Following rapid climate change, tundra plant communities are experiencing extensive compositional shifts. A conservation concern is the potential encroachment of boreal species into the tundra ('borealisation'). Tundra borealisation has been sporadically reported, but not systematically quantified. Here, we synthesised data from across 32 study areas, spanning 1137 plots and 287 vascular plant species, resurveyed between 1981 and 2023. We (i) quantified tundra borealisation as the colonisation and increase in abundance of Boreal and Boreal-Tundra species, (ii) assessed biogeographical, climatic and local borealisation drivers and (iii) identified species contributing to borealisation and their associated traits. Half of the plots experienced borealisation, although borealisation rates were not different to random expectation. Borealisation was greater in Eurasia, closer to the treeline, at higher elevations, in warmer and wetter regions, where climate change was limited, and where initial boreal abundance was lower. Boreal coloniser species were generally short-statured, and more often shrubs and graminoids. Boreal species colonised around three times less frequently than Boreal-Tundra species. Hence, our findings indicate that tundra borealisation is mainly driven by the spread of already established boreal-low Arctic tundra species. These plant community composition changes could have cascading impacts on land-atmosphere interactions, trophic dynamics and Indigenous and local livelihoods.

The Arctic is warming four times faster than the global average, and plant communities are responding through shifts in species abundance, composition and distribution. However, the direction and magnitude of local plant diversity changes have not been quantified thus far at sites across the Arctic. Using a compilation of 42,234 records of 490 vascular plant species from 2,174 plots at 45 study areas across the Arctic, we quantified temporal changes in species richness and composition from repeat surveys conducted over different intervals between 1981 and 2022, and identified the geographic, climatic and biotic drivers behind these changes. We found greater species richness at lower latitudes and warmer sites, but no indication that local species richness was changing directionally over time, on average. However, species turnover was widespread, with 59% of plots gaining and/or losing species. Proportions of species gains and losses were greater where temperatures had warmed most. Shrub expansion, particularly of erect shrubs, was associated with greater species losses and decreasing richness. Despite changes in plant composition, Arctic plant communities did not become more similar to each other over time, suggesting that no biotic homogenisation has occurred thus far. Overall, we found that Arctic plant communities changed in richness and composition in different directions, with temperature and plant-plant interactions emerging as the main drivers of directional change. Our findings demonstrate how climate and biotic drivers can act in concert to alter plant composition, which could be the precursor of future biodiversity change with impacts on ecosystem function, wildlife habitats and livelihoods for Arctic people. 

Light pollution from outdoor lighting impacts astronomical observations, ecology, and human health, with its global increase threatening previously dark environments. This paper examines international obtrusive light thresholds, revealing that current standards are primarily human-centric and based on outdated light sources. Environmental lighting zones, initially designed for inhabited areas, lack the scope to safeguard sensitive ecosystems. Analysis shows that current zones and thresholds need restructuring to include ecological considerations, particularly for conservation areas where species can be affected by very low light levels. Standards need updating to integrate ecological thresholds for effective environmental protection.

In an attempt to reduce the negative ecological impact of outdoor lighting, amber and warm white light sources and delimited light distributions are currently being tested. This study investigates elderly pedestrians’ acceptance and preference regarding sustainable outdoor lighting in a field test along a pedestrian/bicycle path. Three different correlated color temperatures (1800 K-amber, 2200 K and 3000 K) and two different optics for regular and delimited light distributions were evaluated. The results show that the satisfaction with the regular light distribution was significantly higher than with the delimited. The light with correlated color temperature of 2200 K with a regular light distribution was most preferred. When asked about accepting amber lighting on a pedestrian/bicycle path, 53% where positive, 23.5% said no and 23.5% were unsure.

The widespread use of electric lighting has revolutionised society but brought unintended consequences, notably light pollution, impacting ecosystems and human circadian rhythms. Concerns about anthropogenic light at night (ALAN) have prompted innovative solutions, such as spectral tuning of light sources. In Europe, a recent focus involves the enforcement of red light in outdoor settings to minimise ALAN's impact, particularly on bats. This mini review synthesises literature to provide an overview of the advantages and disadvantages of the use of red light outdoors. There is a need for further examination of the potential ecological consequences of red light, considering challenges in lighting design functionality and broader impacts on diverse species.

Anthropogenic light can have adverse effects on species and ecosystems, effects that are numerous and challenging to anticipate due to their high variability and complexity. In this study our objective was to investigate the feasibility of utilising environmental lighting zones for the management of aquatic Natura 2000 conservation areas. The aim of the Natura 2000 network is to ensure the long-term survival of Europe's most valuable and threatened species and habitats. Maintaining a favourable conservation status and sustainable management of these habitats is of utmost importance, necessitating the avoidance of negative impacts of human activities, including anthropogenic light. Our preliminary findings indicate that employing a relatively high number of environmental lighting zones intervals is essential for effective implementation of mitigation measures. This approach facilitates the identification of protected areas experiencing the highest levels of light emissions, aiding in targeted conservation efforts. 

Insects play a critical role in providing numerous ecosystem services. However, insect diversity and biomass have been declining dramatically, with artificial light being suggested as a contributing factor. Despite the importance of understanding the dose–effect responses of insects to light emissions, these responses have been rarely studied. We examined the dose–effect responses of the greater wax moth (Galleria mellonella L.) to different light intensities (14 treatments and a dark control) by observing their behavioural responses in a light-tight box equipped with a LED light source (4070 K) and infrared cameras. Our findings reveal dose–effect responses to light, as the frequency of walking on the light source increased with higher light intensity. Additionally, moths exhibited jumps in front of the light source and jump frequency increased with light intensity. No direct flight-to-light behaviour or activity suppression in response to light was observed. Based on our analysis of the dose–effect responses, we identified a threshold value of 60 cd/m2 for attraction (walking on the light source) and the frequency of jumps. The experimental design in this study offers a valuable tool for investigating dose–effect relationships and behavioural responses of various species to different light levels or specific light sources.

Anthropogenic light is ubiquitous in areas where humans are present and is showing a progressive increase worldwide. This has far-reaching consequences for most species and their ecosystems. The effects of anthropogenic light on natural ecosystems are highly variable and complex. Many species suffer from adverse effects and often respond in a highly specific manner. Ostensibly surveyable effects such as attraction and deterrence become complicated because these can depend on the type of behavior and specific locations. Here, we considered how solutions and new technologies could reduce the adverse effects of anthropogenic light. A simple solution to reducing and mitigating the ecological effects of anthropogenic light seems unattainable, because frugal lighting practices and turning off lights may be necessary to eliminate them.

Light is imperative to achieve viable conditionsfor human activity at night. However, for the lighting to besustainable, it is crucial to reduce unwanted and harmful sideeffectsof light at night (LAN). These unwanted effects andimpacts are often referred to as light pollution. Hitherto, it hasbeen somewhat unclear how all these adverse effects can bedescribed in a systematic way and whether light pollution issimilarly defined among different scientific disciplines andcontexts. Therefore, in this review, we present an overview ofthe identified areas where light pollution can be confirmed fromthe scientific literature and the methods commonly used withinthese areas. We have identified three key areas: astronomicallight pollution (ALP), ecological light pollution (ELP), andimpacts of LAN on humans in two subareas; impacts on humanhealth (physiology and behaviour) and impacts on humans interms of obtrusive light that can be perceived as negative, forexample, discomfort, annoyance, nuisance and distractions.Methods used in various disciplines are partly similar, e.g.,satellite-based sensor collected data are used in all three areasto study impacts, but specific methods are also used within eachfield.