Williams-Climate-change-refugia-for-terrestrial-biodiversity_0

3.4.7.4 Species movement
The projected species turnover was investigated by calculating the number of species
projected to move into an area in 2085 that didn’t occur there in 1990, otherwise
referred to for these purposes as ‘immigrants’. In addition, species that were projected
to be lost from an area in 2085 where they occurred in 1990 are referred to as
‘emigrants’. These models show similar patterns again to those from the distance
metrics (3.4.2) and proportional change in species richness (3.4.4.3). Most of the
‘immigrating’ occurred in the south and the east, along with small areas that species
moved into located in the Einasleigh Uplands, Nullarbor and south-west Western
Australia (Figure 19). The highest number of species emigrating is predicted to occur in
the north and west of the continent; the lowest in the south and east.
Figure 19: The number of immigrants and emigrants across all species. Left:
‘Immigrants’ – the number of species that are projected to have suitable climate
space in 2085 (median) where they were absent in 1990. Right: ‘Emigrants’ – the
number of species that are projected to lose suitable climate space between
1990 and 2085 (median).
Immigrants and emigrants were then calculated as a proportion of the number of
species that originally occurred in the area (the species richness in 1990) (Figure 20).
The immigrants and emigrants as a proportion of the original species richness shows a
pattern fairly consistent with the absolute numbers of immigrants and emigrants. For
the immigrants, South Australia and Tasmania had the highest numbers; whereas most
of the east coast and south-east corner of Australia, including Tasmania, had the
fewest emigrants. The highest concentration of emigrants for both the absolute
numbers and proportional is in central and western Australia, particularly the Murchison
and Gascoyne regions. It is the south-east corner of Australia that therefore has the
greatest biotic refugial potential by 2085.
Climate change refugia for terrestrial biodiversity 33