The mesovoid shallow substratum (MSS) can act as a climatic refuge for invertebrates, as a biogeographic
corridor to deeper substrates or as a permanent habitat for some species. This study characterizes the seasonal
invertebrate diversity and abundance of MSS ecosystems in central Portugal focusing on Diplopoda, Diplura,
Orthoptera and Coleoptera during one year. Sampling was performed with standard MSS pitfalls in scree slopes
(colluvial MSS) of karst areas and environmental parameters (temperature, pH, conductivity, water content,
organic carbon, nitrate, phosphate and ammonium) were quantified. Our results show that winter was the season
with the highest arthropod abundance and that the MSS acts as a permanent habitat for chordeumatidan millipedes
and as a climatic refuge for orthopterans and most beetles. All Diplura collected belong to a single species
known previously from surface habitats in the Iberian Peninsula, which does not seem to use the Portuguese MSS
as a refuge. MSS habitats in central Portugal, classified as western Mediterranean and thermophile deposits
protected by the Natura 2000 network based on plant communities and geology, revealed an abundant and
diverse invertebrate community that urges characterization and protection.