Data from: The global biogeography of lizard functional groups

Aim - Understanding the mechanisms determining species richness is a
primary goal of biogeography. Richness patterns of sub-groups within a
taxon are usually assumed to be driven by similar processes. However, if
richness of distinct ecological strategies respond differently to the same
processes, inferences made for an entire taxon may be misleading. We
deconstruct the global lizard assemblage into functional groups and
examine the congruence among richness patterns between them. We further
examine the species richness – functional richness relationship to
elucidate the way functional diversity contributes to the overall species
richness patterns. Location – Global. Methods – Using comprehensive
biological trait databases we classified the global lizard assemblage into
ecological strategies based on body size, diet, activity times and
microhabitat preferences, using Archetypal Analysis. We then examined
spatial gradients in the richness of each strategy at the one-degree grid
cell, biomes and realm scales. Results – We found that lizards can best be
characterized by seven ‘ecological strategies’: scansorial, terrestrial,
nocturnal, herbivorous, fossorial, large and semi-aquatic. There are large
differences among the global richness patterns of these strategies. While
the major richness hotspot for lizards in general is in Australia, several
strategies exhibit highest richness in the Amazon Basin. Importantly, the
global maximum in lizard species richness is achieved at intermediate
values of functional diversity and increasing functional diversity further
result in a shallow decline of species richness. Main conclusions - The
deconstruction of the global lizard assemblage along multiple ecological
axes offers a new way to conceive lizard diversity patterns. It suggests
that local lizard richness mostly increases when species belonging to
particular ecological strategies become hyper-diverse there, and not
because more ecological types are present in the most species rich
localities. Thus maximum richness and maximum ecological diversity do not
overlap. These results shed light on the global richness pattern of
lizards, and highlight previously unidentified spatial patterns in
understudied functional groups.