Mar 6

Arkive’s Week in Review — Wildlife News

ICYMI: Arkive has compiled some of the biggest and most interesting headlines from this week.

Article originally published on Friday, Feb 27, 2015

Salish Sea seagull populations halved since 1980s

Glaucous-winged-gull-in-flight-ventral-view

Glaucous winged gull in flight

Researchers believe that the decline in the number of glacous winged gulls reflects changes in the availability of marine food. Considering that gulls are the ultimate diet generalist, their decline suggests some profound changes to local marine ecosystems.

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Article originally published on Saturday, Feb 28, 2015

European beavers pair up for life and never cheat

Juvenile-Eurasian-beaver-feeding

Juvenile Eurasian beaver feeding

Less than 5 percent of animals are believed to pair together for life, yet not without instances of cheating. One of the exceptions appears to be the Eurasian beaver who is completely faithful to its partner for its entire life.  Conversely, the American beaver is known to mate with others besides their partner.

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Young-American-beaver-feeding-on-leaves

Young American beaver feeding on leaves

 Article originally published on Sunday, Mar 1, 2015

Hoary bat may become Hawaii’s state mammal

Hoary-bat-roosting

Hoary bat roosting

A bill has been introduced to designate the endangered hoary bat as the state’s official land mammal. They are solitary creatures that have a wingspan of only 12 inches.

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 Article originally published on Monday, Mar 2, 2015

Incredibly rare bird sighted

Aldabra-rail

Aldabra rail

The critically endangered Zapata rail (Cyanolimnas cerverai) was finally seen for the first time in almost four decades. Fewer than 400 Zapata rails are estimated to exist. They belong to the genus Rallidae which includes the Aldabra rail.

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 Article originally published on Tuesday, Mar 3, 2015

Peacocks’ tails make noises too low for humans to hear

Male-Indian-peafowl-displaying

Male Indian peafowl displaying

Peacocks make ‘infrasound’ noises with their tails that are about as loud as a car going by a few meters away. Researchers hypothesize that in males the sound could be used to attract females or ward away other males.

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 Article originally published on Wednesday, Mar 4, 2015

Last ditch: Mexico finally gets serious about saving the vaquita

Vaquita-calf-at-the-surface

Vaquita calf at the surface

There are reportedly less than 100 vaquita on the planet. The Mexican government announced that it would ban gillnet fishing in the vaquita’s habitat for two years and fisherman would be compensated for their lost income.

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Article originally published on Thursday, Mar 5, 2015

WCS re-discovers ‘extinct’ bird in Myanmar

Dorsal-view-of-Jerdons-babbler-

Jerdon’s babbler

Jerdon’s babbler had not been seen in Myanmar since July 1941. At the beginning of the 20th century, the species was common in the vast natural grassland that once covered the Ayeyarwady and Sittaung flood plains around Yangon.

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Enjoy your weekend!

William Lazaro, Arkive Social Media Intern, Wildscreen USA 


Feb 7

Scientists say the reintroduction of grey wolves to Yellowstone National Park is not enough to enable a full recovery of the ecosystem. 

Photo of grey wolf running in the snow

Grey wolf running in the snow

Trophic cascade

When grey wolves all but vanished from Yellowstone National Park in the early 1900s, the absence of this keystone predator had a marked effect on the park’s ecosystem. Elk, the wolves’ natural prey, rapidly increased in numbers, escalating grazing pressure on willow trees that grow by the sides of streams. As a result, the decline in willow led to a severe decrease in the beaver population. Beavers rely heavily on willow to provide food and materials with which to build their dams. Beavers and willows have a mutual relationship whereby the willow also benefits from the beavers’ presence, due to the raised water tables caused by their dams. The loss of Yellowstone’s wolves led to a cascade of dramatic changes in the ecosystem’s structure, known as a trophic cascade.

Photo of American beaver felling a tree

American beaver felling a tree

Wolves return

When wolves returned to Yellowstone National Park in 1995, elk numbers fell and shrub recovery became evident through increased plant height and berry production. This led some scientists to predict ecosystem recovery following the return of the park’s top predator. Authors of a paper in the Proceedings of the Royal Society B have revealed a ‘recovery test’, explaining that if the ecosystem is indeed in recovery, willow trees must be at least two metres tall in order to escape being eaten by elk and to provide the beavers with necessary food and material to build dams.

Photo of male elk calling

Male elk calling

Insufficient recovery

In the study concerned, researchers measured willow trees at four sites in Yellowstone from 2001 to 2010. Some willow tree plots were fenced to prevent the elk from grazing, whereas some had simulated dams. Regardless of fencing and growth time, the researchers found that only the willows that grew in the plots with simulated dams reached heights of more than two metres. The outcome of this study suggests that riparian ecosystems are unable to recover fully due to the presence of wolves alone; tall willows cannot return without the beaver, yet the absence of tall willows inhibits the beaver’s much-needed return. It is clear that the co-existence of beavers and willow trees is able to drive the structure of riparian ecosystems, and that for the Yellowstone ecosystem to continue to recover, beavers will need to enter the equation.

Photo showing grey wolves with different coloured coats

Grey wolves can have different coloured coats

 

Read more on this story at The Guardian – The return of grey wolves ‘not enough to restore Yellowstone’s ecosystem’.

View photos and videos of grey wolves, North American elk and the American beaver on ARKive.

Kaz Armour, ARKive Text Author

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