TEANSACTIONS 



OF THE 



NEW ZEALAND INSTITUTE, 



1895. 



I. — MISCELLANEOUS. 



Art. I. — The Displacement of Species in Netv Zealand. 

 By T. KiEK, F.L.S. 



[Presidential Addre&s to the Wellington Philosophical Society, 



3rd July, 1895.'] 



In the absence of civilisation, the indigenous fauna and flora 

 of any country is liable to little or no change from external 

 causes. Aerial and marine currents may occasionally bring 

 spores or even seeds of exotic plants ; more rarely, insects or 

 birds may be introduced by gales of unusual violence ; migra- 

 tory or aquatic birds may introduce the eggs of insects, or 

 even molluscs, as well as seeds and fragments of terrestrial 

 or lacustrine plants, which have become attached to their 

 feathers ; and certain terrestrial or fiuviatile molluscs may 

 be introduced by drifted logs ; but after a certain thne any 

 increase in the number of species by agencies of this kind 

 must become extremely rare, and can occur only at distant 

 intervals. It may therefore be concluded that in all proba- 

 bility the constituents of the fauna and flora of this colony, 

 with possibly the exception of the larger Ratite birds, were 

 in much the same condition when they were first seen by 

 Cook and Vancouver as they had been for many previous 

 centuries. But with the advent of civilisation vast and far- 

 reaching changes speedily take place : axe and fire rapidly 

 alter the face of the country ; portions of the forest are felled, 

 burnt off, and replaced by grass — a change which of itself 

 involves a multitude of other changes ; the unfelled portions 

 of the forest are laid open to violent winds, so that the 

 surface-rooting trees are blown over in large numbers, while 

 the increasing dryness of the atmosphere acts unfavourably 

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