The United Nations Environment Program has released a study on a collapse of the world’s honey bee colonies and presents scientific data and analysis regarding bee decline, including wild and controlled bee populations.
The report, Global Honey Bee Colony Disorders and Other Threats to Insect Pollinators
(pdf), includes authors who are world-leading honey bee experts, and issues an urgent warning over bee decline. Bees pollinate over 70 percent of the 100 crop species that provide 90 percent of global food supplies.
There are 20,000 known bee species around the world with the honey bee being the most common.
is most prevalent in North America and has been observed in Europe since 1965. However, the report shows that since 1998, colony weakening and mortality has occurred particulary in France, Belgium, the UK, Germany, Switzerland, the Netherlands, Spain and Italy.
“The way humanity manages or mismanages its nature-based assets, including pollinators, will in part define our collective future in the 21st century,” said Achim Steiner, UN Undersecretary-General and UNEP’s Executive Director, in a news release
“Human beings have fabricated the illusion that in the 21st century they have the technological prowess to be independent of nature. Bees underline the reality that we are more, not less, dependent on nature’s services in a world of close to seven billion people,” Steiner added.
Honey bee colony loss in North America since 2004 has resulted in fewer managed pollinators than any other time during the last five decades. The report states that
Current evidence demonstrates that a sixth major extinction of biological diversity event is underway.
Many vegetables, fruits, nuts, legumes and seed crops are dependent on pollination, with that service being provided by wild, free-living organisms, mainly bees, which are the predominant and most economical group of pollinators in most regions. Other winged pollinators include butterflies, moths, flies, and commercially controlled bee species.
The value of honey bees to the economy is staggering, and the report noted that
In 2000, the value of crops pollinated by bees was estimated at $14.6 billion in the USA alone.
Among the factors contributing to declines of honey bee populations is habitat deterioration. Human activities involving degradation, fragmentation and destruction of honey bees’ natural habitat are considered as key causes of honey bee decline.
These activities lead to reduced food sources for honey bees and all pollinators. Turning large food habitat areas into smaller ones decreases food supplies for resident animals. Resulting population declines can no longer benefit plants. The report notes that
As certain wild pollinators need undisturbed habitat for nesting, roosting, foraging and sometimes specific larval host plants, they are very susceptible to habitat degradation and fragmentation in particular.
Increased pathologies are another factor related to habitat deterioration. Various pathogens have been transferred from commercially-controlled bumblebee species used in greenhouse pollination programs, leading to a decline in some native bumblebee populations.
Weak ecosystems can also increase development of parasites that impact controlled and wild pollinators.
Invasive species are introduced to pollinators when their natural habitats are destroyed. These include parasitic mites that feed on bees’ circulation fluids, spreading from hive to hive. The mites introduce viral diseases and bacteria to the colonies and if left uncontrolled, will cause the premature death of the infected colonies within three years.
Since being introduced in the 1980’s, various mites have affected significant losses of bee colonies. Scientists have referred to this as Colony Collapse Disorder
(CCD). CCD accounts for around 7 percent of colony losses in the US while the loss of queen bees results in 25 percent of colony deaths.
Other invasive species are having an impact on the world’s pollinators including the small hive beetle, endemic to sub-Saharan Africa. It is now colonized throughout much of North America and Australia and is expected to arrive in Europe as well. The beetle and its larvae can damage the honeycomb, stored honey and pollen.
Competition from non-native species is taking a toll on natural pollinators, notably the Africanized bee and the Asian hornet. The Asian hornet feeds on European honeybees and as of 2009, had colonized almost half of France.
Pollution is another factor leading to pollinator decline. Pollutants affect plants’ abilities to produce chemicals that attract insects, in turn destroying vital scent trails. Scent trails that once traveled more than 2,000 feet in the 1800’s now extend less than 600 feet from the plant, creating complications for pollinators as they search for food.
Climate change is having an impact on pollinator declines. Shorter growing seasons, a fluctuation in new growth, flowering and aging periods could impact pollinator life cycles. Changing weather patterns, including decreased rainfall in some regions, will likely lead to reduced plant vigor and delayed maturation processes of plants. As a result, a decline in nectar production should be anticipated.
Within coming decades, a global loss of 20,000 flowering plant species is forecast by the International Union for Conservation of Nature (IUCN), according to the report.
Electric and magnetic fields could influence bee behavior, as they have small abdominal crystals containing lead, making them sensitive to these fields. However, the report notes, there is insufficient data on the subject at this time to establish a link to bee mortality.
The report calls for a more holistic approach to preserving and restoring all pollinator species, from the local to landscape level, noting pollination services require investment and good stewardship to preserve and sustain it.
Habitat conservation can increase local pollinating species, a boon for nearby agricultural environments. Creating habitat designations for endangered plants should include considerations for wild pollinators.
Alternative farming methods, including the introduction of natural enemies of pests, insects and weeds is important for reducing wildlife exposure to toxic insecticides, fungicides and herbicides. The flowering season is a critical time for pollinators and any use of pesticide applications during that period should be given serious thought. Although controlled hives can be removed during such applications, wild populations of pollinators are completely vulnerable to such practices.
The introduction of pollinator-friendly plants into the landscape increases feeding opportunities for pollinators and could enhance colonization, pollinator migrations and add strength to restoration programs.
Consideration of the different stages of pollinators’ life cycles should be addressed as well. Winged pollinators require differing needs throughout their lives. For example, honey bee larvae require sufficient protein in brood food during winter months to ensure their proper development. A sufficient amount of stored pollen in the colony in the autumn ensures chances for a successful adult population in the spring time.
It also recommends renewed studies, conservation and management policies of native pollinating species that will complement controlled colony traditions.