Aug 10

The German government is to investigate soundproofing underwater construction sites with a ‘bubble curtain’, to protect whales, dolphins and porpoises in the Baltic Sea.  

A recently released report by the German Federal Agency for Nature Conservation suggests that by using simple, low-cost technology, bubbles released from pipes on the seafloor can create a sound-insulating barrier around developments such as turbines. This simple, yet innovative technique should help protect vulnerable marine mammals from noise pollution.

Photo of adult female Risso's dolphin with young

Adult female Risso's dolphin with young

As countries accelerate their attempts to ‘green’ their economies, offshore wind farms are becoming increasingly more prevalent. While the turbines seem peaceful enough as they harness the wind’s energy, their construction can result in serious noise pollution that threatens underwater mammals like whales, dolphins and porpoises. 

At particular risk are the cetaceans that inhabit the Baltic Sea off the northern German coast – a prime area for wind farm construction. 

Need for an acoustically clean environment 

Marine mammals rely on echolocation to hunt and navigate, and noise from pile-driving work to install turbines can interfere with the animals’ ability to find each other and locate their prey. Young animals can be separated from their mothers, while older animals can suffer hearing loss. 

Karsten Brensing, a biologist at the Whales and Dolphins Conservation Society said: “These animals are so dependent on their acoustic sense … we need an acoustically clean environment.”

Photo of dunlin and sanderling flock flying past a wind farm

Dunlin and sanderling flock flying past a wind farm

However, a German study has shown that by creating a ‘bubble curtain’ it is both technically and economically feasible to reconcile the drive for green energy with protecting aquatic life. 

A pipe or hose is placed on the sea floor to create a ring around noise pollutants, like a pile-driver attempting to break through bedrock. Air is then pushed through holes to create a shield of bubbles around the noise. As sound waves pass through the resulting bubble curtain, they become less intense and noise levels are decreased.

Photo of harbour porpoise underwater

Harbour porpoise underwater

A Greenpeace campaigner, Thilo Maack, believes that if bubble curtains can mitigate the impact on wildlife, they should be used. But he also said quieter construction methods such as drilling need to be investigated. 

We have to be sure that the wind parks don’t harm harbour porpoises and other marine mammals,” Maack said. “On the other hand, we need these renewable energies to fight the consequences of climate change.” 

Read the full article at the Guardian – German ‘bubble curtain’ study hopes to protect whales’ hearing.

Alex Royan, ARKive Species Text Author

Aug 2

A new study has identified the 20 most important regions of the world’s oceans to marine mammal conservation. However, the study, published in the Proceedings of the National Academy of Sciences, also revealed that most of these areas are under pressure from human impacts such as pollution and shipping.

Photo of short-finned pilot whale

Short-finned pilot whale

Marine mammal hotspots 

Sandra Pompa, an ecologist at the National Autonomous University of Mexico, led a team of scientists to try and identify which parts of the world’s oceans are most crucial for the world’s 123 marine mammal species, as well as an additional 6 freshwater mammal species, which includes freshwater seals and dolphins.

The team split the oceans up into a grid of roughly 10,000 boxes, each of a square kilometre, and examined which species lived in which boxes. The boxes were also assigned values based on whether they contained important feeding grounds or if they coincided with migration routes. 

Their results revealed nine key global conservation sites that hold 84% of marine mammal species, as well as 11 “irreplaceable” conservation sites, which contain species that are found nowhere else.

Photo of vaquita as bycatch, being hauled in by a fisherman

Vaquita as bycatch, being hauled in by a fisherman

Human impacts 

The maps were analysed alongside information on human impacts such climate change, pollution and commercial shipping. 

Seventy per cent of the most impacted areas were near a key conservation site,” said Pompa. “We are competing with [the sea mammals] in terms of shipping or ocean pollution. We want to build industry or touristic attractions and it’s their home.” 

According to the paper, the next species of marine mammal most likely to become extinct is the vaquita – a small porpoise that is endemic to the most northern part of Baja California. It is thought to number only around 250 individuals in the wild. 

The Baikal seal, also has a very small-numbered population confined to Lake Baikal in Russia. “Maybe you can think about the vaquita escaping the Gulf into somewhere else but the Baikal seal can’t. It’s a freshwater endemic mammal species. If any disruption in the lake should happen or a new sickness, they’re all packed in one lake” said Pompa.

Photo of Baikal seal

Baikal seal

The researchers said that their maps should allow conservationists to start safeguarding those areas most important to the world’s marine mammals. “Perhaps you are a government or NGO, you can use this information as a tool depending on the aim you have,” said Pompa.

Marine conservation is barely beginning. Marine mammals are great species because they represent healthy ecosystems so, if you begin to lose the species that give you a clue to a healthy ecosystem then you start with the degradation of all of the oceans. A visual projection of where is the richness, where are the endangered species, which corridors we need to protect in order to have all the species present in the world, it’s a nice start to know where to focus the effort.” 

Read the full story at the Guardian – Scientists name world’s most important marine conservation hotspots.

Read the paper published in the Proceedings of the National Academy of Sciences.

Alex Royan, ARKive Species Text Author

Jul 26
Invasive species have long been identified by conservationists as one of the greatest threats to biodiversity. When introduced to natural ecosystems, invasive species can degrade habitats or harm native animals by preying on them or their prey.

However, a number of recent articles in influential scientific journals have questioned the urgency of addressing the threat to biodiversity from invasive species, amid concerns that conservationists may not be making the necessary distinction between invasive species and alien species in their desire to maintain pristine ecosystems.

Photo of a brown rat

The brown rat (Rattus norvegicus) has been the cause of many extinctions worldwide, particularly seabirds restricted to remote, predator-free islands.

Alien species are introduced outside their natural range by humans, and are in many cases harmless. Invasive species on the other hand, are not only introduced outside their range, but also cause substantial harm to biodiversity and human livelihoods. 

In certain cases, alien species may prove beneficial to human wellbeing. Examples include the honey bee, which has been introduced to North America, and various crops such as corn and potato which were introduced to Europe and have become staple dietary components for millions of people. 

Invasive species, not alien species, are however a major cause of biodiversity loss, and are implicated in the majority of extinctions recorded to date. 

To counter the concerns raised by some of the recent articles, a letter recently published in Science magazine aims to highlight the growing threat to biodiversity from invasive species, and addresses some of the dangerous misunderstandings of the issue.

Photo of a Cuban treefrog

The Cuban treefrog (Osteopilus septentrionalis) has been introduced to numerous Caribbean islands outside its native Cuba, and is preying on many rare amphibians.

The letter argues that the concerns raised over tackling the invasive species problem are unfounded, and that conservationists do recognise a clear distinction between alien species and invasive species. 

The letter is signed by several leaders of well-established and respected conservation organizations, including IUCN’s Director General, Julia Marton-Lefèvre; the Chair of the Species Survival Commission (SSC), Simon Stuart; and the Chair of SSC’s Invasive Species Specialist Group, Piero Genovesi. 

The authors highlight that threats from invasive species can be reduced, and that biodiversity can be protected through carefully targeted conservation interventions.

Photo of a swarm of honey bees

The honey bee has been beneficial to humans by providing food and pollinating crops.

Tackling invasive species also addresses the economic damage they cause and the serious threats that they pose to human health and livelihoods,” says Julia Marton-Lefèvre. 

Attempts to remove the most harmful invasive species are proving to be increasingly successful, with more than 1,000 eradications completed worldwide to date.” 

In speaking out and making clear the distinction between invasive and alien species, the authors of the letter have demonstrated their commitment to the fight against invasive species, and now call upon academics for support and, above all, action. 

Read the IUCN press release – Top scientists rally together in fight against invasive species.

Alex Royan, ARKive Species Text Author

Jul 19

Ten years ago the Cayman Island blue iguana numbered just two dozen individuals, but thanks to concerted conservation efforts this rare lizard is on the road to a remarkable recovery.

Photo of Cayman Island blue iguana resting on rock

Last ditch attempt to save the species 

Weighing in at over 11 kilograms and measuring over 1.5 metres in length, the Cayman Island blue iguana is by far the largest native animal on Grand Cayman, the only place in which it occurs. 

Predation was never a concern for this impressive lizard until cats and dogs were introduced to the island. Together with habitat destruction and collisions with cars, this has slowly pushed the species ever closer to extinction. 

In 2002, conservationists began a last ditch attempt to save the iguana. With help from local and international conservation partners, including the Wildlife Conservation Society and Durrell Wildlife Conservation Trust, the Blue Iguana Recovery Program has bred and released more than 500 blue iguanas back into the wild, increasing its population by twenty times.

Photo of Cayman Island blue iguana feeding

Remarkable success 

Blue iguanas are raised in captivity until two years old, when they are big enough to keep feral cats at bay. Once they hit two, the blue iguanas are released and monitored in the Salina Reserve on Grand Cayman. 

The programme has been such a success that conservationists have also started releasing blue iguanas into a new protected area, the Colliers Wilderness Reserve. This month, the programme confirmed the first breeding blue iguanas in the reserve. The goal is now to hit a population of 1,000 blue iguanas and, given recent success, this may be achieved fairly quickly.

Close up of a male Cayman Island blue iguana

For the past several years, we’ve succeeded in adding hundreds of animals to the wild population, all of which receive a health screening before release,” said Dr Paul Calle, Director of Zoological Health for WCS’s Bronx Zoo. 

Fred Burton, Director of the Blue Iguana Recovery Program, said: “We expect to reach our goal of 1,000 iguanas in managed protected areas in the wild in a few years. After that, we will monitor the iguanas to make sure they are reproducing in the numbers needed to maintain the wild population. If we get positive results, we will have succeeded.” 

View more images of the Cayman Island blue iguana on ARKive

Read the WCS press release – Grand Cayman blue iguana: Back from the brink of extinction.

Alex Royan, ARKive Species Text Author

Jul 14

Despite decades of war and poverty, the mountainous regions of north-eastern Afghanistan are still home to a healthy population of the elusive snow leopard, according to a new study by the Wildlife Conservation Society (WCS).

The study, published in the International Journal of Environmental Studies, reports that researchers were able to identify 30 snow leopards in 16 different locations, using camera traps placed by WCS-trained community rangers. The valuable images represent the first camera trap records of snow leopards in Afghanistan.

Photo of wild snow leopard in stalking pose

Wild snow leopard in stalking pose

The discovery gives hope to the world’s most elusive big cat, which numbers between 4,500 and 7,500 individuals scattered across a dozen countries in Central Asia. 

This is a wonderful discovery – it shows that there is real hope for snow leopards in Afghanistan,” said Peter Zahler, WCS Deputy Director for Asia Programs. 

Now our goal is to ensure that these magnificent animals have a secure future as a key part of Afghanistan’s natural heritage.” 

Still imperilled 

Snow leopards remain threatened in the region, with poaching for pelts, persecution by shepherds, and the capture of live animals for the illegal pet trade all documented.  

In response, WCS has developed a set of conservation initiatives to protect snow leopards. These include partnering with local communities, training rangers, and undertaking education and outreach efforts.

WCS also plans to start marking snow leopards to estimate the total population size in the region.

Photo of snow leopard walking through snow

Adult male snow leopard in habitat

Wildlife surviving in war zone 

This positive news comes as WCS reported that a wealth of other rare wildlife has survived along Afghanistan’s eastern border with Pakistan. Records include sightings of carnivores such as Asiatic black bears, grey wolves, golden jackals and leopard cats, as well as more common species like the Indian crested porcupine, rhesus macaque and the yellow-throated marten. 

Unexpectedly, the scientists also saw a few common palm civets, cat-like mammals that had never before been documented in Afghanistan.

Photo of leopard cat

Leopard cat

View more images and videos of the snow leopard on ARKive

View more species from Afghanistan on ARKive

Alex Royan, ARKive Species Text Author


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