GARDEN PESTS IN NEW Z E A LAND 



economic development of the country, had commenced many years 

 earlier. 



When the first Europeans set foot in New Zealand, they must have 

 been impressed by their unique surroundings, totally different from 

 anything to be met with in the Old World. They found the country 

 dominated by a forest quite unlike the forests of any other land, and 

 inhabited by an animal population presenting many unusual features. 

 This terrestrial population was characterised by an abundance of insects 

 and spiders, and a paucity of vertebrates excepting the birds ; the verte- 

 brates consisted of a species or two of frogs, a .few species of lizards, 

 some 200 species of birds, and two species of bats, the last being 1 the 

 only terrestrial mammals. In fact, the insects, spiders and birds were 

 the dominant animals, a feature common to other parts of the world, 

 but the scanty vertebrate population, other than birds, was a character- 

 istic of primeval New Zealand. 



New Zealand being a country fitted for agriculture, settlement by 

 Europeans naturally resulted in extensive and rapid changes, since the 

 settlers brought with them the knowledge, implements, animals and 

 plants of the civilised world; and to make way for settlement, it was 

 necessary to remove the forests and drain the swamps, and to replace 

 them with cultivated crops and pastures. These activities have been so 

 thorough, that, within a period of some 90 years practically the whole 

 of the original North Island forests, and the greater pai't of those of 

 the South Island, have been cleared. 



An outstanding feature of these changes is-that many of the pests 

 associated with the agricultural animals and plants have been brought 

 to New Zealand with the animals and plants they infest, and these 

 exotic pests comprise by far the greater proportion of the destructive 

 animal population, there being but few native species forming the 

 balance. For example, 71 per cent, of the destructive insects are exotic, 

 and 29 per cent, native, while all the parasitic worms of economic import- 

 ance, all the destructive birds (e.g., sparrows) and mammals (e.g., deer, 

 wild pigs, and goats) are introduced. 



The exotic factors that have set up this new environment may be 

 summarised as follows: 



(1) Clearing of the native vegetation." 



(2) Introduced plants: e.g., grasses, forage crops, trees, etc. 



(3) Introduced game animals: e.g., deer, pigs, rabbits, birds, etc. 



(4) Introduced destructive animals, infesting animals and plants 

 of economic value : e.g., parasitic worms, insects, etc. 



(5) Animals imported to control pests, but which have become 

 destructive themselves: e.g., weasels, birds. 



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