Do the effects of substrate complexity influence the emergence position of microalgae on streams?

The spatial distribution of stream algae on substrates may be molded by the spatial arrangement of surface features. The variation of surface complexity on stream bottom may represent the availability of suitable areas for algal growth. Here we showed that different levels of surface complexity, at the scale used, did not affect the abundance of microalgae, however, we did note that specific areas of substrates seem to be more appropriate for initial algal establishment. Our results indicate that scale is fundamental to assess the effects of substrate on spatial distribution of benthic lotic microalgae and this may help us better understand how the different types of structural changes created by human activities in streams can affect algal colonization.