@article{WasiolkaJeltschHenscheletal.2010,
  author    = {Wasiolka, Bernd and Jeltsch, Florian and Henschel, Joh and Blaum, Niels},
  title     = {Space use of the spotted sand lizard (Pedioplanis l. lineoocellata) under different degradation states},
  issn      = {0141-6707},
  doi       = {10.1111/j.1365-2028.2009.01085.x},
  year      = {2010},
  abstract  = {Although the effects of grazing-induced savannah degradation on animal diversity are well documented, knowledge of how they affect space use or responding behaviour remains poor. In this study, we analysed space use of the spotted sand lizard (Pedioplanis l. lineoocellata) in degraded versus nondegraded habitats of southern Kalahari savannah habitats. Lizards were radio tracked, daily movement distances recorded and home range sizes calculated. In degraded Kalahari savannah habitats where plant diversity and perennial grass cover are low but shrub cover high, P. lineoocellata moves larger distances (40.88 +/- 6.42 m versus 27.43 +/- 5.08 m) and occupies larger home ranges (646.64 +/- 244.84 m(2) versus 209.15 +/- 109.84 m(2)) than in nondegraded habitats (high plant diversity, high perennial grass cover and low shrub cover). We assume that this increase in daily movement distances and home range sizes is a behavioural plasticity to limited food resources in degraded savannah habitats. Although P. lineoocellata is able to adjust to resource-poor savannah habitats, the increase in the lizard's movement activities is likely to result in a higher predation risk. This is supported by the lower availability of protective vegetation i.e. perennial grass cover. Hence, we conclude that despite behavioural plasticity of P. lineoocellata, overgrazing has a severe negative impact on the space use of P. lineoocellata.},
  language  = {en}
}
@article{BlaumEngemanWasiolkaetal.2008,
  author    = {Blaum, Niels and Engeman, Richard M. and Wasiolka, Bernd and Rossmanith, Eva},
  title     = {Indexing small mammalian carnivores in the southern Kalahari, South Africa},
  issn      = {1035-3712},
  year      = {2008},
  abstract  = {Monitoring animal populations in changing environments is crucial to wildlife conservation and management, but restrictions in resources are a recurring problem for wildlife managers and researchers throughout Africa. Land-use- induced shrub encroachment in Kalahari savannah rangelands has led to fragmentation of the landscape. Mammalian carnivores are particularly vulnerable to local extinction in fragmented landscapes, but their low numbers and their often nocturnal and secretive habits make them difficult to monitor. In this study, we tested the applicability of a passive tracking method and compared two measurement methods and index calculations for monitoring small carnivores across a grazing gradient in the southern Kalahari. During the four years of monitoring in a five-year period, we used the knowledge of indigenous Khoisan Bushmen for the identification of carnivore tracks on 640 sand transects (5 m x 250 m). Our results showed that this simple and inexpensive observation method enabled detailed monitoring of 10 small carnivore species across the grazing gradient. A binary index calculated an index based on presence/absence of a species' tracks on each transect, whereas the track intrusion index used the number of track intrusions to each transect for each species in its calculations. For less common species, the two indices were similar in trend and magnitude, because the number of intrusions to each transect was typically 1 or 0. Usually, the two indices showed relatively strong correlations. However, species with patchy distributions of higher numbers presented difficulties for the binary index to monitor trends, but not for the track intrusion index.},
  language  = {en}
}
@article{WasiolkaBlaum2011,
  author    = {Wasiolka, Bernd and Blaum, Niels},
  title     = {Comparing biodiversity between protected savanna and adjacent non-protected farmland in the southern Kalahari},
  series = {Journal of arid environments},
  volume    = {75},
  journal   = {Journal of arid environments},
  number    = {9},
  publisher = {Elsevier},
  address   = {London},
  issn      = {0140-1963},
  doi       = {10.1016/j.jaridenv.2011.04.011},
  pages     = {836 -- 841},
  year      = {2011},
  abstract  = {In this study we investigated the effect of different land use options (wildlife versus livestock) on species richness of plants and reptiles in the protected Kgalagadi Transfrontier Park (KTP) versus adjacent non-protected farmland within the same savanna habitat type (Aoub dune veld) in the southern Kalahari, South Africa. Our results show that both plant and reptile species richness as well as plant cover and reptile abundance was significantly higher in the protected KTP than in the non-protected farmland. The higher proportion of shrub but lower proportions of perennial grass cover, herb cover, and herb species richness in the farmland can be explained by higher stocking rates and the differences in feeding behaviour between native wild ungulates (e.g. Antidorcas marsupialis, Oryx gazella) and livestock (mainly sheep). The reptile's prey availability and microhabitats (perennial grass tussocks and rodent burrows) for thermoregulation and protection against predators were significantly lower in the farmland. To conclude, our results clearly show that long term effects of different land use options (wildlife in protected KTP versus extensive livestock production in the non-protected farmland) even within the same habitat type have led to significant changes in vegetation composition, availability of microhabitat structures and in the reptile community.},
  language  = {en}
}
@article{WasiolkaBlaumJeltschetal.2009,
  author    = {Wasiolka, Bernd and Blaum, Niels and Jeltsch, Florian and Henschel, Joh},
  title     = {Behavioural responses of the lizard "Pedioplanis l. lineoocellata" to overgrazing},
  issn      = {1146-609X},
  doi       = {10.1016/j.actao.2008.09.009},
  year      = {2009},
  abstract  = {We studied the effects of overgrazing on the foraging behaviour of the lizard Pedioplanis l. lineoocellata (Spotted Sand Lizard), a sit-and-wait forager, in habitats of differing vegetation states to determine the effects of habitat degradation on this species. At high grazing intensity where vegetation cover and diversity is low, the lizard P. lineoocellata moves more frequently, spends more time moving and covers larger distances than in habitats where vegetation cover and diversity is high. These behavioural changes in movement patterns can be explained by less abundant prey in habitats with low vegetation cover and diversity. Although morphology, phylogeny and physiology of P. lineoocellata should constrain the change in foraging behaviour, the species has modified its foraging strategy from sit- and-wait to actively foraging. We assume that this behavioural flexibility of P. lineoocellata is a buffer mechanism enabling the species to use and survive in degraded (unfavourable) habitats.},
  language  = {en}
}