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DEFINING AND MEASURING THE IMPACT OF DYNAMIC TRAITS ON INTERSPECIFIC INTERACTIONS
Author(s) -
Abrams Peter A.
Publication year - 2007
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/06-1381.1
Subject(s) - terminology , trait , ecology , interspecific competition , predation , term (time) , biology , population , computer science , sociology , demography , philosophy , linguistics , physics , quantum mechanics , programming language
Trait‐ and density‐mediated indirect effects describe different pathways by which indirect interactions in food webs are propagated from one species to another, through changes in intermediate species. A series of articles in Ecology has progressively altered the original definitions of “trait‐mediated” to the point where understanding is being impeded. The most recent of these articles are two meta‐analyses that use “trait‐mediated” to describe the demographic costs to a prey species of employing anti‐predator defenses. These same articles introduce a companion term, “density‐mediated interaction,” apparently to describe direct and indirect interactions that only involve changes in population density due to consumption by predators. This new terminology has many disadvantages, including (1) using a general term for a relatively narrow group of processes; (2) using “mediated” in a manner inconsistent with existing terminology; (3) confusing the accepted definitions of different types of indirect effects; and (4) providing a highly incomplete measure of the impact of behavior on the predator–prey interaction. Solutions to these problems and the meaning of the meta‐analyses are discussed.