Effects of mulch type and depth on the colonization of habitat patches by soil and litter arthropods

Abstract

Mulch is widely used to encourage establishment and growth of replanted vegetation in forest restoration. The presence of mulch may also benefit soil and litter dwelling arthropods, but little is known about how recolonizing arthropods respond to different types and quantities of mulch used in forest restoration. We employed a manipulative field experiment to assess the effects of mulch type and depth on the colonization patterns of ants and other soil and litter arthropods in created habitat patches. Experimental habitat patches of 2.5 m x 2.5 m were established by adding sterilized hay (a conventionally used mulching material) or forest woodchip (a structurally more complex alternative) at two depths (shallow 3-5 cm, deep 10-15 cm) to create conditions similar to those during the initial stages of rainforest restoration. These were deployed at five sites adjacent to rainforest remnants on the Maleny plateau of subtropical eastern Australia. Despite its simple composition, hay performed better than woodchip in facilitating colonization by arthropods characteristic of rainforest. Shallow hay was favored by rainforest-dependent ant species. Although the results supported the use of hay over woodchip as habitat for rainforest arthropods, neither hay nor woodchip excluded arthropods characteristic of pasture.