can pollinating bats), although many have populations that are stable or perhaps even increasing, as are a few of the hummingbird species. It should be noted that there is no evidence of population decline for some species merely because their populations have not been monitored over time. Overall, whether there is a “pollinator crisis” is difficult to ascertain inasmuch as there is no definition of “crisis” that is universally accepted; however, if “decline” is defined as a systematic decrease in population size over time, then there is evidence that some pollinators in North America representing a diversity of taxa are, in fact, in decline. It is accordingly important to ascertain the causes and the consequences of those declines as a step toward informed decision making about action to be taken and what would most likely ensure successful reversal.



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