Desert rodents in disturbed shrub communities and their effects on plant recruitment.
The behaviour of nocturnal, seed-eating rodents of the family Heteromyidae in a desert shrub habitat (mainly Artemisia tridentata subsp. tridentata) near Flanigan, Nevada following a fire were assessed. The site was dominated by Oryzopsis hymenoides and Salsola paulsenii. Dipodomys merriami was the main rodent in the unburned habitat. Six years after the fire the densities of clumps and seedlings of O. hymenoides were significantly greater in the burned than in the unburned habitats. When 1, 2, 10 or 100 seeds were placed on the surface or at depths of 1, 2, 4 or 6 cm on both sites, with <10 seeds/cache at 6 cm depth the rodents did not harvest any seeds but with 100 seeds/cache approximately 10% were removed within 7 d; the greater the depth the less seeds were harvested and the more seeds were harvested from the unburned than from the burned site. The mean and maximum number of seeds/cache were greater on the burned (275 and 1427, respectively) than on the unburned sites (240 and 730, respectively). Germination of seeds in the field in the seed caches of the heteromyids was 90.4% compared with 2% in seed collected by hand and germinated in the laboratory. The survival rates of seedlings in caches was significantly higher than that of single seedlings.