. Biology of the Heteromyidae. Heteromyidae. PANDESERTIC RODENT ECOLOGY 677 No species found in the Kalahari, but absent from the Namib/Karroo system, are eco- logical equivalents of heteromyids. Several rodents found in the deserts of southern Africa have been studied ecolog- ically and physiologically (Christian, 1978, 1979^, \919b, 1980a, 1980^; Nel and Rau- tenbach, 1975; Taylor and Green, 1976; Withers et al., 1980). While not all of the species examined were independent of free water, all produced highly concentrated urine, especially Desmodillus auricidaris and Gerbillus paeba, with the
. Biology of the Heteromyidae. Heteromyidae. PANDESERTIC RODENT ECOLOGY 677 No species found in the Kalahari, but absent from the Namib/Karroo system, are eco- logical equivalents of heteromyids. Several rodents found in the deserts of southern Africa have been studied ecolog- ically and physiologically (Christian, 1978, 1979^, \919b, 1980a, 1980^; Nel and Rau- tenbach, 1975; Taylor and Green, 1976; Withers et al., 1980). While not all of the species examined were independent of free water, all produced highly concentrated urine, especially Desmodillus auricidaris and Gerbillus paeba, with the former being the most efficient at conserving water {Rhab- domyspumilio, an herbivore, was much less efficient at conserving water than the ger- billines). Thus it is clear that physiological similarities to heteromyids characterize those African species that are ecologically similar. Rodents from more mesic parts of the southern African scrublands appear to be less xeric adapted (Taylor and Green, 1976). Madagascar It might seem surprising that Madagas- car, a large (600,000 square kilometers) is- land lying 400 km off the southeastern Af- rican coast (Fig. 23) would be included in a chapter dealing with deserts, but Madagas- car contains an extensive semiarid zone having a pronounced dry season (Rauh, 1986). This semiarid zone is largely the re- sult of rain shadow effects of a mountainous region that parallels the east coast of the island and causes most of the moisture- bearing southeast trade winds to deposit their moisture as orographic rainfall on the eastern slopes of the mountains. Although rainfall in the xeric parts of the island may vary from 350-900 mm, the eight-month droughts in the portion receiving the great- est amounts of precipitation magnify the effects of aridity. The sub-arid zone may receive up to 350 mm of rain per year, but the rainfall is unpredictably sporadic. In- deed, the year's total may be received in a single month (Rauh, 1986). Insolation dur
Size: 1533px × 1629px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionbiodiversity, bookcontributorharv
