The introduction of deer to New Zealand began in the middle of the 19th century, and current populations are primarily European red deer, with only 15 percent being elk. There is significant hybridisation of elk with the more numerous red deer to the extent that pure elk may no longer exist in the wild in New Zealand. These deer have had an adverse impact on forest regeneration of some plant species, as they consume more palatable species which are replaced with those that are less favored by the elk. The long term impact will be an alteration of the types of plants and trees found, and in other animal and plant species dependent upon them. As in Chile and Argentina, the IUCN has declared that red deer and elk populations in New Zealand are an invasive species.