COS 177-1 - Range contractions of the world’s large carnivores

Friday, August 11, 2017: 8:00 AM
B110-111, Oregon Convention Center
Christopher Wolf, Statistics, Oregon State University, OR and William J. Ripple, Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR

The majority of earth’s terrestrial large carnivores have undergone substantial range contractions and many of these species are currently endangered. However, there has been no attempt to fully quantify large carnivore range contractions, which hinders our ability to understand the roles and relative drivers of such trends. Here we present and analyze a newly constructed and comprehensive set of large carnivore range contraction maps. We reveal the extent to which ranges have contracted since historical times, identify regions and biomes where range contractions have been particularly large, and use spatial modeling to explore how rural human population density, cattle density, and cropland relate to range contractions. Motivated by the ecological importance of intact large carnivore guilds, we also examine the spatial extent of intact large carnivore guilds both for the entire world and regionally. Finally, we consider prey depletion as a threat to large hyper-carnivores, using lists of prey species for each large carnivore compiled from the literature. We analyze spatial variation in prey endangerment, changes in endangerment over time and the causes of prey depletion.


In summary, large carnivores that have experienced the greatest range contractions include the red wolf (Canis rufus) (> 99%), Ethiopian wolf (Canis simensis) (99%), tiger (Panthera tigris) (95%), and lion (Panthera leo) (94%). The greatest range contractions occurred in Southeastern Asia and Africa. We found that intact carnivore guilds occupy just 34% of the earth’s land compared to 96% in historic times. Spatial modeling of range contractions showed that contractions were significantly more likely in regions with high rural human population density, cattle density, or cropland. In terms of prey, the clouded leopard (Neofelis nebulosa), Sunda clouded leopard (Neofelis diardi), tiger (Panthera tigris), dhole (Cuon alpinus) and Ethiopian wolf (Canis simensis) all have at least 40% of their prey classified as threatened (according to the IUCN Red List) and all of these species except the Ethiopian wolf have at least 80% of their prey classified as declining. Of the 494 prey species in our analysis, an average of just 6.9% of their ranges overlap protected areas. Our results show the value of a holistic approach to conservation to prevent further range contractions and population declines for the world’s largest carnivores and to conserve these species’ key ecological effects.