Coastal Monitoring & Benthic Surveys (Surveillance côtière et études benthiques)

Introduction (Background/Context/Problem/Scientific Rationale)

Coastal erosion and sea level rise pose significant threats to island ecosystems, particularly in low-lying areas like Mo’orea, French Polynesia. Understanding the current status of Mo’orea’s coastline is essential for developing sustainable management strategies that balance ecological conservation with local economic and cultural interests. This project aims to assess coastal erosion and sea level rise by documenting the current state of Mo’orea’s coastline through observations of coastal armoring, benthic surveys, and boat activity. 

Data collection, conducted between 2022 and 2025 by UC Berkeley's Island Sustainability classes, will help identify potential links between maritime activity and shoreline integrity by correlating these observations with localized erosion patterns. This coastal monitoring procedure has been implemented along most of Mo’orea’s coastline and is designed for long-term assessment.

Project Goals (objectives)

The primary objective of this project is to: 

• Understand current status of coastal erosion and coastal armoring and impacts on the transformation of the island’s coastline.

• Inform local management of current status

• Use information to apply to a management plan to address coastal erosion

• Develop research objectives and sampling strategies collaboratively with local stakeholders, ensuring alignment with cultural values and conservation priorities.

• Empower local communities with knowledge and tools for proactive coastal management.

Methods

We observed and surveyed Mo’orea’s the coastline profile using GAIA GPS to mark each coordinate and noted the following:

• Boat Monitoring: GAIA GPS, Photo capture (associated to a timestamp)

  • Type of vessel: Motorboat, Outrigger, Kayak, Swimming, From Shore (line fishing e.g.)

  • Type of gear used: Line, Net, Spearfishing, Other

  • Crew number: Number of fishers in group

Coastal Armoring: GAIA GPS, Photo capture (associated to a timestamp)

• Type of costal profile:

  • Armored: Rocks, Cement walls and embankments

  • UnArmored:Mangrove, Muddy areas or herbaceous zones, White sand beaches

  • Black sand beaches, Beach rock

Water outlets:

• Categorized types of water outlet: Gutter/Storm drain, Pipe, River

Substrate Transects / Benthic survey: Every 20 minutes after the last Benthic survey and record the time-stamp when transect tape is set out

• Start transect 3 steps from shoreline, Set-out transect tape 21 m distance orthogonally (towards reef-crest) from start-point. Every 3 meters we recorded the substrate, creating 8 observation sites. Within the observation sites there were 9 points along a 60 x 60 cm cross. We then recorded the substrate categories as: Live coral, Dead coral, Macro-algae, Turf, Coral rubble, Sand, Hard substrate (beach rock), Mud / sediment

Data aggregation:

• Each group entered their data including GPS point, timestamps and various characteristics.

• Input data into RStudio

Community Engagement

Given that data collection occurs near residential and commercial properties, community engagement is essential for fostering trust and ensuring ethical research practices.

• Respect for Private Property - Researchers must comply immediately if requested to leave a location.

• Transparent Communication - Field researchers should openly explain project objectives and methodologies to local residents.

• Consent & Permissions - Efforts should be made to seek informal approval before conducting surveys near private properties.

• Stakeholder Involvement - Community members will be invited to participate in discussions regarding coastal changes and potential conservation strategies.

Outreach Activities

To maximize the impact of this research, outreach activities will focus on:

• Public Presentations & Workshops: Sharing findings with local governance, environmental organizations, and community groups.

• Educational Programs: Collaborating with local schools to raise awareness about coastal conservation and climate resilience.

• Citizen Science Initiatives: Encouraging local residents to contribute observations and insights on shoreline changes.

• Online Data Accessibility: Creating an open-access platform where stakeholders can view and interact with research findings.

Project Expected Results

• Comprehensive documentation of Mo’orea’s shoreline, identifying erosion areas and changes over time.

• Quantitative assessment of maritime activity and its correlation with coastal degradation.

• Recommendations for sustainable coastal armoring solutions.

• Development of a long-term monitoring framework, providing a scientific basis for ongoing assessment of shoreline stability.

• Enhanced stakeholder collaboration, strengthening conservation efforts through community engagement and participatory research.

Expected Outputs & Management Plan

• Scientific reports summarizing key findings.

• GIS mapping outputs illustrating erosion patterns.

• Coastal management recommendations proposing adaptive solutions for Mo’orea’s coastal challenges.

• Stakeholder meetings for dialogue between researchers, policymakers, and community members to align conservation efforts with local needs.

Societal Benefits

We aim to contributes to both local and global sustainability efforts by addressing the following:

• Protecting Mo’orea’s coastline sustains tourism, fisheries, and property values by mitigating erosion and preserving natural beauty.

• Educational contributionsand programs.

• Informing evidence-based policies to promote climate resilience and sustainable coastal development.

• Serve as a model for other island communities facing similar climate-driven coastal changes.

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