Sentences with word «overhunting»

Humans killed off the giant birds by overhunting, a new study says, although the hunters did not use bows and arrows.

These threats include overhunting of the bears and oil spills.

«We show that dense - wooded, large - seeded Amazonian tree species are replaced by light - wooded trees that produce smaller seeds, which continue to be dispersed in overhunted forests by more resilient smaller mammal and bird species.»

Low genetic diversity and poor adaptability meant this once ubiquitous bird could not recover from overhunting

Simulations showed that between 77 and 88 per cent of all plots lose above - ground forest biomass in overhunted forests.

Prof Peres said: «Amazonian forest wildlife has been declining through a combination of habitat destruction, habitat degradation and overhunting since the 1950s, but until now there was a poor understanding of the status of wildlife populations in hunted forests that otherwise remain intact and free from other human disturbances.

«My hope for this study is that it will provide a boost for those trying to curb overhunting and provide incentives to stop the wildlife trade.»

But the steep decline of the megafauna in overhunted tropical forest ecosystems can bring about large unforeseen impacts.

Researchers have long known that many African carnivores died out by 1.5 million years ago, and they blamed our ancestor, Homo erectus, for overhunting with its new stone tools.

These extinctions, in fact, were timed with human arrival, thereby supporting the more widely accepted overhunting hypothesis.

«Our research shows that if people continue to overhunt large mammals, tropical forests could lose much of their capacity for carbon storage.

Some scientists lay the blame squarely on humanity's shoulders, arguing overhunting doomed the planet's megafauna.

Off the List Thanks to repopulation efforts during the past few decades, the gray wolf (Canis lupus) now thrives in the U.S., and since 2003 the U.S. Fish and Wildlife Service has been trying to move the top predator off the endangered species list — a plan opposed by groups that believe the wolves are susceptible to being overhunted [see «Out of the Woods»; SciAm, April 2003].

The message that «guns kill trees too» should help put overhunting at the top of the conservation agenda, where it deserves to be.»

«This study fills a major gap in our understanding of how overhunting affects forest trees, particularly in tropical forests,» he said.

Within the tsetse and game - rich areas there is much overhunting of the wild ungulate animals.

In the last few thousand years, the arrival of humans in new territory almost always brought overhunting, habitat destruction, or invasive species that killed off native creatures.

A chronic lack of studies across the region due to past and ongoing insecurity makes it difficult to be certain of the causes of these declines, although overhunting is likely to have played a role.

Having overhunted big game, people started to diversify what they ate by hunting a wide range of smaller animals.

But people overhunted them, and the species went extinct about 800 years ago.

There are currently reintroduction programs of manatees into the reserve, which were overhunted leading to more water hyacinths on the waterways and other ecosystem changes.

(Overhunting took its toll on land in a much earlier era.)

The extinction rates we recorded may be very high compared to theoretical SAR model predictions, but are still conservative given that many more small populations will be driven to extinction if further habitat loss and overhunting continues unabated.

Overhunting inflates the vulnerability of game populations stranded in forest fragments, further aggravating the risk of local extinctions [6].

If the extinction trend continues apace, modern elephants, rhinos, giraffes, hippos, bison, tigers and many more large mammals will soon disappear as well, as the primary threats from humans have expanded from overhunting, poaching or other types of killing to include indirect processes such as habitat loss and fragmentation.

Large carnivores and herbivores (bigger than 10 kilograms or 22 pounds) comprise a small percentage of all mammals listed but tend to be impacted more severely by overhunting, the researchers reported.

Patterns of primate frugivory in Amazonia and the Guianan shield: implications to the demography of large - seeded plants in overhunted tropical forests

Tigers are endangered, largely due to habitat loss, hunting and overhunting of prey species.

To this day, experts debate what caused this late Pleistocene extinction: climate change, overhunting by humans, disease — or something else?

Sept. 1: Flocks of billions of passenger pigeons once darkened skies for hours at a time, but overhunting and habitat loss drove them to extinction.

Either we stand up and effectively protect these wildlife populations, or overhunting will erode their populations until we see major losses in both forest biodiversity and forest ecosystem services.»

The team discovered that trees that grow from seeds transported by those animals being overhunted are hardier and healthier.

Overhunting has been disastrous for elephants, but their forest habitats have also been caught in the crossfire.

Overhunting in the 19th and 20th centuries coupled with deforestation from increased development in modern times has reduced its population to historic lows.

In tropical forests, overhunting has been implicated in widespread local species extinction and the creation of»em pty forests».

In the 1990s, most of the 50,000 otters in the central and western Aleutians vanished, after a century - long recovery from overhunting.

«There are several drivers of animal decline in tropical landscapes: habitat destruction, overhunting, fragmentation etcetera.

It's not certain why the great beasts vanished; maybe they were overhunted.

Another implication is that, since overhunting is largely the culprit, the North Atlantic can support many more whales than it does now.

Meanwhile the American alligator (Alligator mississippiensis) is considered one of the great conservation success stories, having recovered from overhunting and habitat loss in the last century.

Across the Arctic, belugas, which number about 150,000, are suffering from development, overhunting, ship strikes, pollution, and climate change.

Poaching has devastated a national park in Borneo, a case study in the ecological consequences of overhunting

When the last passenger pigeon died in 1914, ecologists blamed deforestation and overhunting; the bird had become a popular source of cheap meat for both human consumption and livestock feed.

Often, the animals disappeared shortly after humans arrived in their habitats, leading some researchers to suggest that we exterminated them by overhunting.

Overhunting or climate change or some combination thereof had wiped them out sometime between 5,000 and 10,000 years ago.

It shows that many living species of plants, trees and animals that thrive today are those that were favoured by our ancestors; and that large - scale extinctions started thousands of years ago due to overhunting or change of land use by humans.

The researchers suggest that, to curb this overhunting crisis, more logistical and financial support will be needed from the richer, developed countries.