Coupling phenotypic changes to extinction and survival in an endemic prey community threatened by an invasive snake

Abstract

Abstract When facing novel invasive predators, native prey can either go extinct or survive through exaptation or phenotypic shifts (either plastic or adaptive). Native prey can also reflect stress-mediated responses against invasive predators, affecting their body condition. Although multiple native prey are likely to present both types of responses against a single invader, community-level studies are infrequent. The invasive California kingsnake (Lampropeltis californiae) a good example to explore invasive predators’ effects on morphology and body condition at a community level, as this invader is known to locally extinct the Gran Canaria giant lizard (Gallotia stehlini) and to notably reduce the numbers of the Gran Canaria skink (Chalcides sexlineatus) and the Boettger’s gecko (Tarentola boettgeri). By comparing a set of morphological traits and body condition (i.e. body index and ectoparasite load) between invaded and uninvaded areas for the three squamates, we found clear evidence of a link between a lack of phenotypic change and extinction, as G. stehlini was the single native prey that did not show morphological shifts. On the other side, surviving C. sexlineatus and T. boettgeri exhibited phenotypic differences in several morphological traits that could reflect plastic responses that contribute to their capacity to cope with the snake. Body condition responses varied among species, indicating the potential existence of simultaneous consumptive and non-consumptive effects at a community level. Our study further highlights the importance addressing the impact of invasive predators from a community perspective in order to gain a deeper understanding of their effect in native ecosystems.