Clark, G. F., Stark, J. S., Johnston, E. L., Runcie, J. W., Goldsworthy, P. M., Raymond, B., et al. (2013). Light-driven tipping points in polar ecosystems. Glob Chang Biol, 19(12), 3749–3761.
Abstract: Some ecosystems can undergo abrupt transformation in response to relatively small environmental change. Identifying imminent 'tipping points' is crucial for biodiversity conservation, particularly in the face of climate change. Here, we describe a tipping point mechanism likely to induce widespread regime shifts in polar ecosystems. Seasonal snow and ice-cover periodically block sunlight reaching polar ecosystems, but the effect of this on annual light depends critically on the timing of cover within the annual solar cycle. At high latitudes, sunlight is strongly seasonal, and ice-free days around the summer solstice receive orders of magnitude more light than those in winter. Early melt that brings the date of ice-loss closer to midsummer will cause an exponential increase in the amount of sunlight reaching some ecosystems per year. This is likely to drive ecological tipping points in which primary producers (plants and algae) flourish and out-compete dark-adapted communities. We demonstrate this principle on Antarctic shallow seabed ecosystems, which our data suggest are sensitive to small changes in the timing of sea-ice loss. Algae respond to light thresholds that are easily exceeded by a slight reduction in sea-ice duration. Earlier sea-ice loss is likely to cause extensive regime shifts in which endemic shallow-water invertebrate communities are replaced by algae, reducing coastal biodiversity and fundamentally changing ecosystem functioning. Modeling shows that recent changes in ice and snow cover have already transformed annual light budgets in large areas of the Arctic and Antarctic, and both aquatic and terrestrial ecosystems are likely to experience further significant change in light. The interaction between ice-loss and solar irradiance renders polar ecosystems acutely vulnerable to abrupt ecosystem change, as light-driven tipping points are readily breached by relatively slight shifts in the timing of snow and ice-loss.
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Davies, T. W., Coleman, M., Griffith, K. M., & Jenkins, S. R. (2015). Night-time lighting alters the composition of marine epifaunal communities. Biology Letters, 11(4), 20150080.
Abstract: Marine benthic communities face multiple anthropogenic pressures that compromise the future of some of the most biodiverse and functionally important ecosystems in the world. Yet one of the pressures these ecosystems face, night-time lighting, remains unstudied. Light is an important cue in guiding the settlement of invertebrate larvae, and altering natural regimes of nocturnal illumination could modify patterns of recruitment among sessile epifauna. We present the first evidence of night-time lighting changing the composition of temperate epifaunal marine invertebrate communities. Illuminating settlement surfaces with white light-emitting diode lighting at night, to levels experienced by these communities locally, both inhibited and encouraged the colonization of 39% of the taxa analysed, including three sessile and two mobile species. Our results indicate that ecological light pollution from coastal development, shipping and offshore infrastructure could be changing the composition of marine epifaunal communities.
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Hölker, F., Wolter, C., Perkin, E. K., & Tockner, K. (2010). Light pollution as a biodiversity threat. Trends Ecol Evol, 25(12), 681–682.
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Kyba, C. C. M., & Hölker, F. (2013). Do artificially illuminated skies affect biodiversity in nocturnal landscapes? Landscape Ecol, 28(9), 1637–1640.
Abstract: The skyglow from cities at night is one of the most dramatic modifications that humans have made to Earth’s biosphere, and it is increasingly extending into nocturnal landscapes (nightscapes) far beyond urban areas. This scattered light is dim and homogenous compared to a lit street, but can be bright compared to natural celestial light sources, such as stars. Because of the large area of Earth affected by artificial skyglow, it is essential to verify whether skyglow is a selective pressure in nocturnal landscapes. We propose two scientific approaches that could examine whether skyglow affects biodiversity.
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Newport, J., Shorthouse, D. J., & Manning, A. D. (2014). The effects of light and noise from urban development on biodiversity: Implications for protected areas in Australia. Ecol Manag Restor, 15(3), 204–214.
Abstract: Global population growth and associated urban development are having profound effects on biodiversity. Two major outcomes of expanding development that affect wildlife are light and noise pollution. In this paper, we review literature reporting the effects of light and noise on biodiversity, and assess implications for conservation planning in Australia. Our results clearly indicate that light and noise pollution have the potential to affect the physiology, behaviour and reproduction of a range of animal taxa. Types of effects include changes in foraging and reproductive behaviours, reduction in animal fitness, increased risk of predation and reduced reproductive success. These could have flow-on consequences at the population and ecosystem levels. We found a significant gap in knowledge of the impact of these pollutants on Australian fauna. To reduce the effect of light and noise pollution, there needs to be careful planning of urban areas in relation to protected areas, and for biodiversity more generally. Potential measures include strategically planning the types of development and associated human activities adjacent to protected areas, and the use of shields and barriers, such as covers for lights or the use of dense native vegetation screens, while still allowing movement of animals. Changes in government standards and regulations could also help to reduce the impacts of light and noise pollution.
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