Assessment of competitive release of endangered beach mouse (Peromyscus polionotus ammobates)

Motivated by conservation concerns, we assessed whether Sigmodon hispidus (hispid cotton rat) affects the realized niche of Peromyscus polionotus ammobates (Alabama beach Mouse). After experimentally removing S. hispidus and accounting for spatial autocorrelation in our data, we found weak evidence for an increase in habitat use by P. p. ammobates at locations previously occupied by S. hispidus. This pattern is consistent with a niche-constriction hypothesis, and was not observed on 2 control grids where removals were not conducted. Our results suggest that removal of S. hispidus from habitat remnants immediately following catastrophic hurricanes ameliorates extinction risk of P. p. ammobates, but we also stress the inferential limitations of Our data and the need for further investigation of competitive interactions between these species.