Impact of future climate change
The expected climatic conditions by the mid-21stcentury are likely to result in smaller climatically suitable areas for
bats in South Asia (average reduction >8%), but with large
portions of the current areas expected to remain suitable (average
retention >59%. Figure 2). However, these average impacts
hide considerable variation among species resulting partly from
different climatic variables being important across species and models
(Supplementary Material 1). In all scenarios there were potential
winners and losers, with some species predicted to have no climatically
suitable areas in the future while for others the area could double, and
retention varied from nearly 0 to 99.8% (Figure 2). These ‘losing’ and
‘winning’ species were more common in some taxonomic groups, with
species in the family Miniopteridae being consistently among the highest
losers, and species in Rhinopomatidae and Pteropodidae predicted to be
among the most affected in the CanESM5 model scenarios and the HadGEM3
model scenarios, respectively. On the other hand, Molossidae and
Emballonuridae showed the highest gain in suitable areas under the
CanESM5 model and the HadGEM3 scenarios, respectively. Nevertheless, in
nearly all scenarios even winning families generally had species
projected to lose suitable area (Supplementary Material 2). In the
CanESM5 scenarios Molossidae showed the highest projected retention of
suitable areas in the future for any family (73.5% in Can2-45 and
71.2% in Can5-85), while Hipposideridae was projected to retain the
highest amount of suitable area in the HadGEM3 scenarios (80.7% in
Had2-45 and 76.8% in Had5-85; Figure 2; Supplementary Material 2).
Overall patterns were largely consistent among the four future climate
change scenarios explored, with smaller impacts predicted under ‘middle
of the road’ SSP2-RCP4.5 socioeconomic scenarios than in the pessimistic
‘fossil-fuelled development’ SSP5-RCP8.5 scenarios (Figure 2). Many
species show consistent losses, like Kerivoula malpasi , known
from five localities, with predicted losses of 66% to 84% in
climatically suitable area across scenarios; while others showed
consistent gains, including Myotis hasseltii that was projected
to increase the area of suitable climate by more than 60% andSaccolaimus saccolaimus which is projected to gain 106% of its
current suitable area (Figure 2; Supplementary Material 2). For some
individual species projected impacts were highly dependent on the
scenario - for example, Myotis csorbai , known from seven
localities, was projected to lose 100% of climatically suitable areas
in the future in CanESM5 scenarios, but had losses around 47% in the
HadGEM3 scenarios. Pteropus medius , with 439 occurrences, andCynopterus sphinx , with 312 occurrences showed moderate projected
retention of suitable areas (25.9 – 57.1% in P. medius , 30.8 –
44.8% in C. sphinx ; Supplementary Material 2), with varied
degrees of projected losses in all scenarios (18 – 61.7% in P.
medius , 37.9 – 60.7% in C. sphinx ; Supplementary Material 2).
Across all climate scenarios and species, and including all projected
spatial changes, future climatically suitable areas were on average 216
km from current climatically suitable areas. However, distances also
varied between scenarios and species. For example, Murina
pluvialis’ climatic suitable area was projected to shift by an average
of 4.5 km in the future, the smallest distance in the CanESM5 scenarios;
however, in the HadGEM3 scenarios the average distance between current
and future areas was 128 km (Supplementary Material 2). For some
species, the disparity in projected suitable areas between socioeconomic
scenarios led to extremely large differences in distance between current
and future. For example, Rhinolophus subbadius , in the
SSP2-RCP4.5 scenarios for both climate models, had a projected distance
of 28 km from current to future; however, in SSP5-RCP8.5, the distance
increased to 2202 km. Most future suitable areas were located northward
from current suitable areas with a trend for more north-eastern shifts
under SSP2-RCP4.5 socioeconomic scenarios and more north-western shifts
under the more pessimistic SSP5-RCP8.5 scenarios (Figure 3;
Supplementary Material 2).