Data from: Non-random latitudinal gradients in range size and niche breadth predicted by spatial patterns of climate

Aim. Tropical species are thought to experience and be adapted to narrow
ranges of abiotic conditions. This idea has been invoked to explain a
broad array of biological phenomena, including the latitudinal diversity
gradient and differential rates of speciation and extinction. However,
debate continues regarding the broad-scale applicability of this pattern
and potential processes responsible. Here, we use a simulation approach to
test two propositions: (1) strong geographic patterns of variation in
realized niche breadth can arise in the absence of variance in the size of
fundamental niches, and (2) realized niche breadths can show latitudinal
patterns as a consequence of spatio-temporal climate change, even when
fundamental niche breadths are unrelated to latitude, and dispersal
abilities are held constant. Location. Global. Time period. Simulations
were conducted using climate models from over the last 120 Ka, with trait
dynamics captured at 95 Ka and present-day. Major taxa studied. We used
virtual species with traits based loosely on plants. Methods. We simulated
latitudinal trends of niche breadth and range size for virtual species
using a cellular automaton algorithm that linked a gridded geographic
domain with a three-dimensional environmental landscape. Results. In all
simulations, strong spatial patterns in realized niches were obtained in
the absence of niche evolution, and realized niches showed geographic
patterns deriving only from real-world spatiotemporal variation in
climate. We noted contrasting patterns of niche breadth in different
environmental dimensions, with temperature breadth increasing with
latitude, but precipitation breadth decreasing with latitude. Overall,
simulation outcomes mimicked real-world pattern of latitudinal range
extent covarying with amount of land area. Main conclusions. Tropical
species can have narrower niche breadths for maximum and minimum
temperature ranges compared to temperate species solely as the result of
the spatial arrangement of environments. We therefore suggest that the
complex spatiotemporal distribution of global abiotic environments has
strong potential for structuring observed latitudinal gradients of niche
breadths.