Urbanisation is associated with changes in stable isotopes across multiple trophic levels.

The increase in urbanisation imposes important threats to biodiversity through habitat destruction, reduced availability of preferred food resources and higher pollution. To support future urban planning, it is necessary to gather more knowledge on how the ecology of organisms from different trophic levels varies across the urbanisation gradient. In our study, we employed carbon and nitrogen stable isotope analysis to investigate the relationship between increasing urbanisation and C and N values across a tri-trophic system of trees (birch and oak), invertebrates (aphids, other Hemiptera, and caterpillars) and a model avian species for urban ecology (the blue tit ).

Partial night lighting may reduce the physiological impact of artificial light at night on captive zebra finches.

Background: Artificial light at night (ALAN) continues to increase at an unprecedented rate globally every year. ALAN can disrupt circadian rhythms and cause behavioural and physiological changes which may have knock on effects for health, yet we still understand very little about these effects. It is becoming increasingly important to investigate potential mitigation strategies, through understanding what aspects of ALAN negatively impact wildlife health.

Artificial light at night weakens body condition but does not negatively affect physiological markers of health in great tits.

Urbanisation brings many novel challenges for wildlife through changes to the natural environment; one of the most unprecedented of these modifications is artificial light at night (ALAN). ALAN has been shown to have profound effects on the behaviour and physiology of many wildlife species, which in turn have negative consequences for fitness and survival. Despite increasing knowledge of the mechanisms by which ALAN can affect health, studies that have investigated this relationship have found contrasting results.

Urban effects on timing and variability of diel activity differ across passerine species and seasons.

Life on Earth is adapted to rhythmic cycles in environmental conditions throughout the day and year via diel patterns of behavioural activity. Urban conditions can disrupt such behavioural rhythms of activity. However, most studies so far have investigated urban effects on patterns of activity of single species in a single season.

It Pays to Sit Tight: Stable Night-Time Incubation Increases Hatching Success in Urban and Forest Great Tits, .

Animals organize their time so that their behaviors do not conflict with each other and align well with environmental conditions. In species with parental care, adults must also accommodate offspring needs into their temporal allocation of resources and activities. Avian parents face harsh constraints on their time budget during incubation, when they must sustain themselves but also transfer heat to eggs.

Robust analysis of diel activity patterns.

Research Highlight: Iannarilli, F., Gerber, B. D.

Environmental constraints can explain clutch size differences between urban and forest blue tits: Insights from an egg removal experiment.

Urban environments present novel ecological challenges to wild species. In birds, urban populations generally exhibit reduced clutch sizes compared to forest populations. However, whether smaller urban clutches are adaptive or a result of environmental constraints is unclear.

The impact of urbanization on health depends on the health metric, life stage and level of urbanization: a global meta-analysis on avian species.

Stressors associated with urban habitats have been linked to poor wildlife health but whether a general negative relationship between urbanization and animal health can be affirmed is unclear. We conducted a meta-analysis of avian literature to test whether health biomarkers differed on average between urban and non-urban environments, and whether there are systematic differences across species, biomarkers, life stages and species traits. Our dataset included 644 effect sizes derived from 112 articles published between 1989 and 2022, on 51 bird species.

Investigating the impacts of artificial light via blackouts.

Natural experiments provide remarkable opportunities to test the large-scale effects of human activities. Widespread energy blackouts offer such an 'experiment' to test the impacts of artificial light at night (ALAN) on wildlife. We use the situation in South Africa, where regular scheduled blackouts are being implemented, to highlight this opportunity.

Part-night exposure to artificial light at night has more detrimental effects on aphid colonies than fully lit nights.

Artificial light at night (ALAN) threatens natural ecosystems globally. While ALAN research is increasing, little is known about how ALAN affects plants and interactions with other organisms. We explored the effects of ALAN on plant defence and plant-insect interactions using barley () and the English grain aphid ().

Experimental light at night explains differences in activity onset between urban and forest great tits.

Artificial light at night (ALAN) is rapidly increasing and so is scientific interest in its ecological and evolutionary consequences. In wild species, ALAN can modify and disrupt biological rhythms. However, experimental proof of such effects of ALAN in the wild is still scarce.

The effects of artificial light at night (ALAN) on the gaping activity and feeding of mussels.

Artificial Light at Night (ALAN) is a common environmental pollutant which affects >22 % of the world's coastlines. However, the impact of ALAN wavelengths on coastal organisms is under-investigated. Here, we tested the impact of red, green, and white ALAN on the gaping activity and phytoplankton consumption of Mytilus edulis mussels and compared these to dark night.

A global meta-analysis reveals higher variation in breeding phenology in urban birds than in their non-urban neighbours.

Cities pose a major ecological challenge for wildlife worldwide. Phenotypic variation, which can result from underlying genetic variation or plasticity, is an important metric to understand eco-evolutionary responses to environmental change. Recent work suggests that urban populations might have higher levels of phenotypic variation than non-urban counterparts.

Experimental warming during incubation improves cold tolerance of blue tit (Cyanistes caeruleus) chicks.

Climate change and increasing air temperature may alter environmental conditions for developing birds, with a range of phenotypic consequences for offspring. The thermal environment during incubation may affect the trade-off between growth and thermoregulation, but the effects of temperature on the ontogeny of endothermy are not fully understood. Therefore, we experimentally tested whether heating the nest cup of Eurasian blue tits (Cyanistes caeruleus) during incubation would influence cold tolerance of the chicks after hatching.

Global urban environmental change drives adaptation in white clover.

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors.

Widespread extinction debts and colonization credits in United States breeding bird communities.

Species extinctions and colonizations in response to land cover change often occur with time lags rather than instantaneously, leading to extinction debts and colonization credits. These debts and credits can lead to erroneous predictions of future biodiversity. Recent attempts to measure debts and credits have been limited to small geographical areas and have not considered multiple land cover types, or the directionality of land cover change.

Integrated molecular and behavioural data reveal deep circadian disruption in response to artificial light at night in male Great tits (Parus major).

Globally increasing levels of artificial light at night (ALAN) are associated with shifting rhythms of behaviour in many wild species. However, it is unclear whether changes in behavioural timing are paralleled by consistent shifts in the molecular clock and its associated physiological pathways. Inconsistent shifts between behavioural and molecular rhythms, and between different tissues and physiological systems, disrupt the circadian system, which coordinates all major body functions.

Feather, But Not Plasma, Glucocorticoid Response to Artificial Light at Night Differs between Urban and Forest Blue Tit Nestlings.

Urbanization drives phenotypic variation in many animal species. This includes behavioral and physiological traits such as activity patterns, aggression, and hormone levels. A current challenge of urban evolutionary ecology is to understand the environmental drivers of phenotypic variation in cities.

Wavelength-dependent effects of artificial light at night on phytoplankton growth and community structure.

Artificial light at night (ALAN) is a disruptive form of pollution, impacting physiological and behavioural processes that may scale up to population and community levels. Evidence from terrestrial habitats show that the severity and type of impact depend on the wavelength and intensity of ALAN; however, research on marine organisms is still limited. Here, we experimentally investigated the effect of different ALAN colours on marine primary producers.

Effects of long-term exposure to microfibers on ecosystem services provided by coastal mussels.

The biofiltration capacity of bivalve populations is known to alleviate the effects of coastal eutrophication. However, this important ecosystem service could potentially be impaired by the increasing microplastic abundance in near shore environments. It is known that relatively large microplastics (∼500 μm) impair the filtration capacity of bivalves.