@article{DrygalaWernerZoller2013,
  author    = {Drygala, Frank and Werner, Ulrike and Zoller, Hinrich},
  title     = {Diet composition of the invasive raccoon dog (Nyctereutes procyonoides) and the native red fox (Vulpes vulpes) in north-east Germany},
  series = {Hystrix : the Italian journal of mammalogy},
  volume    = {24},
  journal   = {Hystrix : the Italian journal of mammalogy},
  number    = {2},
  publisher = {Associazione Teriologica Romana},
  address   = {Roma},
  issn      = {0394-1914},
  doi       = {10.4404/hystrix.-24.2-8867},
  pages     = {190 -- 194},
  year      = {2013},
  abstract  = {Invasive alien species pose a great threat to the integrity of natural communities by competition with and predation on native species. In Germany the invasive raccoon dog (Nyctereutes procyonoides) and the native red fox (Vulpes vulpes) occupy a similar ecological niche. Therefore, the aim of our study was to discover the extent of exploitative diet competition between these two generalist carnivores. Carcasses of red foxes (n=256) and raccoon dogs (n=253) were collected throughout Mecklenburg Western-Pomerania (north-east Germany) and stomachs contains were analysed. Frequency of occurrence and biomass share indicate that both canids are omnivorous and pursue opportunistic feeding strategies. Small mammals and edible plant material were the most important food resources for red foxes and raccoon dogs. Nonetheless, interspecies differences were recorded for edible plant material, small mammals and insects. While red foxes mostly feed on voles, raccoon dogs consumed mice and shrews as often as voles. Only raccoon dogs preyed on amphibians. There were no differences in carrion consumption, both species scavenged on wild boar and we found clear competition for carrion year-round. Moreover, there was evidence that two red foxes foraged on raccoon dogs and vice versa. The mean annual interspecies diet overlap index was relatively high. The diets determined for raccoon dogs and red foxes were quite similar and a similar food niche breadth was recorded. However, only minor competition is assumed to take place since differences in feeding habits do exist.},
  language  = {en}
}
@article{DrygalaZoller2013,
  author    = {Drygala, Frank and Zoller, Hinrich},
  title     = {Spatial use and interaction of the invasive raccoon dog and the native red fox in Central Europe - competition or coexistence?},
  series = {European journal of wildlife research},
  volume    = {59},
  journal   = {European journal of wildlife research},
  number    = {5},
  publisher = {Springer},
  address   = {New York},
  issn      = {1612-4642},
  doi       = {10.1007/s10344-013-0722-y},
  pages     = {683 -- 691},
  year      = {2013},
  abstract  = {The main objective was to discover extent of interference and/or exploitative competition between the native red fox (Vulpes vulpes) and the introduced, invasive raccoon dog (Nyctereues proconoides) in the intensively used, agricultural landscape of northeast Germany (Mecklenburg-Western Pomerania) using very high frequency (VHF) radio telemetry. We recorded location data for 12 foxes and 16 raccoon dogs between July 2004 and December 2006. Species had similar average home range sizes estimated in each season (K95). Home ranges of adjacent raccoon dogs and foxes overlapped from 0.5 to 74.5 \% with a mean of 26.4 \%. We found a significantly different home range overlap index between the species showing that raccoon dog ranges shifted between seasons to a greater extent than red fox ranges. The raccoon dog differed significantly from the red fox in its use of habitat types, preferring dense vegetation cover and avoiding open areas. The red fox displayed less preference for or avoidance of specific habitat types. Moreover, an almost neutral inter-specific interaction index ranging from -0.12 to 0.12 indicates that raccoon dogs and red foxes ignored each other. It is concluded that widespread and available resources and differences in spatial use patterns prevent competition between red foxes and raccoon dogs in the agricultural landscape of northeast Germany.},
  language  = {en}
}