Bats

Pollinating Bats
Pollinating Bats

 

The White House

Office of the Press Secretary

Fact Sheet: The Economic Challenge Posed by Declining Pollinator Populations

Pollinators contribute substantially to the economy of the United States and are vital to keeping fruits, nuts, and vegetables in our diets. Over the past few decades, there has been a significant loss of pollinators—including honey bees, native bees, birds, bats, and butterflies—from the environment. The problem is serious and poses a significant challenge that needs to be addressed to ensure the sustainability of our food production systems, avoid additional economic impacts on the agricultural sector, and protect the health of the environment.

Economic Importance of Pollinators:

  • Insect pollination is integral to food security in the United States. Honey bees enable the production of at least 90 commercially grown crops in North America. Globally, 87 of the leading 115 food crops evaluated are dependent on animal pollinators, contributing 35% of global food production.
  • Pollinators contribute more than 24 billion dollars to the United States economy, of which honey bees account for more than 15 billion dollars through their vital role in keeping fruits, nuts, and vegetables in our diets.
  • Native wild pollinators, such as bumble bees and alfalfa leafcutter bees, also contribute substantially to the domestic economy. In 2009, the crop benefits from native insect pollination in the United States were valued at more than 9 billion dollars.

The Challenge of Pollinator Declines:

  • The number of managed honey bee colonies in the United States has declined steadily over the past 60 years, from 6 million colonies (beehives) in 1947 to 4 million in 1970, 3 million in 1990, and just 2.5 million today. Given the heavy dependence of certain crops on commercial pollination, reduced honey bee populations pose a real threat to domestic agriculture.
  • Some crops, such as almonds, are almost exclusively pollinated by honey bees, and many crops rely on honey bees for more than 90% of their pollination. California’s almond industry alone requires the pollination services of approximately 1.4 million beehives annually—60% of all U.S. beehives—yielding 80% of the worldwide almond production worth 4.8 billion dollars each year.
  • Since 2006, commercial beekeepers in the United States have seen honey bee colony loss rates increase to an average of 30% each winter, compared to historical loss rates of 10 to 15%. In 2013–14, the overwintering loss rate was 23.2%, down from 30.5% the previous year but still greater than historical averages and the self-reported acceptable winter mortality rate.
  • The recent increased loss of honey bee colonies is thought to be caused by a combination of stressors, including loss of natural forage and inadequate diets, mite infestations and diseases, loss of genetic diversity, and exposure to certain pesticides. Contributing to these high loss rates is a phenomenon called colony collapse disorder (CCD), in which there is a rapid, unexpected, and catastrophic loss of bees in a hive.
  • Beekeepers in the United States have collectively lost an estimated 10 million beehives at an approximate current value of $200 each. These high colony loss rates require beekeepers to rapidly, and at substantial expense, rebuild their colonies, placing commercial beekeeping in jeopardy as a viable industry and threatening the crops dependent on honey bee pollination. The loss rates have driven up the cost of commercial pollination: for instance, the cost of renting honey bee hives for almond pollination rose from about $50 in 2003 to $150-$175 per hive in 2009.
  • Some of the viral agents that are impacting honey bee colonies are also now reported to be adversely affecting native pollinators, such as bumble bees, and the pollination services they provide.
  • Population declines have also been observed for other contributing pollinator species, such as Monarch butterflies, which migrate from Mexico across the United States to Canada each year, returning to overwinter in the same few forests in Mexico. The Monarch butterfly migration, an iconic natural phenomenon that has an estimated economic value in the billions of dollars, sank to the lowest recorded levels this winter, with an imminent risk of failure.

 

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Migratory Pollinators Program

Executive Summary

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For over a decade, biologists have been concerned about apparent declines in pollinators, especially those that migrateacross landscapes and between regions.  While protection of plant-pollinator interactions is an emerging national priority, ecological conditions of migratory corridors have received far less attention.  These migratory corridors, or “nectar corridors,” consist of a series of stepping stones, or patches of flowering plants, that provide nectar for refueling during migration along 2000-6000 km flyways.  These flyway habitats are threatened by destruction, degradation, and fragmentation due to land conversion, herbicides, pesticides, and exotic plant invasion.

Map of the nectar corridor

The nectar corridor that extends from southern Mexico north to the Intermountain West of the U.S. and Canada is of particular concern.  Lesser long-nosed bats (Leptonycteris curasoae), rufous hummingbirds (Selasphorus rufus), western white-winged doves (Zenaida asiatica mearnsii), and monarch butterflies (Danaus plexippus), and other migratory pollinators move seasonally along this corridor traveling between the tropics and their northern breeding/birthing grounds.  These types of migrations have been termed“endangered natural phenomena.”  We examined the migratory routes of these four species, and we studied their biology and the floral resources upon which they depend during migration.  Our field research covered approximately 1660 km (straight-line measurement) from Jalisco (south-central Mexico) to central Arizona.  We also provided community outreach and education in Arizona and Mexico to develop local public acceptance of conservation needs and to involve local communities in conservation efforts and in the collection of scientific data.

Night photo of bat about to feed on saguaro flower - by M. Tuttle

The North American subspecies of lesser long-nosed bat (Leptonycteris curasoae yerbabuenae) includes a population of migrators that follow two corridors in their northward spring migration (Coastal Lowland Route and Inland Montane Route; see Map 7).  At least one corridor is utilized in the southward fall migration (Inland Agave Corridor), however it has not been confirmed that all bats using the Spring Coastal Lowland Route follow this Inland Agave Corridor for the return south in the fall.  Pollinator mutualismbetween these bats and their food plants appears to vary latitudinally.  From roost sites, these bats travel great distances at night to find large enough patches of nectar producing plants to sustain themselves and their young, and to prepare for the next leg of their journey. Thus, protection of foraging areas near roosts is critical.

Read more: http://www.desertmuseum.org/pollination/

 

 

 

 

 

 

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