Nighttime Ecology: The “Nocturnal Problem” Revisited

Abstract

The existence of a synthetic program of research on what was then termed 'the nocturnal problem', and which we might now call 'nighttime ecology', was declared more than 70 years ago. In reality this failed to materialise, arguably as a consequence of practical challenges in studying organisms at night and concentration instead on the existence of circadian rhythms, the mechanisms that give rise to them, and their consequences. This legacy is evident to this day, with consideration of the ecology of the nighttime markedly under-represented in ecological research and literature. However, several factors suggest that it would be timely to revive the vision of a comprehensive research program in nighttime ecology. These include (i) that study of the ecology of the night is being revolutionised by new and improved technologies,;(ii) suggestions that far from being a minor component of biodiversity a high proportion of animal species are active at night; (iii) that fundamental questions remain largely unanswered as to differences and connections between the ecology of the daytime and nighttime; and (iv) that the nighttime environment is coming under severe anthropogenic pressure. In this article, I seek to re-establish 'nighttime ecology' as a synthetic program of research, highlighting key focal topics, key questions, and providing an overview of the current state of understanding and developments.Park's vision for such a program failed, to this day, fully to materialise. There are number of possible explanations. These include that (i) ecologists themselves belong to a diurnal species and therefore have found it much easier, and may have had an innate proclivity, predominantly to focus on and study daytime phenomena; (ii) there seems to have been a widespread and long standing belief that in the majority of ecosystems most species are active and most ecological functioning occurs during daytime, and that nighttime is a relatively minor contributor (e.g., Crawford 1934); (iii) the technological challenges of studying ecological systems at night long remained too great, with the limited available techniques (e.g., making observations under various forms of artificial visible light; Finley 1959) having then unknown but likely problematic consequences; and (iv) attention grew, initially during a period when the fields of ecology and physiological ecology were regarded as largely synonymous (see Spicer and Gaston 1999), instead to focus on the existence of circadian rhythms, the mechanisms that give rise to them, and their consequences (e.g.,

A roadmap for survey designs in terrestrial acoustic monitoring

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“…For example, the Consortium for Dark Sky Studies recently established a new undergraduate minor in "dark sky studies" at the University of Utah. Gaston recently made a compelling case in The American Naturalist for why "nighttime ecology" must be established as a synthetic program of research in this scientific field [17], and Shaw has argued for "nightology", proposing an integrated approach to nocturnal urban research [11]. While these are exciting developments, we suggest that the emerging field of night studies must necessarily be much broader.…”

Night Matters – Why the Interdisciplinary Field of “Night Studies” is Needed

“…For example, the Consortium for Dark Sky Studies recently established a new undergraduate minor in "dark sky studies" at the University of Utah. Gaston recently made a compelling case in The American Naturalist for why "nighttime ecology" must be established as a synthetic program of research in this scientific field [15], and Shaw has argued for "nightology," proposing an integrated approach to nocturnal urban research [9].…”