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Changes in Cryptozoan Numbers Due to Systematic Variation of Covering Boards

Jensen, Paul
Ecology 1968 v.49 no.3 pp. 409-418
Araneae, Coleoptera, Collembola, Gryllidae, Lasius niger, color, mites, regression analysis, snails, soaking, summer, Minnesota
The area beneath small square boards and the boards themselves were varied in a systematic factorial experiment placed in a quasi—Latin square on a patch of prairie near Northfield, Minnesota, in the summer of 1961. As compared to small boards (8 x 8 in.), large boards (12 x 12 in.) had per board 5 more animals, one more kind, .5 more of a collembolan, .5 more Entomobrya color (collembola), 1.8 more Lasius niger (ant) and .9 more common crickets. White boards as compared with black boards had per board one more kind and 4.6 more Gastrocopta armifera (snail). The number of animals under boards on peaks was less per board than the number under boards on depressions by 1 spider, 1 lycosid, .25 orobatid mites, 1 beetle, 1.6 crickets, 2.3 Lasius niger and –.5 kinds. Redistribution of E. bicolor beneath the boards had no discernible effect on the numbers of this or any other species. Soaking of the underboard area was also without effect. Diversity (Margalef index) was significantly greater on peaks than on depressions. Regression analysis showed that numbers of collembola were significantly predicted by diversity and were correlated with numbers of kinds of other animals and the number of other animals. Few interactions of factors were observed.