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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Garrett, J. K., Donald, P. F., & Gaston, K. J. (2019). Skyglow extends into the world’s Key Biodiversity Areas. Animal Conservation, , cv.12480.
Abstract: The proportion of the Earth’s surface that experiences a naturally dark environment at night is rapidly declining with the introduction of artificial light. Biological impacts of this change have been documented from genes to ecosystems, and for a wide diversity of environments and organisms. The likely severity of these impacts depends heavily on the relationship between the distribution of artificial night-time lighting and biodiversity. Here, we carry out a global assessment of the overlap between areas of conservation priority and the most recent atlas of artificial skyglow. We show that of the world’s Key Biodiversity Areas (KBAs), less than a third have completely pristine night-time skies, about a half lie entirely under artificially bright skies and only about a fifth contain no area in which night-time skies are not polluted to the zenith. The extent of light pollution of KBAs varies by region, affecting the greatest proportion of KBAs in Europe and the Middle East. Statistical modelling revealed associations between light pollution within KBAs and associated levels of both gross domestic product and human population density. This suggests that these patterns will worsen with continued economic development and growth in the human population
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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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