Ecosystem Effects

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How might Climate Change contribute to "Pollinator Deterioration" and affect Ecosystems that depend on Bees?

I. Biodiversity

     As bees are largely responsible for the continued survival and propagation of so many plant species, it is no wonder some researchers predict that, should bee populations decline severely (bees, the pollinators, are "deteriorating" as a population, hence the term pollinator deterioration), many of the species which depend upon them would also fail to thrive [8, 14]. Furthermore, animal species which use these pollination-dependent plant species for food or shelter (for example, birds and small rodents who feed on the fruit of flowering plants) may also suffer the effects of pollinator deterioration [19].

     It is interesting to note here a difference between species that are specialists and those that are generalists. Generalist species are predicted to and have been observed to best survive the disruption between plant and pollinator that climate change has wrought [13]. Considering the difference between a specialist pollinator, which prefers to or perhaps is only able to pollinate a few species, and a generalist pollinator, which can more easily shift it's preferred nectar sources, this prediction makes sense. Luckily, the pool of bee species is varied, with honey bees and select other species considered to be relative generalists, and other bee species that are far more specialized [7]. This means that generalist plant species, able to be pollinated by many kinds of insects and species of bees, have a good chance of surviving phenological changes, as do bee species which are able to pollinate many different kinds of plants as opposed to a single one which only blooms within a specific time-frame.

II. Possible Range Shifts/ Migration 

   When ecological factors and climate warming converge such that species' natural environments become too stressful for them to exist comfortably within, their range of distribution over a physical space may shift [17]. Should climate change and other stressors cause the trophic mismatch between bees and flowers to become very severe in some areas, flowering plants may find that they are not being adequately pollinated, and bees may be unable to find adequate food.

    In these worst-case scenarios it may be possible that certain plant species who are able to disperse will come to prefer landscapes further towards the limits of their ranges [9], where they can perhaps receive better pollination. Bees too, may shift, that too more easily due to their ability to migrate autonomously, to areas where food sources are more available. In either case, specialized species may find it harder to adjust [7, 9].

   Global climate warming, however, is likely to result not just in shifting spring phenology, but also more extreme seasonal temperatures [9]. This is also likely to affect honey bees and result in possible range shifts, as the climates that bees are adapted to living within may become intolerable, forcing them to move. Bees, like most insects, are very sensitive to environmental temperatures, and are therefore at risk for harm if temperatures change too drastically [11, 15]. Honey bees, especially, prefer temperate weather and calm winds [4], or the peaceful meteorology that we are seeing less and less of as climate warming progresses.

III. Impact on Microorganisms which Infect Honey Bees

   Honey bees can be afflicted by viruses, mites, and bacteria. Particularly over the last decade, these pathogens have grown increasingly resistant to the antibacterial and antiparasitic drugs used to control them [1]. As the climate warms and bees shift ranges, pathogens which existed outside of honey bees' natural ranges, or which were only present in select colonies, may be brought into closer contact and become epidemic [15]. These pathogens may also thrive better in new environments, promoting their invasion [15]. 

    Consequently, bee populations would suffer even more from climate warming, this time resulting from increased pathogenic activity of diseases that are already endemic in bee populations. Possible solutions to this problem would include importing and exporting bees from other nations, such as France, where species have adapted genetic resistance to these diseases [15]. However, the US has import restrictions on insect species, as the hybridization of these foreign species with local bees would pollute the native gene pool and potentially eradicate local species [15]. The best option to prevent the consequences that higher disease incidence in honey bees would bring is to prevent possible range shifts to disease-ridden areas before they can occur. 

IV. Agricultural Implications

  If honey bee numbers continue to decrease, many crops, and the farmers who grow them, will suffer the effects [1, 14]. The markets for many foods popular for human consumption, used in medication production, and sold domestically and internationally, such as honey, certain flowers, herbs, and most fruits, all depend upon the activity of honey bees. There is no telling how greatly the disappearance of bees could potentially affect these markets. As a nation, we may have to shift our consumption of certain products that we previously produced domestically, and resort to international imports. A decline in production of these goods could have worldwide economic effects.

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