Crab burrows within grassland sites were exposed to direct effects of sunlight.
Minor concessions to location and climate were developed, the verandah, for example, keeping direct sunlight from falling on external walls.
For living objects with optical concentrators, the concentration factor increases with the square of distance to compensate for the decrease in sunlight.
The blue sky provides about a tenth of the bright sunlight and is more or less diffused.
Of course the bright sunlight is then, broadly speaking, too bright and it has to be excluded to prevent buildings overheating.
These species are, however, gap specialists and have ready access to sunlight.
Sunlight passes through the steel-framed windows, making the flats even brighter.
These microhabitats are also disturbed in the sense that sunlight is a temporally available resource.
