Collapse of the world's largest herbivores

William J Ripple¹, Thomas M Newsome², Christopher Wolf¹, Rodolfo Dirzo³, Kristoffer T Everatt⁴, Mauro Galetti⁵, Matt W Hayward⁶, Graham I H Kerley⁴, Taal Levi⁷, Peter A Lindsey⁸, David W Macdonald⁹, Yadvinder Malhi¹⁰, Luke E Painter⁷, Christopher J Sandom⁹, John Terborgh¹¹, Blaire Van Valkenburgh¹²

Affiliations

¹ Trophic Cascades Program, Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA.
² Trophic Cascades Program, Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA. ; Desert Ecology Research Group, School of Biological Sciences, The University of Sydney, Sydney, New South Wales 2006, Australia.
³ Department of Biology, Stanford University, Stanford, CA 94305, USA.
⁴ Centre for African Conservation Ecology, Department of Zoology, Nelson Mandela Metropolitan University, Port Elizabeth 6031, South Africa.
⁵ Departamento de Ecologia, Universidade Estadual Paulista (UNESP), C.P. 199, Rio Claro, São Paulo 13506-900, Brazil.
⁶ Centre for African Conservation Ecology, Department of Zoology, Nelson Mandela Metropolitan University, Port Elizabeth 6031, South Africa. ; College of Natural Sciences, Bangor University, Thoday Building, Deiniol Road, Bangor, Gwynedd LL572UW, UK.
⁷ Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331, USA.
⁸ Lion Program, Panthera, 8 West 40th Street, 18th Floor, New York, NY 10018, USA. ; Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, Gauteng 0001, South Africa.
⁹ Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanati-Kaplan Centre, Tubney House, Tubney, Abingdon OX13 5QL, UK.
¹⁰ Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford OX1 3QY, UK.
¹¹ Nicholas School of the Environment and Earth Sciences, Duke University, P. O. Box 90381, Durham, NC 27708, USA.
¹² Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095-7239, USA.

PMID: 26601172
PMCID: PMC4640652
DOI: 10.1126/sciadv.1400103

Review

Collapse of the world's largest herbivores

William J Ripple et al. Sci Adv. 2015.

. 2015 May 1;1(4):e1400103.

doi: 10.1126/sciadv.1400103. eCollection 2015 May.

Authors

Affiliations

¹ Trophic Cascades Program, Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA.
² Trophic Cascades Program, Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA. ; Desert Ecology Research Group, School of Biological Sciences, The University of Sydney, Sydney, New South Wales 2006, Australia.
³ Department of Biology, Stanford University, Stanford, CA 94305, USA.
⁴ Centre for African Conservation Ecology, Department of Zoology, Nelson Mandela Metropolitan University, Port Elizabeth 6031, South Africa.
⁵ Departamento de Ecologia, Universidade Estadual Paulista (UNESP), C.P. 199, Rio Claro, São Paulo 13506-900, Brazil.
⁶ Centre for African Conservation Ecology, Department of Zoology, Nelson Mandela Metropolitan University, Port Elizabeth 6031, South Africa. ; College of Natural Sciences, Bangor University, Thoday Building, Deiniol Road, Bangor, Gwynedd LL572UW, UK.
⁷ Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331, USA.
⁸ Lion Program, Panthera, 8 West 40th Street, 18th Floor, New York, NY 10018, USA. ; Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, Gauteng 0001, South Africa.
⁹ Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanati-Kaplan Centre, Tubney House, Tubney, Abingdon OX13 5QL, UK.
¹⁰ Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford OX1 3QY, UK.
¹¹ Nicholas School of the Environment and Earth Sciences, Duke University, P. O. Box 90381, Durham, NC 27708, USA.
¹² Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095-7239, USA.

PMID: 26601172
PMCID: PMC4640652
DOI: 10.1126/sciadv.1400103

Abstract

Large wild herbivores are crucial to ecosystems and human societies. We highlight the 74 largest terrestrial herbivore species on Earth (body mass ≥100 kg), the threats they face, their important and often overlooked ecosystem effects, and the conservation efforts needed to save them and their predators from extinction. Large herbivores are generally facing dramatic population declines and range contractions, such that ~60% are threatened with extinction. Nearly all threatened species are in developing countries, where major threats include hunting, land-use change, and resource depression by livestock. Loss of large herbivores can have cascading effects on other species including large carnivores, scavengers, mesoherbivores, small mammals, and ecological processes involving vegetation, hydrology, nutrient cycling, and fire regimes. The rate of large herbivore decline suggests that ever-larger swaths of the world will soon lack many of the vital ecological services these animals provide, resulting in enormous ecological and social costs.

Keywords: defaunation; endangerment; extinction; habitat loss; hunting; large herbivores; megafauna; trophic cascades.

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Figures

**Fig. 1. Large herbivore total species richness (A) and threatened (B) at the ecoregion level.**
Ecoregion lists for each species were obtained using the IUCN Red List species range maps and (3) and are based on the ecoregions where each species is native and currently present.

**Fig. 2. Proportion of large herbivore species listed as threatened by IUCN.**
The total number of herbivore species in each family is shown after each family name. Individual threatened species by family include Elephantidae: African elephant (VU), Asian elephant (EN); Hippopotamidae: hippopotamus (VU), pygmy hippopotamus (EN); Hominidae: eastern gorilla (EN), western gorilla (EN); Tapiridae: Malayan tapir (VU), Baird’s tapir (EN), lowland tapir (VU), mountain tapir (EN); Suidae: Philippine warty pig (VU), Oliver’s warty pig (EN), Visayan warty pig (CR), Palawan bearded pig (VU), bearded pig (VU); Rhinocerotidae: Indian rhinoceros (CR), Javan rhinoceros (CR), Sumatran rhinoceros (CR), black rhinoceros (CR); Equidae: Grevy’s zebra (EN), mountain zebra (VU), African wild ass (CR), Przewalski’s horse (EN), Asiatic wild ass (CR); Cervidae: sambar (VU), barasingha (VU), Père David’s deer (EW), white-lipped deer (VU); Camelidae: bactrian camel (CR); Bovidae: Indian water buffalo (EN), gaur (VU), kouprey (CR), European bison (VU), wild yak (VU), banteng (EN), takin (VU), lowland anoa (EN), tamaraw (CR), mountain nyala (EN), scimitar-horned oryx (EW), mountain anoa (EN), Sumatran serow (VU), walia ibex (EN). Scientific names in table S1.

**Fig. 3. Range contractions over time for three iconic African herbivores.**
African elephant (ca. 1600 versus 2008), common hippopotamus (ca. 1959 versus 2008), and black rhinoceros (ca. 1700 versus 1987). The historical ranges are in blue, whereas the most recent ranges are represented by darker-colored polygons. For security purposes, the most recent black rhinoceros range polygons (1987) have been moved by random directions and distances. The black rhinoceros range has continued to shrink since 1987 across most of Africa, but has expanded locally in Zambia, South Africa, and Namibia through recent reintroductions, and the most current range polygons are not shown because of the recent poaching pressure on the rhinoceros. Photo Credits: Elephant and hippopotamus (K. Everatt), rhinoceros (G. Kerley).

**Fig. 4. Proximate threats faced by large herbivores globally.**
Threats faced by each species were categorized using information in the IUCN Red List species fact sheets. The total adds up to more than 100% because each large herbivore species may have more than one existing threat.

**Fig. 5. Conceptual diagrams showing the effects of elephants, hippopotamus, and rhinoceros on ecosystems.**
(A) African elephants (*L. africana*) convert woodland to shrubland (53), which indirectly improves the browse availability for impala (*A. melampus*) (53) and black rhinoceros (*D. bicornis minor*) (54). By damaging trees, African elephants facilitate increased structural habitat complexity benefiting lizard communities (*100*). Predation by large predators (for example, lions) on small ungulates is facilitated when African elephants open impenetrable thickets (48). African elephants are also great dispersers of seeds over long distances (13). (B) Hippopotamus (*H. amphibius*) maintain pathways in swamps, leading to new channel systems (*101*). Areas grazed by hippopotamus are often more nutritious, which benefits kob (*K. kob*) (55). Mutualism and semiparasitism between hippopotamus and birds have also been shown, via the latter eating insects on hippopotamus (73). (C) White rhinoceros (*C. simum*) maintain short grass patches in mesic areas, which increases browse for other grazers (impalas, wildebeests, *C. taurinus*, and zebra, *Equus burchelli*) and changes fire regimes (71).

**Fig. 6. Photos of selected threatened large herbivore species.**
Endangerment status and photo credits include the following: lowland tapir (*Tapirus terrestris*), vulnerable, T. Newsome; mountain nyala (*T. buxtoni*), endangered, H. Hrabar; European bison (*B. bonasus*), vulnerable, G. Kerley; eastern gorilla (*Gorilla beringei*), endangered, P. Stoel; mountain zebra (*Equus zebra*), vulnerable, H. Hrabar.

**Fig. 7. Global change in the collective mass for wild mammals, humans, cattle, and all livestock for the years 1900–2050.**
Values for 1900 and 2000 are from (*102*). Human, cattle, and livestock biomass forecasts are based on projected annual growth in human population, beef production, and meat production, respectively (88, *102*).

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References

1. IUCN, The IUCN Red List of Threatened Species. Version 2013.2 (2013); http://iucnRedList.org.
1. Sandom C., Faurby S., Sandel B., Svenning J.-C., Global late Quaternary megafauna extinctions linked to humans, not climate change. Proc. R. Soc. B Biol. Sci. 281, 20133254 (2014). - PMC - PubMed
1. Olson D. M., Dinerstein E., Wikramanayake E. D., Burgess N. D., Powell G. V. N., Underwood E. C., D’amico J. A., Itoua I., Strand H. E., Morrison J. C., Loucks C. J., Allnutt T. F., Ricketts T. H., Kura Y., Lamoreux J. F., Wettengel W. W., Hedao P., Kassem K. R., Terrestrial ecoregions of the world: A new map of life on Earth. BioScience 51, 933–938 (2001).
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Collapse of the world's largest herbivores

Affiliations

Collapse of the world's largest herbivores

Authors

Affiliations

Abstract

Figures

References

Publication types

LinkOut - more resources

Full Text Sources

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