vertebrate

What Is An Endangered Species? | Earth Wise

March 3, 2020 By EarthWise Leave a Comment

Biodiversity is declining rapidly throughout the world and people are mostly the reason. Species are disappearing because of changes in land and sea use, the direct exploitation of organisms, climate change, pollution, and invasive alien species resulting from globalization. The challenges of conserving the world’s species are many and difficult. Among these challenges are determining which species are endangered and how and when to protect them.

What constitutes an endangered species is not necessarily obvious.

Extinction risk increases as a species is driven to extinction from portions of its natural range. Most mammal species have already been driven to extinction from half or more of their historic ranges because of human activities.

According to a recent survey of ordinary Americans, three-quarters of participants said that a species deserves special protections if it had been driven to extinction from any more than 30% of its historic range. This compares with the language of the U.S. Endangered Species Act that defines an endangered species as one that is “in danger of extinction throughout all or a significant portion of its range.”

Experts and decision-makers are more accepting of risks and losses because they believe greater protection would be impossibly expensive. Decision-makers tend to be influenced by special interest groups with a vested interest in not instituting protections.

Before human activities began elevating extinction risk, a typical vertebrate species would have experienced an extinction risk of 1% over a 10,000-year period. Current policies consider a 5% risk over 100 years to be acceptable. Policies consider whether we can afford to protect species. Given the dangers of declining biodiversity, we should ask whether we can afford not to.

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What Is An Endangered Species?

Photo, posted July 29, 2018, courtesy of Sergio Boscaino via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Decline Of Earth’s Largest Freshwater Creatures

September 23, 2019 By EarthWise Leave a Comment

While nearly 70% of the globe is covered by water, only 2.5% of it is freshwater. The rest is saline and ocean-based. And only 1% of our freshwater is easily accessible, with much of it locked away in snowfields and glaciers.

Despite freshwater only making up a small fraction of all water on the planet, it’s home to one third of all vertebrate species. Some have survived hundreds of millions of years, but many of the world’s largest freshwater creatures – including fish, reptiles, amphibians, and mammals – may soon find themselves on the brink of extinction.

According to a study recently published in the journal Global Change Biology, scientists from the Leibniz-Institute of Freshwater Ecology and Inland Fisheries and international colleagues have quantified the global decline of freshwater megafauna for the first time. In four decades since 1970, the global populations of these freshwater giants have declined 88% – twice as much as the loss of vertebrate populations on land or in the oceans.

Freshwater megafauna include all freshwater animals that weigh 30 kilograms (about 66 pounds) or more, such as certain dolphins, beavers, crocodiles, turtles and sturgeons.

Overexploitation is one of the main threats to freshwater megafauna. (These animals are often targeted for their meat, eggs, and skin). The other main threat is the loss of free-flowing rivers. Many of the world’s large rivers are already highly fragmented, which impacts access to spawning and feeding grounds. The research team says another 3700 large dams are planned or under construction, including 800 in habitats rich with freshwater megafauna, including the Amazon, Congo, and Ganges river basins.

Current conservation measures are clearly failing our freshwater creatures.

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88 percent decline of big freshwater animals

Earth’s largest freshwater creatures at risk of extinction

Photo, posted March 25, 2012, courtesy of the U.S. Fish and Wildlife Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Humans And Vertebrate Mortality

April 9, 2019 By EarthWise Leave a Comment

According to a new study, more than one-quarter of the planet’s land vertebrates die because of humans. This is a “disproportionately huge effect” on the other land vertebrates that share planet’s surface with us.

Researchers from the SUNY College of Environmental Science and Forestry and the U.S. Department of Agriculture reviewed 1,114 published studies in which nearly 43,000 animals had perished. Their study, which was recently published in the journal Global Ecology and Biogeography, found that 28% of the animals’ deaths were directly attributable to humans. The other 72% died from natural sources.

Mammals, birds, reptiles, and amphibians that died between 1970 and 2018 in the Americas, Asia, Africa, Europe, and Oceania were the foundation of the study. All of these vertebrates had been either collared or tagged as part of other research projects.

The researchers point out that humans are only one among more than 35,000 species of terrestrial vertebrates globally. The fact that humans are responsible for more than one-quarter of their deaths illustrates the profound magnitude of the problem. And that statistic is just the direct causes. According to the researchers, when urban growth and other land use changes that erode habitat are considered, the human impact is likely even greater.

The study found that the impact of humans across all the different species was not equal. In fact, larger animals were more likely to be killed by humans than smaller animals. Adult animals were more likely to be killed by humans than juveniles.

The researchers conclude that humans are such a major contributor to terrestrial vertebrate mortality that they could potentially impact both evolutionary processes and ecosystem functioning.

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On the land, one-quarter of vertebrates die because of humans

Photo, posted March 6, 2019, courtesy of USFWS Midwest Region via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wiping Out Wildlife

December 1, 2016 By WAMC WEB

According to a new report from the World Wildlife Fund, the world’s animal populations have suffered widespread population declines in the last half century. And thousands of species are now scrambling to survive.

[Read more…] about Wiping Out Wildlife