Artificial night light and anthropogenic noise interact to influence bird abundance over a continental scale.

The extent of artificial night light and anthropogenic noise (i.e., "light" and "noise") impacts is global and has the capacity to threaten species across diverse ecosystems. Existing research involving impacts of light or noise has primarily focused on noise or light alone and single species; however, these stimuli often co-occur and little is known about how co-exposure influences wildlife and if and why species may vary in their responses. Here, we had three aims: (1) to investigate species-specific responses to light, noise, and the interaction between the two using a spatially explicit approach to model changes in abundance of 140 prevalent bird species across North America, (2) to investigate responses to the interaction between light exposure and night length, and (3) to identify functional traits and habitat affiliations that explain variation in species-specific responses to these sensory stimuli with phylogenetically informed models. We found species that responded to noise exposure generally decreased in abundance, and the additional presence of light interacted synergistically with noise to exacerbate its negative effects. Moreover, the interaction revealed negative emergent responses for several species that only reacted when light and noise co-occurred. Additionally, an interaction between light and night length revealed 47 species increased in abundance with light exposure during longer nights. In addition to modifying behavior with optimal temperature and potential foraging opportunities, birds might be attracted to light, yet suffer inadvertent physiological consequences. The trait that most strongly related to avian response to light and noise was habitat affiliation. Specifically, species that occupy closed habitat were less tolerant of both sensory stressors compared to those that occupy open habitat. Further quantifying the contexts and intrinsic traits that explain how species respond to noise and light will be fundamental to understanding the ecological consequences of a world that is ever louder and brighter.

Direct and Ambient Light Pollution Alters Recruitment for a Diurnal Plant-Pollinator System.

Artificial light at night (ALAN) functions as a novel environmental stimulus that has the potential to disrupt interactions among species. Despite recent efforts to explain nocturnal pollinators' responses to this stimulus, the likelihood and associated mechanisms of attraction toward artificial light and potential consequences on fitness for diurnal pollinators are still largely unclear. Here, we took advantage of the obligate mutualism between yucca moths (Tegeticula maculata maculata) and yucca plants (Hesperoyucca whipplei) to understand how direct light exposure and skyglow can influence a pairwise plant-pollinator interaction. To surmise whether adult moths exhibit positive phototaxis, we deployed a set of field-placed light towers during the peak of yucca flowering and compared the number of moths caught in traps between dark-controlled and light-treated trials. Adult moth abundance was much higher when light was present, which suggests that ALAN may alter this diurnal moth's activity patterns to expand their temporal niche into the night. To evaluate ALAN effects on yucca fruit set and moth larva recruitment, we measured skyglow exposure above yucca plants and direct light intensity from a second set of light towers. Both larva and fruit recruitment increased with skyglow, and fruit set also increased with direct lighting, but the relationship was weaker. Contrarily, larva recruitment did not change when exposed to a gradient of direct light, which may instead reflect effects of ALAN on moth physiology, such as disrupted female oviposition, or misdirecting behaviors essential to oviposition activity. Our results suggest that ALAN can positively influence the fitness of both plants and moths in this tightly co-evolved mutualism, but the benefits to each species may depend on whether night lighting is direct or indirect. Whether such effects and mechanisms could relate to susceptibility to the presence of ALAN on this or other plant-pollinator relationships will remain an important focus of future research.

Sensory pollutants alter bird phenology and fitness across a continent.

Expansion of anthropogenic noise and night lighting across our planet1,2 is of increasing conservation concern3-6. Despite growing knowledge of physiological and behavioural responses to these stimuli from single-species and local-scale studies, whether these pollutants affect fitness is less clear, as is how and why species vary in their sensitivity to these anthropic stressors. Here we leverage a large citizen science dataset paired with high-resolution noise and light data from across the contiguous United States to assess how these stimuli affect reproductive success in 142 bird species. We find responses to both sensory pollutants linked to the functional traits and habitat affiliations of species. For example, overall nest success was negatively correlated with noise among birds in closed environments. Species-specific changes in reproductive timing and hatching success in response to noise exposure were explained by vocalization frequency, nesting location and diet. Additionally, increased light-gathering ability of species' eyes was associated with stronger advancements in reproductive timing in response to light exposure, potentially creating phenological mismatches7. Unexpectedly, better light-gathering ability was linked to reduced clutch failure and increased overall nest success in response to light exposure, raising important questions about how responses to sensory pollutants counteract or exacerbate responses to other aspects of global change, such as climate warming. These findings demonstrate that anthropogenic noise and light can substantially affect breeding bird phenology and fitness, and underscore the need to consider sensory pollutants alongside traditional dimensions of the environment that typically inform biodiversity conservation.

Climate change is projected to outpace rates of niche change in grasses.

Climate change may soon threaten much of global biodiversity, especially if species cannot adapt to changing climatic conditions quickly enough. A critical question is how quickly climatic niches change, and if this speed is sufficient to prevent extinction as climates warm. Here, we address this question in the grass family (Poaceae). Grasses are fundamental to one of Earth's most widespread biomes (grasslands), and provide roughly half of all calories consumed by humans (including wheat, rice, corn and sorghum). We estimate rates of climatic niche change in 236 species and compare these with rates of projected climate change by 2070. Our results show that projected climate change is consistently faster than rates of niche change in grasses, typically by more than 5000-fold for temperature-related variables. Although these results do not show directly what will happen under global warming, they have troubling implications for a major biome and for human food resources.

Bilateral idiopathic sensorineural hearing loss following dental surgery.

BACKGROUND: This is a case study of an 18-year-old female who suffered a bilateral idiopathic sensorineural hearing loss that was coincident with the removal of four impacted wisdom teeth, Throughout childhood the patient had normal hearing for pure tones bilaterally as measured at the pediatrician's office. One month prior to dental surgery (May) the patient volunteered to participate in an auditory experiment at which time her pure-tone audiogram was normal. Immediately following surgery (June), the patient had substantial swelling of the face and complained of some hearing loss with no other auditory/vestibular complaints. The following month (July) during the course of a routine physical examination a pure-tone audiogram revealed bilateral, air-conduction thresholds of 30-35 dB HL (500-4000 Hz) and 20 dB HL (8000 Hz). Because bone conduction was not tested, it is impossible to know whether the hearing loss was conductive, mixed, or sensorineural. The pediatrician thought that the hearing loss was conductive and would resolve as the edema subsided, A month later (August) the subject again volunteered for an auditory experiment at which time her hearing again was tested. PURPOSE: The purpose of this report is to detail the dental procedures involved in the extraction of the wisdom teeth, to report the results of a variety and series of post-op hearing tests, and to discuss the possible mechanisms that might be involved in the "idiopathic" bilateral sensorineural hearing loss. RESEARCH DESIGN: Case report. RESULTS: During the August visit to the laboratory, hearing for pure tones bilaterally was 0 to 5 dB HL at 250-1000 Hz with a 40-45 dB HL notch at 2000 Hz with a return to 10 dB HL at 8000 Hz. Air conduction and bone conduction thresholds were equivalent. Word recognition in quiet was -92 percent correct for both ears, whereas the signal-to-noise ratio (SNR) hearing loss measured with the Words-in-Noise test was high normal in the left ear with a mild SNR hearing loss in the right ear. Tympanometry and acoustic reflex thresholds were normal. Distortion product otoacoustic emissions were reduced in the 1000-3000 Hz region for both ears, which is consistent with cochlear hearing loss. The hearing loss has remained unchanged for the past 19 months. CONCLUSIONS: The possible etiologies, including insults to the cochleae by vibration trauma and through alterations in the blood supply to the cochleae, are considered.