ECOLOGICAL RELEASE OF AN EXOTIC SPECIES UPON SUPPRESSION OF ITS INVASIVE PREDATOR

A FIVE-YEAR CASE STUDY, WITH NOTES ON OTHER SPECIES, AND THE LIFE HISTORY OF THE MEDITERRANEAN GECKO, HEMIDACTYLUS TURCICUS

Abstract

Ecological release allows a species to expand beyond its currently occupied niche upon removal of a limiting mechanism such as a predator or competitor. Unfortunately, these interactions between exotic and invasive organisms are relatively unknown. We examine how a small-scale, intensive Red Fire Ant (Solenopsis invicta) eradication program may influence the herpetological and formicid community on a 1.85 ha plot in northeast Texas. Red Fire Ant mounds were individually treated with a series of pesticides in 2005, with follow up treatments in 2006 and 2007. Populations of Red Fire Ants, other ant species, reptiles, and amphibians were monitored throughout the study. Other ant species showed signs of recovery after two years of Red Fire Ant suppression. Although reptile and amphibian diversity increased during the study, only populations of the Mediterranean Gecko (Hemidactylus turcicus) showed a dramatic response. The removal of Red Fire Ants provided this exotic Gecko with the opportunity to proliferate. The potential for these kinds of unexpected responses must be considered when removing introduced species from communities containing multiple exotic and potentially invasive organisms.