The instability of field experiments: building an experimental research tradition on the rocky seashores (1950–1985)

Abstract

In many experimental sciences, like particle physics or molecular biology, the proper place for establishing facts is the laboratory. In the sciences of population biology, however, the laboratory is often seen as a poor approximation of what occurs in nature. Results obtained in the field are usually more convincing. This raises special problems: it is much more difficult to obtain stable, repeatable results in the field, where environmental conditions vary out of the experimenter's control, than in the laboratory. We examine here how this problem affected an influential experimental research tradition in community ecology, the study of the ecology of the rocky seashores. In the 1960s, a handful of North-American ecologists, most notably Joseph Connell, Robert Paine and Paul Dayton, made the rocky seashores a model study system for experimenting in the field. Their experiments were deceptively simple: they removed species living on the seashore and described the resulting effects on the local ecology. These experiments exerted a deep influence on community ecology. They provided evidence for speculative developments concerning the theory of interspecific competition, the factors responsible for species richness and the ecology of food webs. They also stimulated novel conceptual developments. In particular, Paine developed the predation hypothesis, which states that the presence of predators can favour species richness, before introducing the keystone species concept, according to which some species exert disproportionate effects on ecological systems. More broadly, these experiments gave support to a methodological trend in favour of field experimentation. Only controlled perturbations in the field, it seemed, provided a reliable method to get insights into the structure of ecological communities. However, as experiments were continued in time and repeated in different sites, divergent results appeared. We analyse here how intertidal researchers coped with the variability of environmental conditions and tried to stabilize their results. In the process, they reconsidered not only their early conclusions, but also the exclusive status given to field experiments. Expanding on this case study, we discuss some significant differences between laboratory and field experiments.

Philosophy of sustainability experimentation _ experimental legacy, normativity and transfer of evidence

“…Starting the 1950s and culminating in the 1960s, community ecology field experiments had a profound influence on many other scientific fields and gave support to a methodological trend in favor of field experimentation (Grodwohl et al, 2018). Field experiments have both advantages and disadvantages when compared to laboratory and natural experiments.…”

“…However, not all field experiments necessarily exhibit stronger external validity, since such validity depends on (uncontrollable) background factors and contexts (Dipboye & Flanagan, 1979). In other words, due to their context dependency (as real-world settings differ dramatically), it may be difficult (or even impossible) to generalize the results of field experiments to systems other than those that are being directly studied (Grodwohl et al, 2018) -a problem which will become particularly salient in sustainability experiments, due to their contextual and normative complexities (see §4). As a consequence, there is often a trade-off between internal and external validity, and both are rarely captured in a single experiment -making replication crucial, together with some combination of laboratory, natural and field studies, to obtain stable, repeatable and generalizable results in the field (an approach later taken in social psychology, economics and other social science fields).…”

¿Cómo investigar una práctica social?

“…Los neurocientíficos enfrentan la complejidad de las aulas al tratar de producir resultados estables. Sin embargo, más que aceptar la inestabilidad de los resultados, como señaló Grodwohl et al (2018) para caracterizar a los experimentos de campo, emplean técnicas de control para producir resultados más estables. El control de las variables en las aulas-laboratorio no parte de simplificar el lugar, como en los laboratorios.…”

Measuring Daphnia life history in the wild: The efficacy of individual field cages

“…This may exclude social aspects of the environment and other potentially important biological and environmental interactions (Morin, 1998). Since laboratory studies only capture a small part of the dynamic natural environment (Grodwohl et al, 2018), it can be difficult to know whether the results obtained in the laboratory are applicable to real‐world field conditions (Ieromina, 2014; Poorter, 2016).…”