Presentation on theme: "Summary of CCD causal factors A range of factors have all been identified as possible contributing factors to unsustainable bee losses. Some are prominent."— Presentation transcript:
Summary of CCD causal factors A range of factors have all been identified as possible contributing factors to unsustainable bee losses. Some are prominent smoking guns, others are not likely to be of much relevance A strong body of science has implicated a class of systemic pesticides known as neonicotinoids as a leading driver of bee declines. What are the implications for humans?
What are the implications for humans (and honey bees?)
We depend upon pollinators: 71 of the 100 crops that provide 90% of world’s food are pollinated by bees and honey bees Contributes nearly $20 billion to the U.S. economy annually, 22 billion euros ($26 billion) to the European economy, and $217 billion to the global economy Honey bees are responsible for pollinating one in three bites of food we eat
“If the bee disappears from the surface of the earth, man would have no more than four years to live. No more bees, no more pollination... no more men!”
No more humans? Major food crops (wheat, rice, and corn) wind pollinated Third of food crops bee pollinated, but only some of these are highly dependent upon honey bees (like almonds, 90%) Change in diet, but not human extinction or the apocalypse Honey bee shortage driven by 300% increase (since 1950’s) in the amount of bee-dependent “luxury” crops
More bee-dependent luxury crops (Aizen and Harder, 2009; Hayes 2010)
Demand for luxury crops driven by affluence of new global middle class More disposable income Globalization brings greater diversity of imported specialty crops Healthy eating prioritized over meeting basic caloric needs High antioxidant, vitamin rich and often bee- dependent foods desired Lack of honey bees to meet demand http://www.almonds.com
Fewer bees could impact availability of some vitamin-rich plant foods As much as 50% of production of plant sources of vitamin A requires bee pollination Disruptions in pollination have public health implications in some regions Annually vitamin A deficiency causes 800,000 deaths in women and children. Doubles risk of mortality from common conditions like measles, diarrhea, and malaria, increases the risk of maternal mortality 4.5X
Demand for bees drives up rental fees for hives Increasing issues over bee theft in California
Remaining bees worked harder thus aggravating bee decline
http://www.ent.uga.edu/b ees/OnEinsteinBeesand SurvivaloftheHumanRac eHoneyBeeProgramCAE SEntomologyUGA.html http://www.snopes.com/q uotes/einstein/bees.asp “If the bee disappears from the surface of the earth, man would have no more than four years to live. No more bees, no more pollination... no more men!”
“Dying bees have become symbols of environmental sin. By engaging in simplistic and sometimes misleading environmental narratives — by exaggerating the stakes and brushing over the inconvenient facts that stand in the way of foregone conclusions — we do our field, and our subjects, a disservice” (Nordhaus, 2011) Rethinking the narrative about CCD and bee decline
Neonics are major factor but there are a range of other contributing causes. To address CCD we should consider that there are multiple scenarios for CCD to develop. Causes are processural, emergent, with different and evolving contributing factors
Stable causality Easier to replicate and verify cause and effect Applies across different settings Neonicotinoids exemplify a stable causality –Sublethal chronic exposures lead to weakening of the colony and collapse –Thus we should target immediate regulation of neonics
Unstable causality Contingency more important Unique combination of sublethal exposures to pesticides, nutritional stress, parasites, and viruses lead to collapse May not even be able to identify causes in some cases
Support for an unstable causality: current large-scale hive losses have historic precedents (Underwood and vanEngelsdorp, 2007)
Multiple types of CCD If there is a range of causal situations, then there may be more than one type of CCD In the winter of 2010-2011, the vast majority (>70%) of reported colony losses were not attributed to CCD, as most dead colonies were not missing bee cadavers in the hive or apiary —the hallmark symptom of CCD.
CCD is bad…. Bee losses are unsustainable Bee-dependent vegetables and fruits may become expensive or only available as imports Loss of beekeeping culture
…but: A greedy reductionist strategy, one where causality in singular and focuses only on one factor, obscures, not only the complexity inherent to CCD, but also: 1.The importance of other animal pollinators besides honey bees 2.The longer-term decline in honey bees and broader issues about industrial agriculture 3.Our understanding of the relationships among bee decline, agriculture, and land use 4.Recognition of some of the benefits of a crisis, including the possibilities of adaptation
1. Obscures the role of other animal pollinators Three-quarters of global food crops rely on a broad group animal pollinators. Honey bees are important pollinators for only a third of North American crops 4000 native bee species in North America
Status of Pollinators in North America Decline in the abundance of some pollinators, but the strength of this evidence varies among taxa. Long-term population declines for several wild bee species (notably bumble bees), and some butterflies, bats and hummingbirds Paucity of long-term population data and incomplete knowledge of even basic taxonomy and ecology make definitive assessment of status exceedingly difficult.
Status of bee and flower-visiting wasp species in United Kingdom
Should we address wild pollinator decline more? During the past 50 years, the fraction of animal-pollinator dependent agriculture and the number of managed honey bee hives have increased 300% and 45%, respectively Given ongoing honey bee losses, these numbers suggest renewed emphasis on of practices that reverse declines in richness and abundance of wild pollinators
2. Masks the long-term decline in honey bees and the reasons Current North American colony declines are part of a half-century of accumulating losses from –Day-to-day factors like parasites, diseases, and poor nutrition are greatest challenge to beekeepers –Cheaper honey produced in China, Argentina, and India sent bees overseas
3. Downplays feedbacks between pollinator decline, agricultural, and land use conversion What is the next step in this sequence of events? 1.Demand for luxury crops 2.More farmers plant and grow these crops 3.Ongoing declines in honey bees 4.Declining yields per acre 5.__________________________
Also as more land is converted, greater reductions in native pollinators and enhancement of dependency on honey bees
4. Overlooks some of the opportunities brought on by crisis A.CCD has brought attention to bees and beekeeping B.Beekeeping skills now being passed on to a younger generation
Beekeeping can be a form of development Alternative livelihoods: Nepal | Sudan | KenyaNepalSudanKenya –Beekeeping can provide incomes to replace those incomes: Dependent upon poaching Based on a form of agriculture no longer viable Lost due to government instability and war To offset deforestation by incentivizing conservation of floral resources To provide and improve local pollination services To generate supplemental income To empower women To promote food security
Your consent to our cookies if you continue to use this website.