Threatened with Extinction: 44 Giant Herbivores Need Help

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October 27, 2015 | 11,314 views

Story at-a-glance

  • About 60 percent of the largest terrestrial herbivores (elephants, rhinos, hippos, and more) are threatened with extinction
  • About 58 percent of such animals have decreasing populations
  • The greatest threats facing large herbivores include being hunted for meat and body parts and habitat loss
  • The loss of large herbivores would be devastating to their surrounding environments

By Dr. Becker

Could you imagine a world without elephants, rhinos, gorillas, and other large herbivores? In the first comprehensive review to look into the endangerment status of these majestic creatures, the results weren’t pretty.1

Forty-four of the 74 largest terrestrial herbivores (that’s about 60 percent) are threatened with extinction (and this includes 12 that are critically endangered or extinct in the wild). Further, about 58 percent of such animals have decreasing populations.

The study was conducted by the International Union for the Conservation of Nature (IUCN), which maintains the IUCN Red List of Threatened Species.

What’s Causing Large Herbivores to Disappear from the Earth?

Most large herbivores have already disappeared from North America and Europe, and now are mostly found in pockets throughout southern Asia, Southeast Asia, and Africa. Most of the threats to their existence are human-induced. The greatest threat is hunters.

It’s estimated that more than 70 percent of large herbivore species are hunted for meat, while close to 30 percent are hunted for body parts. A significant 1 billion people worldwide depend on wild meat for sustenance, and the researchers suggested that availability of this food source will decline by up to 80 percent by 2050.2 According to the study, published in Science Advances:3

“Extensive overhunting for meat across much of the developing world is likely the most important factor in the decline of the largest terrestrial herbivores. Slow reproduction makes large herbivores particularly vulnerable to overhunting.

… In synergy with changes in land use, hunting for meat has increased in recent years due to human population growth, greater access to wildlands due to road building, use of modern firearms and wire snares, access to markets, and the rising demand for wild meat. 

… Demand for wild meat is intensifying, supply is declining, and protected area management budgets for protecting wildlife from overhunting are often inadequate, particularly in developing nations. This creates a ‘perfect storm,’ whereby overhunting often imparts catastrophic population declines.”

Aside from hunting for meat, hunting for body parts is also leading to dramatic declines in certain species, including elephants and the rhinoceros. As the price of ivory has climbed in China, ivory poaching has surged, and now 75 percent of elephant populations are declining.

Rhinoceros horns, which are used in traditional Chinese medicine, are also leading to massive slaughters, especially now that they fetch a greater price (per unit weight) than gold, diamonds, or cocaine. The researchers noted:4

“If accelerated poaching by organized crime syndicates continues, Africa’s rhinoceroses may become extinct in the wild within 20 years.”

Other species aside from elephants and rhinos are also targeted for body parts, including the hippopotamus (which has ivory teeth), gorillas (for their heads, hands and feet), and giraffes (for their hides).

Habitat Loss Is Also Devastating Large Herbivores

Habitat loss due to human encroachment, cultivation, and deforestation is another major concern, threatening more than 30 percent of the species. According to the study, published in Science Advances:5

Many of the largest herbivore species have ranges that are collapsing. Estimates of range contractions have been made for 25 of the 74 species, and on average, these species currently occupy only 19 percent of their historical ranges. This is exemplified by the elephant, hippopotamus, and black rhinoceros, all of which now occupy just tiny fractions of their historical ranges in Africa.”

Part of the problem has to do with livestock encroaching on the land these large herbivores depend on to graze (livestock production in developing countries tripled from 1980 to 2002).6 Ironically, this rise in livestock has not necessarily cut down on hunting wild herbivores for meat, as in many areas in Africa livestock are kept as a status symbol and for wealth rather than as a means of subsistence.

Human encroachment, including the building of roads, crop cultivation, and civil unrest, pose further threats, especially among these big species that require large expanses of land (and have difficulty surviving in fragmented areas).

The Loss of Large Herbivores Could Devastate the Environment

The benefits large herbivores bring to their environments are numerous and can’t be replicated by smaller animals. For instance, elephants, by their sheer size, convert woodland to shrubland, which allows impala and the black rhinoceros easier access to food.

They also damage trees, which provides habitat for lizards, and, by making their way through the forest, open impenetrable thickets so large predators (like lions) can have an easier time hunting.

Further, as elephants travel over long distances, their feces help disperse seeds. The hippopotamus also plays a role, helping to maintain pathways in swamps, which leads to new channel systems. The areas they graze also tend to be more nutritious, and birds are known to coexist with hippos, eating insects off their bodies.

The white rhinoceros has another role to play. By grazing they help maintain short grass patches, which increases food access for impalas, wildebeests, and zebra, and also changes fire regimes.7 Large herbivores area also important for nutrient cycling, which is beneficial for the entire landscape. According to the study:

“… [L]arge herbivores directly influence nutrient cycling via the consumption of plants, which indirectly causes the reallocation of carbon and nutrients within the plant, while also shifting plant species composition toward species with different rates of litter decomposition.

Herbivores can greatly accelerate the nutrient cycle in ecosystems through consumption and subsequent defecation, returning nutrients to the soil at rates that are orders of magnitude faster than processes of leaf loss and decay.

Moreover, as leaves and twigs are consumed, large herbivores excrete urine and feces and create patches of concentrated nutrients that can last for several years.”

Not to mention, large herbivores draw many tourists to developing countries, which depend on tourism as part of their economy. If flagship species decline or become extinct, tourism rates will fall along with employment, while poverty rates will rise even more.

Can Large Herbivores Be Saved?

The researchers called for “concerted action” to save the remaining threatened large herbivores. In addition to focusing research efforts on the many threatened species in developing countries, they noted solving the poaching crisis will be an essential step, as will managing protected areas and focusing conservation efforts in developing countries. They concluded:

“The scale and rate of large herbivore decline suggest that without radical intervention, large herbivores (and many smaller ones) will continue to disappear from numerous regions with enormous ecological, social, and economic costs.

We have progressed well beyond the empty forest to early views of the ‘empty landscape’ in desert, grassland, savanna, and forest ecosystems across much of planet Earth.

Now is the time to act boldly, because without radical changes in these trends, the extinctions that eliminated most of the world’s largest herbivores 10,000 to 50,000 years ago will only have been postponed for these last few remaining giants.”

[+]Sources and References [-]Sources and References

  • 1, 3, 4, 5, 6, 7 Science Advances May 1, 2015
  • 2 Salon May 4, 2015