Aerial Dispersal of Invertebrates and Mosses Close to a Receding Alpine Glacier in Southern Norway

摘要

The 73 km~(2) large Hardangerj?kulen glacier in alpine, south Norway is receding. By using sticky and fallout traps, we studied the aerial transport of invertebrates in a foreland with a well-documented succession of mites, springtails, spiders, and beetles. Since mosses are pioneer plants and also food for certain pioneer invertebrates, airborne fragments of mosses were also included in the study. Sampling on 3- to 6-year-old ground revealed aerial transport of several species of mites and springtails. During 4 weeks, the fallout of microarthropods was calculated at around 1000 specimens per m~(2). This number may depend strongly on local variations in climate and must be treated with care. Besides typical pioneer species, some species assumed to depend on older soil were also trapped. This indicates that the ability to survive is more limiting than the ability to disperse. A few spiders assumed to have the capability for “aerial ballooning” were trapped. Moss fragments, including bulbil diaspores, were common in both trap types. Diptera were sometimes taken numerously, and in sticky traps mainly in those facing away from the glacier. Most aerial transport occurred below 0.5 m height, and the presence of sand grains in sticky traps up to this level illustrated the mechanical force of wind transport. We conclude that aerial transport helps colonization of several non-flying pioneer organisms like mites, springtails, aphids, and mosses.