Case study 3: (marine)

Hypothetical Case Study: Industrial Redevelopment of Coastal Area

At the end of this case study, you should be able to:

Apply the SGBA to a development project impacting primarily a marine ecosystem and secondarily resulting in terrestrial ecosystem habitat creation.
Use the SGBA to calculate Habitat Biodiversity Units (HBUs) for baseline and post-development habitats as functions of habitat area, distinctiveness, condition, creation and enhancement multipliers.
Identify habitat trading rules for enhancement across habitats and habitat biodiversity compensation between terrestrial and freshwater ecosystems.
Describe how overall biodiversity net gain may be achieved from biodiversity net loss and gain from terrestrial and freshwater ecosystems, respectively.
Suggest mitigation strategies to enhance, maintain biodiversity or minimise its loss.

This hypothetical example illustrates how the SGBA can provide a quantifiable framework for assessing developmental impacts and guiding mitigation efforts to achieve a biodiversity net gain, even in complex projects involving land transformation.

1. Location and Current Area Use: The project is situated at a coastal area in Singapore historically used as an abandoned fish village. The total area designated for this industrial development is 15 hectares, within which the construction of essential roads and industry-related infrastructure is planned. The baseline assessment revealed a blend of natural and semi-natural marine habitats characteristic of a coastal zone previously influenced by human activity.

2. SGBA Application Overview: The Singapore Biodiversity Accounting Metric (SGBA) is a robust, free-to-use tool designed to quantify the biodiversity value of habitats in Singapore, before and after development. It helps overcome the subjectivity often associated with traditional Environmental Impact Assessments by assigning numerical, unit-based values to habitats, thereby supporting informed decision-making for biodiversity retention, enhancement, and restoration.

Our objective was to use the SGBA to assess the biodiversity impact of the proposed industrial development on the coast and to formulate a mitigation strategy aimed at achieving a positive biodiversity net change.

3. Habitat Baseline, Creation, and Enhancement for the Marine Ecosystem:

Baseline Assessment: Before any development began, a comprehensive baseline assessment was conducted to quantify the existing biodiversity value of the 15-hectare coastal site. The assessment identified the following key marine habitat types present, along with their assigned distinctiveness and condition scores based on SGBA guidelines. Detailed SGBA calculations for what follows may be found herein:

Case study 3 XL vs GS- Copy of Camphora Master - SG Biodiversity Accounting Metric 1.1 DevV01b

Table 1: Baseline Habitat Units (Pre-development) of Marine Ecosystem Habitats.

Note: The habitat types selected, mudflats and artificial marine structures, are not categorized as "Irreplaceable - Avoid at all costs" or "Avoid at all costs" under the SGBA trading rules. Sandy Beach is also a permissible habitat type for development/mitigation.

Development Impact: The planned industrial infrastructure and roads will directly impact most of the entire 15 hectares of the baseline marine habitats, converting them into especially terrestrial "Developed Land" or "Bare Ground." Under the SGBA, these converted land uses are assigned "No Value" (0 HBU) for biodiversity. Therefore, the total loss of marine biodiversity units from the proposed development is 82.0 HBU.

Proposed Mitigation: Habitat creation and enhancement to counteract the biodiversity loss and achieve a net gain (or at least to minimise net loss), a strategic mitigation plan was developed using the SGBA. This plan focused on enhancing existing degraded marine habitats in areas adjacent to the development footprint, leveraging the flexibility of the SGBA to achieve "better outcomes for nature". The calculations incorporate the "Difficulty of Creation/ Enhancement" multiplier, which reflects the inherent risks and challenges associated with establishing or improving habitats.

Table 2: Post-Development Habitat Units (Enhancement) of Terrestrial and Marine Ecosystem Habitats.

a: Enhanced from baseline condition within the same distinctiveness. For enhancement calculations, the HBU gain is derived from the increase in condition value, multiplied by the relevant difficulty factor. Time to Target Condition: 10 (mangrove forest) & 4 (artificial marine structures) years (while not counting towards HBU calculation, this provides a guardrail for developmental planning and monitoring).

b: While classified as terrestrial habitat creation, the loss of baseline habitat area due to planned industrial infrastructure and roads classified in the SGBA carry no HBU value.

SGBA Application: Net Biodiversity Change Summary

Biodiversity Net Change Calculation: The true impact of the project, accounting for both losses and gains, is determined by comparing the total baseline HBU loss with the total HBU gained from the mitigation efforts. By comparing the total HBUs before and after development, we can determine the net change in biodiversity for the coastal project:

Total Baseline HBUs (Pre-Development): 82.00 HBUs
Total Post-Development HBUs: 83.50 HBUs

Combined Net Change in HBUs = Post-Development HBUs - Baseline HBUs

Combined Net Change in HBUs = 83.50 - 82.00 = +1.50 HBUs

Combined Net Percentage Change = (Net Change in HBUs / Total Baseline HBUs) × 100% Combined Net Percentage Change = (+1.50 / 82.00) × 100% = +1.83%

This calculation demonstrates that through careful planning and implementation of habitat creation and enhancement, the industrial redevelopment of coastal area can achieve a +1.83% net gain in marine biodiversity units. This positive outcome reflects a commitment to sustainable development and ensures a quantifiable benefit for nature beyond simply minimizing loss. While Singapore does not mandate a minimum 10% Biodiversity Net Gain by legislation, achieving any positive net gain significantly contributes to the vision of a "City in Nature".

Conclusion: This case study clearly illustrates how the SGBA serves as an invaluable tool for urban planners, developers, and environmental practitioners. By quantifying biodiversity impacts and guiding compensatory measures, the metric enables stakeholders to make informed, objective decisions that lead to tangible, positive outcomes for Singapore's natural heritage. Even in the face of unavoidable land-use changes, such as industrial development on former marine habitats, the SGBA provides a pathway to not just mitigate, but to genuinely enhance biodiversity, fostering a more sustainable and nature-rich urban landscape. This process, much like a meticulous financial ledger, ensures that our ecological accounts remain in credit, promoting a resilient environment for both nature and people.

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