In August 2003 a wildfire destroyed 300 ha of forest above Leuk, VS. In 2006 the repopulation of the Orthoptera fauna was assessed at three altitudinal levels on 147 transects within the burnt area, in the adjacent intact forests, and on unburnt grassland outside these forests. A total of 9117 individuals were registered belonging to 34 species of Orthoptera and Mantodea (Mantis religiosa). Species numbers and species composition varied significantly between habitat types, burnt or unburnt habitats, and altitudes (900 m 1800 m).
Average species numbers and abundances were highest in the burnt area, where the characteristic species were Calliptamus italicus, Chorthippus brunneus, Oedipoda caerulescens, Oedipoda germanica, Phaneroptera nana, Platycleis albopunctata, Podisma pedestris, Sphingonotus caerulans, and Tettigonia viridissima. Red-listed species were also significantly more numerous on burnt plots. Record altitudes for Switzerland were reached on the burnt area by some species such as Mecostethus parapleurus and Sphingonotus caerulans. This is most likely due to increased surface temperatures on the sun-exposed plots with little vegetation.
Three years of pitfall trap sampling revealed a quick increase of Orthoptera species richness and drastic increases of population sizes. Three years after the fire, the burnt area was entirely and evenly populated by Orthoptera, also with species not known to be very mobile.
Once more the results of this study confirm the fact that an ecological disturbance such as a forest fire, which is generally perceived as a catastrophe by most people, may also be a driving force for biodiversity and in the case of grasshoppers even beneficial to rare and threatened red-listed species.