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The evolution of increased competitive ability (EICA) hypothesis was first proposed by Bernd Blossey and Rolf Nötzold in 1995 as a way to explain the success of invasive, non-indigenous species (in particular, plants). Observing that: # there is usually a lag period between the time of introduction of an invasive species and the point at which it is considered invasive, and # invasive plants seem to be more virulent in habitats into which they have been introduced (as compared to their native habitats), the scientists presumed a sort of naturalization through modification for non-indigenous plants. Because of a lack of native predation, the scientists reasoned, introduced plants are able to reallocate resources from defense mechanisms into growth and development. Introduced plants can thereby evolve to grow taller, produce more biomass, and yield more viable offspring than their native counterparts, according to the hypothesis.〔http://www.esf.edu/efb/parry/Blossey_Notzold_1995.pdf〕 Blossey and Nötzold tested their hypothesis on ''Lythrum salicaria'' (purple loosetrife) by potting seeds from plants growing in Ithaca, New York, U.S.A., and Lucelle, Switzerland. The seeds were allowed to germinate in a lab at Christian-Albrechts University in Kiel, northern Germany, and observed for two years. True to the predictions of the EICA Hypothesis, the plants derived from Ithaca produced significantly more biomass that the plants derived from Lucelle (with a p value <0.001). The ''Lythrum salicaria'' plants derived from Ithaca also grew taller and were significantly less resistant to the root-feeding weevil present over its native range. ==Significance== Unlike the notable ideas (concerning the success of invasive non-indigenous organisms) that preceded it, such as the enemy release hypothesis (ERH) and Charles Darwin's Habituation Hypothesis,〔Darwin, Charles. On the Origin of Species. Pg. 114–116. Harvard University Press: eighteenth printing, 2003〕 the EICA hypothesis postulates that an invasive species is ''not'' as fit (in its introduced habitat) at its moment of introduction as it is at the time that it is considered invasive. As suggested by the name of the hypothesis (Evolution of Increased Competitive Ability), the hypothesis predicts that much of the invasive potential of an invasive species is derived from its ability to evolve to reallocate its resources. This idea is troubling in that it adds a new variable to "invasive potential", making it harder to predict whether or not a species will become invasive if it is introduced into a new area. In other words, the EICA hypothesis presents us with a new environmental safety concern. If its postulates hold, in the long run, introduced species may have to be more highly regulated than they are at present, because no set of traits or pattern of introduction can predict the extent to which an organism can reallocate its resources in response to a release from stress. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「EICA hypothesis」の詳細全文を読む スポンサード リンク
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