Variation and diversity of spider assemblages along a thermal gradient in scree slopes and adjacent cliffs

The thermal regime of a phonolite scree slope on Klic Mt., North Bohemia, Czech Republic, was monitored by miniature data loggers. The spiders were collected throughout the entire scree field area and on the adjacent cliff. In 2005 and 2006, the mean internal temperatures at the lower margins of the scree slope were 0.1 and 0.5[degrees]C, whereas the mean external ambient temperatures were 6.8 and 7.2[degrees]C, respectively. The difference, therefore, is 6.7[degrees]C. The long-term cooling of the basal portions, along with the winter heating of the central and upper parts of the scree, are the most specific microclimatic phenomena. The boreomontane species inhabit the extremely cold vents at the lower margins of the scree slope. Species of alpine origin inhabit the middle portions of the scree slope. Six thermophilous species inhabit the sun-exposed rock margins of Klic Mt., which is nearly at the uppermost limit of their vertical distribution in the Czech Republic.