Decreased solar radiation and increased temperature combine to facilitate fouling by marine non-indigenous species.

Studies of the effects of climate changes on marine biofouling have mainly focused on the effects of temperature increase, but a decrease in the level of solar radiation could also influence the establishment and persistence of fouling species. To test if decreased solar radiation and/or increased temperature influenced marine fouling communities, solar radiation, and temperature were manipulated by deploying shading devices in the intertidal zone of a central California estuary. Non-indigenous species (NIS) recruiting to artificial substrata had greater coverage under the shading treatments than under transparent plates, indicating that low radiation facilitates recruitment and growth of NIS. In contrast, the coverage of NIS underneath warmer black plates was higher than that on white plates. Furthermore, spatial comparisons of recruitment showed that NIS had a tendency to grow better in the warmer region of the estuary whereas native species showed the opposing trend. The results suggest that both lower radiation and higher temperature may facilitate the spread of marine NIS.