Clément Violet
clementviolet.bsky.social
Clément Violet
@clementviolet.bsky.social
PhD Marine Ecology | Postdoc on Marine Non Indigenous Species | IFREMER 🐬🇫🇷
A big thank also to you, all the Reef Life Survey
volunteers, without whom this work would not have been possible!
February 13, 2025 at 10:00 AM
I would like to warmly thank all the co-authors for their invaluable help with this @aurelien-boye.bsky.social, Rick Stuart-Smith, Graham J. Edgar, Elizabeth Oh, Stanislas Dubois and Martin Marzloff.
February 13, 2025 at 10:00 AM
🌍 Understanding habitat states & transitions is key for conservation!

🏝️ Helps track ecosystem shifts from climate change

🛑 Detects early warning signs of degradation (e.g., kelp loss → urchin barrens).
February 13, 2025 at 10:00 AM
🌍 With our data-driven standardized way to classify & monitor marine habitats, what did we find?

🏝️ 17 distinct habitat states, including kelp forests, coral reefs & transitional zones

📉 Our pipeline captures fine-scale ecological changes over time
February 13, 2025 at 10:00 AM
This study wouldn’t be possible without citizen scientists! 🌍🌊

👩‍🔬 Reef Life Survey divers collected 6554 transects worldwide
📸 Standardized photoquadrat sampling ensured consistency
📊 It enabled us to track habitat transitions over time
February 13, 2025 at 10:00 AM
Machine learning models like UMAP & HDBSCAN are powerful, but they’re often hard to interpret.

So, we used SHAP to:
📌 Identify which features drive cluster formation
📌 Uncover non-linear interactions in benthic ecosystems
📌 Improve ecological interpretability of results
February 13, 2025 at 10:00 AM
We used better methods: UMAP (for dimension reduction) & HDBSCAN (for clustering).

✅ Captures complex ecological structures
✅ Finds clusters of varying shapes & sizes
✅ Filters noise instead of forcing data into clusters
February 13, 2025 at 10:00 AM
Clustering is widely used in ecology to define community types, habitat states & biodiversity patterns. But common methods used in ecology have major drawbacks. (See this excellent video of @JohnDataHealy
youtu.be/dGsxd67IFiU?...)
HDBSCAN, Fast Density Based Clustering, the How and the Why - John Healy
YouTube video by PyData
youtu.be
February 13, 2025 at 10:00 AM