KEVIN J GASTON

Soga, M., Gaston, K.J., Fukano, Y. & Evans, M.J. 2023. The vicious cycle of biophobia. Trends in Ecology and Evolution 38, 512-520.

People can express irrational fears and disgust responses towards certain wild organisms. This so-called ‘biophobia’ can be useful and indeed necessary in some circumstances. Biophobia can, however, also lead to excessive distress and anxiety which, in turn, can result in people avoiding interactions with nature. Here, we highlight concern that this reduction in interactions with nature might lead to progressive increases in biophobia, entrenching it more in individuals and across society. We propose the ‘vicious cycle of biophobia’, a concept that encapsulates how excessive aversion towards nature might emerge and grow in society. The vicious cycle of biophobia risks accelerating the extinction of experience, leading to long-term adverse consequences for the conservation of biodiversity.

Bullough, K., Gaston, K.J. & Troscianko, J. 2023. Artificial light a night causes conflicting behavioural and morphological defence responses in a marine isopod. Proceedings of the Royal Society B 290, 20230725.

Encroachment of artificial light at night (ALAN) into natural habitats is increasingly recognized as a major source of anthropogenic disturbance. Research focussed on variation in the intensity and spectrum of ALAN emissions has established physiological, behavioural and population-level effects across plants and animals. However, little attention has been paid to the structural aspect of this light, nor how combined morphological and behavioural anti-predator adaptations are affected. We investigated how lighting structure, background reflectance and the three-dimensional properties of the environment combined to affect anti-predator defences in the marine isopod Ligia oceanica. Experimental trials monitored behavioural responses including movement and background choice, and also colour change, a widespread morphological anti-predator mechanism little considered in relation to ALAN exposure. We found that behavioural responses of isopods to ALAN were consistent with classic risk-aversion strategies, being particularly exaggerated under diffuse lighting. However, this behaviour was disconnected from optimal morphological strategies, as diffuse light caused isopods to become lighter coloured while seeking out darker backgrounds. Our work highlights the potential for the structure of natural and artificial light to play a key role in behavioural and morphological processes likely to affect anti-predator adaptations, survival, and ultimately wider ecological effects.

Cox, D.T.C., Baker, D.J., Gardner, A.S. & Gaston, K.J. 2023. Global variation in unique and redundant mammal functional diversity across the daily cycle. Journal of Biogeography 50, 629-640.

Aim: Organisms primarily influence ecosystems through their functional traits when they are physically active. Following the nocturnal bottleneck, the expansion of mammals into the daytime expanded mammalian functional diversity (FD), however there is also notable overlap in trait space across diel niches leading to redundant FD. We explore how the unique and redundant contribution of each diel niche varies spatially and in relation to natural variation in light and temperature.

Location: Global.

Taxon: Extant mammals.

Methods: Based on five major functional traits (body mass, litter size, diet breadth, foraging strata, habitat breadth) for 5033 extant terrestrial mammals, we determine biogeographical variation in nocturnal, crepuscular, cathemeral and diurnal FD. We calculate the proportion of mammalian FD that is unique to each diel niche, and the proportion that is redundant across the daily cycle.

Results: The diversification of mammals into the daytime resulted in the creation of new FD (28.5% of FD is not nocturnal; Lower Quartile 17.3%; Upper Quartile 38.2%). Most of this expansion occurred at higher latitudes where uniquely cathemeral FD dominates (>55°N, 41.1% of mammalian FD; Lower Quartile 33.3%, Upper Quartile 53.6%), associated with fewer hours of biologically useful moonlight and daylight. Where there are more hours of biologically useful daylight, unique diurnal FD is common. However, more than half of non-nocturnal FD is redundant, increasing ecosystem stability as different species carry out similar functions at different times of day, and suggesting that many mammals have not diversified far from their nocturnal ancestors.

Main conclusions: Over much of the land surface more than a half of FD only occurs at night, underscoring the importance of nocturnal mammals for ecosystems. Understanding diel variation in FD not only informs on community structure and ecosystem function but also on ecosystem functional persistence in the Anthropocene, with pressures at night being particularly concerning.

Gaston, K.J., Gardner, A.S. & Cox, D.T.C. 2023. Anthropogenic changes to the nighttime environment. BioScience 73, 280-290.

How the relative impacts of anthropogenic pressures on the natural environment vary between different taxonomic groups, habitats, and geographic regions is increasingly well established. By contrast, the times of day at which those pressures are most forcefully exerted or have greatest influence are not well understood. The impact on the nighttime environment bears particular scrutiny, given that for practical reasons (e.g., researchers themselves belong to a diurnal species), most studies on the impacts of anthropogenic pressures are conducted during the daytime on organisms that are predominantly day active or in ways that do not differentiate between daytime and nighttime. In the present article, we synthesize the current state of knowledge of impacts of anthropogenic pressures on the nighttime environment, highlighting key findings and examples. The evidence available suggests that the nighttime environment is under intense stress across increasing areas of the world, especially from nighttime pollution, climate change, and overexploitation of resources. 

Soga, M. & Gaston, K.J. 2023. Global synthesis reveals heterogeneous changes in connection of humans to nature. One Earth 6, 131-138.

The connection that individuals have with nature impacts their well-being and their support for pro-nature policies. While it is generally believed that the connection between humans and nature is decreasing, the extent of this trend is uncertain. Here, we present a global analysis of the temporal changes in people’s psychological and physical connections to nature. Using a systematic review protocol, we identified 71 articles consisting of 100 case studies. Most of these studies used cross-sectional, rather than longitudinal, approaches, which examine the connection to nature among people of different ages. The literature we reviewed indicates that there has been a decline in human connection to nature over time. However, the magnitude of changes in nature connection varied by geographic and socio-economic settings, with some studies showing an increasing trend. These findings suggest that there are opportunities to limit and reverse ongoing disconnection of humans from nature where it does occur.