SICB 2019: High Juvenile Mortality following Anolis sagrei Island Introductions

Recent increases in non-native species introductions by humans have spurred a flurry of research examining the subsequent impacts of species invasions. However, often times non-native species introductions go unnoticed until the species is already established. When predicting the effects of a species invasion, it is important to understand how population demographics change during the colonization and establishment stages. Amélie Fargevieille addressed this issue in her talk entitled “Population demographics of an invasive lizard following experimental introduction on small islands.”

Fargevieille and colleagues released adult Anolis sagrei onto islands off the northeast coast of Florida prior to the reproductive season and monitored survival and reproduction over the first reproductive season. The total density of lizards introduced to islands were the same, but four of their islands were introduced with male-biased populations and four with female-biased populations. They then examined the survival and reproduction of the descendants of the founding populations over the next two years. They found that male-biased and female-biased founding populations did not differ in survival rates. In addition, across all islands, juveniles had the highest mortality, which suggests that the ecological factors facilitating or deterring colonization in the earliest stages following an introduction play an important role in invasion biology. Looking forward to future work from Fargevieille and colleagues in the Warner lab!