Fire Increases Genetic Diversity of Populations of Six-Lined Racerunner.

Wildfires are highly variable and can disturb habitats, leading to direct and indirect effects on the genetic characteristics of local populations. Florida scrub is a fire-dependent, highly fragmented, and severely threatened habitat. Understanding the effect of fire on genetic characteristics of the species that use this habitat is critically important.

Fire alters patterns of genetic diversity among 3 lizard species in Florida Scrub habitat.

The Florida Sand Skink (Plestiodon reynoldsi), the Florida Scrub Lizard (Sceloporus woodi), and the Six-lined Racerunner (Aspidoscelis sexlineata) occur in the threatened and fire-maintained Florida scrub habitat. Fire may have different consequences to local genetic diversity of these species because they each have different microhabitat preference. We collected tissue samples of each species from 3 sites with different time-since-fire: Florida Sand Skink n = 73, Florida Scrub Lizard n = 70, and Six-lined Racerunner n = 66.

Phenotypic population divergence in terrestrial vertebrates at macro scales.

Phenotypic divergence between populations, i.e. how much phenotypes within a species vary geographically, is critical to many aspects of ecology and evolution, including eco-geographical trends, speciation and coexistence.

When Rensch meets Bergmann: does sexual size dimorphism change systematically with latitude?

Bergmann's and Rensch's rules describe common large-scale patterns of body size variation, but their underlying causes remain elusive. Bergmann's rule states that organisms are larger at higher latitudes (or in colder climates). Rensch's rule states that male body size varies (or evolutionarily diverges) more than female body size among species, resulting in slopes greater than one when male size is regressed on female size.

Sensitivity of intraspecific latitudinal clines of body size for tetrapods to sampling, latitude and body size.

Recent studies have shown that most tetrapod groups (mammals, birds, chelonians, amphibians) show general intraspecific tendencies for increasing body size with latitude, whereas squamates (lizards and snakes) show an intraspecific tendency towards decreasing body size with latitude. Here I evaluate whether these size trends are general by using independent contrasts analysis to investigate the dependence of intraspecific size-latitude relationships (r), and the magnitude alone of size-latitude relationships ([r]), for tetrapod vertebrates, on sample size, range of latitudes sampled, average latitude sampled, and body size. Range of latitudes sampled, average latitude sampled, and body size did not influence body size-latitude relationships (r) or the magnitude alone of body size-latitude relationship ([r]).

The phylogeny of a species-level tendency: species heritability and possible deep origins of Bergmann's rule in tetrapods.

One of the most widely recognized generalizations in biology is Bergmann's rule, the observation that, within species of birds and mammals, body size tends to be inversely related to ambient temperature. Recent studies indicate that turtles and salamanders also tend to follow Bergmann's rule, which hints that this species-level tendency originated early in tetrapod history. Furthermore, exceptions to Bergmann's rule are concentrated within squamate reptiles (lizards and snakes), suggesting that the tendency to express a Bergmann's rule cline may be heritable at the species level.

Bergmann's rule in nonavian reptiles: turtles follow it, lizards and snakes reverse it.

Bergmann's rule is currently defined as a within-species tendency for increasing body size with increasing latitude or decreasing environmental temperature. This well-known ecogeographic pattern has been considered a general trend for all animals, yet support for Bergmann's rule has only been demonstrated for mammals and birds. Here we evaluate Bergmann's rule in two groups of reptiles: chelonians (turtles) and squamates (lizards and snakes).

Is Bergmann's Rule Valid for Mammals?

Bergmann's rule states that, within species of mammals, individuals tend to be larger in cooler environments. However, the validity of the rule has been debated. We examined the relationship between size and latitude as well as size and temperature within various species of mammals.