As extreme weather is expected to become more frequent with global climate change, it is crucial to evaluate the capacity of species to respond to short-term and unpredictable events. Here, we ...examined the effect of a strong storm event during the chick-rearing stage of little penguins (Eudyptula minor) from a mega colony in southern Australia. We investigated how a 3-day storm affected the foraging behaviour of little penguins by comparing their foraging activities and body mass change before, during and after the storm event. As strong winds deepened the mixed layer in the birds' foraging zone during the storm, penguins increased their foraging trip duration, had a lower prey encounter rate and a lower body mass gain. The adverse effects on the foraging efficiency of little penguins continued several days after the storm ceased; even though the water column stratification had returned as before the storm, suggesting a prolonged effect of the storm event on the prey availability. Thus, short-term stochastic events can have an extended impact on the foraging efficiency of penguins. When occurring at a crucial stage of breeding, this may affect breeding success.
Light pollution is increasing around the world and altering natural nightscapes with potential ecological and evolutionary consequences. A severe ecological perturbation caused by artificial lights ...is mass mortalities of organisms, including seabird fledglings that are attracted to lights at night on their first flights to the sea. Here, we report on the number of fledging short-tailed shearwaters Ardenna tenuirostris found grounded in evening and morning rescue patrols conducted at Phillip Island, Australia, during a 15-year period (1999-2013). We assessed factors affecting numbers of grounded birds and mortality including date, moon phase, wind direction and speed, number of visitors and holiday periods. We also tested experimentally if birds were attracted to lights by turning the lights off on a section of the road. Of 8871 fledglings found, 39% were dead or dying. This mortality rate was 4-8 times higher than reported elsewhere for other shearwater species, probably because searching for fledglings was part of our systematic rescue effort rather than the opportunistic rescue used elsewhere. Thus, it suggests that light-induced mortality of seabirds is usually underestimated. We rescued more birds (dead and alive) in peak fledging, moonless and windy nights. Mortality increased through the fledging period, in the mornings and with increased traffic on holiday periods. Turning the road lights off decreased the number of grounded birds (dead and alive). While moon, wind and time are uncontrolled natural constraints, we demonstrated that reduction of light pollution and better traffic management can mitigate artificial light-induced mortality.
Reproductive performance typically improves with age, reaching a plateau at middle age and subsequently declining in older age classes (senescing individuals). Three potential non‐exclusive ...mechanisms can explain the improvement in reproductive performance with age: (1) selection (poor quality individuals are removed from the population with increasing age), (2) constraint (individual efficiency increases through experience), and (3) restraint (reproductive investment increases with age as the residual reproductive value decreases). While all three mechanisms received strong empirical support, few studies have aimed at teasing apart those hypotheses and understanding their underlying functioning. In little penguins (Eudyptula minor), we used a 19‐yr longitudinal dataset on breeding and foraging of more than 450 individuals to investigate the effect of age on breeding success. We separated within‐individual from among‐individual age effects using state‐of‐the‐art statistical methods (within‐subject centering and population change decomposition). We then assessed whether within‐individual changes in breeding resulted from ontogenetic changes in foraging performances, breeding phenology or access to mates and nest sites. Fidelity and assortative pairing explained the high correlation in male and female ages within a pair. Breeding performances followed a typical bell‐shaped curve with performance increasing up to 8 yr old, before reaching a plateau and subsequently declining after age 16. Both selection and within‐individual processes occurred, although within‐individual changes dominated differences in age‐dependent breeding success. The selective appearance had almost no effect (apart from ages 2–3), and selective disappearance mostly affected changes at old ages (above 16), although they were also responsible for the slight increase in reproductive performances from ages 5–8. Focusing on within‐individual changes, birds exhibited higher performances at middle ages, with birds foraging better, laying earlier and changing partner and nest less often. Their reproductive investment did not vary with age for females and slightly decreased for males. This supports the constraint hypothesis but not the restraint one. Finally, the increase in breeding performances at young ages was explained by the age‐related increase in foraging performances during chick‐rearing and advancement of laying. In contrast, reproductive senescence was defined by a general decrease in bird performances.
While differences in foraging and reproductive success are well studied between seabird colonies, they are less understood at a smaller subcolony scale. Working with little penguins (
) at Phillip ...Island, Australia, we used an automated penguin monitoring system and performed regular nest checks at two subcolonies situated 2 km apart during the 2015/2016 breeding seasons. We examined whether foraging and reproductive success differed between subcolonies. We used satellite data to examine how sea surface temperature, as environmental pressure, in the foraging regions from each subcolony influenced their foraging performance. In the pre-laying and incubation breeding stages, the birds from one subcolony had a lower foraging success than birds from the other. However, this pattern was reversed between the subcolonies in the guard and post-guard stages. Breeding success data from the two subcolonies from 2004-2018 showed that reproductive success and mean egg-laying had a negative relationship with sea surface temperature. We highlighted that variation in foraging and reproductive success can arise in subcolonies, likely due to different responses to environmental conditions and prey availability. Differences at the subcolony level can help refine, develop and improve appropriate species management plans for conserving a range of colonial central place seabirds.
Diet‐related breeding failure in seabirds has been attributed to declines in key prey abundance, the quality of prey and overall prey availability. However, identifying which aspect of diet is ...responsible for reproductive failure is challenging due to the practicalities of measuring prey utilization and the actual availability and abundance of those resources. In this study, stable isotope‐based Bayesian models, in combination with indices of resource availability, were used to assess the links between prey availability, seabird diet and reproductive success in a generalist, inshore top predator, the little penguin, Eudyptula minor. The most probable causes for the sharp decrease in little penguin reproductive performance were diminished localized populations of anchovies, Engraulis australis, in combination with the scarcity of alternative prey. Low dietary diversity and the consumption of low trophic value prey were observed in this period. In the contrasting following year, penguins consumed increased levels of anchovy as well as a high diversity of prey. High dietary diversity and the consumption of high trophic value prey were observed in birds' pre‐breeding and breeding diet and likely led to early breeding and high reproductive success. Our results highlight that resource abundance and the availability of a variety of prey taxa are critical factors in enabling this inshore seabird to adjust to changes in environmental conditions and fluctuations in prey. An understanding of seabird diet is integral to their conservation and management. Monitoring seabird trophic niche dimensions and reproductive parameters can elucidate causes for population declines and can provide information about particular prey species and foraging locations that require protection.
The extrinsic and intrinsic factors affecting differing reproductive strategies among populations are central to understanding population and evolutionary ecology. To evaluate whether individual ...reproductive strategies responded to annual patterns in marine productivity and age‐related processes in a seabird we used a long term (2003–2013), a continuous dataset on nest occupancy and attendance at the colony by little penguins (Eudyptula minor) at Phillip Island (Victoria, Australia). We found that concurrent with a secondary annual peak of marine productivity, a secondary peak in colony attendance and nest occupancy was observed in Autumn (out of the regular breeding season in spring/summer) with individuals showing mating‐like behavior. Individuals attending this autumn peak averaged 2.5 years older than those individuals that exclusively bred during spring/summer. Rather than being a naïve response by younger and inexperienced birds misreading environmental cues, our data indicate that the autumn peak attendance is an earlier attempt to breed by older and more experienced penguins. Therefore, we provide strong support for the fundamental prediction of the life‐history theory of increasing investment in reproduction with age to maximize lifetime fitness as future survival prospects diminish and experience increases.
We use an eleven‐year dataset of bird breeding to test the life‐history theory that predicts a relationship between reproductive investment and age. We examined the pattern of attendance at the colony and demographic information of little penguins to detect a peak in breeding activity during autumn, in addition to the usual breeding peak in spring/summer. We found that there was a significant difference in age of birds that bred in one or both these peaks, indicating an increased investment by older birds in accordance with theory predicting their diminished future reproductive potential and capacity to accurately detect environmental cues.
Artificial lights at night cause high mortality of seabirds, one of the most endangered groups of birds globally. Fledglings of burrow-nesting seabirds, and to a lesser extent adults, are attracted ...to and then grounded (i.e., forced to land) by lights when they fly at night. We reviewed the current state of knowledge of seabird attraction to light to identify information gaps and propose measures to address the problem. Although species in families such as Alcidae and Anatidae can be grounded by artificial light, the most affected seabirds are petrels and shearwaters (Procellariiformes). At least 56 species of Procellariiformes, more than one-third of them (24) threatened, are subject to grounding by lights. Seabirds grounded by lights have been found worldwide, mainly on oceanic islands but also at some continental locations. Petrel breeding grounds confined to formerly uninhabited islands are particularly at risk from light pollution due to tourism and urban sprawl. Where it is impractical to ban external lights, rescue programs of grounded birds offer the most immediate and employed mitigation to reduce the rate of light-induced mortality and save thousands of birds every year. These programs also provide useful information for seabird management. However, these data are typically fragmentary, biased, and uncertain and can lead to inaccurate impact estimates and poor understanding of the phenomenon of seabird attraction to lights. We believe the most urgently needed actions to mitigate and understand light-induced mortality of seabirds are estimation of mortality and effects on populations; determination of threshold light levels and safe distances from light sources; documentation of the fate of rescued birds; improvement of rescue campaigns, particularly in terms of increasing recovery rates and level of care; and research on seabird-friendly lights to reduce attraction. Las luces artificiales nocturnas causan una mortalidad alta de aves marinas, uno de los grupos de aves en mayor peligro de extinción a nivel mundial Lospolluelos de aves marinas que anidan en madrigueras, y en menor medida los adultos, son atraídos y forzados a aterrizar por las luces cuando vuelan de noche. Revisamos el estado actual del conocimiento sobre la atracción de las aves marinas por la luz para identificar vacíos de información y proponer medidas para resolver el problema. Aunque las especies de familias como Alcidae y Anatidae pueden ser forzadas a aterrizar por la luz artificial, las aves marinas más afectadas son los petreles y las pardelas (Procellariiformes). Por lo menos 56 especies de Procellariiformes, más de un tercio (24) de ellas amenazadas, son propensas al aterrizaje atraídas por las luces. Las aves marinas forzadas a aterrizar han sido halladas en todo el mundo, principalmente en islas oceánicas, pero también en algunas localidades continentales. Los sitios de anidación de los petreles confinados anteriormente a islas deshabitadas están particularmente en riesgo de sufrir contaminación lumínica debido al turismo y al crecimiento urbano. En donde no es práctico prohibir las luces externas, los programas de rescate de las aves accidentadas ofrecen la mitigación más inmediata y empleada para reducir la tasa de mortalidad inducida por la luz y salvar a miles de aves cada año. Estos programas también proporcionan información útil para el manejo de aves marinas. Sin embargo, estos datos están típicamente fragmentados, sesgados y son inciertos, y pueden llevar a estimaciones inexactas del impacto y a un entendimiento pobre del fenómeno de la atracción de las aves marinas por la luz. Creemos que las acciones necesarias de mayor urgencia para mitigar y entender la mortalidad de aves marinas producida por la luz son: la estimación de la mortalidad y los efectos sobre la población; la determinación de umbrales de niveles de luz y de distancias seguras a las fuentes de luz; el estudio del destino de las aves rescatadas; la mejora de las campañas de rescate, particularmente en términos de incrementar las tasas de recogida y el nivel de cuidado; y la investigación sobre las características de la luz para reducir la atracción de las aves marinas.
Human activities drive environmental changes at scales that could potentially cause ecosystem collapses in the marine environment. We combined information on marine biodiversity with spatial ...assessments of the impacts of climate change to identify the key areas to prioritize for the conservation of global marine biodiversity. This process identified six marine regions of exceptional biodiversity based on global distributions of 1729 species of fish, 124 marine mammals, and 330 seabirds. Overall, these hot spots of marine biodiversity coincide with areas most severely affected by global warming. In particular, these marine biodiversity hot spots have undergone local to regional increasing water temperatures, slowing current circulation, and decreasing primary productivity. Furthermore, when we overlapped these hot spots with available industrial fishery data, albeit coarser than our estimates of climate impacts, they suggest a worrying coincidence whereby the world's richest areas for marine biodiversity are also those areas mostly affected by both climate change and industrial fishing. In light of these findings, we offer an adaptable framework for determining local to regional areas of special concern for the conservation of marine biodiversity. This has exposed the need for finer-scaled fishery data to assist in the management of global fisheries if the accumulative, but potentially preventable, effect of fishing on climate change impacts is to be minimized within areas prioritized for marine biodiversity conservation.
Abstract
Culturally dependent human social behaviours involving artificial light usage can potentially affect light pollution patterns and thereby impact the night‐time ecology in populated areas, ...although to date this has not been examined globally.
By analysing continuous (monthly), highly resolved, spatially explicit data on global night lights (Visible and Infrared Imaging Radiometer Suite–Day/Night Band‐VIIRS‐DNB; 2014–2019) with circular statistical techniques, we evaluated whether macro‐cultural activities involving social aggregations and the use of artificial lights shape annual lighting patterns globally.
Scheduled routines associated with cultural‐specific festivities appear to be important drivers of observed seasonal patterns in urban night‐time lights. For instance, the display of Christmas lights between Christmas and Epiphany Day celebrations (December–January) coincides with the annual peak in urban night‐time light intensity in Christian countries. Analogously, night celebrations during the Holy Month of Ramadam (from May to July) or the month‐long period of Karthika Masam (from October to November) fits with annual night light peaks in Muslim and Hindu countries. Annual peaks of urban light intensity in China and Vietnam also match with Chinese and Vietnamese (Tê't) New Year celebrations (January–February). In contrast, predominantly Buddhist countries, which do not have such prominent and prolonged celebrations involving artificial lights, show a relatively uniform distribution of night light peaks throughout the annual cycle.
Social behaviour and sociocultural contexts help explain how people modify the global nightscape and contribute to light pollution globally. Understanding the cultural contexts responsible for peaks in artificial light usage is an important first step if humans are to mitigate any deleterious effects associated with global increases in night‐time light pollution.
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Resumen
Determinados comportamientos humanos que llevan asociados el uso de luces artificiales pueden afectar a los patrones de contaminación lumínica y, por lo tanto, al paisaje nocturno en zonas urbanas y sus alrededores. Hasta la fecha, esto no se ha examinado a nivel mundial.
Analizamos datos continuos (mensuales) de alta resolución espacial y temporal sobre luces nocturnas (Visible and Infrared Imaging Radiometer Suite–Day/Night Band‐VIIRS‐DNB; 2014–2019) con técnicas estadísticas circulares, para evaluar si actividades culturales y sociales que involucran grandes agregaciones humanas modulan los patrones anuales de contaminación lumínica a nivel mundial.
Las grandes festividades culturales parecen modular los patrones estacionales de intensidad lumínica nocturna observados en zonas urbanas. Por ejemplo, la exhibición de luces entre la Navidad y el Día de la Epifanía (diciembre‐enero) coincide con el pico anual de intensidad de la luz nocturna urbana en los países cristianos. Análogamente, las celebraciones nocturnas durante el mes sagrado del Ramadán (de mayo a julio) o el de Karthika Masam (de octubre a noviembre) encajan con los picos anuales de luz nocturna en los países musulmanes e hindúes respectivamente. En China y Vietnam, los picos anuales de intensidad de la luz urbana también coinciden con las celebraciones del Año Nuevo chino y vietnamita (Tê't) (enero‐febrero). Por el contrario, los países predominantemente budistas, que no tienen celebraciones tan destacadas y prolongadas con luces artificiales, muestran una distribución relativamente uniforme de los picos de luz nocturna a lo largo del ciclo anual.
Los contextos socioculturales explican cómo las personas modificamos el paisaje nocturno y contribuimos a la contaminación lumínica de nuestro planeta. Comprender estos contextos constituye un primer paso importante hacia la mitigación de los efectos nocivos asociados al aumento global de la contaminación lumínica nocturna.
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The use of artificial light at night and its ecological consequences are increasing around the world. Light pollution can lead to massive mortality episodes for nocturnally active petrels, one of the ...most threatened avian groups. Some fledglings can be attracted or disoriented by artificial light on their first flights. Studies testing the effect of artificial light characteristics on attractiveness to seabirds have not provided conclusive results and there is some urgency as some endangered petrel species experience high light-induced mortality. We designed a field experiment to test the effect of three common outdoor lighting systems with different light spectra (high pressure sodium, metal halide and light emitting diode) on the number and the body condition of grounded fledglings of the short-tailed shearwater Ardenna tenuirostris. A total of 235 birds was grounded during 99 experimental hours (33h for each treatment). 47% of birds was grounded when metal halide lights were on, while light emitting diode and high pressure sodium lights showed lower percentages of attraction (29% and 24%). Metal halide multiplied the mortality risk by a factor of 1.6 and 1.9 respectively in comparison with light emitting diode and high pressure sodium lights. No differences in body condition were detected among the birds grounded by the different lighting systems. We recommend the adoption of high pressure sodium lights (or with similar spectra) into petrel-friendly lighting designs together with other light mitigation measures such as light attenuation, lateral shielding to reduce spill and appropriate orientation.
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