Everything about Pollinator Decline totally explained
Pollinator decline is based on observations made at the end of the twentieth century of the reduction in abundance of
pollinators in many
ecosystems worldwide.
Pollinators participate in sexual reproduction of many
plants, by ensuring cross-
pollination, essential for some
species, or a major factor in ensuring
genetic diversity for others. Since
plants are the primary
food source for
animals, the reduction of one of the primary pollination agents, or even their possible disappearance, has raised concern, and the
conservation of pollinators has become part of
biodiversity conservation efforts.
Observation of pollinator decline
As
plantings have grown larger, the need for concentrated pollinators at
bloom time has grown. At the same time populations of many pollinators has been declining, and this decline has become a major
environmental issue today.
Pollination management seeks to protect, enhance, and augment agricultural pollination.
For example, feral
honey bee populations in the US have dropped about 90% in the past 50 years, except for the Southwest where they've been replaced by
Africanized bees. At the same time
managed honey bee colonies have dropped by about two thirds. On the other hand, this has been offset by a natural increase in native pollinator populations in parts of the US, where such had been partially displaced by the invasive honey bees imported from Europe.
Monoculture needs very high populations at bloom, but can make the area quite barren, or even toxic when the bloom is done.
The study of pollinator decline is also interesting some scientists, as bees have the potential to become a keystone
indicator species of environmental degradation. Any changes in their abundance and diversity will influence the abundance and diversity of the prevailing plant species. This is a mutual dependency as bees rely on a steady
nectar source and
pollen source throughout the year to build up their hive.
Consequences
The value of bee pollination in human
nutrition and
food for
wildlife is immense and difficult to quantify.
It is commonly said that about one third of human nutrition is due to bee pollination. This includes the majority of
fruits, many
vegetables (or their
seed crop) and secondary effects from
legumes such as
alfalfa and
clover fed to livestock. In the United States, only about 30% of crops utilize honeybees for their pollination, and even among those some of the bee usage is superfluous, native pollinators actually doing the work
(External Link
).
In
2000 Drs.
Roger Morse and Nicholas Calderone of
Cornell University, attempted to quantify the effects of just one pollinator, the
Western honey bee, on only
US food crops. Their calculations came up with a figure of US $14.6 billion in food crop value.
There hasn't been sufficient study to quantify the effects of pollinator decline on wild plants and wild life that depends on them for feed. Some plants on the endangered species list are endangered because they've lost their normal, native pollinators because of displacement by invasive honey bees. It is important to recognize that
honey bees are not native to the
Western Hemisphere, so any loss of honey bees doesn't represent a threat to native plants; the role of honey bees in the Western Hemisphere is almost exclusively agricultural. To the extent that honey bees compete with native bee species, a decrease in the honey bee population may be beneficial to native plants and pollinators.
Increasing public awareness
The steady increase in beekeeper migration (for pollination service on agricultural crops) has masked the issue of pollinator decline from much public awareness, however sudden blocks to such migration could have catastrophic results on the global food supply.
Possible explanations for pollinator decline
It is a label violation to apply most
insecticides on crops during bloom, or to allow the pesticide to drift to blooming weeds that bees are visiting. Yet such applications are frequently done, with little enforcement of the bee protection directions. Pesticide misuse has driven beekeepers out of business, but can affect native wild bees even more, because they've no human to move or protect them.
Bumblebee populations are in jeopardy in
cotton-growing areas, since they're dosed repeatedly when pesticide applicators apply insecticides on blooming cotton fields while the bees are foraging.
Widespread aerial applications for
mosquitoes,
med-flies,
grasshoppers,
gypsy moths and other insects leave no islands of safety where wild insect pollinators can reproduce and repopulate. One such program can reduce or
endanger pollinator populations for several years.
Many homeowners feel that
dandelions and
clover are weeds, that lawns should only be grass, and that they should be highly treated with pesticides. This makes a hostile environment for bees,
butterflies and other pollinators.
See articles:
Rapid transfer of parasites and diseases of pollinator species around the world
Increased international commerce within modern times has moved
diseases such as American foulbrood and chalkbrood, and parasites such as
varroa mites,
acarina mites, and the small African hive beetle to new areas of the world, causing much loss of bees in the areas where they don't have much resistance to these pests.
Imported fire ants have decimated ground nesting bees in wide areas of the southern US.
The push to remove hedgerows and other "unproductive" land in some farm areas removes habitat and homes for wild bees. Large tractor mounted rotary mowers may make farms and roadsides look neater, but they remove bee habitat at the same time. Old crops such as
sweet clover and
buckwheat, which were very good for bees have been disappearing. Urban and suburban development pave or build over former areas of pollinator habitat.
Clearcut
logging, especially when mixed
forests are replaced by uniform age
pine planting, causes serious loss of pollinators, by removing
hardwood bloom that feeds bees early in the season, and by removing hollow trees used by feral honey bees, and dead stubs used by many solitary bees.
Nectar corridors
Migratory pollinators require a continuous supply of
nectar sources to gain their energy requirements for the migration. In some areas development or agriculture has disrupted and broken up these traditional corridors, and the pollinators have to find alternative routes or discontinue migration. A good example is the endangered lesser long-nosed bat (
Leptonycteris curasoae) which was formerly the main pollinator of a number of cactus species in southwestern United States. Its numbers have severely declined, in part due to disruption of the nectar corridors that it formerly followed. Other migratory pollinators include
monarch butterflies and some
hummingbirds.
Hive destruction
Bees are often viewed negatively by homeowners and other property owners. A search for "
carpenter bees" on the Internet primarily yields information on removal rather than information regarding bees in a positive light. Recent hysteria regarding
killer bees has contributed to these views. Beekeepers find increased
vandalism of their hives, more difficulty in finding locations for bee yards, and more people inclined to
sue the local beekeeper if they're stung, even if it's by a
yellow jacket.
Increasing use of outside artificial lights, which interfere with the navigational ability of many
moth species, and is suspected of interference with
migratory birds may also impact pollination. Moths are important
pollinators of night blooming
flowers and moth disorientation may reduce or eliminate the
plants ability to reproduce, thus leading to long term
ecological effects. This is a new field and this
environmental issue needs further study.
Threat by invasive honey bees
Many native pollinators decline in population when faced with competition from invasive honey bees. For example, the western honey bee is invasive in the United States, the wild population comprised entirely of feral bees escaped from European bee colonies imported to fertilize non-native, old-world crops. Where
colony collapse disorder reduced invasive honey bee populations in the US, native pollinators sometimes have made recoveries, restored to their natural niche by the loss.
Air pollution
Researchers at the
University of Virginia have discovered that
air pollution from
automobiles and
power plants has been inhibiting the ability of
pollinators such as
bees and
butterflies to find the
fragrances of
flowers.
Pollutants such as
ozone,
hydroxyl, and
nitrate radicals bond quickly with volatile scent molecules of flowers, which consequently travel shorter distances intact. There results a
vicious cycle in which pollinators travel increasingly longer distances to find flowers providing them
nectar, and flowers receive inadequate
pollination to reproduce and diversify.
(External Link)
Solutions to pollinator decline
The decline of pollinators is compensated to some extent by beekeepers becoming migratory, following the bloom northward in the spring from southern wintering locations. Migration may be for traditional
honey crops, but increasingly is for
contract pollination to supply the needs for growers of crops that require it.
Conservation and restoration efforts
Efforts are being made to sustain pollinator diversity in agro- and natural eco-systems by some
environmental groups. Prairie restoration, establishment of wildlife preserves, and encouragement of diverse wildlife landscaping rather than monoculture lawns, are examples of ways to help pollinators.
Use of alternative pollinators
Honey bees are usually the most widely chosen insects in most managed pollination situations. However they're not the most efficient pollinators of some flowers. Alternative pollinators, such as for example,
leafcutter and
alkali bees in alfalfa pollination and
bumblebees in greenhouses for tomatoes are used to augment and in some cases replace honey bees. A wide variety of other bees can be found in the environment that are specialist pollinators (some only using one plant species). However, most of these alternative insects' value as pollinators and their relationships with plants are as yet little known.
In the US, some think that other pollinators will in time replace the lost honey bees, blamed on
introduced acarine and varroa mites, but general pollinator decline was already happening before these entered the picture. Only in a few areas are wild populations of pollinators building up; in most areas they're declining as quickly as honey bees.
Furthermore pollinators can't be exchanged on a one-for-one basis. They are not all equal. Some are generalists, some are specialists. Some are brawny; some are feeble. Some have long tongues; some short. Some work at colder temperatures than others. Bees may deliberately collect pollen, but have different collection techniques, which can greatly affect their efficiency as pollinators.
Flowers are frequently specifically
adapted to one pollinator, or a small group of pollinators because of floral structure, color, odor, nectar guides, etc. Proposed alternative pollinators may not be physically capable of accomplishing pollination, or they may not be attracted to the flower of that plant species, or they may rob nectar by cutting sepals, thus avoiding pollination. Understanding the pollination needs of a species is vital to understanding of a plant species, yet this is often poorly understood. In horticulture it's critical to the economic success of the grower, and crops have sometimes been abandoned from general use in an area because of lack of understanding of pollinator needs.
Further Information
Get more info on 'Pollinator Decline'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://pollinator_decline.totallyexplained.com">Pollinator decline Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
