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| Aim Species distribution modelling (SDM) is commonly used to predict spatial
patterns of biodiversity across sets of taxa with sufficient distributional records,
while omitting narrow-ranging species due to statistical constraints. We investigate
the implications of this dichotomy for conservation priority setting in
Africa, now and in the future.
Location Sub-Saharan Africa (excluding islands).
Methods We use multivariate ordination to characterize climatic niches of 733
African amphibians, distinguishing between species eligible for large-scale correlative
SDM (= 10 records at 1° resolution) and those omitted due to insufficient
records. Species distributions are projected under current and future
climates using simple niche envelopes. Empirical priorities are derived separately
on the eligible and omitted sets and compared with three existing largescale
conservation schemes.
Results Of the 733 amphibian species, 400 have too few records for correlative
SDM, including 92% of those threatened with extinction (VU/EN/CR). Omitted
species typically occupy topographically complex areas with cooler, wetter
and less seasonal climates, which are projected to experience lower rates of climatic
change. Priorities derived from omitted species have greater congruence
with existing conservation schemes. Under future climate, priorities for eligible
species shift towards those for omitted species. Similarly, while omitted species
often lose climate space at 1° resolution, persistent populations tend to coincide
with existing conservation schemes.
Main conclusions Under current climate, statistical restrictions on SDM systematically
downplay important sites for narrow-ranging and threatened species.
This issue spans taxonomic groups and is only partially mitigated by
modelling at finer scales. Effective biodiversity conservation, now and in the
future, relies on our capacity to project geographic determinants of all species,
and thus, a wider range of approaches is essential. We conclude, however, that
future persistence among narrow- and wide-ranging species alike will be highest
within sites already identified for conservation investment and that the focus
on these sites ought to be maintained. | |
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