Density-dependent habitat selection between maize cropfields and their borders in two rodent species (Akodon azarae and Calomys laucha) of Pampean agroecosystems

Hodara, K Busch, M Kittlein, MJ Kravetz, FO

K. Hodara et al., Density-dependent habitat selection between maize cropfields and their borders in two rodent species (Akodon azarae and Calomys laucha) of Pampean agroecosystems, EVOL ECOL, 14(7), 2000, pp. 571-593

61

INGLESE

Article

Environment/Ecology

EVOLUTIONARY ECOLOGY

0269-7653 → ACNP

14

7

2000

571 - 593

ISI

0269-7653(2000)14:7<571:DHSBMC>2.0.ZU;2-E

We studied habitat preferences and intra and interspecific density-dependen t effects on habitat selection by Akodon azarae and Calomys laucha between maize fields and their adjacent borders, during different developmental sta ges of the crop. Akodon azarae detected quantitative differences between ha bitats, using preferentially borders throughout the year, while C. laucha p erceived borders and cropfields as quantitatively similar during spring and summer and it detected borders as quantitatively better at the high densit y period (autumn and winter). These results support the prediction of diffe rential habitat preferences as a model of community organisation at the low density period, while they are consistent with shared habitat preferences during autumn and winter when both species apparently coexist in the better habitat (border). Akodon azarae showed intraspecific density-dependent hab itat selection throughout the year, except in spring, while habitat selecti on by C. laucha was density-dependent in spring, autumn and winter. The eff ect of interspecific density on habitat selection was detected in both habi tats and changed seasonally. The effect of A. azarae over C. laucha by reso urces exploitation was detected in borders, while competitive effects of C. laucha over A. azarae was observed within cropfields. Both species were mo re affected by exploitation competition than interference, which was more c ommon in borders than in maize fields. We conclude that seasonally have a p rofound effect in habitat selection of these species because it changes the intensity of intra and interspecific competition and affects different hab itat preferences and basic suitability of habitats.