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Accueil du site → Doctorat → États-Unis → 1978 → ECOLOGICAL DISTRIBUTION OF NOCTURNAL RODENTS IN A PART OF THE SONORAN DESERT

University of Arizona (1978)

ECOLOGICAL DISTRIBUTION OF NOCTURNAL RODENTS IN A PART OF THE SONORAN DESERT

Hoagstrom, Carl William

Titre : ECOLOGICAL DISTRIBUTION OF NOCTURNAL RODENTS IN A PART OF THE SONORAN DESERT

Auteur : Hoagstrom, Carl William

Université de soutenance : University of Arizona

Grade : Doctor of Philosophy (PhD) 1978

Résumé
The ecological distribution of seven coexisting rodent species was investigated to determine the part habitat differences played in the subdivision of community resources. Nonhabitat factors of poten tial importance in coexistence of the species were also considered, especially in the case of species without apparent habitat differences. The Sonoran Desert community studied was located 60 km NW of Tucson, Arizona, and contained the following rodent species : Perognathus penicillatus, Perognathus baileyi, Perognathus intermedius, Perognathus amplus and Dipodomys merriami of the family Heteromyidae and Peromyscus eremicus and Neotoma albigula of the family Cricetidae. Multiple discriminant analysis was used to find habitat vari ables which discriminated between the habitats of the five heteromyid rodents. The percentage of the surface covered with bedrock and with stones and cobbles were two of the consistently important variables. Both were interpreted as contributors to a soil-surface dimension, which was important to the coexistence of the five species. P » intermedius was most frequently taken in areas of coarse substrate (including both soil and surface factors), ] ?. baileyi in areas of in termediate substrate, and the other three heteromyids in areas of less coarse substrate• Another consistently important variable was the density (number of individuals per unit area) of the Acacias and other large spinescent shrubs* Smaller and less spinescent shrubs* as v/ell as trees, were im portant variables in some analyses. Together, these observations were interpreted as indicating importance of a shrub and tree density dimen sion in heteromyid coexistence. P_. intermedius and P. baileyi were taken in areas of relative high densities of such plants. Apparently discriminating more specifically, P. penicillatus was taken in areas of relatively high densities of large, spinescent shrubs. JD. merriami and P. amplus, on the other hand, were taken in areas of relatively low densities of most shrubs and trees. The cricetids were taken in the rocky habitats (both species) and in the areas of high shrub and tree densities (II. albigula only). Specific variables of importance to each species were not determined because of high habitat specificity and relatively small samples. Temporal differences were found between species which were not well separated by habitat differences (P. amplus and D. merriami ; Peromyscus eremicus and P. intermedius). Annual activity patterns differed between both pairs. In addition, the first named pair showed different responses to an increase in food supply. P. amplus popula tions increased more quickly. This difference, in conjunction with food storage and periods of winter inactivity, was hypothesized to further contribute to coexistence of P. amplus and D. merriami in the area.

Mots clés : Rodents — Behavior — Sonoran Desert. ; Rodents — Ecology — Sonoran Desert. ; Sonoran Desert.

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