New Zealand Journal of Ecology 

About: New Zealand Journal of Ecology is an academic journal. The journal publishes majorly in the area(s): Biology & Population. It has an ISSN identifier of 0110-6465. It is also open access. Over the lifetime, 676 publications have been published receiving 18564 citations. The journal is also known as: N.Z. Journal of Ecology.

Introduced species: a significant component of human-caused global change

Abstract: Humans move species beyond their native ranges both deliberately and inadvertently, and many of these species become established and spread in their new habitat. The list of established introduced species grows annually, as does the number of them that cause significant economic and ecological effects. One recent and notorious example in North America is the Eurasian zebra mussel which like many other aquatic organisms entered in the ballast water of ships, and like many others spread rapidly once it arrived. The invasion of zebra mussels is unusual in the magnitude of its economic consequences; the mussels grow and reproduce rapidly, covering river and lake bottoms and municipal and industrial water inlets. The cost of clearing blocked intake pipes has been calculated to be approximately US$2 billion (Office of Technology Assessment, 1993). Zebra mussels also alter populations of algae and the concentrations of nutrients in whole ecosystems (Caraco et al., 1997), and they are continuing to spread in rivers, lakes, and canals throughout North America. We suggest that biological invasions by notorious species like the zebra mussel, and its many less-famous counterparts, have become so widespread as to represent a significant component of global environmental change. This point has been made before (eg Elton, 1958), but is not widely appreciated, even by the global change research community or by those who study and/or work to control biological invasions. In part, this lack of appreciation reflects the fact that our perception is limited spatially it is possible to document the presence and importance of biological invasions almost anywhere, but more difficult to perceive that invasions are almost everywhere. In part, it may also reflect a narrow view of global environmental change, one that emphasizes climate change (global warming) at the expense of other, equally significant components of human-caused global change. In this paper, we place biological invasions in context with other human-caused global environmental changes; briefly describe the global extent of biological invasion; illustrate the consequences of particular invasions as they affect human health and wealth, and/or the functioning and biological diversity of natural ecosystems; discuss interactions between biological invasions and other components of global change; and describe ways that society can prevent, manage, and/or cope with invasions.

The Polynesian settlement of New Zealand in relation to environmental and biotic changes

Abstract: Polynesian settlement of New Zealand (c. 1000 yr B.P.) led directly to the extinction or reduction of much of the vertebrate fauna, destruction of half of the lowland and montane forests, and widespread soil erosion. The climate and natural vegetation changed over the same time but had negligible effects on the fauna compared with the impact of settlement. The most severe modification occurred between 750 and 500 years ago, when a rapidly increasing human population, over-exploited animal populations and used fire to clear the land. Human predation, and destruction of forest habitat eliminated the moa and other large ground birds. Moa appear to have been more abundant in drier conifer-broadleaved forest on fertile lowland sites, than in wetter areas and in cool upland forests. Most forests remaining today are wet mountain land communities, and may never have experienced severe browsing pressure until Europeans introduced browsing mammals. The moderate amount of browsing pressure exerted in them by moa may have been insufficient for the plants to develop browsing adaptations capable of coping with the impact of mammals. Knowledge of these climatic, physical and cultural forces which shaped the biota of present day New Zealand are important for understanding how to manage the remaining estate.

Microclimate gradients across a forest edge

Abstract: Despite the importance of forest edges in ecology, only one study has previously been carried out in New Zealand on the modification of climate across forest edges. We measured light exposure, wind speed, air and soil temperature, and vapour pressure deficit (VPD) perpendicular to a north-south aligned, mature, edge of native broadleaf rainforest adjoining grazed pasture. At a point 80 m into the forest from the edge, light was only c. 0.7% and wind speed c. 20% of that in the open, and there was much less diurnal fluctuation in soil temperature, air temperature and VPD. The gradient of microclimate near the edge, as measured with a third (mobile) weather station, was abrupt for soil temperature and similar to the pattern of light exposure, with almost complete change over about 10 m. The gradient was less steep for wind speed, air temperature and VPD, with at least 40 m being required to stabilise these variables when wind was directed into the forest. These findings suggest that forest buffers of at least 40 m may be needed to protect forest reserves and streams from climatic exposure.

Predation and other factors currently limiting New Zealand forest birds.

Abstract: Holdaway (1989) described three phases of historical extinctions and declines in New Zealand avifauna, the last of which (Group III, declining 1780-1986) was associated with European hunting, habitat clearance, and predation and competition from introduced European mammals. Some forest bird species have continued to decline since 1986, while others have increased, usually after intensive species-specific research and management programmes. In this paper, we review what is known about major causes of current declines or population limitation, including predation, competition for food or another resource, disease, forest loss, and genetic problems such as inbreeding depression and reduced genetic variation. Much experimental and circumstantial evidence suggests or demonstrates that predation by introduced mammals remains the primary cause of declines and limitation in remaining large native forest tracts. Predation alone is generally sufficient to explain the observed declines, but complex interactions between factors that vary between species and sites are likely to be the norm and are difficult to study. Currently, the rather limited evidence for food shortage is mostly circumstantial and may be obscured by interactions with predation. Climate and food supply determine the number of breeding attempts made by herbivorous species, but predation by introduced mammals ultimately determines the outcome of those attempts. After removal of pest mammals, populations are apparently limited by other factors, including habitat area, food supply, disease or avian predators. Management of these, and of inbreeding depression in bottlenecked populations, is likely to assist the effectiveness and resilience of management programmes. At the local or regional scale, however, forest area itself may be limiting in deforested parts of New Zealand. Without predator management, the number of native forest birds on the New Zealand mainland is predicted to continue to decline.

New Zealand's pre-human avifauna and its vulnerability

Abstract: In the past 1000 years New Zealand has experienced a major 'extinction event', losing 40-50% of the avifauna, at least 50% of the frog fauna, and unknown proportions of the lizard and invertebrate faunas. During this period, bird species became extinct at different times and rates depending on the particular aspects of their ecology and life history which made them vulnerable to habitat loss, hunting, predation, and competition for food resources. Three groups of species with different levels of vulnerability are recognised within this event: Group I, 1000-1200 AD species susceptible to initial impact of hunting by Polynesians and dogs, and predation and competition for food after an explosive irruption of kiore (Rattus exulans); Group II, 1200-1780 AD species more resilient but gradually reduced by Polynesian hunting and continuous clearance and fragmentation of habitat; Group III, 1780-present species susceptible to hunting with European weapons and predation by Rattus norvegicus, R. rattus, mustelids, cats, and to competition by mammalian herbivores, and destruction of wet forest and wetland habitat. Climatic change is seen as a negligible influence relative to these major intrusions. Discussions of the pre-human avifauna have so far concentrated almost exclusively on moas (Aves: Dinornithidae, Anomalopterygidae), partly because information on the other extinct species is sparse. The ecology of 12 species in the pre-human avifauna is inferred from their anatomy, relationships to extant species, sub-fossil evidence of diets, and analogy with related forms elsewhere.