5. Conclusions
Current policies to control and to prevent costs and impacts of
coastal modification by urbanization are defined by social and
ecological information (Scyphers et al., 2014). Knowledge of
emergent impacts of urbanization, as presented herein, is essential
for designing effective ecosystem restoration plans (Abelson et al.,
2015). We showed that artificial reefs can have the potential to
degrade local habitats by enhancing retention and accumulation of
human-derived litter material. Specifically, we found that the
structural complexity at scales of dozens of centimetres to few
meters (e.g. made by spaces between artificial boulders) contributes
to the high density of AL on urban breakwaters, which is
further enhanced by both adjacent urban activities and entrapment
of floating debris. Therefore, the direct relationship between
habitat modification and pollution seems to be an emergent phenomenon
related to urbanization of coastal ecosystems. The environmental
impacts of AL material and infrastructures derived from
urbanization are still emerging areas of research. Future work on
this issue will contribute to the development of better methods for
controlling and re-designing coastal infrastructures providing them
with ample ecological value.