The effect of artificial light on male breeding-season behaviour in green frogs, Rana clamitans melanota
Abstract
Artificial night lighting (or ecological light pollution) is only now gaining attention as a source of long-term effects on the ecology of both diurnal and nocturnal animals. The limited data available clearly indicate that artificial light can affect physiology and behaviour of animals, leading to ecological consequences at the population, community, and ecosystem levels. Aquatic ecosystems may be particularly vulnerable to such effects, and nocturnally breeding animals such as frogs may be especially affected. To address this potential, we quantify the effects of artificial light on calling and movement behaviour in a rural population of male green frogs (Rana clamitans melanota (Rafinesque, 1820)) during the breeding season. When exposed to artificial light, frogs produced fewer advertisement calls and moved more frequently than under ambient light conditions. Results clearly demonstrate that male green frog behaviour is affected by the presence of artificial light in a manner that has the potential to reduce recruitment rates and thus affect population dynamics.
... The negative impact of ALAN has been rarely reported e.g. Buchanan (1993), Baker and Richardson (2006), and Hall (2016). However, it is possible that gray treefrogs in our study were silent when present in brighter areas, resulting in few detections and low estimated occupancy. ...
... This close association with aquatic habitats is the most likely reason we found a high correlation between occupancy and sites close to water bodies. ALAN has been shown to cause a reduction in calling behavior by green frogs (Baker and Richardson 2006). Frogs are likely more vulnerable to predation in bright areas, so vocalizing less attracts less predators by not letting their location be known (Baker 2006). ...
... ALAN has been shown to cause a reduction in calling behavior by green frogs (Baker and Richardson 2006). Frogs are likely more vulnerable to predation in bright areas, so vocalizing less attracts less predators by not letting their location be known (Baker 2006). Also, frogs are not able to adapt to changing light levels quickly and so frogs may avoid habitats that are made up of dark and light areas close as they cannot adapt to the changing in light levels (Baker 2006). ...
Artificial light at night (ALAN) and noise pollution have been shown to affect urban wildlife everywhere, but little is known about the effects of these variables on urban frogs. Our objective was to model the effects of ALAN and noise pollution (as well as a suite of other habitat variables) on site occupancy of gray treefrogs (Hyla versicolor) and green frogs (Lithobates clamitans) in the city of Syracuse, New York, USA. We conducted frog call surveys at a total of 43 sites during the breeding seasons of 2018–2020 throughout the Syracuse metropolitan area. Estimated gray treefrog occupancy (with 95% confidence intervals in parentheses) ranged from 40% (24–72%) to 66% (43–81%) and was highest at sites with minimal ALAN, low noise pollution levels, and high tree coverage. Green frog occupancy rates ranged from 24% (17–30%) to 64% (35–85%) and was highest at sites near standing water but was not as affected by ALAN or noise pollution as was gray treefrog occupancy. Ultimately, frog occupancy was negatively related to ALAN and noise pollution and thus conservation plans for urban frogs should address both of these variables.
... ALAN also affects signalling rate in frogs. Northern green frogs, Rana clamitans melanota, exposed to artificial lights sang at a lower rate when in brightly lit sites (Baker & Richardson, 2006). Similarly, the introduction of ALAN to a dark site in Texas, U.S.A., led to reduced call rates in all five frog species recorded, likely as an antipredation response, an indirect effect (Hall, 2016). ...
... Animals may use structural changes, such as shorter, simpler songs, to avoid attracting predators when exposed to ALAN (Brown, 1982;Marler, 1955). One study on northern green frogs showed an immediate effect of ALAN; frogs used simpler calls in response to intermittent ALAN provided by flashlights (Baker & Richardson, 2006). ...
Acoustic communication is prevalent throughout the animal kingdom, from insects and fish to birds and mammals and has been strongly conserved over evolutionary time. It is influenced by environmental variables, such as light, through direct and indirect mechanisms. Whereas visual perception depends on light for the majority of species, acoustic communication does not, yet nocturnal vocalizations can be affected by natural light at night from the moon. Subtle changes in illumination across the lunar cycle promote population and community level changes in acoustic communication. These are often driven by intra-and interspecific factors, such as social interactions, foraging and predation pressures. We have some understanding of how moonlight affects acoustic communication across a limited number of species. However, given the recent worldwide spread of artificial light at night (ALAN), the lack of knowledge of broader baseline effects of natural light at night is critical to understanding the effect of ALAN on communication behaviours. ALAN has rapidly and drastically changed the night-time light environment resulting in shifts in the timing, duration, rate and structure of acoustic communication. Inconsistencies in research methods and lack of diversity in taxa studied make results hard to compare and generalizations challenging. Further, aspects of light beyond its presence or absence, such as its intensity, colour and scale, have seldom been examined. Here, we review the current evidence for the relationship between acoustic communication and light at night, both natural and artificial. We highlight gaps in our understanding and potential methodological oversights and suggest directions for future research.
... In certain species of frogs, artificial light at night can affect mating behavior, including the calling behavior and movement of male frogs (Baker and Richardson 2006), mate selection by female frogs (Rand et al. 1997), and nest locations (Tárano 1998). Some of this behavior is believed to result from avoidance of predation in illuminated areas. ...
Outdoor lighting at night is considered essential to modern human life. It allows us to safely extend our daytime activities into the night hours. Without proper precautions, the addition of artificial light at night can change the natural night sky conditions and affect scenic, historic, cultural, scientific, recreational,
and ecological values that depend on darkness and dark night skies. The mission of the Bureau of Land Management (BLM) is to sustain the health, diversity, and productivity of the public lands for the use and enjoyment of present and future generations. BLM-managed lands provide differing types of activities, developments, and visitor services that include outdoor lighting where appropriate to provide for worker and visitor safety, security, and enjoyment. Due to growing public concern and research available about light pollution, this technical note provides a set of best practices for outdoor lighting. The information comes from research and practical experience published by industry and other sources and provides knowledge on the relationships between dark night skies and scenic, historic, cultural, scientific, recreational, and ecological values. This technical note provides an easy reference for a variety of ways the BLM can protect night skies and dark environments by reducing or avoiding sources of light pollution from BLM-managed lands to maintain visible clarity of night skies and ensure a healthful dark environment for wildlife and people.
... Given the importance of light as a source of both energy and information for wildlife (Gaston et al., 2012), ALAN can have diverse consequences for wildlife. For example, ALAN may alter hormone levels (Alaasam et al., 2018;Russart and Nelson, 2018), accelerate development (Dananay and Benard, 2018), alter behavior (Baker and Richardson, 2006;Touzot et al., 2020), and change activity patterns (May et al., 2019;Miner et al., 2021;Ouyang et al., 2017). The variety and extent of these impacts on wildlife makes ALAN a pollutant of growing concern, especially considering the presence of nighttime lighting has expanded rapidly in recent years (Kyba et al., 2023). ...
Artificial light at night (ALAN) is a global pollutant of rising concern. While alterations to natural day-night cycles caused by ALAN can affect a variety of traits, the broader fitness and ecological implications of these ALAN-induced shifts remain unclear. This study evaluated the interactive effects of ALAN and background color on traits that have important implications for predator-prey interactions and fitness: crypsis, background adaptation efficacy, and growth. Using three amphibian species as our models, we discovered that: (1) Exposure to ALAN reduced the ability for some species to match their backgrounds (background adaptation efficacy), (2) Crypsis and background adaptation efficacy were enhanced when tadpoles were exposed to dark backgrounds only, emphasizing the importance of environmental context when evaluating the effects of ALAN, (3) ALAN and background color have a combined effect on a common metric of fitness (growth), and (4) Effects of ALAN were not generalizable across amphibian species, supporting calls for more studies that utilize a diversity of species. Notably, to our knowledge, we found the first evidence that ALAN can diminish background adaptation efficacy in an amphibian species (American toad tadpoles). Collectively, our study joins others in highlighting the complex effects of ALAN on wildlife and underscores the challenges of generalizing ALAN's effect across species, emphasizing the need for a greater diversity of species and approaches used in ALAN research.
... It is likely to have a Purkinje shift from longer to shorter wavelength sensitivity when shifting from photopic to scotopic vision. For all the reasons to avoid impacts from artificial light at night on frogs , Baker and Richardson 2006, Hall 2016, May et al. 2019, Forsburg et al. 2021), strategies to do so could exploit this Purkinje shift by using longer wavelengths so long as intensity of light reaching habitats is low. Frogs have a long refractory time to recover from bleaching when exposed to bright lights during scotophase, so lights should nevertheless be kept dim, distant, and shielded to avoid this. ...
1. Systematic Map of Effects of Light from LEDs at Night on Terrestrial Wildlife
2. Relative Importance of Intensity and Spectrum of Artificial Light at Night in Disrupting Behavior of a Nocturnal Rodent
3. A Database of Species Visual Responses to the Spectral Distribution of Light
4. Assessing and Mitigating Taxon-Specific Light Pollution Impacts from Roadway Lighting Projects
5. Guidance for Evaluating and Mitigating Impacts to Sensitive Species from Artificial Light at Night in Caltrans Projects
... Artificial lights create an illuminated world at night, and this novel environment influences wild animals, in particular those living in urban areas. Because several animals are attracted to the environment created by artificial lights at night (i.e., ALAN), light pollution induces negative impact on several aspects of their ecological and behavioral traits such as disruption of biological clocks, mis-orientation, high probability of roadkill, increased predation, and reduction of mating activity (Baker and Richardson, 2006;Beier, 2006;Gauthreaux and Belser, 2006;Salmon, 2006;Perry et al., 2008;Sanders et al., 2021). However, the environment created by ALAN sometimes provides benefit to nocturnal predators. ...
Nocturnal predators of many taxa are known to come to artificial light at night for foraging on clumped food resources. Both innate and acquired light preferences seem to be possible mechanisms of light approaching behavior although empirical tests are lacking in most nocturnal predators. Here, using a Japanese gecko Gekko japonicus, we investigated whether geckos have a light preference and how foraging experiences under the light reinforce light approaching tendency. In a comparative experiment, there was no difference in light approaching behavior between urban and suburban geckos irrespective of their original light habitats. In an associative learning experiment, geckos did not significantly change light approaching behavior even after repeated opportunities to forage crickets near a lamp in the laboratory setting. These results imply that light approaching behavior of Japanese geckos may not be easily reinforced by foraging experiences under the light. Although we often witness geckos coming to artificial light at night, our findings may not suggest their light preference. Geckos may approach the light-up foraging spot based on other cues relating to the artificial light environment.
... La rythmicité de synthèse de la mélatonine et de ses récepteurs lui confère un rôle important dans l'organisation circadienne des organismes (Delgado and Vivien-Roels, 1989;Reiter, 1993;Pevet and Challet, 2011). Elle est notamment connue pour ses fonctions dans la régulation du cycle éveil/sommeil (Bell-Pedersen et al., 2005;Jessop et al., 2014) ainsi que dans la régulation de la reproduction (Mayer et al., 1997;Baker and Richardson, 2006;Tan et al., 2010). La synthèse de nombreuses hormones est sous le contrôle de la mélatonine (Fonken and Nelson, 2014). ...
La lumière artificielle nocturne (ALAN), reconnue comme pollution environnementale, perturbe tous les écosystèmes et affecte la photopériode, synchronisateur externe de nombreux processus biologiques. Par une approche intégrative, cette thèse a pour but d’évaluer expérimentalement l’influence d’ALAN sur le crapaud commun, Bufo bufo, amphibien nocturne couramment retrouvé en zones urbaine et péri-urbaine. Mes travaux montrent qu’en période de reproduction, ALAN réduit l’activité physique nocturne et modifie l’allocation énergétique, sans affecter ni la prise alimentaire, ni la masse corporelle des mâles. De plus, bien qu’aucun effet n’ait été observé sur la testostéronémie salivaire, ALAN affecte le comportement et le succès reproducteurs des mâles en augmentant le temps de latence pour s’accoupler avec la femelle, en diminuant le maintien de l’amplexus et en réduisant le taux de fécondation des œufs. Par ailleurs, une analyse sans a priori de transcriptomes de têtards élevés en présence d’ALAN montre une sous expression nocturne de gènes, notamment ceux impliqués dans l’immunité. Une seconde étude gène-spécifique montre une faible influence d’ALAN sur l’expression des gènes codant deux enzymes impliquées dans la synthèse de la mélatonine ou ses trois récepteurs et ne permet pas de conclure quant au rôle central de la mélatonine dans les perturbations liées à ALAN. Ainsi, cette thèse met en évidence les effets très larges d’ALAN chez le crapaud commun, affectant les processus biologiques de l’expression génique à la fitness. Ces résultats doivent être replacés dans le contexte de biologie de la conservation et pris en compte dans la préservation de l’environnement nocturne.
The natural environment can be negatively impacted by a variety of human activities, including the production of artificial light at night. Recent studies suggest that pollution from anthropogenic light alters animal behavior. Despite being highly nocturnal, little attention has been given to anurans and the effects artificial light at night has on their behavior. This study investigated whether artificial light influenced male call site selection in east Texas anurans. Ambient light levels were quantified at five sites that varied in urbanization and artificial light levels. Calling males were located and ambient light was then measured at the male's call location. Light levels at those call locations were compared to the general light environment as measured at random locations in the area. There was a consistent pattern where males at the brightest sites called from locations darker than the general light environment. However, male call locations at the brightest sites were generally brighter than those at the darker sites suggesting that, while male anurans avoid illuminated areas for calling, males in more urbanized populations may be unable to do so. As such, male anurans at sites with higher light pollution may experience a form of habitat loss where preferred darker habitat is not available.
Background & Aim: Global biodiversity decline is a major ecological problem around the world today. As an important indicator for measuring the environment, amphibians have received more and more attention from researchers in recent years. In this paper, we focus on amphibians which are the most threatened species of vertebrate to analyze the existing problems and suggest the corresponding solutions. Method：Firstly, we analyze the effects of three most prominent factors in human activities, i.e., anthropogenic noise, artificial light at night and road kills on amphibians reproduction, population growth rate, physiology, and behavior by retrieving existing literature from 2003 to 2021, and extracting and integrating key words. Secondly, the mitigation measures regarding anthropogenic noise, artificial light at night and road kills are summarized and suggestions for improvement are made. Review Results: Amphibian calling behavior was altered by anthropogenic noise, showing variations in call rate, dominant frequency, and call duration. It is yet unclear how different amphibians calling respond to anthropogenic noise differently and whether call variations are advantageous to the amphibians' long-term growth. By obscuring the perception of male acoustic signals by females and impacting sperm count and sperm viability in males, anthropogenic noise can also affect the reproductive behavior of amphibians. Amphibian growth rates and behavioral activity time were slowed down by artificial light at night. In addition, artificial light at night can change corticosterone levels in amphibians and hence have an impact on their physiology. Amphibian population size was directly impacted by road kills. This study makes recommendations for improvement in light of the aforementioned detrimental effects, including
Light is an extrinsic factor that exerts widespread influence on the regulation of circadian, physiologic, hormonal, metabolic, and behavioral systems of all animals, including those used in research. These wide-ranging biologic effects of light are mediated by distinct photoreceptors, the melanopsin-containing intrinsically photosensitive retinal ganglion cells of the nonvisual system, which interact with the rods and cones of the conventional visual system. Here, we review the nature of light and circadian rhythms, current industry practices and standards, and our present understanding of the neurophysiology of the visual and nonvisual systems. We also consider the implications of this extrinsic factor for vivarium measurement, production, and technological application of light, and provide simple recommendations on artificial lighting for use by regulatory authorities, lighting manufacturers, designers, engineers, researchers, and research animal care staff that ensure best practices for optimizing animal health and wellbeing and, ultimately, improving scientific outcomes.
Astronomers consider light pollution to be a growing problem, however few studies have addressed potential effects of light pollution on wildlife. Sunlight is believed to initiate song in many bird species. If light initiates song, then light pollution may be influencing avian song behavior at a population level. This hypothesis predicts that birds breeding in areas with large amounts of artificial light will begin singing earlier in the day than birds in areas with little artificial light. Birds in highly illuminated areas might begin singing earlier than did birds in those same areas in previous years when artificial light levels were known to be, or were presumably, lower. Also, birds should begin singing earlier within a site on brightly lit nights. In 2002 and 2003 I documented initiation of morning song by breeding American Robins (Turdus migratorius) in areas with differing intensity of artificial nocturnal light. I compared my observations among sites and against historical studies. Robin populations in areas with large amounts of artificial light frequently began their morning chorus during true night. Chorus initiation time, relative to civil twilight, was positively correlated with amount of artificial light present during true night. Robin choruses in areas with little, or presumably little, artificial light have almost never begun during true night, instead appearing to track the onset of civil twilight. Proliferation of artificial nocturnal light may be strongly affecting singing behavior of American Robins at a population level.
Field studies were conducted on factor affecting embryo mortality in bullfrogs, Rana catesbeiana, in 1975 and 1976 at the E. S. George Reserve of the University of Michigan. Larger @V produced significantly larger clutches than smaller @V (6000 to >20,000). Older @V produced 2 clutches each year with 2nd clutches containing significantly fewer eggs than 1st clutches. Egg size appeared to be unrelated to @V size; however, 2nd clutches contained significantly smaller eggs than initial clutches for all @V @V. Embryo mortality depended on @V choice of oviposition sites. Such sites were controlled by territorial @M @M. Larger @M @M controlled oviposition sites that had significantly lower embryo mortality than the sites of smaller @M @M. Sources of embryo mortality included developmental abnormalities and predation. Choice of oviposition sites included: (a) advance of areas with high water temperatures (>32 degrees C) that result in increased developmental abnormalities and (b) preference for areas that increase embryo survival by increasing developmental rate and/or decreasing efficiency of predation on embryos by the leech. Macrobdella decora.
Vertebrate rod photoreceptors adjust their sensitivity as they adapt during exposure to steady light. Light adaptation prevents the rod from saturating and significantly extends its dynamic range. We examined the time course of the onset of light adaptation in bullfrog rods and compared it with the projected onset of feedback reactions thought to underlie light adaptation on the molecular level. We found that adaptation developed in two distinct temporal phases: (1) a fast phase that operated within seconds after the onset of illumination, which is consistent with most previous reports of a 1–2-s time constant for the onset of adaptation; and (2) a slow phase that engaged over tens of seconds of continuous illumination. The fast phase desensitized the rods as much as 80-fold, and was observed at every light intensity tested. The slow phase was observed only at light intensities that suppressed more than half of the dark current. It provided an additional sensitivity loss of up to 40-fold before the rod saturated. Thus, rods achieved a total degree of adaptation of ∼3,000-fold. Although the fast adaptation is likely to originate from the well characterized Ca2+-dependent feedback mechanisms regulating the activities of several phototransduction cascade components, the molecular mechanism underlying slow adaptation is unclear. We tested the hypothesis that the slow adaptation phase is mediated by cGMP dissociation from noncatalytic binding sites on the cGMP phosphodiesterase, which has been shown to reduce the lifetime of activated phosphodiesterase in vitro. Although cGMP dissociated from the noncatalytic binding sites in intact rods with kinetics approximating that for the slow adaptation phase, this hypothesis was ruled out because the intensity of light required for cGMP dissociation far exceeded that required to evoke the slow phase. Other possible mechanisms are discussed.
Foraging behavior is responsive to changes in predation risk; increased illumination reduces foraging in open areas without cover. Foraging behavior is also affected by resource enrichments. Differences among species in habitat selection are correlated with specific abilities to detect and avoid predators. The least vulnerable species, Dipodomys deserti, foraged heavily in the open and was largely unaffected by treatments; the other species of kangaroo rats and kangaroo mice (D. merriami, D. microps, and Microdipodops pallidus) also prefer the open, but responded to both risk and resource manipulations; highly vulnerable Peromyscus maniculatus was restricted to bushes, even under the best of circumstances; Perognathus longimembris was displaced from preferred microhabitats by the presence of kangaroo rats. Predation risk provides an axis along which habitat segregation occurs. -from Author