Figure 5
From: Mapping behaviorally relevant light pollution levels to improve urban habitat planning
Chicago’s greenspace illuminated at over 6 lux is substantially different in extent and spatial structure from its total greenspace. This graphic presents percent changes in a range of landscape metrics between the entire greenspace and greenspaces estimated to be lit at above 6 lux. The metrics are based on patches, which are blocks of continuous greenspace cover. Over one-third of the greenspace areas in Chicago are exposed to illumination levels > 6 lux, and light-exposed areas split large greenspaces patches, resulting in substantial reductions in the mean patch size. At the same time, small greenspace patches tend to be completely exposed to behaviorally relevant artificial light levels, resulting in only small increases in the total number of patches. The splitting of the largest and elimination of the smallest patches further results in substantial declines in the standard deviation of patch size, a decline in the total edge of all patches, and a moderate increase in the mean distance between patches and their nearest neighboring patch.
