Tuckett Quenton M, Kinnison Michael T, Saros Jasmine E, Simon Kevin S
School of Biology and Ecology, University of Maine, Orono, ME, 04469, USA.
Tropical Aquaculture Laboratory, University of Florida, Ruskin, FL, 33570, USA.
Oecologia. 2016 Nov;182(3):765-78. doi: 10.1007/s00442-016-3714-2. Epub 2016 Aug 27.
Studies of ecological stoichiometry typically emphasize the role of interspecific variation in body elemental content and the effects of species or family identity. Recent work suggests substantial variation in body stoichiometry can also exist within species. The importance of this variation will depend on insights into its origins and consequences at various ecological scales, including the distribution of elemental phenotypes across landscapes and their role in nutrient recycling. We investigated whether trophic divergence can produce predictable patterns of elemental phenotypes among populations of an invasive fish, the white perch (Morone americana), and whether elemental phenotypes predict nutrient excretion. White perch populations exhibited a gradient of trophic phenotypes associated with landscape-scale variation in lake trophic state. Perch body chemistry varied considerably among lakes (from 0.09 for % C to 0.31-fold for % P) casting doubt on the assumption of homogenous elemental phenotypes. This variation was correlated with divergence in fish body shape and other trophic traits. Elemental phenotypes covaried (r (2) up to 0.84) with lake trophic state. This covariation likely arose in contemporary time since many of these perch populations were introduced in the last century and the trophic state in many of the lakes has changed in the past few decades. Nutrient excretion varied extensively among populations, but was not readily related to fish body chemistry or lake trophic state. This suggests that predictable patterns of fish body composition can arise quickly through trophic specialization to lake conditions, but such elemental phenotypes may not translate to altered nutrient recycling by fish.
生态化学计量学研究通常强调种间身体元素含量变化的作用以及物种或科属特征的影响。近期研究表明，物种内部的身体化学计量也可能存在显著差异。这种差异的重要性将取决于对其在不同生态尺度上的起源和后果的深入理解，包括元素表型在景观中的分布及其在养分循环中的作用。我们调查了营养分化是否会在入侵鱼类银鲈（Morone americana）的种群中产生可预测的元素表型模式，以及元素表型是否能预测养分排泄。银鲈种群表现出与湖泊营养状态的景观尺度变化相关的营养表型梯度。不同湖泊中鲈鱼的身体化学成分差异很大（碳含量从0.09%到磷含量的0.31倍），这让人对元素表型均一的假设产生怀疑。这种差异与鱼体形状和其他营养特征的分化相关。元素表型与湖泊营养状态协变（r²高达0.84）。这种协变可能是在当代产生的，因为这些鲈鱼种群中的许多是在上个世纪引入的，而且在过去几十年里许多湖泊的营养状态发生了变化。不同种群之间的养分排泄差异很大，但与鱼体化学成分或湖泊营养状态没有直接关系。这表明，通过对湖泊条件的营养特化，鱼体组成的可预测模式可以迅速出现，但这种元素表型可能不会转化为鱼类改变的养分循环。
