Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : HOME RANGE STUDIES OF A DESERT NOCTURNAL RODENT FAUNA

Auteur : Bateman, Gary C.

Université de soutenance : University of Arizona

Grade : Doctor of Philosophy (PhD) 1967

Résumé
A multispecies rodent population inhabiting an area in the Lower Sonoran Life Zone of southern Arizona was investigated to determine the effects of "poor" habitat quality on spatial requirements, as reflected by home range sizes and movements. The effects of other influencing factors (species, sex, season, size, food habits, population density, and social behavior) were also considered. Data were collected by live trapping, marking, and releasing animals on a permanent quadrat over a thirteen-month period (April, 1966 through May, 1967) ; and by live trapping animals in adjacent areas for use in laboratory studies of social behavior. The trapping program also yielded data on population fluctuations, microhabitats occupied, and annual activity patterns.
The total population of rodents was at a high during September following the a turner rains. Young of four species (Peroenathus amplus. • bailevi. P. PTllflVMlfrlflr and Neotoaa albigula) were produced during spring and summer. During late fall and winter the population level decreased as a result of winter mortality ; P. amslus and £. were very rarely taken during late fall and winter, presumably because they spent most of their time underground, Peromyscus erenicua continued to produce young even in winter, and the population of this species was at a peak during January. The trend in population size of the cactus mouse was inversely related to that of and there is some evidence that the presence of large numbers of Neotoaa nay suppress activity of cactus mice during unfavorable seasons.
Hone ranges of the three species analyzed averaged between one-fifth and three-fifths of an acre. Movements of individuals representing two additional species of pooket mioe indicate that they had hone ranges of approximately this same magnitude. Well-defined mutually exclusive home ranges were maintained on an annual basis by female Perognathus bailey 1. Males had home ranges which broadly overlapped those of other males and females. No other species had such an obvious pattern of non-overlapping spatial dispersion as the female Bailey’s pooket mioe. Distances between successive recaptures (D) were used as indices of spatial utilization to detect changes in movement patterns related to certain influencing factors. In three of the five species studied males had significantly larger movements than females. The exceptions were Naotoma alhlmil* in which there were no apparent differences in this regard, and Perognathus aanalus in which captures of females were too few for an adequate analysis. Evaluation of movements of three species according to season showed a definite tendency toward longer movements during the spring months. In arioetids these apparently resulted from scarcity of moisture. In P. bailevi only males showed significantly longer movements during these months. Female Bailey’s pooket mice were presumed to show stable movement patterns all year because of their habit of maintaining mutually-exclusive areas.
Trap-revealed home ranges of woodrats were much smaller than those of their smaller competitor, Peromrsous eremlcua. Uoodrat home ranges may have been larger than indicated, however, since the vertical component of their activity area was not measured. Consideration of the ages of animals making the longer movements indicates that dispersal tendencies were as pronounced in adults as in young. Although the desert has often been considered as a "biological vacuum", for those rodents adapted to an existence under such conditions it is certainly not an "unfavorable habitat". Spatial requirements of the desert rodents included in this study are no greater than those of comparable animals living in eastern deciduous forests or prairie grasslands.

Mots clés : Rodents. ; Nocturnal animals. ; Mammals — Arizona.

Présentation

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