Predicted impacts of climate change on New Zealand’s biodiversity.

Abstract

In New Zealand, climate change impacts have already been observed, and will increase in future decades. Average air temperature is predicted to warm by 2.1°C by 2090 for a mid-range IPCC scenario (A1B), with larger increases possible for some IPCC scenarios with higher rates of future emissions. Sea-level rise projections range between 0.18 -0.59 m by 2100, based on six IPCC future emission scenarios excluding future rapid dynamical changes in polar ice-sheet flow. Global surface ocean pH is predicted to decrease by an additional 0.14 -0.35 units by 2100, with a similar decrease expected in New Zealand waters. Rainfall is predicted to change significantly, with increased precipitation in the west, and reduced precipitation in the east, and more intense rainfall events. Increasing temperature is likely to result in species' range shifts southward and upward, and mortality during extreme heat events. Ocean acidification is expected to cause declines in carbonate communities, with cold water communities predicted to decline first due to a lower aragonite saturation horizon in cold waters. Sea-level rise is likely to impact on coastal biota, reducing coastal habitats, changing inundation patterns, and increasing vulnerability to storm surges and tides. Changes in storm and rainfall intensity are predicted to increase disturbance to terrestrial and aquatic communities. Areas with increased precipitation will amplify rates of disturbance, erosion and sedimentation into aquatic, estuarine and coastal ecosystems, while areas with low precipitation will experience increased fire risk. In New Zealand, climate change projections are being integrated into management, including increasing protection and improving management of coastal habitats. Contributing to a global reduction in greenhouse gas emissions, New Zealand is the first country to include forestry in their Emissions Trading Scheme, already positively affecting biodiversity by reducing deforestation.

Climate Change in Oceania – A synthesis of biodiversity impacts and adaptations.

“…Rainfall patterns are highly variable across Oceania, with some regions receiving significantly more rainfall than others (Prowse and Brook 2011;Lundquist et al 2011). The consequences for terrestrial ecosystems will be highly dependent on the direction of movement in rainfall patterns, not only the magnitude but also the variability.…”

“…It is one of the most serious and well-known consequences of global climate change (Hughes et al 2003). Less understood are the ramifications of increasing temperatures for cold-adapted species such as kelp species (Lundquist et al 2011). Ocean acidification may even be of greater concern, affecting entire food webs because it attacks the fundamental ability of organisms to calcify, an essential build block of many life forms.…”

“…For example, many ecosystems were severely affected by the recent dry period, the "Big Dry" (Prowse and Brook 2011) in Australia and the death of large swathes of jarrah forests Eucalyptus marginata may be due to drying (Wardell-Johnson et al 2011). The drying of vegetation communities may shift terrestrial ecosystems from a tree dominated landscape to a grassland community, increasing the likelihood of fires which may also be hotter in regions because of increased fuel loads (Lundquist et al 2011;Wardell-Johnson et al 2011).…”

“…Also, the green ringtail possum Pseudochirops archeri and other species in Australian tropical rainforests are intolerant to high temperatures (Williams et al 2003). When ecosystems are considered, tolerances to increasing temperatures are likely to be particularly adverse for alpine and tropical montane forests (Lundquist et al 2011;WardellJohnson et al 2011).…”

“…Climate change is already acutely affecting Oceania. In this special issue, contributors review our current understanding for the impacts of anthropogenic climate change on biodiversity throughout Oceania, from the perspective of geographical regions, Australia (Prowse and Brook 2011), New Zealand (Lundquist et al 2011) and Pacific Islands (Duffy 2011) and also the main realms: terrestrial (Wardell-Johnson et al 2011), marine (Grantham et al 2011) and freshwater (Jenkins et al 2011). Within each of these regions and realms, authors also discuss possible adaptations to anthropogenic climate change that limit impacts on the conservation of biodiversity.…”