New Zealand's environment has been substantively changed in a time span that is very short in evolutionary terms. Though, from today's perspectives, we may wonder whether it was necessary to remove quite so much forest, drain quite so many wetlands, introduce quite so many alien species, create quite so much pasture, and extinguish quite so many native species, New Zealand's economic and social progress was based on these changes . We are what we are today because of our past. We cannot undo history - we can only learn from it.
In recent decades, New Zealanders have become less complacent about their natural environment. There is a growing awareness of what has been irrevocably lost. New Zealanders are also seeing how people from other parts of the world admire what does remain, which is reflected in the ecotourism boom and in the success of our 'clean and green' export promotions. A large majority of New Zealanders now support efforts to save our threatened species and their habitats.
Their sentiments are reflected in our key environmental laws which require that native species, habitats or ecosystems, including fisheries, be protected from use or sustainably managed during use, not just for resource purposes but also for their intrinsic value. More specific laws provide varying degrees of harvesting protection to most of our native vertebrates and vascular plants. These laws and the success of the Department of Conservation's species management and habitat protection programmes have markedly improved the survival prospects of some threatened and declining species.
Despite this, however, many species remain threatened and more appear to be joining them. New Zealand has lost a third of its native land and freshwater birds, and now has a greater percentage of threatened endemic birds than almost any other country. Two thirds of our land is now a biodiversity desert in which 1,000 known taxa of plants, animals and fungi are struggling to survive. Some may not even reach the next century. The threat is greatest for our endemic vertebrates and for plants, fungi and invertebrates with restricted populations.
The reasons for the continuing pressure on our threatened species are partly perceptual and partly historical. The perceptual problem is shared by most New Zealanders. It rests on the belief that the remaining area of natural habitat, in the mountains and isolated reserves, is sufficient to support our surviving indigenous species, provided it is protected or properly managed. In fact, the remaining area is not sufficient. For many of our threatened species, the existing habitat is in the wrong location or in reserves which are too small.
The historical problem is a dual legacy: habitat loss and introduced species. The massive habitat change wrought by previous generations has incurred an 'extinction debt' which is still being paid by our indigenous species. With each generation, the vulnerable populations shrink further. If the damage is to be undone, native forests will need to be restored to at least 10-20 percent of the lowlands and foothills, particularly along streams and rivers. Other native habitats, such as wetlands, will also have to be expanded. Because of the slow regrowth of native forest, some of the habitat-deprived species will need intensive conservation programmes for several generations while this restoration is occurring.
The remnant areas of forest and wetland that have been deliberately spared by private landowners provide an opportunity to make some biodiversity gains in lowland areas without large changes in area. Significant recovery and rehabilitation of the indigenous biodiversity in these habitats could be achieved by landowners modestly increasing the width of some forest strips and working together, voluntarily or with community support, to form larger forest areas by joining up some of the existing forest remnants.
Our second historical legacy is the army of predatory and browsing animals and aggressive weeds which were introduced by previous generations and which now threaten our remaining natural habitats. They have turned many reserve areas into war zones where ceasefires are temporary and the pressure is constant. Costly though it is, pest and weed control is now a necessary component of the modified New Zealand ecosystem.
Faced with these pressures and problems, the future seems bleak for many of our indigenous species unless current rescue and restoration efforts can be expanded. To meet this huge challenge, land uses will need to become more accommodating to native species, effective pest control will need to be maintained over large areas, systematic monitoring of biodiversity will need to be undertaken in all regions and fishery areas. In addition, our recently increased rescue and restoration efforts for vulnerable species and habitats on the protected estate will need to be consistently maintained or increased to ensure success. More effort will also need to go into public awareness and education programmes.
Even our marine species are increasingly vulnerable, despite being substantially removed from the pressures affecting the land and freshwater species. They, too, are experiencing environmental changes as a result of increasing harvesting pressures from commercial fishing, rising sea temperatures and sediment entering coastal waters from land-based activities.
Although New Zealand's fisheries are now managed on a strong scientific footing, the principle of Maximum Sustainable Yield on which quotas are based, has a single-species focus which is largely blind to the ecological impacts of stock reductions. New fisheries legislation now makes the tension between single species management and ecosystem management explicit by requiring the impacts of fishing on ecosystems and non-target species to be minimised. This will require wider monitoring and a more precautionary approach to fisheries management.
New Zealanders are slowly beginning to realise that indigenous species have been the main victims and the silent cost-bearers of our impacts on the environment. Sacrificing them on the march toward economic progress was once seen as a small price to pay. But a small price in human terms converted to a massive cost for the species concerned. Now that commitments have been made to safeguard our remaining species, the true cost of our environmental destruction is becoming more apparent as we seek affordable methods of halting and reversing the damage.
If lasting solutions are to be found, they will be based, in part, on new attitudes to the species which were once sovereign here - and to those which have displaced them. Vilifying introduced pests has become a part of the New Zealand psyche, but these innocent killers did not come here of their own volition. In making scapegoats of them, we lose sight of our own role. Our historical hunger for land and often poor self-control when harvesting indigenous plants and animals are significant causes of the nation's biodiversity crisis. Likewise, our earlier careless importation of pests and weeds has compounded the problem.
Ultimately, the fate of New Zealand's biodiversity will depend on our ability to better manage the exotic species we have brought here, including ourselves, and on our willingness to share more of the nation's land and water resources with the depleted species which have nowhere left to run. It may also depend on our willingness to accept a simple ethical proposition: that the species which evolved here have a basic right to be here, whether we need them or not.