One potential consequence of declining populations of pollinators is a decline in the rate of pollination. This may lead to a decrease in the reproduction of a large number of flowering plants, including many rare species and a number of crops. Recent estimates suggest that around 87.5% of the world's flowering plant species are animal-pollinated (Ollerton et al. 2011). Reduced pollination of these plants will lead to lower seed or fruit set, lower plant regeneration rates and knock-on effects to the animals that rely on plants and their products for food.
While humans are unlikely to starve due to lack of pollinators because a number of staple crops such as grains are self-fertilising or wind-pollinated, the balanced diets that we currently enjoy and which are important for healthy nutrition will be threatened. Insect pollinators contribute directly to the quality and quantity of a large number of crops including vegetables, fruits, nuts, oils and stimulant crops like coffee. As a result the service of crop pollination is considered to be very valuable globally. Estimates in 2005 suggest that global pollination was worth £131 billion or 9.5% of global food production (Gallai et al. 2009). In the UK alone, this figure was estimated at £1057 million during 2007 (Breeze et al. 2011).
Ecologically, the decline of pollinators is potentially serious. Plants form the building blocks of all ecosystems and disruption to their pollination and subsequent reproduction is likely to result in similar declines in plant species diversity and knock-on effects to the animals and birds that rely on them. This would threaten ecosystem function and other ecosystem services that nature provides.
Breeze, T.D. et al. 2011 Pollination services in the UK: how important are honey bees? Agriculture, Ecosystems & Environment 142: 137-143
Gallai, N et al. 2009. Economic valuation of the vulnerability of world agriculture confronted with pollinator decline. Ecological Economics 68: 810-821
Ollerton, J. et al. 2011. How many flowering plants are pollinated by animals? Oikos 120: 321-326