Question

求翻译~~

If functional diversity is a determinant of maximum trophic position, then the ultimate cause of variation in food-chain length
will be factors that in¯uence the functional diversity of species in
food webs. Human-mediated modi®cations of natural systems that
affect the functional diversity of food webs, such as cultural
eutrophication, species invasions and habitat fragmentation, will
also affect food-chain length. Changes in food-chain length may, in
turn, cause further changes in community dynamics, ecosystem
function and contaminant concentrations in apical predators.
The importance of primary productivity in explaining variation
in food-chain length has been debated for 40 years4,10,12,16. Unlike the
few studies that indicate some relationship between productivity
and food-chain length12,20,26,27, we found that ecosystem size was the
only determinant of food-chain length in our study lakes. In
contrast to many previous studies12,20,26,27, we adopted a continuous
measure of food-chain length and used independent gradients of
productivity and ecosystem size in a natural setting. Although
productivity must be an ultimate constraint of food-chain
length16,17, and may be important in small systems12,26 or where
productivity is very low16,18, our results and those of others4,8,10 show
that productivity is a poor predictor of, and has a limited direct role
in controlling food-chain length.

Answer 1

原文校正：If functional diversity is a determinant of maximum trophic position, then the ultimate cause of variation in food-chain length will be factors that influence the functional diversity of species in food webs. Human-mediated modifications of natural systems that affect the functional diversity of food webs, such as cultural eutrophication, species invasions and habitat fragmentation, will also affect food-chain length. Changes in food-chain length may, in turn, cause further changes in community dynamics, ecosystem function and contaminant concentrations in apical predators. The importance of primary productivity in explaining variation in food-chain length has been debated for 40 years. Unlike the few studies that indicate some relationship between productivity and food-chain length, we found that ecosystem size was the only determinant of food-chain length in our study lakes. In contrast to many previous studies, we adopted a continuous measure of food-chain length and used independent gradients of productivity and ecosystem size in a natural setting. Although productivity must be an ultimate constraint of food-chain length, and may be important in small systems or where productivity is very low, our results and those of others show that productivity is a poor predictor of, and has a limited direct role in controlling food-chain length.
翻译：如果功能的多样性是营养水平最大化的一个决定性因素，那么食物链长度变化的根本原因将是引起物种多样性的因素。有人类参与的自然变化，如人为富化作用，外来物种的引入，栖息地的碎片化，都将影响食物链的长度。食品链长度的变化，反过来，可能会造成进一步的群落动态的变化，生态系统功能和顶层生物的污染物浓度。初级生产力的重要性对食品链长度的变化的影响已经被争论了40年。不像一些研究指出，一些生产力和食品链长度之间的关系，我们发现食品链长度在我们的研究湖泊生态系统的大小是唯一的决定因素。相反，许多以往的研究中，我们通过食品链长度的连续测量，并使用独立的梯度生产力和生态系统的大小，在一个自然的环境中。虽然生产力必须的食品链长度的最终约束，可能是重要的小型系统或效率是非常低的，我们的结果和其他人表明，生产力是一个贫穷的预测，并有一个有限的直接作用，在控制食品链的长度。

Answer 2

如果功能的多样性是最大营养状况的一个决定性因素，那么最终的变异的原因。食品链长度
的因素，在功能的物种多样性，
食物网。人介导的作案阳离子的
影响自然系统的功能多样性，食物网，，如文化
富营养化，物种入侵和栖息地破碎化，
也将影响食物链的长度。食品链长度的变化可能
导致进一步的社区动态，
在顶端的捕食者生态系统的功能和污染物浓度的变化。
初级生产力的重要性，解释
食品链长度的变化已经争论了40 年，4，10,12 ，16。不同的
一些研究表明生产力
和食物链长度12，20,26,27 一定的关系，我们发现
食品链长度在我们的研究湖泊生态系统的大小是唯一的决定因素。
相反，许多研究表明12，20,26,27，我们采取了持续的
措施食物链的长度和梯度的
生产力和生态系统的大小，在一个自然的环境中使用独立。虽然
生产率必须食物链
长度16，17 是一个最终的约束，并可能是重要的小systems12，26或
生产率非常低16，18，我们的结果，并与其他4，8,10显示
，生产率是一个好的预测的，并具有有限的
在控制食品链长的直接作用。