Ambiguity in guideline definitions introduces assessor bias and influences consistency in IUCN Red List status assessments

1 College of Natural Sciences, Bangor University, Bangor, UK, 2 Centre for African Conservation Ecology, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa, 3 Department of Animal and Wildlife Sciences, Centre for Wildlife Management, University of Pretoria, Pretoria, South Africa, 4 Endangered Wildlife Trust, Johannesburg, South Africa, 5 Panthera, New York, NY, USA, 6 Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Pretoria, South Africa, 7 Department of Animal and Wildlife Sciences, Centre for Invasion Biology, University of Pretoria, Pretoria, South Africa, 8 School of Biological Science, University of Auckland, Auckland, New Zealand