Abstract: Alligator snapping turtle (Macroclemys temmincki) and red-eared slider (Trachemys scripta elegans) are harmful alien invasive species. Both of them have been found in many aquatic ecosystems in China. Here, we examined the antipredation ability of a native species in China, carp (Cyprinus carpio), against those invasive species. By observing whether the carp would try to far away from them during the appearance of alligator snapping turtle and red-eared slider, we estimated the visual recognition ability and anti-predatory behavior of carp. The results showed that when only alligator snapping turtle was present, the carp was able to visually identify the predator within a short period of time (10 min) and stayed away from it. When both invasive species presented simultaneously, the number of carp moving away from alligator snapping turtle was significantly higher than that moving away from red-eared slider at all time points (0-10 min). This may be due to the large range of action, high risk and the fierce movement of the snapping turtle. Our results indicate that the carp can visually identify predators and adopt appropriate survival strategies. Alien invasive species in aquatic ecosystems are harmful to native aquatic organisms. The control of invasive alien species should be strengthened to prevent the release of alien species and reduce their ecological hazards.

Key words: soil type, desert steppe, soil moisture, time stability