Data from: Climate‐driven shifts in the distribution of koala browse species from the Last Interglacial to the near future

The koala's (Phascolarctos cinereus) distribution is currently
restricted to eastern and south‐eastern Australia. However, fossil records
dating from 70 ± 4 ka (ka = 103 years) from south‐western Australia and
the Nullarbor Plain are evidence of subpopulation extinctions in the
southwest at least after the Last Interglacial (128‐116 ka). We
hypothesize that koala sub‐population extinctions resulted from the
eastward retraction of the koala's main browse species in response to
unsuitable climatic conditions. We further posit a general reduction in
the distribution of main koala‐browse trees in the near future in response
climate change. We modelled 60 koala‐browse species and constructed a set
of correlative species distribution models for five time periods: Last
Interglacial (128‐116 ka), Last Glacial Maximum (~ 23‐19 ka), Mid‐Holocene
(~ 7‐5 ka), present (interpolations of observed data, representative of
1960‐1990), and 2070. We based our projections on five hindcasts and one
forecast of climatic variables extracted from WorldClim based on two
general circulation models (considering the most pessimistic scenario of
high greenhouse‐gas emissions) and topsoil clay fraction. We used 17 dates
of koala fossil specimens identified as reliable from 70 (± 4) to 535 (±
49) ka, with the last appearance of koalas at 151 ka in the southwest. The
main simulated koala‐browse species were at their greatest modelled extent
of suitability during the Last Glacial Maximum, with the greatest loss of
koala habitat occurring between the Mid‐Holocene and the present. We
predict a similar habitat loss between the present and 2070. The spatial
patterns of habitat change support our hypothesis that koala extinctions
in the southwest, Nullarbor Plain, and central South Australia resulted
from the eastward retraction of the dominant koala‐browse species in
response to long‐term climate changes. Future climate patterns will likely
increase the extinction risk of koalas in their remaining eastern ranges.