🌿 Distribution and Habitat Modeling of Marine Macrophytes

Coastal Islands of Santa Catarina in the Context of the Climate Crisis

Master's Project - PPGOceano/UFSC | 2026

Student: Ronan Armando Caetano

Key message: spatial evidence to support monitoring and conservation of island habitats.

🌐 PT EN ES

πŸ“‹ Project Overview

Central Theme

To investigate how environmental and geomorphological variables influence the diversity and distribution of marine macrophytes across three coastal islands of Santa Catarina, focusing on spatial mapping and habitat suitability modeling.

Context and Relevance

  • Marine macrophytes are ecosystem engineers that sustain high coastal biodiversity.
  • These communities respond to changes in temperature, water transparency, and substrate structure.
  • The climate crisis and anthropogenic pressure increase the vulnerability of island habitats.
  • The project integrates biological inventory, geoprocessing, and SDMs (models that estimate where species are most likely to occur) to support applied conservation.

The Problem the Project Addresses

There is still a lack of detailed and comparable maps showing where marine macrophytes occur on the coastal islands of Santa Catarina and how they respond to environmental changes. Without this foundation, it becomes harder to prioritize monitoring and plan conservation actions.

What Will Be Done in Practice

1) Field Survey

The team records species, abundance, and environmental conditions on the three islands using a standardized methodology to enable fair comparison.

2) Mapping and Modeling

Field data are integrated into maps and models to indicate the most favorable areas for macrophytes and priority areas for monitoring.

3) Applicable Deliverables

The project generates scientific and technical products that can be used by research, environmental management, and coastal monitoring planning.

Why Does This Matter for Non-Specialists?

  • Helps identify the most sensitive marine areas that need protection.
  • Improves the technical basis for public decisions on coastal conservation.
  • Creates a comparable record to track changes over the years.
  • Translates complex data into maps and useful information for different audiences.

Questions the Project Answers

  1. Which macrophyte species dominate each island and how do they vary with depth?
  2. Which habitat conditions favor greater occurrence and relative abundance?
  3. How to spatially represent priority zones for monitoring and management?
  4. How might warming scenarios shift areas of greatest habitat suitability?

How to Read This Presentation

  • Study Areas: shows where the project takes place and why these islands were chosen.
  • Objectives: clearly explains what the project aims to deliver.
  • Methodology: details how data will be collected, analyzed, and transformed into maps.
  • Products: presents the expected results for science and environmental management.
  • Glossary: defines technical terms in accessible language.
  • Timeline: shows when each stage will be carried out.

πŸ—ΊοΈ Study Areas

Geographic Scope

Three coastal islands of Santa Catarina with a gradient of size, isolation, and anthropogenic pressure.

🟠 REBIO Marinha do Arvoredo

Centroid: 27Β°13'33"S, 48Β°21'56"W

Area: 17,131.72 ha

Status: Federal Conservation Unit

Distance from shore: ~15 km

Study depth range: 0–15 m

  • Largest study area
  • Conservation reference site
  • Regulated diving
  • High microhabitat heterogeneity
  • Rocky substrate with rocky shores and high-energy zones
  • Greater potential for internal ecological gradients

πŸ”΅ Ilha do Campeche

Centroid: 27Β°41'48"S, 48Β°27'55"W

Area: 76.19 ha

Status: Archaeological/Scenic Heritage

Distance from shore: ~1.5 km

Study depth range: 0–15 m

  • Close proximity to the mainland
  • High tourist pressure
  • Good fieldwork accessibility
  • Ideal environment to assess anthropogenic influence
  • Mixed substrate (rocky/sandy) in distinct sectors
  • Greater exposure to recreational use and boat traffic

🟒 Ilha Xavier

Centroid: 27Β°36'36"S, 48Β°23'11"W

Area: 16.98 ha

Status: No specific protection

Distance from shore: ~8 km

Study depth range: 0–15 m

  • Smallest study area
  • Group of islets
  • Intermediate pressure conditions
  • Least studied area in local literature
  • Good sensitivity for detecting rapid changes
  • Intermediate connectivity between mainland and Arvoredo

Complete Comparison of Study Areas

Criterion Arvoredo Campeche Xavier
Area (ha)17,131.7276.1916.98
Relative size~1,000x larger than XavierIntermediateSmallest in the gradient
Distance from shore~15 km~1.5 km~8 km
Protection statusFederal Conservation Unit (REBIO)Archaeological/Scenic HeritageNo specific protection
Anthropogenic pressureLow (regulated)HighModerate
Tourist pressureControlledIntense in summerLower than Campeche
Logistical accessibilityMore complex (vessel and weather window)Simpler and fasterIntermediate
Degree of isolationHighLowIntermediate
Habitat complexityHigh (multiple microenvironments)Medium (contrasting sectors)Medium/high at small scale
Dominant substrateRocky shores with high-energy zonesRocky and sandy mosaicRocky shores and islets
Relevance for modelingReference for more preserved conditionsReference for high anthropogenic influenceReference for a small, understudied area
Role in study gradientExtreme of largest area/isolationExtreme of greatest human use/proximityIntermediate connectivity point

🎯 Selection Rationale

The selection of Arvoredo, Campeche, and Xavier was made to represent a realistic and comparable ecological gradient at a regional scale, enabling robust tests on macrophyte distribution and habitat suitability.

  • Area gradient: strong contrast between large, medium, and small islands.
  • Isolation gradient: variation in connectivity with the coast and between islands.
  • Anthropogenic pressure gradient: from regulated use to intense tourist use.
  • Different protection regimes: comparison between a federal conservation unit and areas without equivalent protection.
  • Operational feasibility: a set with feasible logistics for repeated surveys and spatial modeling.

πŸ—ΊοΈ Maps of the Study Areas

The maps below show the spatial basis used to compare Arvoredo, Campeche, and Xavier. These are the cartographic products providing the territorial context of the study.

How to use the interactive map: click the button below to open a dynamic view of the three study areas. On the map, you can switch basemaps, check the legend and cartographic metadata, use both the graphic and numeric scales, and zoom in/out to explore spatial details of each island.

Open interactive map of study areas
General map of the study areas

Reference map of the three island study areas.

Comparative map of the study areas

Spatial comparison of REBIO Arvoredo, Campeche, and Xavier.

🎯 Objectives

General Objective

To assess the diversity and spatial distribution of marine macrophyte communities in Ilha do Campeche, Ilha Xavier, and REBIO Marinha do Arvoredo, correlating biological patterns with environmental and geomorphological variables to generate habitat suitability models.

Specific Objectives

1 Floristic Inventory

Conduct an inventory of macrophytes in the 0–15 m depth range.

2 GIS Mapping

Map spatial distribution and relative abundance using geoprocessing.

3 Drone Photogrammetry

Generate orthophotos and surface models to refine habitat mapping.

4 Abiotic Variables

Characterize rocky substrate and local variables such as water transparency.

5 Habitat Modeling

Build a habitat suitability index (HSI) and SDMs to estimate occurrence patterns (i.e., where species tend to be found).

6 Reference Collection

Consolidate a reference collection (herbarium) for long-term monitoring.

πŸ”¬ Methodology

Methodology in Plain Language

The study logic is straightforward: measure macrophytes in the field, record environmental conditions, and then transform that into maps and models to understand where each species is most likely to occur.

Methodological Flow Infographic

Connected visual summary: from field collection through to final conservation products.

1

Planning

Points, transects, and logistics.

2

Biological Sampling

Freediving/SCUBA, presence, abundance (DAFOR), and rocky shore collection.

3

Environmental Sampling

Depth, transparency, and substrate.

4

Photogrammetry

Orthophoto and DSM with RGB/multispectral.

5

GIS

Spatial data integration.

6

HSI + SDMs

Suitability and distribution modeling.

7

Validation

Field checks and performance metrics.

8

Final Products

Maps and synthesis for monitoring.

1) How the Study Will Be Conducted

Study type: comparison between three islands (Arvoredo, Campeche, and Xavier).

Depth range: 0 to 15 m.

Strategy: apply the same method across all three areas to allow fair comparisons.

2) Practical Steps (Step by Step)

StepWhat Will Be DoneExpected Outcome
Step 1Define sampling points, transects, and operational windows (tide/weather) for each islandStandardized fieldwork plan
Step 2Conduct underwater sampling by freediving (shallow sectors) and SCUBA diving (deeper sectors), with safety protocols and buddy systemStandardized coverage of the 0–15 m range under different depth conditions
Step 3Record macrophyte presence and abundance (DAFOR), with georeferenced photos per point/transectSpecies list and occurrence intensity per point and per island
Step 4Collect material on rocky shores (samples/vouchers) with labeling, storage, and traceabilityReference material for taxonomic confirmation and herbarium
Step 5Collect environmental variables at the same point (e.g., transparency, depth, substrate type, geomorphology)Environmental data linked to biological records
Step 6Georeference all data in GIS and integrate field data, drone data, and environmental layersOrganized, auditable, and campaign-comparable spatial database
Step 7Calculate HSI, run SDMs, and validate results with independent field dataSuitability and potential distribution maps with quality-controlled outputs
Step 8Check final consistency, generate thematic maps, and consolidate products for dissertation and managementTechnical and scientific products ready for use and communication

🧭 Underwater Sampling and Rocky Shore Collection Protocol

  • Freediving: applied in shallow sections with fast operational pace, using standardized transect recording.
  • SCUBA diving: applied in deeper sections of the study depth range (up to 15 m), maintaining bottom time and team safety.
  • Rocky shore collection: careful removal of representative samples, minimizing impact and maintaining point georeferencing.
  • Traceability: unique sample code, field tag, context photo, and depth/substrate record.

3) What Will Be Measured in the Field

πŸ“Œ Biological Data

  • Sampling method (freediving and/or SCUBA)
  • Species presence/absence
  • Relative abundance (DAFOR)
  • Supporting photographic record
  • Voucher collection on rocky shores for herbarium

🌊 Environmental Data

  • Depth
  • Water transparency (Secchi)
  • Substrate type
  • Geomorphology (crevice/crack, boulder/wall, slab)

πŸ—ΊοΈ Spatial Data

  • Point coordinates
  • Layers per island
  • Occurrence maps
  • Suitability maps

4) Drone Photogrammetry (Plain Language)

Drone photogrammetry transforms multiple aerial photos into detailed, measurable maps of the coastal area.

  • What is generated: orthophotos (corrected, undistorted images) and a Digital Surface Model (DSM).
  • How it helps: improves the mapping of habitat features and rocky shore contour.
  • Practical advantage: greater spatial accuracy for comparing campaigns over time.
  • Integration: drone products are incorporated into GIS alongside dive data.

In summary: the drone improves the cartographic foundation of the study and increases confidence in habitat models.

πŸ”Ž Test Protocol: RGB vs Multispectral

To strengthen the methodology, a comparative test will be conducted between an RGB camera and a multispectral camera in the same area and under similar tidal and lighting conditions.

Test StageHow It Will Be ExecutedProduct/Indicator
1. Flight planningSame area, equal altitude and overlap for both sensorsFair comparison between RGB and multispectral
2. Data acquisitionShort flight window to reduce variation in light, wind, and sea conditionsPaired image dataset
3. Photogrammetric processingOrthomosaic and DSM generation for both sensorsComparable orthophotos and surface models
4. Spectral productsIn multispectral, calculate indices (e.g., NDVI/GNDVI/NDRE or coastal equivalent)Layers to discriminate cover type and vegetation vigor
5. Resolution metricsCompare GSD, visual sharpness, and geometric error (RMSE of checkpoints)Objective spatial performance by sensor
6. Ecological validationCheck maps against field points (presence/absence and DAFOR)Thematic accuracy for habitat/macrophytes
7. Final synthesisCompare sensor advantages and recommend standalone or combined useOptimized protocol for future campaigns

πŸ“ Integrated Operational Test Table (Parameters and Quality Criteria)

IndicatorIdeal TargetAcceptable RangeHow to VerifyCorrective Action
GSD (ground resolution)2–5 cm/pixelup to 7 cm/pixelPhotogrammetric processing reportAdjust flight altitude and/or focal length
Front overlap80%75–85%Flight plan + drone logRecalculate flight lines and speed
Side overlap70%65–75%Flight plan + orthomosaic inspectionReduce spacing between flight strips
Flight altitude60–100 m (sensor dependent)up to 120 m (current regulation)Drone telemetry and field notebookStandardize altitude per campaign and sensor
Flight speed3–6 m/sup to 8 m/sMission logReduce speed in rough sea/wind conditions
Acquisition time10am–2pm, low cloud cover9am–3pmField record and EXIF metadataReschedule flight to reduce shadow and glare
Sea/wind conditionsCalm sea and low windwind up to ~20 km/hWeather bulletin + local observationSuspend flight in critical conditions
Geometric RMSE< 10 cm10–15 cmIndependent checkpoints/GCPsRedo block adjustment and review GCPs
GCP/Checkpoint densityDistributed across entire mosaicminimum 5 well-distributed pointsControl point mapAdd points at edges and center
Radiometric quality (multispectral)Calibration panel before/after flightAt least 1 calibration per missionMetadata and panel imagesRecalibrate and repeat acquisition if needed
Thematic validationOverall accuracy > 85% and Kappa > 0.75Accuracy > 80% and Kappa > 0.65Confusion matrix with field pointsRevise classes, training, and sampling
Cross-campaign reproducibilitySame protocol and key settingsDocumented and justified differencesStandardization checklist per campaignUpdate protocol and record deviations

🌀️ Meteorological Sources and Flight Planning Software

Source/ToolWhen to ConsultPurposePractical Criterion (go/no-go)
INMET (forecast and alerts)24–48 h before and on the morning of the flightCheck wind trend, rain, and official alertsNo-go: active alert for strong wind, heavy rain, or storm
CPTEC/INPE (models)24 h before + day-of reviewCompare wind/cloud scenarios to reduce uncertainty in the mission windowNo-go: high model divergence and instability risk during planned time
Navy (DHN/CHM: tide and sea state)24 h before and immediately before departureAssess navigation safety, swell, and coastal conditionsNo-go: rough sea/swell for safe vessel access and drone launch
METAR/TAF (REDEMET/nearest airport)2–6 h before the missionConfirm real-time observed conditions and very short-term trendNo-go: low visibility, strong gusts, or approaching rain cells
Windy/Meteoblue (visual support)Initial planning and final adjustmentVisualize wind by altitude and clouds; logistical decision supportUse only as support; final decision must follow official sources + local observation
Local field observationImmediately before launchValidate actual wind, water glare, low cloud, and operational safetyNo-go: gusts above drone limit, rain, poor visibility, or excessive glare
Drone type/scenarioRecommended flight planning softwareProject strengthOperational note
DJI Enterprise (Mavic 3E, Matrice)DJI Pilot 2Stable and fast automated mapping mission in the fieldStandardize altitude, overlap, and speed between campaigns
DJI with iPad workflowDJI GS ProSimple interface for photogrammetric gridCheck model compatibility before the campaign
Campaigns focused on academic photogrammetryPix4Dcapture ProGood mission standardization and processing integrationKeep fixed parameters for temporal comparison
Multi-area operation with cloud managementDroneDeployAgile field workflow and mission centralizationReview costs/licensing for continuous use
Complex missions and high customizationUgCSAdvanced planning for coastal scenariosSteeper learning curve, but greater operational control
ArduPilot/PX4 platformsQGroundControl or Mission PlannerHigh flexibility for technical parameterizationCheck telemetry, failsafe, and logs before each mission

Operational recommendation for this project: flight decision based on official sources (INMET + Navy + METAR), validated by local observation at the launch point, and use of a standardized flight plan per sensor to ensure comparability between campaigns.

πŸ“· RGB Camera

  • Detailed visual representation of rocky shores and geomorphological features
  • Excellent texture and patch contour reading
  • Good foundation for manual interpretation and reference mapping

πŸ›°οΈ Multispectral Camera

  • Better class separation by spectral signature
  • Allows index calculation to support thematic classification
  • Useful for detecting subtle variations not visible in RGB

βœ… Expected Outcome

  • RGB as a high-visual-readability cartographic base
  • Multispectral for thematic/ecological refinement
  • Integration of both sensors as the preferred strategy

5) How Data Becomes Decision

  • QGIS and R: data organization, analysis, and integration.
  • HSI: identifies areas with the greatest habitat potential for macrophytes.
  • SDMs (ODMAP): estimate the probable distribution of species based on the environment, in a transparent and reproducible way.
  • Final maps: show priority areas for monitoring and conservation.

6) Quality Assurance

  • Single, replicable method across all three islands.
  • Standardized records to reduce collection bias.
  • Data and products in open formats (GPKG, CSV, and HTML).
  • Traceability from field data to analysis to final map.

Methodological Synthesis

Integrated, replicable, decision-oriented methodology connecting field observation, geotechnologies, and ecological modeling to support the monitoring and management of marine macrophyte habitats.

πŸ“¦ Expected Products

The products of this research were designed to transform field data into evidence useful for science and coastal management. Each deliverable answers a stage of the project's central question: where are the macrophytes, what conditions favor their occurrence, and how to prioritize monitoring.

Scientific Deliverables

Practical Application of Results

In addition to scientific output, results will be delivered in an applicable format with clear documentation and standardized organization. This facilitates reuse by research teams, environmental agencies, and island habitat monitoring initiatives.

  • Identification of priority areas for periodic monitoring.
  • Comparable baseline to assess temporal changes across the three islands.
  • Technical support for local conservation and management planning.

πŸ“š Glossary

Key terms used in this presentation, explained in plain language. The goal is to make reading accessible to non-specialists without sacrificing technical accuracy.

Ecology and Coastal Environment

Marine Macrophytes

Large plants and algae that live in the sea and help maintain ecological balance.

Habitat

A place with the necessary conditions for a species to live (light, substrate, temperature, etc.).

Habitat Suitability

The level of "favorability" of a location for the occurrence of a species.

Rocky Shore

A coastal area of exposed rocks with many crevices and microenvironments.

Substrate

The surface on which organisms settle, such as rock, sand, or sediment.

Geomorphology

The physical shape of the environment (walls, slabs, boulders, crevices), important for biodiversity.

Anthropogenic Pressure

Impact caused by human activities (tourism, pollution, construction, boat traffic).

Connectivity

Degree of connection between areas; influences species dispersal and recolonization.

Fieldwork and Collection

Freediving

Diving without a tank, used in shallow areas with fast operations.

SCUBA

Self-Contained Underwater Breathing Apparatus, used in deeper areas.

Transect

A sampling line placed in the field to standardize observations between areas.

Sample Point

A defined location for collecting biological and environmental data.

DAFOR

Abundance scale: Dominant, Abundant, Frequent, Occasional, and Rare.

Voucher

A physical sample collected for identification confirmation and storage in a scientific collection.

Herbarium

An organized collection of plant specimens used as a scientific reference.

Traceability

The ability to link each data point to its location, date, method, and collector.

Field Checklist

A verification list to ensure safety, standardization, and completeness of the survey.

Georeferencing

Associating data with exact geographic coordinates.

Mapping, Drone and Imagery

Photogrammetry

A technique that transforms multiple photos into maps and models with real-world measurements.

Orthomosaic

A corrected aerial image β€” like a "photo-map" without significant distortion.

DSM (Digital Surface Model)

A 3D model of the surface, including terrain and above-ground elements.

GSD (Ground Sampling Distance)

Pixel size on the ground. A smaller pixel means greater detail.

Front/Side Overlap

Percentage of repetition between photos to ensure stable 3D reconstruction.

RGB

Standard camera (red, green, blue) with excellent visual resolution.

Multispectral

A camera that records bands beyond the visible spectrum, useful for separating cover types.

NDVI / GNDVI / NDRE

Vegetation indices calculated from light reflectance data.

EXIF

Photo metadata (date, time, coordinates, and camera settings).

Telemetry

Flight data recorded by the drone (altitude, speed, position, battery).

GCP / Checkpoint

Ground control points used to adjust and validate mapping accuracy.

RMSE

Root Mean Square Error β€” a positioning error indicator; the lower, the better.

Modeling and Statistics (Plain Language)

GIS (Geographic Information System)

A tool for combining maps, tables, and analyses in a single environment.

HSI (Habitat Suitability Index)

An index that summarizes whether a location is more or less favorable for a species.

SDM (Species Distribution Model)

A model that predicts where a species may occur based on environmental conditions.

ODMAP

A documentation standard that helps explain and reproduce ecological models.

Overall Accuracy

Total percentage of correct classifications in a map or model.

Kappa

An agreement metric that discounts chance-level matches.

Confusion Matrix

A table comparing predicted class with the class observed in the field.

Validation

A testing stage to verify whether the result is reliable.

Reproducibility

The ability to repeat the method and obtain comparable results.

Climate Scenario

A projection of future conditions used to assess possible shifts in species distribution.

Flight Planning and Operations

Operational Window

A period with adequate conditions to safely conduct fieldwork and drone flights.

Go / No-go

Decision to proceed or cancel a mission based on prior safety and quality criteria.

Weather Forecast

Official weather forecast used to plan and adjust field activities.

METAR / TAF

Airport weather messages useful for observed conditions and very short-term forecasts.

Sea State

Wave and water agitation conditions, essential for safety in coastal areas.

Failsafe

The drone's safety mode triggered in case of signal loss or critical problems.

Campaign Standardization

Using the same parameters across surveys to allow fair comparisons over time.

Contingency

An alternative plan for unexpected events (strong winds, rain, rough seas, technical failure).

πŸ“… Timeline (Mar/2026 – Dec/2027)

Planned start: March 2026

Main duration: 22 months + post-defense stage

The timeline was structured to maintain a continuous flow between planning, fieldwork, analysis, and writing, reducing workload toward the end of the program and ensuring time for result validation.

Visual Timeline (Gantt Style)

M1 M5 M10 M15 M22
Phase 1 (M1-M5)
Theory + preparation
Phase 2 (M6-M10)
Fieldwork 1 + organization
Phase 3 (M11-M15)
Fieldwork 2 + modeling
Phase 4 (M16-M22)
Synthesis + defense
M5: protocol finalized M10: campaign 1 consolidated M15: HSI/SDMs validated M18: qualification M22: defense Jan/2028: article
Phase 1 Phase 2 Phase 3 Phase 4
Timeline Progress Calculating...

Phase Overview

PhasePeriodCentral Objective
Phase 1M1–M5Theoretical foundation, sampling design, and operational preparation
Phase 2M6–M10First fieldwork campaign and initial data consolidation
Phase 3M11–M15Second campaign, final integration, and ecological modeling
Phase 4M16–M22Scientific synthesis, qualification, defense, and publication

Month-by-Month Breakdown (with Deliverables)

PeriodMain ActivitiesPlanned Deliverables
M1–M2Literature immersion, methodological alignment, and final sampling design definition.Consolidated methodological protocol and work plan validated with supervisor.
M3–M5Permits, field logistics, form standardization, and collection training.Complete operational checklist and finalized field schedule.
M6–M81st campaign: inventory, DAFOR, environmental variables, and georeferenced records.Primary field data (biological + environmental + spatial) organized.
M9–M10Data cleaning, GIS organization, and preliminary descriptive analysis.Initial occurrence maps and partial technical report for campaign 1.
M11–M132nd campaign for sampling reinforcement, pattern validation, and gap filling.Integrated data from both campaigns and final geospatial working database.
M14–M15HSI calculation, SDM execution, and model performance assessment.Suitability and potential distribution maps with statistical validation.
M16–M18Ecological interpretation of results and writing of qualification Stage 1.Partial chapters and intermediate qualification presentation (M18).
M19–M21Final dissertation writing, technical review, and figure/table adjustments.Complete dissertation version ready for the examination board.
M22Public defense and incorporation of examination board recommendations.Defended dissertation and final version for institutional deposit.
Post-defense (Jan/2028)Conversion of results into a scientific manuscript for a journal.Article submitted.

Academic and Management Milestones

  1. M5: sampling design finalized and fieldwork ready.
  2. M10: campaign 1 completed and first spatial synthesis produced.
  3. M15: HSI/SDM modeling completed and validated.
  4. M18: intermediate qualification with robust results.
  5. M22: public defense and academic completion.
  6. Post-defense (Jan/2028): scientific article submitted.

Execution and Control Logic

  • Cyclic pace: each phase combines collection, organization, and partial synthesis to avoid task accumulation.
  • Checkpoint: at the end of each phase, there is a concrete deliverable for supervisor review.
  • Contingency window: the sequence allows margin for rescheduling field trips due to weather/sea conditions.
  • Cumulative output: results from one phase directly feed the next (fieldwork β†’ GIS β†’ modeling β†’ writing).

Feasibility

The project is feasible given the alignment between the topic and the supervisor's research line, the availability of laboratory infrastructure at UFSC, and a fieldwork plan compatible with the master's program timeline.