Spellerberg, Ian F.Morrison, T.2010-05-121998-061173-2946https://hdl.handle.net/10182/1837The brief was as follows: 1. identify and critically assess the impacts (during construction and use) of new roads on the natural environment, habitats and species in protected areas; 2. identify ways of mitigating impacts (such as by way of ecological buffer zones) with reference to specific case studies in New Zealand and in other similar biogeographical regions; 3. identify future research agendas relevant to the topic. The research is a first step in which information on the topic is assembled. The methods included searches of journals, library databases, advertisements in journals and on the Worldwide Web and through the generosity of many colleagues. A few literature databases relevant to the area of research do exist; the largest being that compiled by Wildlands Centre for Preventing Roads (CPR) in the USA. There are also a few literature reviews on the ecological effects of roads (to ensure an independent approach was taken, these were not consulted until this report was completed). There are many reports on the physical and chemical effects of roads, associated structures and road traffic. These include soil erosion, alteration to surface water hydrology and pollutants in water run-off. There is a large number of reports on the presence of pollutants in biota inhabiting roadside verges. Most of the literature simply reported surveys in which levels of heavy metals and other pollutants are recorded. Very few reports discuss the effects of pollutants; no generalisation can be made because the effects of biota vary from group to group. Some reports indicate that plants on roadside verges become more susceptible to disease and attacks by pests. There is a need for long-term monitoring studies and research which looks at the fate of pollutants in ecosystems. The ecological effects of roads include physical disturbance, habitat loss, extinction of populations and species near the road edge, mortality of wildlife on roads, use of road edges has habitats, dispersal of wildlife (including invasive species and alien species) along road networks. The most important and serious impact of roads on nature is through habitat fragmentation; that is, not only loss of habitats but fragmentation of previously contiguous habitats and subsequent isolation of habitat fragments. Habitat fragmentation is considered by many to be the greatest and most serious threat to nature. Fragmentation of habitats has implications for loss of biological diversity at species, population and genetic levels. New roads may take traffic, people and introduced species to what were previously undisturbed areas with subsequent impacts on the ecology of the area. Roads facilitate more roads and there is an incremental and long lasting effect. The detrimental effects of roads on nature by far outweighs any advantages to wildlife; both in the short-term and particularly in the long-term. Attempts to reduce the ecological effects have been addressed in many ways. Pollutants in surface water from roads can be contained. The barrier effects of roads can be reduced with tunnels and nature overpasses. The road edge can be managed for indigenous wildlife. Loss of habitat can be compensated by establishing similar habitats elsewhere (mitigation banking). However, habitat fragmentation has not and can not been addressed fully; road routes can be changed to reduce fragmentation but the only real answer is not to build the road. There are several areas in need of further research. The long term effects of pollution on roadside wildlife have not been investigated in depth. The effectiveness of tunnels and other routes for wildlife seems not well quantified. The effects of roads on dispersal of alien species is an area of particular relevance to New Zealand. The methodology and methods for assessment of likely ecological impacts requires much more research and development.1-58enCopyright © June 1998, Department of Conservationroadsenvironmental effectsimpactshabitat fragmentationphysical disturbancehabitat lossEcologyMonographMarsden::300800 Environmental ScienceANZSRC::0501 Ecological Applications