EFFECT OF INCREASED PRODUCTIVITY ON THE ABUNDANCES OF TROPHIC LEVELS
EFFECT OF INCREASED PRODUCTIVITY ON THE ABUNDANCES OF TROPHIC LEVELS
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DOI：
10.1086/285478
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发表时间：
1993-03-01
影响因子：
2.9
通讯作者：
ABRAMS, PA
中科院分区：
文献类型：
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作者：
ABRAMS, PA
提高生产力可以对高营养水平的丰度产生各种影响。先前的工作基于每个营养级一个类型的模型，表明增加对最低营养级的营养投入(1)总是增加最高营养级的丰度，(2)增加比顶部低偶数个水平的丰度，而其他水平不变。本文研究了这些预测如何被不同物种或类型（即异质性）在营养水平上的存在所改变。所研究的模型是lotka - voltera型的食物网模型，具有两个或三个营养级，每个营养级有一个或两个类型。对于具有更多级别和每个级别更多类型的模型，得到的结果不太完整。几种不同的食物网结构可能导致最高水平独立于营养输入或实际上随着营养输入而降低。然而，大多数可能的食物网配置中，两个物种在某些或所有水平上可以产生类似于营养水平均匀时所获得的生产力-丰度关系。除水平异质性外，其他因素也会影响生产率-丰度关系；讨论了这些因素和有关自然界关系的现有信息。
Increasing productivity can have a variety of effects on the abundances of higher trophic levels. Previous work, based on models with one type per trophic level, has suggested that increasing nutrient input to the lowest trophic level (1) always increases the abundance of the highest trophic level and (2) increases the abundances of levels that are an even number of levels below the top, while leaving others unchanged. This article investigates how these predictions are altered by the presence of different species or types (i.e., heterogeneity) within trophic levels. The models investigated are Lotka-Volterra-type models of food webs with two or three trophic levels and one or two types per level. Less complete results are derived for models with more levels and more types per level. Several different food web structures may cause the highest level to be independent of nutrient input or actually decrease with nutrient input. However, the majority of possible food web configurations with two species on some or all levels can produce productivity-abundance relationships similar to those obtained when trophic levels are homogeneous. Factors other than heterogeneity within levels can affect the productivity-abundance relationships; these factors and available information on relationships in nature are discussed.