Pitfalls in ecological research – transgenerational effects

Abstract

The phenotype of an individual can be affected by the environment of its predecessors, a phenomenon commonly referred to as transgenerational effects. These effects, if not properly acknowledged and/or controlled, can impede proper interpretation of ecological studies. Using examples from more than 40 recently published studies, I discuss the most frequently used methodological approaches to deal with unwanted transgenerational effects in ecological research. In this literature, growing one generation in a common environment before the experiment or fitting seed and/or seedling size as a covariate were the most prevalent tools used to account for or even out transgenerational effects. Although these methods can efficiently control for transgenerational effects of limited generational persistence, usually just one generation of offspring, they cannot sufficiently control for effects across multiple generations. I propose that, whenever possible in ecological experiments, two generations of plants be grown in a common environment prior to the main experiment and that extreme caution should be exercised in interpreting results if the degree of transgenerational effects is not known. I also suggest that in addition to controlling for transgenerational effects in ecological research, we should actively investigate transgenerational effects as a source of plant variation.