Metropolitan lizards? Urbanization gradient and the density of lagartixas (Tropidurus hispidus) in a tropical city

Abstract

Urbanization, with its cohort of environmental stressors, has a dramatic effect on wildlife, causing loss of biodiversity and decline in population abundance customarily associated with increasing levels of impervious surface and fragmentation of native habitats. Some studies suggest that faunal species from open habitats, and with higher abundance in natural environments, seem more likely to tolerate and live in urban environments. Here I evaluate how the level of urbanization affects lagartixas (Tropidurus hispidus) one of the most common lizards found in open vegetation ecosystems in NE Brazil. I surveyed a total of 47 transects across sites that differed in proportion of impervious surface (high, mild, peri‐urban, and rural). I also collected specific biotic (herbaceous cover, tree, and arthropod abundance) and abiotic (amount of shelters and impervious surfaces) factors that could affect lagartixas abundance. Ants were the most common arthropod both in the rural and urban environment. Lagartixas thrive in urban environments, and trees and shelter were key predictors of their abundance. Lagartixas show a clear association with use of artificial structures. The low densities of lagartixas in rural areas and higher density in urbanized areas suggest that they colonized urban areas due to the hard surfaces and they probably are not exploiting a novel habitat, but somewhat responding to conditions resembling those in which they evolved. Finally, lagartixas are extremely common in tropical cities, they have a suite of features that are associated with selective pressures in cities and they might play a key functional role in urban ecosystems making this lizard an excellent system for the study of ecology and adaptation to the urban environments.

Increased herbivory but not cyanogenesis is associated with urbanization in a tropical wildflower

“…Thus, cities create distinct environmental conditions that filter community composition for species that are able to colonize and survive within this unique ecosystem (Grimm et al, 2008; Miles et al, 2019). Despite the harmful effects of urbanization, urban tolerant species can become extremely abundant compared to rural environments (de Andrade, 2020; Korányi et al, 2021; Pignataro et al, 2020; Raupp et al, 2010).…”

A global assessment of research on urban ecology of reptiles: patterns, gaps and future directions

“…Anolis , Podarcis ; Avilés‐Rodríguez & Kolbe, 2019; Sacchi et al ., 2019) and tropical urban environments (e.g. Tropidurus , Intellagama ; de Andrade, 2019; Littleford‐Colquhoun et al ., 2019). As common and abundant organisms, relatively successful in urban areas, lizards have been widely used as ecological models to evaluate multiple urban effects such as fragmentation, metal contamination, and environmental stress (e.g.…”

Environmental temperature predicts resting metabolic rates in tropidurinae lizards

“…We classified lizards in terms of substrate usage with a modified version of a percentage‐based ecological index devised for Tropidurinae (Grizante et al, 2010). When lizards were sampled in artificial substrates (e.g., walls, wooden fences, or pavement), we considered them to be on “impervious surfaces,” following Andrade (2020). Table 1 contains all the ecological parameters used to characterize microhabitat usage for the species we considered herein.…”

“…While species from forested areas are mostly arboreal, those from open habitats vary substantially with respect to substrate usage; this can be appreciated even among sister species (Grizante et al, 2010; Vitt & Zani, 1996). Some are sand‐ or rock‐specialists (e.g., Eurolophosaurus amathites (Rodrigues, 1984) and Eurolophosaurus nanuzae (Rodrigues, 1981), respectively), whereas others are generalists that are often found in urban areas (e.g., Tropidurus hispidus (Spix, 1825); Andrade, 2020; Xavier et al, 2021). Despite the use of these categories to classify species with respect to habitat usage, those deemed to be habitat specialists may also use other substrate types, such as trunks, branches, leaf litter, and soil at smaller proportions (Grizante et al, 2010).…”