The decline of the world’s large herbivores, especially in Africa and parts of Asia, is raising the specter of an “empty landscape” in some of the most diverse ecosystems on the planet, according to a newly published study.
Many populations of animals such as rhinoceroses, zebras, camels, elephants and tapirs are diminishing or threatened with extinction in grasslands, savannahs, deserts and forests, scientists say.
An international team of wildlife ecologists led by William Ripple, Oregon State University distinguished professor in the College of Forestry, conducted a comprehensive analysis of data on the world’s largest herbivores (more than 100 kilograms, or 220 pounds, on average), including endangerment status, key threats and ecological consequences of population decline. They published their observations today in Science Advances, the open-access online journal of Science magazine.
The authors focused on 74 large herbivore species – animals that subsist on vegetation – and concluded that “without radical intervention, large herbivores (and many smaller ones) will continue to disappear from numerous regions with enormous ecological, social, and economic costs.” Ripple initiated the study after conducting a global analysis of large-carnivore decline, which goes hand-in-hand, he said, with the loss of their herbivore prey.
“I expected that habitat change would be the main factor causing the endangerment of large herbivores,” Ripple said. “But surprisingly, the results show that the two main factors in herbivore declines are hunting by humans and habitat change. They are twin threats.”
The scientists refer to an analysis of the decline of animals in tropical forests published in the journalBioScience in 1992. The author, Kent H. Redford, then a post-doctoral researcher at the University of Florida, first used the term “empty forest.” While soaring trees and other vegetation may exist, he wrote, the loss of forest fauna posed a long-term threat to those ecosystems.
Ripple and his colleagues went a step further. “Our analysis shows that it goes well beyond forest landscapes,” he said, “to savannahs and grasslands and deserts. So we coin a new term, the empty landscape.” As a group, terrestrial herbivores encompass about 4,000 known species and live in many types of ecosystems on every continent except Antarctica.
The highest numbers of threatened large herbivores live in developing countries, especially Southeast Asia, India and Africa, the scientists report. Only one endangered large herbivore lives in Europe (the European bison), and none are in North America, which, the authors add, has “already lost most of its large mammals” through prehistoric hunting and habitat changes.
The authors note that 25 of the largest wild herbivores now occupy an average of only 19 percent of their historical ranges. Competition from livestock production, which has tripled globally since 1980, has reduced herbivore access to land, forage and water and raised disease transmission risks, they add.
Meanwhile, herbivore hunting occurs for two major purposes, the authors note: meat consumption and the global trade in animal parts. An estimated 1 billion humans subsist on wild meat, they write.
The Latest on: Decline of large herbivores
via Google News
The Latest on: Decline of large herbivores
- Humans Were Actually Apex Predators For 2 Million Years, New Study Findson April 6, 2021 at 11:25 pm
But the frequency with which they preyed on these herbivores hasn't been so easy to figure ... hunter-gatherer communities become a little more useful as a decline in populations of large animals and ...
- Stone Age humans were HYPERCARNIVORES: Our ancestors survived on mostly meat until just 80,000 years ago when larger animals died out and they were forced to start eating more ...on April 6, 2021 at 7:53 am
Study authors discovered that humans were an apex predator for about two million years and it was only the extinction of larger animals that changed their diets.
- Most Wild Dogs in Australia Are Pure Dingoeson March 29, 2021 at 2:08 am
"As apex predators, dingoes play a fundamental role in shaping ecosystems by keeping number of herbivores and smaller predators in ... says the timing of this paper is important. "There is a large ...
- Feds declare manatee deaths in Indian River Lagoon an 'unusual mortality event'on March 25, 2021 at 11:46 am
Manatees are herbivores and get much of their nutrients ... indicate the high number of emaciated manatees is likely due to a decline in food availability. Seagrass and macro algae coverage ...
- A World Without Turtles? - New Study Considers Global Impact Of Turtle Declineon March 24, 2021 at 4:59 pm
Should turtles’ decline continue, the ecological consequences ... This paper provides the first major review of the various roles that large populations and diverse communities of turtles ...
- OU research study named finalist for PNAS Cozzarelli Prizeon March 16, 2021 at 5:00 pm
The article, "Nutrient dilution and climate cycles underlie declines in a dominant insect herbivore," draws on ... contributing factor to this decline is attributable to rising carbon dioxide ...
- What fueled humans' big brains? Controversial paper proposes new hypothesis.on March 12, 2021 at 5:44 am
(1,000 kilograms) began to decline across Africa around 4.6 million years ago, with herbivores over 770 lbs ... There are human cut marks on large-mammal bones at some sites, but no one knows ...
- Cascading impacts of large-carnivore extirpation in an African ecosystemon March 3, 2021 at 4:00 pm
The worldwide decline in populations of large mammalian carnivores ... Accordingly, the extirpation of top carnivores should create “landscapes of fearlessness” where large herbivores seek out the ...
- These widely used insecticides may be a threat to mammals tooon February 16, 2021 at 3:03 pm
and cotton—might affect large herbivores. The scientists ran a first-of-its-kind experiment on a captive herd of white-tailed deer, consisting of 21 adult females and 63 fawns born to those ...
- Mekong giant catfishon August 13, 2020 at 9:23 pm
They are distinguished from other large catfish species by their near ... After about a year, they become herbivores, and eat plants and algae. The Mekong giant catfish has one of the fastest ...
via Bing News