Experimental removal of introduced slider turtles offers new insight into competition with a native, threatened turtle

• DOI: 10.7717/peerj.7444
• Publication Date: 2019-08-15T11:00:21Z
• Authors: Max R. Lambert; Jennifer M. McKenzie; Robyn M. Screen; Adam G. Clause; Benjamin B. Johnson; Genevieve G. Mount; H Bradley Shaffer; Gregory B. Pauly
• Keywords: Mesocosm

The red-eared slider turtle ( Trachemys scripta elegans ; RES) is often considered one of the world’s most invasive species. Results from laboratory and mesocosm experiments suggest that introduced RES outcompete native turtles for key ecological resources, but such can overestimate strength competition. We report on first field experiment with a wild community, involving declining species conservation concern, western pond Emys marmorata WPT). Using before/after experimental design, we show after removing an population, remaining dramatically shifted their spatial basking distribution in manner consistent strong intraspecific WPT also altered removal, ways inconsistent interspecific However, documented reduced levels post-removal, which may reflect behavioral shift attributable to lower density community. body condition increased removed RES, either indirect or direct competition between providing evidence compete wild. conclude negative impacts by natural contexts are more limited than suggested captive turtles, although do appear food RES. Our results highlight importance manipulative when studying biological invasions, potential value removal as management strategy WPT.