The global biogeography of lizard functional groups

Abstract

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, biome, 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 slow 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.

Latitudinal and environmental patterns of species richness in lizards and snakes across continental North America

“…Alroy, 2019) and improve our understanding of how environmental factors influence the distributions of those clades, which might not all follow the same trends (e.g. Marquet et al., 2004; Vidan et al., 2019).…”

Tetrapod diversity facets in jeopardy during the Anthropocene

“…Afrotropics showed the highest values of sesFRic with respect to random expectations especially for mammals and reptiles (Supplementary Figure 3). This pattern might be explained by the high intrinsic megafaunal diversity reported for this continent 56,57 . African continent was probably the first one which experienced some moderate megafaunal loss (e.g.…”

Correlated evolution between herbivory and gastrointestinal tract in a prolific lizard adaptive radiation

“…More widely, these findings suggest interesting opportunities to address the impact that the significant enlargement of a highly energetically costly trait (i.e., the gastrointestinal tract) can have on the expression of trade-offs with other energetically costly traits during evolutionary radiation across extreme climates. Key biological processes such as brain development (Aiello & Wheeler, 1995;Striedter, 2005;Smil, 2013) and reproduction (Roff, 2002;Scharf et al, 2015) are energy-demanding and could therefore be prime candidate traits to be affected by trade-offs resulting from the allocation of energy into gastrointestinal enlargement during herbivory evolution (Aiello & Wheeler, 1995;Kaufman et al, 2003).…”

“…Lizards have radiated across most regions on Earth, including extreme cold climates at high latitudes and elevations (Pianka & Vitt, 2003;Pough et al, 2015;Roll et al, 2017;Vidan et al, 2019). Evidence suggests that the saturation of novel ecological opportunities encountered by ancestral lineages in such environments was facilitated by innovative adaptations in life history (Shine, 2005;Pincheira-Donoso et al, 2013;Ma et al, 2018), ecophysiological (Meiri et al, 2013;Pough et al, 2015) and ecological traits (Pough, 1973;Espinoza et al, 2004;Sites et al, 2011), whereas the role of body size remains contested (Slavenko et al, 2019).…”