Reproduction in Relation to Heavy-Metal Contamination Along an Urbanization Gradient in anInvasive Florida Lizard Species (Anolis sagrei)
Master of Science (M.S.)
Degree Granting Department
Biology (Integrative Biology)
Alison Gainsbury, Ph.D.
Deby Cassill, Ph.D.
Melanie Riedinger-Whitmore, Ph.D.
ecotoxicology, heavy metals, reproductive parameters, urban level, lizards
Environmental contamination is accumulating rapidly worldwide due to increasing urbanization rates. Heavy metals are known to be particularly toxic to organisms, to accumulate in biological systems, and to be found in higher concentrations in animals located in areas of high urban levels. However, the physiological impacts of these toxic heavy metals in wildlife remain largely unknown. Lizards are excellent bioindicator species for environmental contaminants due to their trophic level as mesopredators and their susceptibility of exposure via air, water, diet, and soil through egg deposition. To assess the impacts heavy-metal contamination has on reproductive parameters in lizards and how these effects vary across an urbanization gradient, a total of 36 brown anoles (Anolis sagrei) were taken from 9 different field sites with urbanization levels ranging from low to moderate to high. Breeding pairs from each urban level were bred in a laboratory and reproductive parameters (hatchling survivorship, initial body size , and growth rates) were monitored. I found with statistical significance that hatchlings born from adults from areas of high urban levels have higher mortality, smaller initial body size and slower growth rates than those from adults captured from areas of low and moderate urban levels. Additionally, soil samples from all 9 field sites along with tissue samples from tail clippings were taken from the adult females to test for contamination levels of heavy metals (Arsenic, cadmium, chromium, copper, lead, mercury, and zinc). Interestingly, soil contamination increased with urban level, but there was no significant relationship of heavy-metal contamination levels in tissue samples across different urban levels. These results suggest that high urban levels are negatively impacting A. sagrei reproduction, but factors other than heavy-metal contamination may be contributing to these effects. Future experimental studies are required to further understand the adverse physiological impact urbanization has on lizards, and specifically test various factors that may be contributing to decreased reproductive parameters.
Scholar Commons Citation
Hauck, Elizabeth, "Reproduction in Relation to Heavy-Metal Contamination Along an Urbanization Gradient in anInvasive Florida Lizard Species (Anolis sagrei)" (2022). USF Tampa Graduate Theses and Dissertations.