nematodes

Replacing native forests and grasslands with plantations, pastures and crops has resulted in both contraction of ranges and exploitation of modified habitats by native species, and both general and restricted dispersal of introduced species of soil fauna. Contraction is shown by native earthworms, land snails, ring nematodes and various arthropods, while the areas with changed land use suggest certain native insects are more numerous than 150 years ago. Damage to pastures by grass grub and porina show clearly how native species can exploit modified habitats.

The establishment and subsequent impacts of invasive plant species often involve interactions or feedbacks with the below-ground subsystem. We compared the performance of planted tree seedlings and soil communities in three ectomycorrhizal tree species at Craigieburn, Canterbury, New Zealand – two invasive species (Pseudotsuga menziesii, Douglas-fir; Pinus contorta, lodgepole pine) and one native (Nothofagus solandri var. cliffortioides, mountain beech) – in monodominant stands. We studied mechanisms likely to affect growth and survival, i.e.