In an unusual evolutionary twist, local stick spiders have come up with an almost identical repertoire of color morphs in multiple locations.
As populations of top predators decline in ecosystems the world over, researchers chart the widespread effects.
January 13, 2014|
WIKIMEDIA, DOUG SMITH - NATIONAL PARK SERVICEMore than three quarters of Earth’s large carnivorous animal species are now in decline, a trend that has far-reaching ecological impacts, according to a research published on Friday (January 10). The study, published in Science, tracked the conservation status and ecological roles of the planet’s 31 largest predators, including lions, gray wolves, dingos, and bears. “Globally, we are losing our large carnivores,” lead author William Ripple of Oregon State University told the BBC. “Their ranges are collapsing. Many of these animals are at risk of extinction, either locally or globally.”
Habitat loss, hunting, and prey depletion are key among the forces conspiring against many of the imperiled carnivore species, the authors wrote. Seventeen of the 31 species considered in the new research are now restricted to territories that are less than half their historic range.
The effects of what the authors describe as human “persecution” of these predatory animals ripple through the ecosystems and food webs they find themselves atop. For example, fewer wolves and cougars in the Greater Yellowstone ecosystem has meant less predation on herbivorous mammals, such as elk and deer, whose expanded populations have degraded vegetation, which disrupts the habitat and food sources of birds and small mammals. Similar patterns of disruption play out from the Amazon and Africa to South East Asia and North America.
The answer to the problem, according to Ripple and his coauthors, lies in human hands. “It will probably take a change in both human attitudes and actions to avoid imminent large carnivore extinctions,” the authors wrote. “A future for these carnivore species and their continued effects on planet Earth's ecosystems may depend on it.”
January 13, 2014
Humans are the top predator in every food web and we're not declining in numbers.
January 13, 2014
wctopp has hit the nail on the head.
Human overpopulation is the 'elephant in the room'.
When are ecologists and economists and politicians going to openly start addressing the issue?
January 16, 2014
Human overpopulation is not the issue. The US has a replacement rate of 1.9 babies per woman right now, which is well below what is needed to sustain a country. Many countries are trying to promote their people to have kids. Japan is in the worst situation.
It seems to me that we need to care for our carnivores better by cutting their habitat loss and stop hunting them.
January 20, 2014
@PD: I realized neither that the US population determines earth-wide population nor that there was a glimmer of possibility that the US Congress would abide, let alone enforce a reduction of access to what now passes for wilderness within the US boundaries.
You forgot to mention the mythical holy nostrum for ills heavenly and earthly, the "free market."
February 24, 2014
I wonder if anyone has done work on sea critters to see what the effects have been there. If overfishing predator fish has the same impact in the Gulf of Mexico as well as Oceans, it would be an additional arrow in the quiver bolstering the argument.