AND INTRODUCED FAUNAS 505 



ideas as propounded twenty years previously, and see how far these 

 views were correct. It soon, however, became apparent to me that 

 it would be a much more important work, and one preliminary to 

 any exhaustive examination of the subject, to ascertain as far as 

 possible what species of animals and plants had become naturalised 

 in the country; what species had failed to establish themselves; to 

 seek for the reasons of their success or failure ; and to ascertain what 

 effects had been produced on the native fauna and flora. 



Changes in Indigenous Fauna due to Naturalisation of Foreign Species 



The question is sometimes asked: "What effects have been pro- 

 duced on the native fauna by the introduction of foreign animals 

 and plants into the islands of the New Zealand group ? " Any answer 

 which can be given can only at best suggest some of the changes 

 which have taken place. The effects have been so far-reaching and 

 so complex that it is impossible to present any summary of them, 

 and all that can be done is to show various aspects of the problem, 

 and to consider facts in detail. 



When knowledge of the native fauna first began to be acquired 

 considerable changes had already commenced to take place, and 

 others were in progress. It was, however, long before any systematic 

 knowledge of the indigenous animals was accumulated and published, 

 and it must be borne in mind that as far as the terrestrial invertebrates 

 are concerned, this knowledge is still very fragmentary. Indeed for 

 many groups, as for example, that of the Insects, it is probably the 

 case that the fullest catalogue which could be made to-day would 

 not include many species which were in existence at the time of 

 Cook's first visit to these islands. Probably very many species have 

 either ceased to exist, or have become very rare. There is no actual 

 knowledge of the fact, it is only inferred from what we know to have 

 taken place with regard to native birds and lizards. But that profound 

 changes have taken place is familiar to all who have observed the 

 development of the last fifty years. The changes have, necessarily, 

 been most rapid during the latter half of last century and since, and 

 especially from the time that the various acclimatisation societies 

 sprang into activity. 



An examination of the published papers and books on the zoology 

 of New Zealand shows that very much of the present knowledge of 

 the subject is quite recent. Since the days of Captain Cook isolated 

 papers on the zoology appeared in many and various publications, 

 especially during last century, and a good deal of general information 

 was accumulated. A good summary of this is to be found in Hutton's 

 Introduction to the Index Faunce Novee Zealandice. Apparently the 



