Rodent seed predation on tree invader species in grassland habitats of the inland Pampa, Buenos Aires, Argentina

BUSCH, M; KNIGHT C; MAZIA CN; HODARA K; MUSCHETTO E; CHANETON E

ECOLOGICAL RESEARCH

SPRINGER TOKYO

Lugar: Tokyo; Año: 2012 vol. 27 p. 369 - 376

0912-3814

Woody plant invasion in grassland ecosystems is a worldwide phenomenon, and bioticinteractions as competition and predation have been invoked as a possible barrier towoody enchroachment in many ecosystems. We evaluated the role of rodents as seedpredators in pampean grasslands, and we assessed the differences in removal byrodents between one native species, Prosopis caldenia (Caldén) and one exoticspecies, Gleditisia triacanthos (Honey locust). The experiment was conducted atdifferent phases of the rodent population cycle in two grassland communities, aremnant of a native grassland and a post agriculture grassland (old field). The amountof seed loss caused by predation was estimated by a bait-removal experiment inforaging stations. We estimated the frequency of foraging stations with consumption,the overall amount of seed predation and the individual rate of seed predation. Thetotal amount of seed removal and the individual rate of seed removal were higher for P.caldenia than for G. triacanthos, in the native grassland than in the old field, and inAutumn when rodent density was maximum. Overall, the role of rodents on woodyseed removal varied according to the plant species and depending on the localconditions that vary through time and space.