Data from: Modelling species distribution at the boundaries of the Earth's climate

Correlative species distribution models (SDMs) are widely used to project
species’ responses to global changes. The climatic niche of a species is
calibrated under current climate conditions and then projected in space
and/or time, making model extrapolation an important concern. This issue
is particularly relevant when considering species that live simultaneously
at the boundaries of the current Earth’s climate and at the edges of their
physiological tolerance, such as desert-adapted species. Modelling
approaches alternatives to SDMs (e.g., hybrid SDMs) have been proposed as
a better solution to tackle model extrapolation. These models should
explicitly consider the species’ physiological thermal tolerance,
producing outputs closer to the species’ ecology. We compared
correlative SDMs with different extrapolation options (no-extrapolation,
clamping, fade by clamping, full extrapolation) and hybrid SDMs
incorporating species-specific thermal tolerances of mammals of the
Arabian Peninsula. We projected all models under current and
future climate scenarios and measured the differences between the
outcomes. We found that different extrapolation options and
hybrid SDMs produced important differences at least in future projections,
especially for species physiologically adapted to the extreme climate
conditions of the desert. Correlative SDMs blocking extrapolation beyond
the current climate conditions led to more conservative projections, while
SDMs allowing for extrapolation were extremely more flexible. Hybrid SDMs
produced intermediate results, with up to 93% of the species losing parts
of their suitable ranges under future climate scenarios. Our
findings highlight that correlative SDMs cannot track the true thermal
tolerances of desert species. Hybrid SDMs hold the premises for a better
understanding of the impact of global changes on such species, turning on
a spotlight on a neglected but highly endangered component of
biodiversity.