Biodiversity and Ecosystem Dynamics in Mediterranean Marine Caves

Marine caves of the Mediterranean host unique assemblages of organisms adapted to low light and restricted water flow. These habitats sustain sessile taxa—sponges, algae and bryozoans—alongside specialised motile fauna such as decapods and cave fish. Environmental gradients from entrance to inner recesses shape community structure and nutrient dynamics, with mobile species acting as trophic vectors linking caves to neighbouring waters. High endemism and cryptic diversity highlight their conservation importance, yet they face threats from harvesting, coastal development and warming. The adoption of non-invasive survey methods and ecosystem-based management within protected areas is crucial to preserve these biodiversity hotspots and to guide regional conservation planning.

Research from Nature Portfolio

High-resolution photogrammetry has been adapted to map sessile benthic assemblages within semi-submerged caves. Using Structure from Motion, researchers reconstructed three-dimensional cave surfaces to quantify species richness, cover of dominant taxa—particularly sponges—and impacts of illegal bivalve extraction. Comparison with traditional photo-quadrats confirmed similar inventories but demonstrated superior spatial resolution, establishing a non-invasive baseline tool for detecting future community shifts.

Studies on cave fish have illuminated their role in alleviating trophic limitation in dark habitats. Visual censuses and stomach analyses demonstrated that a common cave-dwelling species forages nocturnally outside caves, transporting organic matter into the cavern interior. This behaviour underscores the importance of mobile fauna as trophic vectors and suggests that preserving faunal connectivity is vital for sustaining cave ecosystem productivity.

Biodiversity and Ecosystem Dynamics in Mediterranean Marine Caves publication trend

The graph below shows the total number of articles in biodiversity and ecosystem dynamics in mediterranean marine caves across all publications each year (not limited to Nature Index journals).

Technical terms

Sessile: fixed in place, non-motile organisms.

Benthic assemblage: community of organisms on or in the seabed.

Speleophilic: preferring or exclusively inhabiting caves.

Structure from Motion (SfM): photogrammetric method reconstructing 3D models from images.

Trophic vector: organism transferring energy or nutrients between habitats.

Surrogate taxon: representative species used to infer broader community patterns.

References

1. Photogrammetry as a promising tool to unveil marine caves’ benthic assemblages. Scientific Reports (2023).
2. Fish mitigate trophic depletion in marine cave ecosystems. Scientific Reports (2018).
3. Taxonomic and functional surrogates of sessile benthic diversity in Mediterranean marine caves. PLOS ONE (2017).
4. Distribution and Ecology of Decapod Crustaceans in Mediterranean Marine Caves: A Review. Diversity (2022).
5. Comparative Study of Marine Cave Communities in a Protected Area of the South-Eastern Aegean Sea, Greece. Journal of Marine Science and Engineering (2022).