Prickly coexistence or blunt competition? Opuntia refugia in an invaded rodent community

摘要: Endemic Nesoryzomysswarthi and invasive Rattusrattus exist in unlikely sympatry Galapagos as female N. swarthi suffer from competition with R. rattus. This study evaluates the role of feeding habits facilitating their co-occurrence. Spool-and-line tracking 85 33 rattus was used to quantify selected diets, foods which were captive trials 46 34 preferred diets. Selected diets compared between species seasons using niche measures, contrasted qualify inferences about competition. Diet overlap highest wet season when food—particularly fruit—abundance diet breadth broadest. Preferred marginally correlated for but uncorrelated swarthi, suggesting that interfere foraging. rattus, perhaps due breeding requirements. Male avoided rattus-preferred foods, possibly avoid aggressive encounters During dry season, declined population crashed, lowest narrowed absence fruits. Female, particularly male, broadened, emphasis on acquiring Opuntia swarthi-preferred uncorrelated, foraging inhibited by In conclusion, narrower contrast suggests this may be less adapted food acquisition at site, fruits are absent. The year-round presence however, appears inhibit its diet, they instead specialise uneaten provide a localised refuge