Research Opportunities & Field Methods – Hawaiʻi Coastal Ecology

Field Sites & Geographic Context

  • Three primary field locations
    • Waimānalo (mauka-makai slope of Oʻahu) ▸ current base location; steep mountain cliffs act as biogeographic barrier
    • Kāneʻohe/KoLoko Inlet (often pronounced "Coloco") ▸ coastal estuary being considered for conversion back to loko iʻa (traditional fishpond)
    • Pōhonu ▸ fully walled loko iʻa (turtle/fish enclosure) fronted by reef flats and outer reef crest
  • Five research teams (≈ 4 students each) will rotate across these sites but ultimately tell two integrative stories:
    1. "Mapping freshwater – shaping loko iʻa"
    2. "Stories of connection & pathways in Pōhonu"

Invasive Coqui Frogs on Waimānalo

  • Origin: native to Puerto Rico (critically endangered there) → introduced to Hawaiʻi via nursery trade
  • Morphology & bio­acoustics
    • Body length: 1{-}2 \text{ in} (~2.5–5 cm)
    • Male call intensity: \le 95\ \text{dB} at 2 m (louder than many lawn mowers)
    • Call pattern: "ko-KEE"; males chorus synchronously dusk→dawn, creating sound-scape disruption (noise pollution)
  • Ecological impacts
    • Densities 2–3× higher in Hawaiʻi than native range
    • Heavy predation on native insects → loss of pollination services, altered food webs
    • Secondary effects: reduction in endemic arthropods, altered nutrient cycling
  • Range expansion mechanics
    • Temperature tolerance increasing via altitudinal “wintering”; now recorded at >3{,}500\ \text{ft} (~1 070 m)
    • Risk of irreversibility once they crest Waimānalo ridge
  • Control method demonstrated
    • Night capture: approach quietly with headlamp, trap with large plastic tube, seal; frogs often remain motionless under light
    • Post-capture: specimens euthanised / frozen to prevent pathogen transfer; not used as food because of rat-lungworm risk
  • Thermal-imaging application
    • FLIR cameras detect frogs as cooler blobs against warm vegetation (example: frog 22\ ^\circ!C vs. foliage 23{-}24\ ^\circ!C)
    • Spot-meters & rainbow palettes help quantify micro-habitat temps

Overview of the Five Student Projects

  • Project 1 – 3-D Mapping & Drone Survey (Pōhonu)

    • Tools: DJI drones, 360° GoPro, underwater photogrammetry rigs
    • Deliverables: Extended-Reality (XR) model of rock wall, reef edge & sluice gate (mākāhā) showing fish pathways
    • Ideal for: tech-oriented students, minimal water time

  • Project 2 – Benthic Habitat Survey (Pōhonu)

    • Full-time snorkel team traversing sand flats → reef crest
    • Data sheets: substrate type, live/dead coral, native vs. invasive limu (seaweeds)
    • Instrumentation: underwater cameras, \text{PAR} meter (photosynthetically active radiation) to link light levels & benthic cover

  • Project 3 – Fish Presence, Movement & Behaviour (Pōhonu)

    • Kilo (patient observation) of fish guilds; differentiate species such as manini, uhu, humuhumunukunukuāpuaʻa (state fish)
    • Equipment: cameras in dry-bags, full-colour fish ID slates
    • Emphasis on slow, horizontal snorkelling to minimise disturbance

  • Project 4 – Freshwater & Water-Quality Hunt (Kāneʻohe Inlet)

    • Goal: locate springs (puna) feeding prospective loko iʻa
    • Six-in-one SMART DO meter records: \text{DO},\ T,\ pH,\ \text{salinity},\ \text{TDS},\ \text{EC} (electrical conductivity)
    • Other gear: long-tube Secchi disk for turbidity/clarity, handheld depth sounder; kayak or shoreline transects

  • Project 5 – Mangrove Impact Assessment (Kāneʻohe Inlet)

    • Compare cleared vs. dense Rhizophora mangle stands
    • Abiotic measures (soil probe): pH, moisture, salinity, temperature; Anemometer for wind & chill; FLIR for fauna within roots (mongoose, crabs, birds)
    • Ecological questions: How do mangroves alter flow, light, organic matter, community composition?

Equipment Quick-Reference

  • FLIR Cx-series (−20→120 °C, ±3 %) for nocturnal spotting & micro-climate mapping
  • SMART DO 6-in-1: (DO)=\frac{\text{mg}}{\text{L}}, \text{EC}\,[\mu\text{S/cm}], etc.
  • PAR meter: \text{µmol photons m}^{-2}\text{s}^{-1}
  • Anemometer: v{\text{wind}}\,[\text{m s}^{-1}], T{wind}\,[^\circ!C], wind-chill index T_{wc}=13.12+0.6215T−11.37v^{0.16}+0.3965Tv^{0.16} (reference)
  • Underwater data sheets: laminated, grease-pencil ready; later digitised to ArcGIS Field Maps

Snorkelling Technique & Kilo (Deep Observation)

  • Maintain horizontal flotation to reduce effort & avoid silting bottom
  • Use sand-ripple orientation (ripples run parallel to shore) instead of lifting head
  • Slow, deliberate fin-kicks → minimise wake; linger to witness natural fish behaviour
  • Safety: buddy checks, gear rinse (rat-lungworm & leptospirosis risk), post-frog hand-washing

Hawaiian Cultural & Linguistic Connections

  • Loko iʻa = fishpond; Hale iʻa = house of fish; Honu = turtle
  • Mauka (mountainward) vs. Makai (seaward)
  • Kai = saltwater; Vai = freshwater; wealth (waiwai) derives from fresh-water abundance
  • Restoring loko iʻa revives Indigenous food systems that once ensured island food security

Ethical & Practical Considerations

  • Avoid introducing new biocontrol agents (e.g.
    mongoose mistake) – prioritise do-no-harm principle
  • Noise pollution, coastal access, and biosecurity (frog fungal pathogens, rat-lungworm) discussed as interdisciplinary concerns
  • Data & media products will be shared with local stewardship groups; accuracy and cultural sensitivity are paramount

Numbers & Stats Highlighted

  • Coqui call: 95\ \text{dB}
  • FLIR palette example: dog face 35\ ^\circ!C; habitat 22{-}23\ ^\circ!C; frog 22\ ^\circ!C
  • FLIR range: -20→120\ ^\circ!C (student units); personal unit 0→1{,}500\ ^\circ!C (lava imaging)
  • Elevation limit reached on Hawaiʻi Isl.: 3{,}500\ \text{ft}$$

Logistics & Next Steps

  • Tonight: ensure ArcGIS Online login works (troubleshoot 10 min pre-session)
  • Tomorrow: rank projects 1→5; instructors form balanced teams
  • Field-day responsibilities: operate equipment, log metadata, observe safety protocols, contribute to group story map