Geoscience Reference
In-Depth Information
Regions in Australia considered most vulnerable to transformational change
and biodiversity loss
Region/ecosystem
Projected impacts
Alpine &
sub-alpine zones
True alpine habitat occupies only 0.15% of the Australian
land surface and has limited high altitude refuge. Warming in
the Australian Alps has occurred at about 0.2
o
C per decade
(Hennessy et al. 2008) and substantial declines in spring snow
depth have occurred since the 1960s (Nicholls 2005). A “worst
case scenario” modeled for 2050 (+2.9
o
C, -24% precipitation)
projects substantial declines in snow cover (e.g. areas with more
than 60 days per year of snow decline by 95%) (Hennessy et al.
2008). Disappearing snow cover will have dramatic effects on
many species already considered rare and threatened, especially
those mammals dependent on snow cover to protect them from
predation (Pickering, Good and Green 2004). Other potential
impacts include expansion of woody species to higher elevations
at the expense of herbaceous plants, increased competition from
lower elevation species (both native and exotic), increased fire,
and increasing mismatches in the timing of life cycles, especially
between key resources such as bogong moths and the species that
depend on them. The brutal reality is that the alpine zone as we
know it today, is unlikely to exist at all in a Four Degree World.
Non-alpine
montane areas
Higher elevation peaks in areas such as the Wet Tropics of North
Queensland, are biodiversity hotspots with extremely high species
richness and endemism. Warming and the lifting of the cloud
base will increase extinction risks of sensitive species. An increase
of 3.5°C has been projected to result in complete loss of the
bioclimate of 30 of the 65 vertebrate species and the remaining
species to retain, on average, only 11% of current climatic habitat
(Williams et al. 2003). Another study projects 74% of rainforest
bird species will become threatened as a result of projected
mid-range warming (Shoo, Williams and Hero 2005). Major
impacts on the endemic invertebrate fauna are also projected
(Wilson et al. 2007, Yeates, Bouchard and Monteith 2002). Any
decline in rainfall will increase the risk of fires penetrating into
rainforests. Physical damage from increases in tropical cyclone
intensity will also affect recruitment and successional dynamics
within the forests (Shoo et al. 2011, Stork et al. 2007).
Freshwater
wetlands
Many freshwater species in Australia have evolved under
conditions of high inter-annual and seasonal variability but
continuing reductions in the quantity and quality of river flows in
regions such as the Murray Darling Basin will have severe impacts,
especially on breeding habitat for birds (e.g. Pittock and Finlayson
2011). Ongoing competition for water from agriculture and urban
areas will exacerbate the threats.
