Avoid rocks with regular shapes although some flat ones are necessary as stepping stones to reach all parts of the scree. The chief purpose of rocks is to provide free-draining higher spots for cushion-forming plants, especially those with hairy and blue-green foliage.
Cover the remainder of the scree bed with a layer of small broken stones - of the same material as the rocks and no more than 2in thick - to raise the surface to ground level.
Where a rock garden or scree is neither possible nor needed, why not build a raised bed for growing alpines?
The position of the traps was strongly negatively correlated with the incidence of ice at the traps (r = -0.49), implying that traps situated at the lower margin of the screes were often surrounded by permanent ice whereas traps placed at the upper margin were free of ice.
Even if elevations of the sites (270-1550 m) spanned the range of elevations in the Czech Republic almost completely, surprisingly the screes with ice formation were found at rather low elevations; the screes with permanent ice filling were situated at 350-650 m a.s.1., the screes with temporal ice filling at 270-700 m a.s.1.
The cluster analysis of samples revealed two distinct groups, indicating that two clearly separated spider communities can be identified in the screes (Fig.
The species occurring mainly at the scree surface included Acantholycosa norvegica, Diplocentria bidentata, whereas Porrhomma myops, Rugathodes bellicosus, Meta menardi, Nesticus cellulanus, Wubanoides uralensis were found mainly in the depth of the screes.
Elevation patterns in spiders and mites of screes also have been documented by Ruzicka & Zacharda (1994) who focused on scree habitats in our highest mountains in the Krkonos-e National Park, and by V.
Spatial distribution of spiders in screes was studied by Ruzicka 1999a, 2002 and Ruzicka et al.
Deep layers of screes represent shallow subterranean spaces, in which gradual adaptation to the stable environment of deep subterranean spaces takes place (Ruzicka 1999b).
As long as it is made properly, a scree garden needs next to no maintenance - simply a little hand weeding from time to time.
The mixture is used to fill the scree bed and should be then lightly trodden, raked over and topped with a surface layer of at least a quarter of an inch of shingle, gravel, limestone or granite chips.