Joppa L.N.,Microsoft |
Butchart S.H.M.,BirdLife International |
Hoffmann M.,IUCN Species Survival Commission International Union for Conservation of Nature 28 rue Mauverney CH 1196 Gland Switzerland |
Bachman S.P.,University of Nottingham |
And 6 more authors.
Conservation Biology | Year: 2015
In International Union for Conservation of Nature (IUCN) Red List assessments, extent of occurrence (EOO) is a key measure of extinction risk. However, the way assessors estimate EOO from maps of species' distributions is inconsistent among assessments of different species and among major taxonomic groups. Assessors often estimate EOO from the area of mapped distribution, but these maps often exclude areas that are not habitat in idiosyncratic ways and are not created at the same spatial resolutions. We assessed the impact on extinction risk categories of applying different methods (minimum convex polygon, alpha hull) for estimating EOO for 21,763 species of mammals, birds, and amphibians. Overall, the percentage of threatened species requiring down listing to a lower category of threat (taking into account other Red List criteria under which they qualified) spanned 11-13% for all species combined (14-15% for mammals, 7-8% for birds, and 12-15% for amphibians). These down listings resulted from larger estimates of EOO and depended on the EOO calculation method. Using birds as an example, we found that 14% of threatened and near threatened species could require down listing based on the minimum convex polygon (MCP) approach, an approach that is now recommended by IUCN. Other metrics (such as alpha hull) had marginally smaller impacts. Our results suggest that uniformly applying the MCP approach may lead to a one-time down listing of hundreds of species but ultimately ensure consistency across assessments and realign the calculation of EOO with the theoretical basis on which the metric was founded. © 2015 Society for Conservation Biology.
Naidoo V.,University of Pretoria |
Wolter K.,University of Pretoria |
Cromarty D.,Vulture Programme of the Rhino and Lion Non profit Organisation |
Diekmann M.,Rare and Endangered Species Trust |
And 6 more authors.
Biology Letters | Year: 2010
Three Gyps vulture species are on the brink of extinction in South Asia owing to the veterinary non-steroidal anti-inflammatory drug (NSAID) diclofenac. Carcasses of domesticated ungulates are the main food source for Asia's vultures and birds die fromkidney failure after consuming diclofenaccontaminated tissues.Here, we report on the safety testing of the NSAID ketoprofen, which was not reported to cause mortality in clinical treatment of scavenging birds and is rapidly eliminated from livestock tissues. Safety testing was undertaken using captive non-releasable Cape griffon vultures (Gyps coprotheres) and wild-caught African white-backed vultures (G. africanus), both previously identified as susceptible to diclofenac and suitable surrogates. Ketoprofen doses ranged from 0.5 to 5 mg kg-1 vulture body weight, based upon recommended veterinary guidelines and maximum levels of exposure for wild vultures (estimated as 1.54mg kg-1). Doses were administered by oral gavage or through feeding tissues from cattle dosed with ketoprofen at 6 mg kg-1 cattle bodyweight, before slaughter.Mortalities occurred at dose levels of 1.5 and 5mg kg-1 vulture body weight (within the range recommended for clinical treatment) with the same clinical signs as observed for diclofenac. Surveys of livestock carcasses in India indicate that toxic levels of residual ketoprofen are already present in vulture food supplies. Consequently, we strongly recommend that ketoprofen is not used for veterinary treatment of livestock in Asia and in other regions of the world where vultures access livestock carcasses. The only alternative to diclofenac that should be promoted as safe for vultures is the NSAID meloxicam. © 2009 The Royal Society.
Fisher G.,Royal Society for the Protection of Birds The Lodge |
Walker M.,Royal Society for the Protection of Birds The Lodge
Conservation Evidence | Year: 2015
Changes were made to the management of moorland and adjacent in-bye land at the Royal Society for the Protection of Birds' Lake Vyrnwy reserve in Wales with the aim of improving breeding habitat for Eurasian curlew Numenius arquata. Areas of tall, rank, moorland vegetation were cut to provide a mosaic of short areas for foraging and taller areas for nesting habitat. Some new moorland pools were also created, and enclosed improved grassland was managed with the aim of reducing compaction and improving invertebrate levels. The initial response of the breeding curlew population was encouraging but short-lived, although the population has remained at a slightly higher level than before the management was carried out. © 2015, University of Cambridge. All rights reserved.