Light pollution as an ecological edge effect: Landscape ecological analysis of light pollution in protected areas in Korea

•Effects of patch geometry on light pollution in 22 Korean national parks are examined.•Light pollution levels are assessed with VIIRS DNB monthly nighttime images.•Light from outside protected areas is a primary source of light pollution.•Larger and more simple-shaped protected areas are less vulnerable to light pollution.•Lights in periphery is needed to mitigate light pollution in protected areas. Protected areas have been increasingly encroached upon by light pollution. This paper examines whether patch geometry and land development intensities in protected areas affect the light pollution levels in 22 Korean national parks. Light pollution levels were assessed based on mean nighttime radiance of these national parks derived from nighttime satellite images. Total floor areas of buildings in the parks and in a 1 km buffer zone outside the park boundaries were calculated to assess land development intensities both inside and surrounding the parks. Two landscape metrics (patch area and fractal dimension) were measured to assess the patch geometry of the parks. Results show that the mean nighttime radiances in the Korean national parks are significantly affected by total floor areas in the 1 km buffer zone, but not by the total floor area within the park. This suggests that skyglow caused by artificial light in periphery is a major source of light pollution in the Korean national parks. In other words, light pollution can be seen as an ecological edge effect in protected areas where land development is stringently restricted. This conclusion is also supported by significant effects of two patch geometry variables, i.e., light pollution was more severe in a protected area with smaller size and a more complex shape. Based on these findings, it is suggested to make protected areas larger and more simple-shaped to protect biodiversity from light pollution. Managing lights in periphery of protected areas is also suggested.