Pollinating Birds, Mammals Falling Victim to Extinction

Allen's hummingbird pollinates flowers in Santa Anita, California, 2013 (Photo by David Levinson)


GLAND, Switzerland, March 13, 2015 (ENS) – It’s not just bees, the world is losing its pollinating birds and mammals, new research shows. More pollinating bird and mammal species are moving towards extinction than away from it, finds the first global assessment of trends in pollinators.

About 90 percent of flowering plants are pollinated by animals and birds, and humans rely on many of these plant species for food, livestock forage, medicine and materials.

Allen’s hummingbird pollinates flowers in Santa Anita, California, 2013 (Photo by David Levinson)

Nine percent of all known bird and mammal species are pollinators. Among mammals, bats perform this work, pollinating a large number of economically and ecologically important plants such as agave and cacti.

Key pollinating birds include hummingbirds, honeyeaters, sunbirds and white-eyes.

The study, “Global Trends in the Status of Bird and Mammal Pollinators,” was produced jointly by the UN Environment Programme’s World Conservation Monitoring Centre, Sapienza University of Rome, BirdLife International and the International Union for the Conservation of Nature, which maintains the authoritative IUCN Red List of Threatened Species.

Lead author Eugenie Regan of the World Conservation Monitoring Centre said the research results are alarming. “It shows a worrying trend that may be impacting negatively on global pollination services, estimated to be worth more than US$215 billion.”

The assessment shows that on average, 2.4 bird and mammal pollinator species a year have moved one category towards extinction in recent decades, a “substantial increase in extinction risk” across this set of species, the IUCN said in a statement releasing the study today.

“The vast majority of pollination is carried out by invertebrates, such as bees, but unfortunately the lack of available resources for species assessments means that we cannot yet determine the global trend in the status of these pollinator species,” says co-author Michael Hoffmann, senior scientist with IUCN’s Species Survival Commission.

“However, these initial results for bird and mammal pollinators do not bode well for trends in insect pollinators,” Hoffmann said.

Habitat loss from unsustainable agriculture was found to be the main cause of decline for many species among both mammals and birds.

fruit bats
The Indian flying fox, also known as the greater Indian fruit bat, is found in Bangladesh, China, India, the Maldives, Nepal, Pakistan, and Sri Lanka. (Photo by Daniel Mennerich)

Pollinating mammals, such as the large-bodied fruit bats, are hunted for bushmeat, while birds are affected by invasive alien species.

During the period 1988 to 2012, 18 pollinator bird species qualified for being ‘up-listed’ to a higher threat category.

For example, the Regent Honeyeater, Xanthomyza phrygia, was up-listed from Endangered to Critically Endangered due to rapid population decline driven by drought, habitat loss caused by historic clearance for agriculture, and possibly competition with other species.

No pollinating bird species qualified for ‘down-listing’ to lower categories of threat.

Between 1996 and 2008, 13 mammal species identified as pollinators were up-listed to a higher threat category and two species qualified for down-listing to a lower category of threat.

For example, the Choco Broad-nosed Bat, Platyrrhinus chocoensis, moved from Vulnerable to Endangered due to habitat conversion to agriculture for cocoa, while among non-flying mammals the Sunda Slow Loris, Nycticebus coucang, moved from Near Threatened to Vulnerable due to harvesting for the pet trade and habitat loss.

On the other hand, the Pemba Flying Fox, Pteropus voeltzkowi, was down-listed from Critically Endangered to Vulnerable thanks to community conservation programs which provide protection at specific roost sites.

To determine the trend in the global status of pollinating birds and mammals, the authors used the Red List Index, an established method that shows trends in survival probability over time for sets of species using data from the IUCN Red List.

The Index is based on the proportion of species that move through the IUCN Red List categories over time, either away from or towards extinction.

The authors advise that this approach now needs to be expanded to include bees, wasps  and butterflies.

The study is published online today in the journal “Conservation Letters.”

Copyright Environment News Service (ENS) 2015. All rights reserved.


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