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

Nov 28

Organic horticulturist, Andy Dean, shares his views with us on Christmas trees and how to have a green Christmas…

In 1841, Queen Victoria’s new husband Albert, introduced a German Christmas tradition into the British royal household. From that point on the popularity of the Christmas tree has been on the up in the UK, Western Europe, America and most other parts of the world.

The custom of putting up a decorated fir tree in your home at Christmas began in Germany in the 17th century.

Unlike in England, the fir tree is native to Germany, Scandinavia and Eastern Europe, being part of the natural biodiversity and offering habitat for native wildlife. Even in its native Germany, the fir tree has been through periods of threat, with legislation being passed to protect it from harvesting due to the popularity of having a cut tree indoors during the festive holiday season.

Photo of American red squirrel searching for fir cones at top of Douglas fir tree

Fir trees are important to wildlife: American red squirrel searching for fir cones at the top of a Douglas fir tree

I am in no way a ‘bah humbug’ person about Christmas and love the celebrations, but it breaks my heart to see the cut trees that are discarded after two weeks, laying outside almost every household, browning on their sides.

It strikes me as evidence of our detachment to source and, in our innocent excitement for the season, we forget that it is not just the one tree that we have cut, but many trees – almost one for each household. In fact, it is reported that 7 million real fir trees were sold in England last year alone.

With the approaching festivities, I would like to set a challenge to everyone. Instead of spending good money on a cut tree that will be tossed aside once the festivities are all over – putting a strain on both the environment and local amenities – why not gather up your family and take a walk in the countryside to pick a couple of sprigs of holly or ivy and perhaps a broken branch that could be decorated.

Common holly photo

Common holly

So long as this is done sympathetically, without greed and with good common sense, there is no reason why this should hamper the environment at all. In fact a gentle prune will help promote growth of the plant, and in gathering it ourselves we have both filled our lungs with fresh air and stretched our legs.

If you do want a real tree and have the outside space to accommodate it, why not grow one in a pot and enjoy it all year round, bringing it indoors for the holiday season?

With the money saved every year, you could even plant a native tree – either on your own land or even by making a donation to charities like the Woodland Trust  who strive to plant, proliferate and protect our native broadleaved woodlands. These are the very woodlands that add beauty to our landscapes and support our native wildlife.

Photo of a  subalpine fir forest

The beauty of a subalpine fir forest

And if you’re looking for something a little different this year, have a look at my post on alternatives to the cut tree .

Andy Dean, NOCN, is an organic horticulturist and owner of landscape & garden design company, Blue Sky Landscapes .

Nov 5

Each year in the UK, the 5th November marks Fireworks Night, an annual commemoration of Guy Fawkes’ failed attempt to blow up the Houses of Parliament. Across the country tonight you can expect to see sparklers, blazing bonfires and spectacular fireworks. Of course, it’s not just us humans who enjoy a dazzling display. They might not be quite as explosive, but the natural world has some fantastic fireworks of its very own…..

Fountains of feathers

Male birds are some of the biggest show-offs in the animal kingdom, and their extravagant feathers can be the key to a female’s heart. We thought we would kick off our display with some of the most flamboyant, including the Atlantic royal flycatcher, the raggiana bird of paradise and an unusual albino Indian peafowl….

Atlantic royal flycatcher photoRaggiana bird of paradise photo








Indian peafowl photo

Fancy Flowers

For some explosions of colour, what better place to look than the world of plants? Our top picks are the pretty ribbon pincushion and the aptly named fire bush!

Ribbon pincushion photo

Fire bush photo








Underwater wonders

The marine world is full of incredible species, and the jewel anemone and purple sea urchin are certainly as beautiful as any firework. Lets hear an oooooh and an ahhhhh for the lovely lionfish too!

 Jewel anemone photoPurple sea urchin photo








Common lionfish photo


Pinwheels and rockets

No display would be complete without some spectacular rockets, and we don’t think they come much brighter than the golden rocket frog! For good measure we have thrown in an impressive pinwheel too, the Dlinza pinwheel to be precise!

Golden rocket frog photoDlinza pinwheel photo








A creature from the flames…

Most of us know to check our bonfires for hibernating hedgehogs before lighting them, but I bet not many of you have thought to look for salamanders before. It is believed that the common fire salamander is so-called as it often hides in damp logs, and would be forced to emerge when the wood was used in fires, giving the impression that it had crawled out of the flames!

Common fire salamander photo

Claire Lewis, ARKive Researcher

Oct 28

Species: Queen of the Andes (Puya raimondii)

Queen of the Andes  (Puya raimondii) photo

Queen of the Andes (Puya raimondii)

Status: Endangered (EN)

Interesting Fact: The Queen of the Andes may take as long as 80 to 150 years to flower and will only flower once before dying.

The Queen of the Andes is best known for its spectacular flower spike, which can reach up to 10 metres high. These spikes bear over 8,000 whitish-green blooms, which turn purple with age. The Queen of the Andes is a monocarpic species, meaning that it will die after flowering for the first time. These plants produce as many as 8 to 12 million seeds, but if conditions are not suitable few seeds will survive to germination. This means that a plant that is more than a century old may never actually reproduce successfully. The Queen of the Andes grows in the harsh, high-altitude environment of the Andes in Peru and Bolivia. This highly adapted species produces an anti-freeze chemical in its sap to survive freezing temperatures.

Today, the Queen of the Andes has an extremely fragmented distribution. Vegetation destruction, grazing by livestock, fires, and the introduction of exotic species all threaten this species. The Andean region is regarded as a priority for plant conservation, meaning action is urgently required to preserve this unique ecosystem and its important vegetation.

Find out more about the Queen of the Andes on the IUCN Red List website.

See images and videos of the Queen of the Andes on ARKive.

Oct 17

A worrying 83% of Madagascar’s palm species are threatened with extinction, according to an assessment carried out by the IUCN Species Survival Commission (SSC) Palm Specialist Group as part of the latest update to The IUCN Red List of Threatened Species.

Ravenea delicatula image

Ravenea delicatula in flower

Endangered endemics

Drawing on research by experts at Royal Botanic Gardens, Kew, this latest study is part of an ongoing project to assess the conservation status of all palms worldwide. It has helped bring the total number of plant, animal and fungus species assessed on the IUCN Red List to an impressive 65,581, of which 20,219 are threatened with extinction.

All 192 palm species found on Madagascar are endemic to the island, meaning that they are found nowhere else on Earth. These plants form an integral part of Madagascar’s biodiversity, yet they are at risk from habitat loss and palm heart harvesting.

The majority of Madagascar’s palms grow in the island’s eastern rainforests, which have already been reduced to less than one quarter of their original size and which continue to disappear,” said Dr William Baker, Chair of the IUCN/SSC Palm Specialist Group and Head of Palm Research at the Royal Botanic Gardens, Kew. “The high extinction risk faced by Madagascar’s palms reflects the decline in these forests, which threatens all of the remarkable wildlife that occurs there.”

Dimaka image

The dimaka is also known as the suicide palm

The importance of palms

While the species that form Madagascar’s unique wildlife face the severe impacts of the reduction in palm forests, so too do many of the country’s poorest communities, which rely on palm species to provide materials for the construction of houses, as well as food in the form of edible palm hearts.

The figures on Madagascar’s palms are truly terrifying, especially as the loss of palms impacts both the unique biodiversity of the island and its people,” said Dr Jane Smart, Global Director of the IUCN Biodiversity Conservation Group. “This situation cannot be ignored.”

Dimaka leaf image

Dimaka leaf

Palm problems

Madagascar’s palm species face several threats, including land clearance for agriculture and logging. One such Critically Endangered species is Ravenea delicatula, known from just one site on the island. Worryingly, this site is not protected, and Ravenea delicatula is under threat from local people clearing areas of forest to cultivate hill rice, as well as from mining activities launched in search of gems and minerals.

The dimaka (Tahina spectabilis), also known as the suicide palm, is a species large enough to be viewed on Google Earth, growing to a spectacular height of up to 18 metres. Within months of flowering and producing seeds, the palm dies. With only 30 mature individuals left in the wild and with much of its habitat being converted to agricultural lands, this species has been classified as Critically Endangered.

Seed collection poses an additional risk to many palm species, including Dypsis tokoravina, classified as Critically Endangered, and the majestic palm (Ravenea rivularis), whose status has changed from Vulnerable to Endangered due to the ongoing harvest of its seeds despite strict trade regulations.

Urgent action

A prime example of why conservation action must be taken sooner rather than later is the palm Dypsis brittania. This species is only found in Makira Natural Park, which provides a certain level of protection. However, the reserve was only recently established, and with no Dypsis brittania plants found during a survey carried out in 2007, there are fears that this species may already have been lost as a result of habitat degradation.

Majestic palm image

Majestic palm

Direct action on the ground

As a result of this assessment of Madagascar’s palms, conservationists now have a firm basis on which to establish direct conservation action on the ground.

The key to saving Madagascar’s palms, and its biodiversity in general, is strongly dependent on the closest possible collaboration with local communities – especially in this period of severe political instability during which government agencies are working well below standard. Unfortunately this extremely high degree of threat in Madagascar is not unique to palms,” said Dr Russell Mittermeier, President of Conservation International and Chair of the IUCN/SSC Primate Specialist Group.

Royal Botanic Gardens, Kew, has initiated several conservation projects based around community involvement in well-managed seed harvesting and habitat protection. Assisted by Madagascar’s national seed bank, one particular project aimed at protecting the suicide palm sells sustainably harvested seeds through a commercial palm seed merchant, with the money flowing back to the local people who use it to renovate buildings and to grow food more productively.

Wide-scale efforts

While these targeted projects are important in the survival of specific species, IUCN warns that wide-scale efforts are needed to truly secure the future of Madagascar’s palms.

While some species of palm may respond to focused species conservation action, securing the future for Madagascar’s palms requires wide-scale efforts,” said Dr Smart. “Madagascar has made great progress to preserve its unique wildlife by conserving 10% of the island in protected areas. But a game-changing conservation effort is needed to protect the remaining habitat and create more protected areas.”

Read more on this story at IUCN – Madagascar’s palms near extinction.

Learn more about species found in Madagascar on ARKive.

Find out more about palm species on ARKive.

Kathryn Pintus, ARKive Text Author


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