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The burrowing activity of the scorpion Scorpio maurus palmatus was studied on a 1200 m 2 slope of a so-called “Hamra” sandy soil in Karkur, Israel. The main results were (1) The scorpions excavate soil material after rain storms, preparing this material for erosion processes by rain splash and rainwash. (2) The burrowing activity stops in the dry summer and during cold days of the winter. This means that Scorpio Maurus Palmatus is preparing soil for erosion from one storm to the next, and not from one season to the next as was previously thought. Further, it was found that the amount of soil material excavated from the burrow is proportional to the size of the scorpion and that most of the mounds were deposited toward the upper part of the slope which means that part is washed back into the burrow itself.

A study of the erosion rate and the stability of sandy slopes was conducted on an eastern arm of a parabolic coastal sand dune, De Blink, central Netherlands. The contribution of rabbits to these processes was found to depend on two types of activity; the building of caves and sand mounds of up to 1·5 m2 in area; and the digging of shallow burrows, whereby amounts of sand up to 1 kg per burrow were excavated. The burrowing activity was found over the whole dune, while cave holes were dug mainly on the northern slope. The total amount of sand actually transported on the dune due to this activity is not clear yet, but their influence on the development of stepped slopes is well established.

A recent study conducted in the Sde Boqer experimental site drew the attention to the possible influence of the burrowing and digging activity of some desert animals on the spatial variation of erosion rates over arid limestone slopes. Such activity provides loose soil aggregates which are easier to remove by shallow overland flows, than is the compacted and crusted loessial soil. In order to study the regional extent of available sediment amounts produced by the biological activity, six plots were selected in the northern Negev in the range of 65 mm to 310 mm average annual rainfall amount. All plots had the same, north facing, aspect and the same lithologic composition. Their size varied from 1110 m2 to 5470 m2. Available sediment produced was found to vary from 3 g to 70 g/m2, increasing with rainfall amount. The distribution of available sediment within each plot was not spatially uniform depending greatly on the spatial distribution of bedrock surfaces and soil cover. The overall possible influence of the biotic activity on short term cycles of soil erosion over limestone arid slopes in the Negev is discussed.