NATURE NOTES

Evening Post, Volume CXVIII, Issue 60, 8 September 1934, Page 17

NATURE NOTES

ACCLIMATISATION DAN.GERS BIRDS AND FORESTS SUFFER (By R. H. D. Stidolph, R.A.O.tT.) Many Of New Zealand's most notablo birds have entirely disappeared and the rising generations will only be ablo to gaze upon them as stuffed specimens in museums. ..Unfortunately, the inhabitants of islands are more liable to this fate than those of more extensive land areas, due to the presence'of man upsetting the balance of Nature by clearing the forest and introducing alien animals and birds. The disturbing influence of man's work is nowhera better illustrated than in New Zealand, where extensive areas of forest, having been cleared, have been found to be ill-fitted for farming pursuits and are now deteriorated lands. Moreover, many kmds of animals have become established in the country from rats to moose, and these.also exert a destruc- . tive influence on the, native fauna. It is no wonder —especially in view of the faet that the fauna of most islfTnds'is peculiar to that region, largely consisting of species not found elsewhere —that the fauna is unable to withstand the rapid change that takes placa following settlement. In this respect New Zealand birds have suffered severely and several of the most interesting and .most cherished species have vanished. All that we can do now is to ensure that no further species dies out, but in order to do that it'is necessary to make a thorough investigation .into tho position of our birdlife without delay,' as there are certain species that appear to be rapidly following others on the road to extinction* No more sweeping condemnation of the evil effects of acclimatisation was made than that of Professor Alfred Newton, who referred to the condition of the New Zealand fauna as one that must grieve to the-utmost: every ornithologist who cared for more than the stuffed skin of a bird on a shelf. Although the moa had passed away, he stated, before the settlement of white men, what was left of s*3 avifauna had features of interest unsurpassed by others. "It was indeed, long before these features were appreciated, and then by but few ornithologists, yet no sooner was their value recognised than it was found that nearly all_ of their possessors were rapidly expiring and the destruction of the original avifauna of this important colony, so thriving and so intellectual,, is being attended by circumstances of extraordinary atrocity," he wrote. "Under the evil influence of what was some thirty years ago called 'acclimatisation' not onjy were all sorts of birds introduced, which being of strong species speedily established themselves with the usual effect on the weak aboriginals, but in an evil day rabbits were liberated." Proceeding to refer to the liberation of ferrets, stoats, and weasels to combat the rabbit plague, the ■ Professor, who unhesitatingly condemned their introduction, observed that these bloodthirsty beasts would find an easy prey in the heedless and harmless members of the aboriginal fauna, many of which are incapable of flight. "Assuredly," he continued, "the scientific naturalist of another generation, especially if he be of NewZealand birth, will brand with infamy the short-sighted folly, begotten of greed, which will have [deprived him of interpreting some of the great seerets of Nature, while utterly failing to put an end to tho [rabbit] nuisance —admittcdily a great one." The late Professor Newton .wrote at a time when he knew nothing of the introduction of such, animals as the moose, wapiti, thar, and chamois. Notwithstanding the lesson to-be derived from the establishment of rabbits, and. later of the weasel tribe in Kew Zealand, further importations were mads of all kinds'of deer, including those mentioned, and history repeats itself. This time it is the native forest that is threatened with destruction by browsing animals that have increased greatly in the back country, especially in the South Island. Moose and wapiti roam at in some of the roughest country in New Zealand and the amount of food eaten by these large animals is considerable. Moreover, their bulk means the breaking up of the undergrowth and destruction of the natural spongy nature, of the forest floor, noticeable when animals become numerous in a particular locality, such as in the Haurangi Mountains, where deer and goats have played havoc with, the bush. On account of the precipitous country in the West Coast Sounds, where moose and wapiti are established, any undue disturbance of the forest floor is liable to start shingle slides, which, once commenced, extend their devastating., effects .until the riyer-beds of the lower lands, are raised in many eases above the level of the surrounding lands, with serious flooding of farm lands as a result. This process may be seen in the 'Wellington district, where, at Lake Wairarapa, costly works are at present under way to check the blocking up of the'Wairarapa Lake outlet by shingle washed downstream "from forest-denuded hills. Not only is tho menace' a grave one in tho West Coast Sounds; but thar and chamois are equally destructive in. the Southern Alps, where, to reports, many of the beautiful alpine plants are being destroyed by these animals. The control of these imported deer is a costly and difficult job, yet it is essential that they should be kept strictly within bounds if not exerminated altogether. If the native fauna'is to be preserved these animals cannot be tolerated in our forests, but' their complete removal is'probably now beyond human agency. At best it can only be hoped to keep/their numbers sufficiently small so that'the damage to the forest is hardly noticeable.