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The influence of the shrub canopy on the spatial distribution of above and below ground arthropod communities in desertified ecosystems is largely unknown. Using the shrubs Hedysarum scoparium (H. scoparium) and Artemisia ordosica (A. ordosica) as model systems, the above and belowground arthropod communities were sampled by using pitfall trapping and hand-sorting, in order to examine the linkage between above and belowground arthropods across shrub microhabitats. Different profile layers harboured mostly distinct arthropod taxon and trophic groups that preferred specific microhabitats. Even the common taxa, including the Carabidae and Formicidae families, were found to have different abundance distributions in above and belowground soil layers across shrub microhabitats. Total abundance distribution was found to differ, while taxon-richness and Shannon-index distributions were similar in above and belowground parts across the shrub microhabitats. Markedly higher taxon-richness and Shannon-index values were found beneath the shrub canopy compared to the open spaces, particularly beneath the A. ordosica shrub canopy. The abundance distribution in above and below ground arthropod communities were affected by the shrub microhabitats along vertical and horizontal axes more than the richness and diversity of these communities. The A. ordosica shrub canopy (compared with the H. scoparium shrub) was found to have greater ecological implications on the spatial distribution of the arthropod communities. All these findings were expected to be helpful for the conservation of biodiversity, shrub plantation management, and desertification control.
Studies were conducted in littoral sand deposits of a eutrophic, deep lake (Lake Mikołajskie, Masurian Lakeland, Poland) in aim to test the hypothesis that epihydroarenal (the most upper layer of sand deposits) may play a role of a refuge from visual predators for rotifers from adjacent water layer. However, a comparison of the daily vertical distribution of the rotifer community structure and densities in microlayers of the lake psammolittoral, i.e. adjacent water layer (5.0-0.0 cm), epihydroarenal (0-0.5 cm) and three microlayers of endohydroarenal (0.5-1.0 cm, 1.0-1.5 cm and 1.5-2.0 cm) revealed a lack of up-and-down vertical migrations of the animals. During day and night hours, both on 5/6 and 11/12 July, rotifers were concentrated in epihydroarenal. In all cases 64 to 85% of rotifer community inhabited this layer, whereas up to 4% occurred in adjacent water layer. Large and permanently renewed food resources (algae and bacteria) in the most upper layer of sand deposits form a very thin layer that can be called "a canteen". This may explain permanent concentration of rotifers in the layer.
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