Oct 23

Pesticides used in farming are killing bumblebees and affecting their ability to forage, putting colonies at risk of failure, according to a new study.

Photo of a buff-tailed bumblebee

Buff-tailed bumblebee on flower

An estimated one-third of all plant-based foods eaten by humans rely on bees for pollination, and bees and other pollinators have been estimated to be worth around $200 billion a year to the global economy. However, bee numbers have been plummeting in recent years, particularly in North America and Europe.

As bees provide around 80% of pollination by insects, it is vital to understand and deal with the causes of these declines.

Colony effects

Recent studies have suggested that pesticides may play a role in bee declines, as pesticide exposure can cause changes in bee behaviour and reduce the production of queens in colonies. However, the overall effects at the colony level are less well understood. Bees are also exposed to a number of different pesticides while foraging, but their combined effects have rarely been investigated.

Photo of honey bee performing waggle dance

Honey bees

In the new study, published in Nature, scientists exposed colonies of bumblebees to the pesticides neonicotinoid and pyrethroid over four weeks, at levels similar to those found in the field.

Most previous studies have focused on honey bees, which are smaller than bumblebees but have much larger colonies, sometimes numbering tens of thousands of individuals. In contrast, bumblebees form colonies of just a few dozen individuals, potentially making them more vulnerable to impacts at the colony level.

Photo of a small garden bumblebee nest

Nest of the small garden bumblebee

The findings showed that long-term exposure to the two pesticides impaired the foraging behaviour of the bees and increased worker mortality, leading to significant reductions in colony success. The researchers also found that being exposed to a combination of more than one pesticide increased the likelihood of a colony failing.

Effects at the individual level can have a major knock-on effect at the colony level. That’s the novelty of the study,” said Richard Gill, the lead author of the study.

Important piece of the jigsaw

According to the researchers, the new findings emphasise the need for wider testing of pesticides. They endorsed the recommendations of the European Food Safety Authority (EFSA) that pesticides should be tested over longer periods and that new protocols should be developed to detect the cumulative effects of multiple chemicals on bees. There should also be separate assessments for different bee species.

Photo of female common carder bumblebee feeding from flower

Common carder bumblebee foraging

Parasites and habitat destruction, leading to a reduction in food supplies, have also been blamed for the decline in bee populations. A number of different factors are likely to be involved, and more research is still needed.

My guess is that the decline of bees is like a jigsaw – there are probably a lot of pieces to put into place. This is probably a very important piece of that jigsaw,” said Gill.

Read more on this story at The Guardian – Pesticides put bumblebee colonies at risk of failure, study finds.

View photos and videos of bees on ARKive.

Liz Shaw, ARKive Text Author

Oct 21
European eel (Anguilla anguilla) photo

European eel (Anguilla anguilla)

Species: European eel (Anguilla anguilla)

Status: Critically Endangered (CR)

Interesting Fact: It is thought that all European eels spawn in the Sargasso Sea after a migration of around 5000 km from European rivers.

European eels are catadromous fish, meaning they spend much of their lives in freshwater but migrate to the sea to breed. Transparent eggs hatch into larvae known as leptocephalli, which drift in the sea for up to three years. Pushed towards the European coast by ocean currents, they then undergo metamorphosis into young, transparent eels known as glass eels. Becoming darker, the young eels, now known as elvers, start to migrate up freshwater streams in large numbers. These eels remain in freshwater for up to 20 years, growing up to 1 metre long. Once sexually mature, the eels migrate back to the Sargasso Sea to spawn. Relatively little is known about the life history and migration routes of the European eels once at sea.

Eel populations have declined in recent years. The threats facing the species are not clear but it is thought that pollution, overfishing, habitat degradation, parasite infection and climate changes are all potential causes of the decline. Regulations are in place to protect these rare eels, including reducing fisheries, restocking, improving habitats and making rivers passable.

Find out more about European eels and their conservation on the eeliad project website.

See videos and images of the European eel on ARKive.

Lauren Pascoe, ARKive Researcher

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

Oct 15

The world’s 25 most endangered primate species have been revealed in a new report released today at the UN’s 11th meeting of the Conferences of the Parties (COP 11) to the Convention on Biological Diversity.

Northern sportive lemur, portrait photo

Northern sportive lemur, one of the world’s most endangered primates

The report, entitled ‘Primates in Peril: The World’s 25 Most Endangered Primates 2012-2014’, lists the primate species which experts believe are most in danger of extinction.

Updated every two years and now in its seventh edition, the list has been compiled by the IUCN/SSC Primate Specialist Group and the International Primatological Society (IPS), in collaboration with Conservation International (CI) and the Bristol Conservation and Science Foundation (BCSF).

Under increasing threat

Of the 25 primate species highlighted in the report, nine are from Asia, six from Madagascar, five from Africa and five from South America. Madagascar tops the list in terms of individual countries, having 6 out of the 25 most endangered primate species.

Photo of a young male variegated spider monkey in captivity

The variegated spider monkey is under threat from habitat loss and hunting

Once again, this report shows that the world’s primates are under increasing threat from human activities. Whilst we haven’t lost any primate species yet during this century, some of them are in very dire straits,” said Dr Christoph Schwitzer, Head of Research at the Bristol Conservation and Science Foundation.

In particular the lemurs are now one of the world’s most endangered groups of mammals, after more than three years of political crisis and a lack of effective enforcement in their home country, Madagascar. A similar crisis is happening in South-East Asia, where trade in wildlife is bringing many primates very close to extinction.”

An assessment carried out earlier this year by the IUCN found that 91% of Madagascar’s lemurs are threatened with extinction, giving one of the highest levels of threat recorded for any group of vertebrates.

Photo of male cao-vit crested gibbon

The cao-vit crested gibbon has an estimated population of just 110 individuals

Primates in peril

Of the world’s 633 primate species and subspecies whose conservation statuses are known, over half are currently classified as threatened with extinction on the IUCN Red List of Threatened Species.

The main threats to primates include habitat destruction, particularly the clearing and burning of tropical forests, as well as hunting for food and the illegal wildlife trade.

Conservationists hope that the new report will help to highlight the plight of some of the most endangered primates. For example, one of the species on the list, the pygmy or lesser spectral tarsier, was only known from museum specimens until a few individuals were captured in 2008. Sadly, its few remaining populations are fragmented, isolated and under threat from human encroachment and armed conflict.

Photo of lesser spectral tarsier in the hands of a researcher

The pygmy or lesser spectral tarsier is one of the world’s least known primates

Hope for the future

Despite the gloomy assessment, experts are hopeful that conservation measures for primates can be successful. The efforts of dedicated primate conservationists, together with considerable public support and media interest, mean that no primate species have yet become extinct in either the 20th or 21st centuries.

Several primates that previously appeared on the list of 25 most endangered have now been removed due to their improved conservation statuses, although not all are out of danger. These include the lion-tailed macaque of southwest India, and the greater bamboo lemur of Madagascar.

Photo of greater bamboo lemur on tree branch

The greater bamboo lemur has now been taken off the list of 25 most endangered primates

According to Dr Russell Mittermeier, Chair of the IUCN/SSC Primate Specialist Group and President of Conservation International, primates play a key role in their tropical forest habitats, acting as seed dispersers and helping to maintain forest diversity.

Amazingly, we continue to discover new species every year since 2000. What is more, primates are increasingly becoming a major ecotourism attraction, and primate-watching is growing in interest and serving as a key source of livelihood in many local communities living around protected areas in which these species occur,” he says.

Primates are our closest living relatives and probably the best flagship species for tropical rain forests, since more than 90 percent of all known primates occur in this endangered biome…  It is increasingly being recognised that forests make a major contribution in terms of ecosystem services for people, providing drinking water, food and medicines.”

Read the full report at Primates in Peril: The World’s 25 Most Endangered Primates 2012-2014.

View photos and videos of primates on ARKive.

Liz Shaw, ARKive Text Author

Oct 14
African wild dog (Lycaon pictus) photo

African wild dog (Lycaon pictus)

Species: African wild dog (Lycaon pictus)

Status: Endangered (EN)

Interesting Fact: African wild dogs hunt in groups and can bring down wildebeest weighing up to 250 kg!

The African wild dog was previously found across sub-Saharan Africa, but now only fragmented populations remain in southern and eastern Africa. Their scientific name means ‘painted wolf-like animal’ in Greek, referring to their yellow, grey, black and white coat. African wild dogs are highly sociable and exhibit an unusual social system. Within the pack, dogs of the same sex are closely related to each other, but not to dogs of the opposite sex. Only the dominant male and female will breed, and the litter size averaging 10 pups is the largest of any canid. African wild dogs cooperatively hunt prey, and this enables them to bring down animals much larger than themselves. When a kill is made, pups in the pack are allowed to eat first.

African wild dogs require large home ranges to support viable populations, and recent habitat fragmentation has caused population declines. These wild dogs are often persecuted wherever they come into contact with humans. They are susceptible to disease, particularly those carried by domestic dogs such as canine distemper and rabies. Protecting large areas of valuable habitat and preventing persecution through education are vital to the conservation of this unique canid.

Find out more about the African wild dog and its conservation on the The African Wild Dog Conservancy website.

See images, videos, and learn more aboutthe African wild dog on the ARKive.

Lauren Pascoe, ARKive Researcher


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