Systematic investigation of the coral-inclusive potential of marine infrastructure

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Ecosystems are under pressure worldwide, due to both natural and anthropogenic stresses. Stresses on ecosystems can cause a decline in biodiversity, a loss of habitat and a deterioration in ecosystem services. To avoid further pressure on ecosystems caused by advancing economic development, new infrastructure projects should be integrated into the ecosystem. Environmental Impact Assessments (EIAs) are now mandatory for projects that are likely to have significant environmental effects. EIAs have primarily focused on mitigating negative impacts. However, recently new design philosophies have emerged such as ‘Engineering with Nature’, ‘Working with Nature’ and ‘Building with Nature’ which also focus on promoting positive impacts.
Constructively realizing nature-inclusive projects is complicated due to involving stakeholders with dif-fering perspectives. Therefore, in an integrated approach towards new marine infrastructure devel-opment, the next step is to promote constructive collaboration between stakeholders to systematically investigate the nature-inclusive potential of infrastructure. This thesis describes a proposed strategy for doing so, within the context of nearshore infrastructure development located in or nearby coral ecosys¬tems. The focus is on how nature-inclusive potential of new marine infrastructure might be maximised, taking into account the local ecosystem.
The aim of this research is to find an optimal approach to develop coral-inclusive infrastructure. This is done by structuring the required discussions between stakeholders considering socio-economic, ecolo¬gical and engineering perspectives regarding the nature-inclusive design potential of new marine infra¬structure. For this purpose, a method was developed that proposes a step-by-step strategy to promote constructive collaboration between relevant stakeholders, consisting of the following five steps:1. project description, outlining the basic challenge at hand

2. project location analysis, involving a systematic assessment of
the relevant ’natural system’ as well as the ’anthropogenic system’

3. Development of marine infrastructure design applications,
involving an inventory of project ele­ments that can have negative or positive
effects on the overall ecosystem

4. inventory and ranking of potential measures, objectively outlining
feasibility and potential effect­iveness of measures and design modifications

5. summary of sustainable design recommendations, leading to a
systematic ranking of potential measures proposed to support further decision
We have investigated the effectiveness of the systematic method, by applying it to a case study in Sint Eustatius that investigates whether the intended extension of a breakwater in Sint Eustatius can be designed as a coral-inclusive project. Sint Eustatius was chosen because Rijkswaterstaat offered research opportunities on location. In an ideal case, the use of long-term consistent data maps the nat¬ural factors over a longer period of time. This provides greater certainty of results and recommended actions. However, the values that were reported for the Sint Eustatius case were not derived from long term systematic data collection. Furthermore, the substrate from the existing breakwater looks to be promising for coral recruitment. However, there is not a lot of coral development evident on the existing breakwater. Possible negative factors hindering coral development on the existing breakwater are: 1) poor water quality; 2) high hydrodynamic circumstances with high wave action in shallow waters which limits the type of coral species; 3) inconsistent larval supply through ocean currents.
Coral reef connectivity seems sufficient and potential substrate is already present in the existing break¬water. Extension of the breakwater will lead to substrate increase which could improve the chance for coral recruitment in a hurricane-risk area as Sint Eustatius. A valid next step that could be proposed to aid a better understanding of this habitat is to invest in an extensive and dedicated data gathering campaign.

In conclusion, the main improvements derived from the application
of the systematic approach for nature-inclusive potential for infrastructure
projects are:

·  providing
an overview of the steps required to create coral-inclusive infrastructure,

·  instigating
the investigation of the status or the possibilities for coral development,

·  assisting
ecologists and engineers to structure the discussion on coral-inclusiveness,

·  lowering
the barrier to use (new) design philosophies,

and stimulating coral development and decreasing negative effects
by providing design recom­mendations.

Bringing stakeholders with different
perspectives together in one nature-inclusive project plan remains challenging.
Environmental data can play a role in arriving at a realistic approach
supported by ecolo­gists and civil engineers to realize nature-inclusivity for
infrastructure. This requires knowledge, money and time and could provide
insight into the threats and opportunities. The systematic approach, derived in
this thesis, has been proven to support stakeholders in assessing the
nature-inclusive potential of marine infrastructure.