POPULATION ECOLOGY OF THE ENDEMIC RODENT NESORYZOMYS SWARTHI IN THE TROPICAL DESERT OF THE GALÁPAGOS ISLANDS

摘要: Ancestrally continental forest species of the tribe Oryzomyini, endemic cricetid rodents Galapagos, have had to adapt harsh tropical desert Islands. Following recent rediscovery Santiago nesoryzomys (Nesoryzomys swarthi) Isla Santiago, we conducted 1st autecological study this species. Our 3-year revealed mean annual survival 23.2% and maximum 812 days. Reproductive activity was restricted wet season with a stable proportion breeding females consistent peak in pregnancy April. The likelihood postpartum increased rainfall when 2 litters were produced. growth development juveniles slow they did not reproduce their natal year. Positive correlations between adult body weight vegetation density (particularly prickly pear cactus [Opuntia galapageia]) population levels supported hypothesis food limitation. Comparisons Galapagos oryzomys (Oryzomys bauri), Santa Fe, review members Oryzomyini suggest that ephemeral, unpredictable environment arid zone has selected for strategy relatively high low reproduction N. swarthi O. bauri is more typically found among Heteromyidae than other Oryzomyini. We also present data on sex ratio, home range, philopatry together indicate promiscuous or polygynous mating system. findings may help guide future conservation strategies endangered rodent