How and when should flightless, saproxylic, litter‐dwelling coleoptera be surveyed?
2016
Cateau, Eugénie | Courtin, Olivier | Brustel, Hervé
The limited dispersal and the high trophic requirements of flightless saproxylic beetles makes them good indicators of spatial and temporal continuity. Few studies have been conducted on these species, and the two main studies produced contradictory results. Knowledge is thus lacking on this fauna, but before performing experiments to assess their value as indicators, it is important to know how and when they can be sampled. Sieving litter and Berlese extraction in six oak woodlands showed that sampling 10 trees per forest is sufficient to capture 97.2% of the fauna present. Two stands were surveyed at monthly intervals for 2 years to determine the species phenology. All the species were present throughout the year. Variation in abundance was only observed in four out of 11 species. Spring and fall were shown to be the best periods to survey them in the litter. No significant variation in abundance was observed between the two sampling years. This fauna thus appears to be very stable over time. Certain climate parameters, high humidity (little sunshine and rainfall several days before sampling) may result in the beetles being more abundant in the litter at certain times. For efficient sampling, long periods of fine weather should thus be avoided.
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