Phenotypic shifts in urban areas in the tropical lizardAnolis cristatellus

Abstract

Urbanization is an increasingly important dimension of global change, and urban areas likely impose significant natural selection on the species that reside within them. Although many species of plants and animals can survive in urban areas, so far relatively little research has investigated whether such populations have adapted (in an evolutionary sense) to their newfound milieu. Even less of this work has taken place in tropical regions, many of which have experienced dramatic growth and intensification of urbanization in recent decades. In the present study, we focus on the neotropical lizard, Anolis cristatellus. We tested whether lizard ecology and morphology differ between urban and natural areas in three of the most populous municipalities on the island of Puerto Rico. We found that environmental conditions including temperature, humidity, and substrate availability differ dramatically between neighboring urban and natural areas. We also found that lizards in urban areas use artificial substrates a large proportion of the time, and that these substrates tend to be broader than substrates in natural forest. Finally, our morphological data showed that lizards in urban areas have longer limbs relative to their body size, as well as more subdigital scales called lamellae, when compared to lizards from nearby forested habitats. This shift in phenotype is exactly in the direction predicted based on habitat differences between our urban and natural study sites, combined with our results on how substrates are being used by lizards in these areas. Findings from a common-garden rearing experiment using individuals from one of our three pairs of populations provide evidence that trait differences between urban and natural sites may be genetically based. Taken together, our data suggest that anoles in urban areas are under significant differential natural selection and may be evolutionarily adapting to their human-modified environments.

The interplay between plasticity and evolution in response to human-induced environmental change

“…For example, Winchell and colleagues 59 have found phenotypic shifts in lizard morphology in urban areas where lizards use artificial surfaces as perches as opposed to vegetation in unaltered habitats (an interesting parallel with the structural changes in urban habitats altering plant seed dispersal); a common garden experiment suggested a genetic basis for these changes in morphology, though the adaptive nature of these changes has yet to be demonstrated, and maternal effects cannot be fully excluded with their use of first-generation offspring from field-collected parents. Interestingly, evolutionary responses to urban heat islands appear to be one of the least-studied aspects of the urbanization process despite the ubiquity of the urban heat island signal among cities.…”

Disentangling the Influence of Urbanization and Invasion on Endemic Geckos in Tropical Biodiversity Hot Spots: A Case Study ofPhyllodactylus martini(Squamata: Phyllodactylidae) along an Urban Gradient in Curaçao

“…The increased locomotor performance of shorter limbs on walls suggests that urbanized P. martini may be under selective pressures that limit the natural range of ecomorBulletin of the Peabody Museum of Natural History 57(2) • October 2016 phological variation in the species. As urbanization has been found to drive rapid evolution in other species (Winchell et al 2016), further research is clearly warranted.…”

Urbanization reshapes a food web

“…However, while the responses of individual species (e.g. Altermatt & Ebert, ; Cheptou, Carrue, Rouifed, & Cantarel, ; Thompson, Renaudin, & Johnson, ; Winchell, Reynoilds, Prado‐Irwin, Puente‐Rolon, & Revell, ) and their collective diversity (McKinney, , ) to urbanization have been well documented, we know far less about how city life reshapes (or does not reshape) the complex networks of species interactions inherent to virtually every biological system on the planet (McCann, ).…”