Differences in geographic distribution and habitat of some cryptic species in the Pardosa lugubris group (Lycosidae, Araneae) in Belgium

The habitat and distribution of some closely related species of the P. lugubris s.l. group in Belgium are described to contribute to our understanding of the coexistence and speciation of these `cryptic' species. With a few exceptions, P. lugubris has its main distribution in the lower part of Belgium where it occurs on sandy, nutrient poor soils. P. saltans occurs widely in Belgium except for in the Campine region where the species is totally absent. P. alacris was only found at three localities where limestone outcrops are present. The habitat of P. lugubris is pine and birch forests while in Fagus woodlands, only P. saltans was found. In Quercus forests, both species were found, often in mixed populations. A combination of micro- and macroclimatological features and habitat characteristics cause the differences in distribution of these species.