Genetic Diversity of Florida Scrub Lizards (Sceloporus woodi) Varies with Wildfire History
Fire shapes habitats and therefore influences the genetic characteristics of populations. Florida scrub is a fire-dependent habitat with several precinctive species, including Florida Scrub Lizards (Sceloporus woodi). Fire history of scrub patches could affect the movement patterns of Florida Scrub Lizards, thereby altering the genetic characteristics of local populations. We characterized the effect of time since fire (TSF) on genetic diversity and differentiation at 6 microsatellite loci in the Florida Scrub Lizard (n = 413) collected from 17 sites in Highlands County, Florida. Private allelic richness was positively correlated with TSF (r = 0.56, P = 0.009). In sites with a TSF of 3–17 yr, TSF was negatively correlated with expected heterozygosity (r = −0.90, P = 0.009), inbreeding (r = −0.77, P = 0.04), allelic richness (r = −0.79, P = 0.03), and private allelic richness (r = −0.80, P = 0.03); TSF was positively correlated with mean pairwise relatedness (r = 0.85, P = 0.02). Therefore, a consequence of TSF is short-term change to local population genetics that is likely precipitated by responses of Florida Scrub Lizards to habitat modification. At a TSF of >20 yr, TSF and genetic diversity were not correlated, indicating that factors other than fire shape genetic diversity in long-unburned locations. We detected genetic differentiation using Bayesian clustering and estimates of F-statistics. Our results highlight the importance of consistent fire regimes in the Florida scrub on the genetic diversity of Florida Scrub Lizards. The presence of Florida Scrub Lizard populations in long-unburned sites, however, warrants further investigation.ABSTRACT
Map of sample sites where Florida Scrub Lizards were collected, with Bayesian genetic clustering results indicated for each site with a pie chart. The black bar indicates the location of the Lake Wales Ridge, and the star indicates the location of Highlands County. All sites are isolated from each other by development, except for those at Archbold Biological Station (labeled SSr). The colored portion of each pie chart indicates the proportion of individuals from that site assigning to each of the three genetic clusters using the criterion of highest q-value. Also, note that each pie chart covers a geographic area much larger than the true site, but their location is accurate. The map is modified from Schrey et al. (2015).
Bayesian clustering results for Florida Scrub Lizards screened at microsatellite loci from Highlands County Florida. Individual assignment results are provided for k = 2, 3, and 4. Sites are listed north to south, left to right on each graph.
Among Florida scrub habitat sites, private allelic richness of Florida Scrub Lizard populations is positively correlated (r = 0.564, P = 0.009) with time since last fire in this scatterplot (best-fit regression line shown).
Scatterplots and best-fit regression lines showing correlations between genetic diversity estimates of Florida Scrub Lizard with time-since-last-fire (TSF) at sites with TSF of 3–17 yr. For each estimate, the correlation and statistical significance estimate are provided. The correlation with observed heterozygosity is not statistically significant, but all others are significant.
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