title: An underground index of rangeland degradation: cicadas in arid southern Africa.
abstract: The prediction that density of long-lived, underground herbivores (Cicadidae) is a function of rangeland condition was examined in arid shrublands in the Karoo, South Africa. It was found that the density of adult cicadas was correlated with cover of deep-rooted, perennial plants. Differences in perennial plant cover were independent of soil type and rock cover. On degraded rangelands, where perennial plants had been replaced by ephemerals and short-lived plants, cicada densities were significantly depressed. We concluded that vegetation transformation by domestic livestock is likely to affect invertebrate populations and their vertebrate predators.
authors.affiliation: FitzPatrick Institute, University of Cape Town, 7700, Rondebosch, South Africa.
authors.forename: Suzanne J
authors.initials: SJ
authors.lastname: Milton
authors.affiliation: FitzPatrick Institute, University of Cape Town, 7700, Rondebosch, South Africa.
authors.forename: W R J
authors.initials: WR
authors.lastname: Dean
keywords: Amensalism; Herbivory; Homoptera; Karoo; Vegetation change