Meiofauna is an important, yet often overlooked, component of biodiversity in the ecosystem formed by <scp> <i>Posidonia oceanica</i> </scp>

The ecosystem formed by the marine flowering plant Posidonia oceanica is a biodiversity reservoir and provides many services in coastal Mediterranean regions. Marine meiofauna also major component of that biodiversity, its study can be useful addressing both theoretical applied questions ecology, evolution, conservation. We review meiofaunal diversity meadow P. combining literature case study. First, we gathered records 672 species from 71 published studies, as well unpublished sources, highlighting 4 exclusive to this ecosystem. Eighteen those studies quantified spatial temporal changes composition, habitat-specific assemblages fluctuate following annual experienced these meadows. Hydrodynamics, habitat complexity, food availability, all three inherently linked seagrass phenology, are recognized main factors shaping complex distribution patterns These drivers have been identified mainly Copepoda Nematoda, their effect may depend ultimately on species-specific preferences. Second, tested generality observations using mites model group, showing similar ecological preferences might found other less abundant groups. Overall, our highlights high meadows compared with algae sessile macrofauna associated shows complexity interactions use seagrass.