Does Predation or Moisture Explain Distance to Edge Distribution of Soil Arthropods?

Abstract

Abstract Ecological trap theory suggests that greater predator activity occurs along edge habitat, thereby reducing prey abundance. Alternatively, environmental gradients associated with edge habitat may be responsible for changes in prey abundance irrespective of predator spatial distribution. To test these alternative hypotheses, I measured the distance soil arthropods were to edge of boxes (21 × 9.5 cm) placed on the forest floor of prairie (precipitation-limited; 1977–1999) and boreal forest (moderate precipitation; 2000–2001) sites. Predator theory predicted that in either environment predatory groups would be located close to edge and herbivore/detritivore groups would not be distributed different from random. In support of this hypothesis, in the precipitation-limited environment 7 of 11 soil arthropod groups were distributed as predicted; however, only 7 of 13 groups followed predator predictions in the moderate-precipitation environment. In support of the environmental gradient hypothesis, 22 of ...