Pollination Value Calculator

This is a production function valuation, the standard method for pricing pollination as an ecosystem service. Rather than asking what people would pay for bees, it asks how much of an existing crop revenue stream would disappear if animal pollination were removed, and assigns that portion to the pollinators. The key parameter is the dependency ratio, an experimentally derived number obtained by bagging flowers to exclude insects and comparing fruit set and yield against open-pollinated controls. Published ratios cluster into bands: essentially total dependence for almonds, vanilla and most cucurbits; roughly 65 to 90 percent for apples, cherries, blueberries and avocados; a modest 10 to 40 percent for partially self-fertile crops such as tomatoes, cotton and coffee; and effectively zero for wind-pollinated staples including wheat, rice and maize. Multiplying area by yield by price gives gross crop revenue, and multiplying that by the dependency ratio isolates the pollination-attributable share. The abundance input then splits that dependent value into the part currently being realised and the part forgone to a pollination deficit, which is the condition where fruit set is limited by insufficient visitation rather than by water, nutrients or genetics. Deficits have been documented in intensively farmed landscapes with little semi-natural habitat within foraging range, typically a few hundred metres to two kilometres for most wild bees. The method has well-known caveats. It attributes revenue rather than profit, ignores the price rebound that would follow a supply collapse, and takes yield and price as fixed. Abundance is treated as linearly proportional to yield, whereas pollination response usually saturates once visitation exceeds what the flowers require, so gains from raising already-adequate populations will be overstated.

Charles Darwin established the productive consequences of insect visitation in the nineteenth century, and his 1876 book on the effects of cross and self fertilisation in the vegetable kingdom documented the vigour advantage of outcrossed plants. Commercial recognition followed in the twentieth century as orchard growers began renting honeybee colonies, and by mid-century pollination contracts were routine in North American fruit and nut production. Early economic estimates of pollinator contribution to United States agriculture were published by researchers including S. E. McGregor, whose 1976 USDA handbook Insect Pollination of Cultivated Crop Plants compiled crop-by-crop pollination requirements and remained a standard reference for decades. The dependency ratio framework in its modern form came from a 2007 paper in Proceedings of the Royal Society B by Alexandra-Maria Klein, Bernard Vaissiere and co-authors, which reviewed 115 leading global crops and classified each by degree of pollinator dependence, concluding that 87 depended on animal pollination to some extent. Nicola Gallai and colleagues applied those ratios in a 2009 Ecological Economics paper, estimating the value of insect pollination to world agriculture at roughly 153 billion euros for the year 2005. Concern sharpened after Colony Collapse Disorder was named in the United States in 2006 and after documented declines in wild bee and hoverfly populations in Europe. The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services published its thematic assessment of pollinators, pollination and food production in 2016, giving the widely cited 235 to 577 billion dollar annual range.