landscape engineering and urban renewal, reflecting the emphasis on environmentally friendly construction in urbanized areas. Additionally, harbor-related cases are primarily concentrated in the coastal areas of Keelung.

According to the distribution of ECI within the engineering life cycle, the highest number of cases occurred in the proposal stage, with 12 cases (24%). This was followed by the planning and design stages, each with 11 cases (22%). The number of cases in the maintenance and management stage is relatively low, with only seven cases (14%). The primary reasons for this discrepancy may include:

• Engineering has not yet progressed to the construction and subsequent stages.
• After the early stages, due to budget constraints, time pressures, or the absence of major ecological concerns, the later stages are deemed unnecessary and thus discontinued.

This not only limits the assessment of long-term ecological impacts but may also affect the environmental protection and habitat improvement effects of engineering on the ecosystem. Figure 2 shows the geographical distribution and project type distribution of these cases in Taiwan.

As shown in Figure 3, the proposal and design stages are primarily dominated by landscape engineering and river restoration engineering, indicating that the demand for ECI is higher in the early planning phases. This may be due to the fact that these engineering projects require greater consideration of ecological integration and aesthetics.

Hydraulic engineering and slope improvement engineering are primarily distributed in the planning and construction stages, reflecting that these types of engineering focus more on technical implementation and structural safety. As a result, the demand for ECI in the early stages is relatively lower. In the maintenance and management stage, the proportion of ECI generally decreases. However, river restoration and landscape engineering still maintain a certain number of inspections, indicating that these types of engineering place relatively greater emphasis on the ecological impacts in later stages. However, in the maintenance and management stage, the proportion of ECI for harbor and building engineering is nearly zero, indicating that long-term ecological impact monitoring for these engineering may have been overlooked. This distribution characteristic reflects that the focus of ECI varies significantly across different engineering types at various life cycle stages.

Landscape engineering and river restoration engineering emphasize ecological compatibility in the early planning phase, whereas hydraulic engineering and slope improvement engineering focus more on monitoring requirements during the technical implementation stage. However, in the post-construction maintenance and management stage, the proportion of ECI in most types of engineering remains low, which may be attributed to insufficient resource allocation or inadequate policy requirements.

In analyzing 35 public construction cases involving ECI, it was found that ecological surveys varied significantly in scope and focus. Most cases concentrated on terrestrial organisms such as mammals, birds, and amphibians, while relatively fewer incorporated aquatic ecological components. This trend highlights a practical emphasis on terrestrial over aquatic surveys.

As shown in Figure 4, 17 cases did not conduct any ecological surveys, while the remaining cases primarily focused on terrestrial ecological assessments. This outcome is influenced by several factors. First, the constraints of engineering project timelines often lead to the use of existing or historical data instead of conducting field-based ecological surveys to save time. Second, aquatic ecological surveys generally require more specialized expertise and longer implementation periods, resulting in higher costs that may discourage their adoption.

A review of the relevant literature indicates that, even in coastal engineering projects, ecological investigations have often emphasized terrestrial organisms (e.g., vegetation and birds) over aquatic or benthic species [18,59]. This suggests a gap in current ecological assessment practices in marine-related environments.

This imbalance in survey focus suggests a disproportionate allocation of ecological assessment resources, which may lead to insufficient evaluation of potential impacts on aquatic ecosystems. Therefore, although terrestrial ecological surveys are more commonly implemented in practice, the limited attention to aquatic ecosystems may weaken the comprehensiveness and scientific integrity of ECI efforts.

The analysis of form usage across the 35 public construction cases reveals substantial variation in the implementation of ECI documentation. Some projects completed up to 10 different forms, indicating a high level of engagement with the ecological assessment process. In contrast, 17 cases had almost no forms completed, suggesting limited application of the formal inspection mechanism.

As illustrated in Figure 5, this uneven distribution in form completion may reflect inconsistencies in how different competent authorities design and enforce ECI procedures. In some cases, the absence of completed forms may not necessarily indicate a lack of ecological assessment but rather a failure to publicly disclose relevant data. This highlights a potential gap in transparency and documentation standards across agencies, which could hinder consistent implementation and comparison of ecological check practices.

However, unfilled or extremely small numbers of forms not only affect data integrity but also reduce the transparency and credibility of the ecological verification process, limiting cross-case comparisons and subsequent analysis. On the other hand, the figure indicates a significant deficiency in the recording of focal species. The majority of 20 cases did not document any focal species, while only a few cases recorded a higher number of focal species, with only two cases documenting 14 species. This phenomenon may be attributed to multiple factors, including construction sites being located far from ecologically sensitive areas, being situated in already developed or heavily disturbed regions, and the insufficient depth of the ECI process.

For example, some cases may lack comprehensive ecological surveys and only use historical data instead, further leading to the neglect of ecological conservation objects. At the same time, it can also be seen that there is no obvious positive correlation between the number of forms filled in and the records of species of concern. For example, in some cases, multiple forms were filled out, but species of concern were still under-documented. This shows that relying solely on filling out forms cannot fully guarantee the effectiveness of ECI. In areas that may have potential ecological value within the construction scope, failure to record species of concern may result in irreversible ecological losses.

Therefore, the implementation of ECI should be further strengthened by enhancing the requirements for focal species surveys and documentation while optimizing the standardized design of inspection forms. These improvements would ensure the comprehensiveness and comparability of ecological assessments and enhance the specificity of conservation strategies.

4.2. Actual Participation Case Analysis

This section analyzes two engineering that were actually implemented. Case A primarily involves port engineering, where aquatic ecological surveys and the delineation of ecologically sensitive areas were considered during the design phase. Case B, on the other hand, applied a tiered inspection system in which the scope of ECI tasks was adjusted based on the ecological significance of the habitat, aiming to enhance execution precision and applicability. The work execution of Case A and Case B is described in the following two sections.

4.2.1. Case A

Case A was sponsored by the Yilan County Government and implemented in accordance with the “ECI Operation Manual” of the Fisheries Department [63].

This project is applicable to public construction related to aquaculture and fishing ports and is currently in the design phase. Its primary objective is to ensure that the engineering design complies with the ecological conservation goals established during the approval phase and to develop specific impact mitigation measures, which are incorporated into the construction plan to facilitate implementation and effectiveness tracking.

During the implementation process, natural and ecological environmental data within the project area are first collected and verified to supplement any incomplete aspects from the approval phase. At the same time, ecological issues and conservation targets within the project site are identified. On this basis, conservation strategies incorporating the principles of avoidance, minimization, mitigation, and compensation are formulated based on the results of ecological surveys and assessments. The detailed design is completed through close communication between ecological and engineering personnel.

Additionally, public participation is emphasized in the project, with ecology experts, relevant authorities, local residents, and concerned NGOs being invited to gather and integrate diverse opinions through planning briefings. This approach enhances the transparency and applicability of the planning process.

Similar experiences in other countries have also demonstrated the value of multi-stakeholder involvement in environmental planning and infrastructure decision-making processes [64,65].

This engineering project plans to extend the east breakwater by 60 m, aiming to improve the static stability of the port area. The engineering scope and planning scope are shown in Figure 6. Since this project falls under port and coastal engineering, its impact on marine ecology is direct. Therefore, surveys on aquatic organisms and water quality were conducted, covering the distribution of phytoplankton, zooplankton, fish, and benthic organisms. Additionally, an ecological concern map (Figure 7) was completed for reference by regulatory authorities and construction teams, indicating ecologically sensitive areas and key protection priorities within the project site.

4.2.2. Case B

Case B was sponsored by the Miaoli County Government and implemented in accordance with the “Standard Operating Procedures for Project Management of the Department of Rural Development and Soil and Water Conservation of the Ministry of Agriculture ECI Standard Operating Book” from the Department of Rural Development and Soil and Water Conservation of the Ministry of Agriculture [66].

The ecological review of this case adopts a two-level grading system. Level 1 inspections apply to areas with high ecological sensitivity or public concern and require detailed evaluations by an ecological team. Level 2 inspections apply to lower-risk areas and are conducted independently by project personnel under guidance.

Additionally, if a construction site falls under Level 2 inspection but meets certain conditions, such as being located in a critical water reservoir catchment area or adjacent to a Level 1 ECI zone, a “reinforced Level 2 inspection” must be conducted to enhance the completeness and accuracy of the inspection process. This case is adjacent to the Jhonggang River, an Ecological Park, and a Mangrove Reserve. The ECI belongs to Enhanced Level 2. The tasks to be performed according to regulations are as shown in

Table 5. Enhanced content for secondary ECI work.

Execution Unit	Handling Content and Process	Check Form
Ecological team	1. Help clarify ecological issues (including ecological protection objects). 2. Rapidly assess the impact of engineering on ecology and provide eco-friendly suggestions 3. Provide public participation suggestions and cooperate with relevant meetings or site surveys. 4. Submit the list on the right to the project execution agency for compilation.	1. Summary form of ecological guidance or related opinions 2. Public participation record sheet
Competent authority	1. Conduct an assessment and preliminary classification of ecological issues involved in the scheduled project. 2. Notify the ecological team to assist in the verification operation. 3. Invite the public to participate in platform meetings or field surveys. 4. When submitting the project for review, the form on the right must be attached. The project design can only proceed after confirming compliance with the processing principles and inspection levels.	1. Engineering survey record sheet 2. Ecological information query results table 3. Summary form of ecological guidance or related opinions

, including the content, procedures, and forms to be completed by the competent authority and the ecological team. The engineering scope and ecological concern map are shown in Figure 8 and Figure 9.

5. Discussion

5.1. Current Implementation Status of ECI

In this section, case data and previous research findings are used to examine five key aspects: regional distribution, inspection stages, inspection standards, focal species surveys, and other relevant criteria. Recommendations for improvement are also proposed.

• Regional distribution and differences in engineering types

Significant differences are observed in engineering types and ECI priorities across different regions. In the eastern region, engineering is primarily focused on inland river engineering, while in the northern region, landscape engineering is more prevalent. The southern region predominantly features hydraulic engineering.

These regional differences may lead to challenges in standardizing inspection criteria. Additionally, the lack of ecological information management systems may further affect the efficiency of ECI.

Shiau et al. [67] stated that if Geographic Information Systems and data integration technologies are incorporated into the ecological impact assessment of coastal engineering, the efficiency of inspections can be improved. The Marine Aggregate Levy Sustainability Fund [68], in a case study on the East Coast of the United Kingdom, emphasized the importance of data integration and monitoring technologies in enhancing the effectiveness of ECI and recommended that a standardized ecological monitoring system be established.

The implementation of information management systems across different regions in Taiwan could play a crucial role in addressing the observed inconsistencies in ECI standards. By integrating ecological data through standardized platforms, regional engineering variations can be more effectively managed, leading to greater consistency in ecological assessments.

2.

Implementation rate of ECI across engineering life cycle stages

ECIs are primarily conducted during the proposal and design stages, while the proportion of inspections during the post-construction maintenance phase accounts for only 14%. This indicates that the lack of a long-term monitoring mechanism may negatively impact the long-term effectiveness of ecological conservation. A study by Chu et al. [69] indicated that in wetland conservation engineering if a standardized long-term monitoring mechanism is not established, the impact of ECI may not be sustained.

Additionally, a study by Barrera [70] introduced the real-time ocean monitoring network in the Macaronesia region. This network was designed in accordance with the Coastal Ocean Observations Panel of the Global Ocean Observing System to enhance environmental monitoring and forecasting capabilities in coastal and open ocean areas. Real-time data have been provided by this system, integrating physical, geological, and chemical parameters to support marine resource management, pollution monitoring, and coastal disaster early warning systems. Similarly, coastal engineering should incorporate relevant mechanisms and long-term monitoring systems to ensure sustainable environmental management and effective impact assessment.

3.

Coverage of ecological surveys and insufficiencies in standardized inspection criteria

Ecological surveys were not conducted in 49% of cases, and the proportion of aquatic ecological surveys was relatively low, indicating that the understanding of underwater ecological impacts in some engineering is limited. Chu et al. [71] indicated that the construction of fishing ports has a significant impact on biodiversity and emphasized the importance of benthic organism monitoring. Furthermore, a study by Coombes et al. [72] suggested that fine-scale surface heterogeneity should be incorporated into the design of coastal infrastructure to enhance ecological value and serve as a component of eco-engineering applications.

Additionally, E. Ostalé-Valriberas [16] conducted research in which artificial tide pools were excavated on existing coastal defense structures (seawalls) to enhance biodiversity and mimic natural environments. Through the application of green infrastructure, habitat creation can be promoted, and the ecological impact of coastal engineering can be minimized.

Moreover, a wide variety of inspection forms were used in the cases analyzed, with up to 10 different forms being completed, highlighting the lack of standardized criteria. This inconsistency has increased the implementation burden and affected the comparability of data. Therefore, the standardization of ECI forms should be considered as a key improvement for future ECI mechanisms.

4.

Carbon reduction and sustainable development mechanisms in ECI

In recent years, climate change concerns have necessitated the inclusion of carbon sequestration and carbon reduction mechanisms in ECI. Wang et al. [73] indicated that coastal blue carbon ecosystems, such as mangroves and salt marshes, can effectively absorb carbon dioxide, and if incorporated into coastal engineering designs, carbon reduction benefits can be enhanced.

Yang and Yuan [74] further demonstrated that constructed saline wetlands vegetated with mangroves not only support wastewater treatment but also provide effective carbon sink functions, highlighting the importance of considering habitat-based carbon sequestration in coastal engineering. Therefore, WRA [75] has promoted the “Green Water Conservancy” policy, which emphasizes the use of low-carbon construction materials and permeable concrete to reduce carbon emissions in hydraulic and coastal engineering.

5.

ECI: dimensions and challenges

Based on the findings of this study, the areas that require further enhancement in the future are summarized in

Table 6. Summary of ECI aspects and challenges (collected cases).

Physiognomy	Important Findings from the Case	Key Questions	Improvement Suggestions
Area distribution and type differences	1. The eastern area is dominated by river inland engineering and lacks coastal engineering cases. 2. The north focuses on landscape engineering and urban renewal, while the south focuses on water conservancy engineering.	Engineering requirements and inspection priorities vary widely in different areas, making it difficult to integrate implementation standards.	1. Combine regional needs and characteristics to improve the applicability of inspection standards [76,77]. 2. Compilation of regional inspection reference manual [78].
Engineering life cycle stage execution ratio	1. The reviews focused on 24% of the proposals (12 items) and 11% of the design and plan stages (11 items each). 2. The maintenance and management stage accounts for only 14% (7 cases).	Insufficient post-processing inspections make it difficult to track and assess long-term ecological impacts.	1. Promote full life cycle inspection, especially post-construction maintenance management. 2. Strengthen the monitoring and feedback mechanism after construction [79,80].
Ecological survey coverage	1. 49% of cases (17 cases) did not perform ecological surveys and mostly used historical data instead of field surveys. 2. the proportion of aquatic ecological surveys is low, and land area surveys are given priority.	The lack of basic ecological data may affect the accuracy and implementation of conservation strategies.	Increase resource investment in ecological surveys and promote the popularization of field surveys [81].
Check form standard differences	The number of cases filling forms is up to 10, and there is a lack of unified standards.	The lack of standardization in form design increases the execution burden and reduces the comparability of inspection results.	Unify form format and content and promote data sharing platform [82,83].
Pay attention to species recording rates	Only 2 cases recorded as many as 14 species of concern. Most engineering was located far away from ecologically sensitive areas or areas subject to human interference, and 20 cases were not recorded.	Insufficient attention is paid to the survey and recording of indicator species, which affects the comprehensiveness of conservation strategies.	Strengthen the recording mechanism of indicator species as the basis for subsequent conservation measures [79,81].

, with detailed explanations provided below.

(1)

Regional distribution and engineering type differences: In the eastern region, coastal engineering is lacking, with most cases concentrated on inland river engineering and no recorded coastal-related cases. This absence may indicate a lower demand for coastal engineering or the fact that related engineering has not yet undergone public ECI. In contrast, the northern region primarily focuses on landscape engineering and urban renewal engineering, while the southern region is predominantly engaged in hydraulic engineering. These regional differences highlight variations in engineering demands and ECI priorities, which may lead to challenges in the standardization of implementation criteria.

(2)

Implementation rate of ECI across engineering life cycle stages: The proposal stage had the highest number of cases (twelve cases), followed by the planning and design stages (eleven cases each), while only three cases were recorded during the maintenance phase. This finding reflects the insufficient execution of ECI after construction, which may be attributed to several factors:

A

Engineering projects not advancing to the construction and subsequent phases.

B

Decisions made to discontinue inspections after the early stages because of budget constraints, time pressures, or the absence of significant ecological concerns.

The lack of maintenance-phase inspections may hinder long-term ecological impact assessments.

(3)

Coverage of ecological surveys: Among the 35 cases analyzed, ecological surveys were not conducted in 17 cases. This finding indicates that some engineering projects did not thoroughly assess ecological conditions, which may be attributed to several factors: Project schedule constraints, leading to the use of historical data instead of field investigations, and the higher time and financial costs associated with aquatic biological surveys, resulting in prioritization of terrestrial biological investigations.

(4)

Differences in verification form standards: A wide variety of inspection forms were used across different cases, with up to 10 different forms being completed. Although a single standard form exists as a baseline, additional forms were introduced by regulatory agencies to address varying jurisdictional requirements, resulting in a lack of consistency in implementation.

(5)

Recording rate of species of concern: In most cases, focal species were not documented, with only two cases recording up to fourteen species of concern. This may be due to the fact that many engineering sites are located far from ecologically sensitive areas or in already developed regions where the environment has been impacted by human activities.

As a result, insufficient emphasis may have been placed on focal species during inspections, potentially affecting the formulation of subsequent conservation measures.

5.2. Discussion on Actual Implementation Cases

This section examines two engineering cases (Case A and Case B) in which active participation was involved, further validating the issues identified in the analysis of 35 cases. Additionally, the implementation status, challenges, and potential improvements of ECI in different engineering contexts are analyzed and summarized in

Table 7. Summary table of ECI aspects and challenges (actual participation).

Physiognomy	Important Findings from the Case	Key Questions	Improvement Suggestions
Area distribution and type differences	1. The port engineering in Case A is implemented in accordance with the regulations of the Fisheries Department, and will mainly conduct an investigation of the directly affected sea area ecology. 2. Case B is implemented in accordance with the regulations of the Department of Rural Development and Soil and Water Conservation of the Ministry of Agriculture. It will appropriately strengthen or simplify the ECI work according to the habitat environmental classification system.	Same as in Case 35, the engineering requirements and inspection priorities in different areas vary greatly, making it difficult to integrate implementation standards.	1. Combine regional needs and characteristics to improve the applicability of inspection standards [76,77]. 2. Compilation of regional inspection reference manual [78].
Engineering life cycle stage execution ratio	Cases A and B were only involved in the design phase of this study, and the construction phase was not continued by the same ecological team.	Different stages will be executed by different ecological teams, which may cause the standards to be inconsistent and make it difficult to track and evaluate the long-term ecological impact.	1. Promote full life cycle inspection, especially post-construction maintenance management. 2. Strengthen the monitoring and feedback mechanism after construction [79,80].
Ecological survey coverage	1. Case A: Conduct surveys on water quality, aquatic ecology (phytoplankton, zooplankton, fish, benthic organisms), and terrestrial ecology (mammals, birds, amphibians, reptiles, butterflies and plants) 2. Case B conducts surveys of water quality, aquatic ecology (fish, benthic organisms), and terrestrial ecology (mammals, birds, butterflies).	In both cases, a survey was conducted on organisms related to the engineering’s impact area, but it was only conducted once, which may result in insufficient representation due to seasonal factors.	Increase resource investment in ecological surveys and promote the popularization of field surveys [81].
Check form standard differences	Both cases A and B fill out 6 forms	The form designs of the two cases are different, which increases the execution burden and reduces the comparability of the inspection results.	Unify form format and content and promote data sharing platform [82,83].
Pay attention to species recording rates	1. Case A has no recorded species of concern 2. Case B records 1 species of concern	Insufficient attention is paid to the survey and recording of indicator species, which affects the comprehensiveness of conservation strategies.	Strengthen the recording mechanism of indicator species as the basis for subsequent conservation measures [79,81].

.

• Case A: Port engineering at the design stage

Case A represents the design stage of a port engineering project, where the direct impact of the project on the marine ecosystem was thoroughly considered. A survey of aquatic organisms, including phytoplankton, zooplankton, fish, and benthic organisms, was conducted, and an ecological concern map was developed to provide clear conservation recommendations for the construction team.

However, this case also revealed common challenges associated with port engineering, including the high cost and extended duration required for aquatic biological surveys. Additionally, although a public participation mechanism was planned, the effective integration of local residents’ opinions remains an area that requires further optimization in the future.

2.

Case B: Tiered inspection in rural soil and water conservation engineering

Case B was conducted based on the tiered ECI system established by the Rural Development and Soil and Water Conservation Agency of the Ministry of Agriculture. This case demonstrated a flexible management model that adapts to different levels of ecological sensitivity.

Under this system, inspections are categorized into Level 1 and Level 2 to distinguish the ecological sensitivity of construction sites and adjust the depth of inspection accordingly. In particular, Level 2 inspections are reinforced, covering key areas such as watershed zones, perennial river segments, and national ecological conservation areas, with clear inspection criteria provided.

However, this case also revealed potential issues in the tiered management system, such as the lack of nationwide standardized guidelines, which may result in inconsistencies in implementation standards across different regions. The relevant literature and discussion topics are summarized below:

3.

Ecological concern maps: Applications and implications

Compared with traditional environmental surveys that rely solely on textual descriptions or tabular data, the development of ecological concern maps in ECI processes may significantly enhance the understanding and accuracy of environmental and engineering information. These maps can help ensure that construction activities more precisely avoid sensitive areas, thereby reducing potential ecological disturbances during the construction process.

4.

Literature-based insights and international comparisons

To further validate the issues identified in Cases A and B, this study reviews academic discussions in the fields of ecology, environmental science, and marine engineering and proposes the following improvements.

(1)

Incorporation of the “Ecological Engineering” Concept into ECI: Chu et al. (2005) found that benthic organisms can serve as key indicators of the ecological impact of coastal engineering. However, 49% of cases in Taiwan did not conduct ecological surveys, leading to insufficient baseline data [82].

A study by Dugan et al. (2018) recommended that living shorelines or permeable structures should be prioritized to minimize ecological impacts, and artificial tide pools should be incorporated into engineered shorelines to provide microhabitats and enhance biodiversity. Additionally, long-term monitoring of nutrient cycling and ecological connectivity should be strengthened, and comparative assessments of different shoreline designs should be conducted to develop environmentally adaptive coastal management strategies [83].

Therefore, by utilizing living shorelines, artificial tide pools, and biodegradable native materials as part of nature-based solutions (NbS), the environmental impact of infrastructure can be reduced while simultaneously enhancing the ecological resilience and adaptive capacity of coastal communities. As advocated by Porri (2023), this approach aims to balance engineering requirements with ecological conservation [84].

(2)

Future development directions and international comparisons: The global trend in the sustainable development of coastal engineering is shifting toward the standardization of ECI and adaptive management. In Taiwan, Su et al. (2020) [5] proposed that a unified ecological check standard should be established to improve the integration of engineering and ecological considerations. This reflects an approach that aligns with emerging international perspectives.

Powell et al. (2019) suggested that hybrid infrastructure, incorporating natural and engineered solutions, should be prioritized to enhance coastal resilience against sea-level rise and extreme climate events. The feasibility of nature-based solutions (NbS) can be improved through policy support, interdisciplinary collaboration, and long-term monitoring [85].

Additionally, by incorporating economic assessments of ecosystem services and risk management analyses, decision-makers’ acceptance of natural infrastructure can be increased, positioning it as a core strategy in coastal management [85].

Furthermore, Kuo et al. (2012) proposed a mangrove benthic habitat model and emphasized the need to improve the scientific basis of ECI through Habitat Suitability Index (HSI) assessments [86]. Chang et al. (2004) investigated the spatial and temporal distribution of biota attached to wave-dissipating blocks and found a direct relationship between engineering design and species diversity, suggesting that future inspection standards could incorporate these key variables [87].

Kuo et al. (2012) also developed a rapid assessment model for Taiwan’s coastal hydrogeomorphology (CHGM, Coastal Hydrogeomorphic Model), which could serve as a reference for future ECI mechanisms [88].

5.3. Summary of Case Findings and Strategic Recommendations

Through the analysis of 35 coastal engineering cases and two actively participated projects, this study identified key challenges associated with the implementation of Taiwan’s Ecological Check and Identification (ECI) mechanism. The results revealed significant regional differences in project types, with landscape engineering predominant in the northern region and hydraulic engineering in the southern region, while no coastal engineering cases were observed in the eastern region.

The results revealed significant regional differences in project types, with landscape engineering predominating in the northern region and hydraulic engineering in the southern region, while no coastal engineering cases were observed in the eastern region. Furthermore, 49% of the projects did not conduct ecological surveys, and inconsistencies in inspection form usage were common. The insufficient documentation of focal species, with only two cases recording up to 14 species, highlighted gaps in ecological data and conservation strategies.

In response to these challenges, the following strategic recommendations are proposed to enhance the effectiveness of Taiwan’s ECI mechanism:

• Establish a unified ECI indicator system: Develop a comprehensive national standard for ECI, incorporating principles from the United Nations SDGs, particularly Goal 13 (Climate Action) and Goal 14 (Life Below Water).
• Standardize inspection regulations and procedures: Implement a nationwide tiered inspection system and standardize forms and databases to enhance consistency.
• Enhance implementation resources and professional support: Increase funding and establish cross-sector collaboration platforms for technical support.
• Strengthen public participation and transparency mechanisms: Create public participation platforms and promote data disclosure to build trust.
• Promote long-term monitoring and effectiveness evaluation: Establish dynamic ecological monitoring systems for post-project assessment.
• Expand Research Scope and Foster Future Studies: Incorporate practitioner interviews and focus on carbon reduction and local adaptation technologies.

6. Conclusions

This study highlights critical gaps in the implementation of Taiwan’s ECI mechanism for coastal engineering, particularly regarding standardization, long-term monitoring, and ecological survey comprehensiveness. By analyzing thirty-five cases and two actively participated projects it demonstrates that inconsistent practices undermine ecological protection efforts and sustainable development goals. The findings underscore the urgent need for a unified inspection framework, integration of SDGs principles, and enhancement of resource allocation and public participation. This study contributes by providing a systematic analysis of ECI challenges and offering strategic recommendations to strengthen future practices. Its insights serve as a valuable reference for policy revisions, engineering planning, and the advancement of ecological governance in Taiwan and beyond.