Impact of climate change on invertebrate pests in New Zealand
The climate over much of New Zealand will remain physiologically temperate in character after the two climate-change scenarios predicted for the next 4-5 decades. Distribution margins for many pest species will alter in relation to their upper and lower temperature or moisture thresholds, but the nature and intensity of pest burdens should largely have present day precedences. In the far north of New Zealand, and possibly other coastal areas of the northern North Island, more of the thermophilic species already present may achieve pest status, and the range of potentially destructive species, which could become established, will be markedly increased. Increased pest status following any increase in temperature cannot automatically be assumed for individual pest species. Pest status, as influenced by climate change, will be affected by changes in the pests' habitat or hosts, and its biological controls, in addition to the effects on its phenology and physiology directly. These effects may be counterbalancing. Examples of important pasture and crop pests are discussed. The greater the present understanding of the long-term population ecology of a pest, the better one is placed to make meaningful predictions for the future.