KEVIN J GASTON

Cox, D.T.C. & Gaston, K.J. 2024. Ecosystem functioning across the diel cycle in the Anthropocene. Trends in Ecology and Evolution39, 31-40.

Given the marked differences in environmental conditions and active biota between daytime and nighttime, it is almost inevitable that ecosystem functioning will also differ. However, understanding of these differences has been hampered due to the challenges of conducting research at night. At the same time, many anthropogenic pressures are most forcefully exerted or have greatest effect during either daytime (e.g., high temperatures, disturbance) or nighttime (e.g., artificial lighting, nights warming faster than days). Here,we explore current understanding of diel (daily) variation in five key ecosystem functions and when during the diel cycle they primarily occur [predation (unclear), herbivory (nighttime), pollination (daytime), seed dispersal (unclear), carbon assimilation (daytime)] and how diel asymmetry in anthropogenic pressures impacts these functions.

Cox, D.T.C. & Gaston, K.J. 2024. Cathemerality: a key temporal niche. Biological Reviews 99, 329-347.

Given the marked variation in abiotic and biotic conditions between day and night, many species specialise their physical activity to being diurnal or nocturnal, and it was long thought that these strategies were commonly fairly fixed and invariant. The term ‘cathemeral’, was coined in 1987, when Tattersall noted activity in a Madagascan primate during the hours of both daylight and darkness. Initially thought to be rare, cathemerality is now known to be a quite widespread form of time partitioning amongst arthropods, fish, birds, and mammals. Herein we provide a synthesis of present understanding of cathemeral behaviour, arguing that it should routinely be included alongside diurnal and nocturnal strategies in schemes that distinguish and categorise species across taxa according to temporal niche. This synthesis is particularly timely because (i) the study of animal activity patterns is being revolutionised by new and improved technologies; (ii) it is becoming apparent that cathemerality covers a diverse range of obligate to facultative forms, each with their own common sets of functional traits, geographic ranges and evolutionary history; (iii) daytime and nighttime activity likely plays an important but currently neglected role in temporal niche partitioning and ecosystem functioning; and (iv) cathemerality may have an important role in the ability of species to adapt to human-mediated pressures.

Baker, D.J., Maclean, I.M.D. & Gaston, K.J. 2024. Effective strategies for correcting spatial sampling bias in species distribution models without independent test data. Diversity and Distributions 30, e13802.

Aim: Spatial sampling bias (SSB) is a feature of opportunistically sampled species
records. Species distribution models (SDMs) built using these data (i.e. presence-background models) can produce biased predictions of suitability across geographic
space, confounding species occurrence with the distribution of sampling effort. A
wide range of SSB correction methods have been developed but simulations suggest
effects on predictive performance are highly variable. Here, we aim to identify the
SSB correction methods that have the highest likelihood of improving true predictive
performance and evaluation strategies that provide a reliable indicator of model performance when independent test data are unavailable.
Location: Global, simulation.
Time Period: Current, simulation.
Methods: A meta-analysis was used to evaluate the performance of SSB correction
methods in studies where there were direct comparisons between corrected and uncorrected SDMs. A simulation model was then developed to test evaluation strategies against a known truth using four common SSB correction methods.
Results: Effect sizes from published studies suggest some support for small positive
effects of SSB correction on predictive performance when assessed using independent
test data, but this was not evident using internal cross-validation and no single method stood out as consistently effective. Simulations support these findings and show that evaluation using internal test data was generally a poor indicator of the true effect of SSB correction. Methods that adjust models relative to a known driver of SSB produced the largest performance gains, but were also the most inconsistent.
Main Conclusions: Correcting SSB in presence-background SDMs without independent test data to evaluate the effect on model performance requires careful implementation. We recommend clearer documentation of SSB correction effects on SDMs, presenting results from models with and without correction, evaluating effects of different assumptions of SSB implementation on predictions, as well as greater efforts to collect independent test datasets to validate model predictions.

Sanders, D., Hirt, M.R., Brose, U., Evans, D.M., Gaston, K.J., Gauzens, B. & Ryser, R. 2023. How artificial light at night may rewire ecological networks: concepts and models. Philosophical Transactions of the Royal Society B 378, 20220368.

Artificial light at night (ALAN) is eroding natural light cycles and thereby changing species distributions and activity patterns. Yet little is known about how ecological interaction networks respond to this global change driver. Here, we assess the scientific basis of the current understanding of community-wide ALAN impacts. Based on current knowledge, we conceptualize and review four major pathways by which ALAN may affect ecological interaction networks by (i) impacting primary production, (ii) acting as an environmental filter affecting species survival, (iii) driving the movement and distribution of species, and (iv) changing functional roles and niches by affecting activity patterns. Using an allometric–trophic network model, we then test how a shift in temporal activity patterns for diurnal, nocturnal and crepuscular species impacts food web stability. The results indicate that diel niche shifts can severely impact community persistence by altering the temporal overlap between species, which leads to changes in interaction strengths and rewiring of networks. ALAN can thereby lead to biodiversity loss through the homogenization of temporal niches. This integrative framework aims to advance a predictive understanding of community-level and ecological-network consequences of ALAN and their cascading effects on ecosystem functioning.

Gaston, K.J., Phillips, B.B. & Soga, M. 2023. Personalised ecology and the future of biodiversity. Cambridge Prisms: Extinction 1, e18.

The future of biodiversity lies not just in the strategies and mechanisms by which ecosystems and species are practically best protected from anthropogenic pressures. It lies also, and perhaps foremost, in the many billions of decisions that people make that, intentionally or otherwise, shape their impact on nature and the conservation policies and interventions that are implemented. Personalised ecology – the set of direct sensory interactions that each of us has with nature – is one important consideration in understanding the decisions that people make. Indeed, it has long been argued that people’s personalised ecologies have powerful implications, as captured in such concepts as biophilia, extinction of experience and shifting baselines. In this paper, we briefly review the connections between personalised ecology and the future of biodiversity, and the ways in which personalised ecologies might usefully be enhanced to improve that future.

Gaston, K.J. 2023. Common ecology. International Ecology Institute, Oldendorf/Luhe.

This book is a manifesto and a synthesis. It is a manifesto for increased attention to common ecology. Common species shape much of the natural world, provide much of ecosystem functioning and services, and are under great pressure from human activities, but this significance seems often not to receive the focus that it should. The book is also a synthesis of much present understanding of common ecology, and with a focus on general principles it covers a lot of ground in a short space. It addresses how commonness is defined and some of its fundamental features, its temporal dynamics, and what determines which species become common. It then turns to evolutionary issues, followed by the ecological importance of common species. Finally, it considers how anthropogenic impacts on common species have manifested themselves, addressing in turn species declines, the loss of wildlife spectacles and extinctions, and then what might be done to keep the common, common. In the midst of a global biodiversity crisis, and profound concerns over the loss of rare species, this book argues the case also for those species that are often more familiar and literally commonplace.

Gardner, A.S., Trew, B.T., Maclean, I.M.D., Sharma, M.D. & Gaston, K.J. 2023. Wilderness areas under threat from global redistribution of agriculture. Current Biology 33, 4721-4726.

Agriculture expansion is already the primary cause of terrestrial biodiversity loss globally; yet, to meet the demands of growing human populations, production is expected to have to double by 2050. The challenge of achieving expansion without further detriment to the environment and biodiversity is huge and potentially compounded by climate change, which may necessitate shifting agriculture zones poleward to regions with more suitable climates, threatening species or areas of conservation priority. However, the possible future overlap between agricultural suitability and wilderness areas, increasingly recognized for significant biodiversity, cultural, and climate regulation values, has not yet been examined. Here, using high-resolution climate data, we model global present and future climate suitability for 1,708 crop varieties. We project, over the next 40 years, that 2.7 million km² of land within wilderness will become newly suitable for agriculture, equivalent to 7% of the total wilderness area outside Antarctica. The increase in potentially cultivable land in wilderness areas is particularly acute at higher latitudes in the northern hemisphere, where 76.3% of newly suitable land is currently wilderness, equivalent to 10.2% of the total wilderness area. Our results highlight an important and previously unidentified possible consequence of the disproportionate warming known to be occurring in high northern latitudes. Because we find that, globally, 72.0% of currently cultivable land is predicted to experience a net loss in total crop diversity, agricultural expansion is a major emerging threat to wilderness. Without protection, the vital integrity of these valuable areas could be irreversibly lost.