Predictable Variation of Range-Sizes across an Extreme Environmental Gradient in a Lizard Adaptive Radiation: Evolutionary and Ecological Inferences

Abstract

Large-scale patterns of current species geographic range-size variation reflect historical dynamics of dispersal and provide insights into future consequences under changing environments. Evidence suggests that climate warming exerts major damage on high latitude and elevation organisms, where changes are more severe and available space to disperse tracking historical niches is more limited. Species with longer generations (slower adaptive responses), such as vertebrates, and with restricted distributions (lower genetic diversity, higher inbreeding) in these environments are expected to be particularly threatened by warming crises. However, a well-known macroecological generalization (Rapoport's rule) predicts that species range-sizes increase with increasing latitude-elevation, thus counterbalancing the impact of climate change. Here, I investigate geographic range-size variation across an extreme environmental gradient and as a function of body size, in the prominent Liolaemus lizard adaptive radiation. Conventional and phylogenetic analyses revealed that latitudinal (but not elevational) ranges significantly decrease with increasing latitude-elevation, while body size was unrelated to range-size. Evolutionarily, these results are insightful as they suggest a link between spatial environmental gradients and range-size evolution. However, ecologically, these results suggest that Liolaemus might be increasingly threatened if, as predicted by theory, ranges retract and contract continuously under persisting climate warming, potentially increasing extinction risks at high latitudes and elevations.

How mountains shape biodiversity: The role of the Andes in biogeography, diversification, and reproductive biology in South America's most species‐rich lizard radiation (Squamata: Liolaemidae)

“…; Pincheira‐Donoso et al. ; Pincheira‐Donoso ; Pincheira‐Donoso et al. ), but to understand this remarkable adaptive radiation, we need to put liolaemid evolution in the context of the rapid development of its geological domain.…”

Global Taxonomic Diversity of Living Reptiles

“…Indeed, the uplift of the Andes has increasingly been implicated in the proliferation of high biodiversity in other organisms [49]–[51]. The access to such ecological opportunities appears to have been facilitated by the adaptive potential of Liolaemus to exploit all possible structural and thermal microhabitats [15], [52]–[55], food resources [56], and to evolve alternative life history strategies to reproduce efficiently across extreme climatic gradients [57], [58]. As a result, Liolaemus species are the dominant (and in extreme elevations and latitudes, sometimes the only) reptiles in most areas of their distribution [14], [15], [59]–[61].…”

“…The access to such ecological opportunities appears to have been facilitated by the adaptive potential of Liolaemus to exploit all possible structural and thermal microhabitats [15], [52]–[55], food resources [56], and to evolve alternative life history strategies to reproduce efficiently across extreme climatic gradients [57], [58]. As a result, Liolaemus species are the dominant (and in extreme elevations and latitudes, sometimes the only) reptiles in most areas of their distribution [14], [15], [59]–[61]. In Liolaemus , the identification of underlying key innovations remains less clear, although multiple independent episodes of evolution of viviparity have apparently opened multiple opportunities to colonize cold climates [24].…”

“…Indeed, some of the most remarkable examples of vertebrate evolutionary radiations have occurred within squamates. Particularly notorious cases are the hyperdiverse iguanian genera Anolis , within which nearly 400 species are known from tropical America [11], [13], and Liolaemus , consisting of 220+ species occurring across one of the widest climatic and ecological ranges known among living reptiles [14], [15]. These two lizard genera are the most species-rich among amniote vertebrates on earth.…”

Cautionary comments on the influence of chemical‐based interactions as potential drivers of sexual speciation in Liolaemus lizards

“…However, this is a questionable statement that may result from her use of a very limited literature (she only cites Jaksic, Núñez & Ojeda, 1980;Mella, 2005) only involving a minor proportion of Liolaemus biodiversity restricted to central Chile. In contrast, broader-scale (in phylogeny, ecology and distribution) studies have consistently shown that these lizards have evolved substantial morphological and ecological diversity, expressed as large variation in body size, body shape, sexual dimorphism, use of microhabitats and of thermal environments, diets, life histories and dispersal potential (Cei, 1986(Cei, , 1993Harmon et al, 2003;Espinoza et al, 2004;Schulte et al, 2004;Cruz et al, 2005;Pincheira-Donoso et al, 2007, 2008b, 2009Pincheira-Donoso, 2011;Pincheira-Donoso & Tregenza, 2011). Therefore, regardless of whether chemical systems of communication have or have not rapidly evolved in Liolaemus, it is difficult to support the view that the evolution of these chemical traits have prevented or limited the evolution of morphological and ecological diversity in these lizards.…”