Notes on Iowa Tardigrades

Five species of tardigrades, Macrobiotus areolatus, M. islandicus M. hufelandii, Milnesium tardigradum, and Hypsibius tuberculata are reported from lichens growing on Iowa trees. Factors influencing tardigrade distribution are discussed, especially with reference to the lichen species represented in the samples, and the tree substrate. Hypsibius tuberculata was found to be most abundant about 2 meters above ground level, and to become less abundant below, while the other four species were found to be most abundant near the ground and decline steadily with increasing height. No clear evidence of preference of northern, southern, eastern, or western exposures was found