Effects of colliery waste on littoral communities in north-east England

Colliery waste input has a detrimental effect on the species richness and alpha diversity of sandy and rocky shore communities in north-east England. On sandy shores at the shore levels Chart Datum (CD) + 1.2 to 1.5 m (low shore) and CD + 2.7 to 3.0 m (mid-shore), a maximum of two species of macroinvertebrates per shore level was found at sites heavily contaminated by colliery waste input. In contrast, typically about eight species were found at uncontaminated shores. At the shore level CD + 4.2 to 4.5 m (high shore), the species richness and diversity of fauna were not detectably affected by colliery waste input. On rocky shores that were uncontaminated, 12-15 species of macroalgae were found, whereas only five to eight species were found at contaminated shores. The absentees were usually ephemeral, early successional species. Macroalgal biomass, although less at contaminated shores, showed no significant relationship with colliery waste input. However, the alpha diversity of animal communities on rocky shores was, on occasions, significantly increased where colliery waste inputs occurred. The physical properties of colliery waste are likely to be the reason for the effects observed on both sandy and rocky shores, since many of the leachable chemicals in colliery waste are leached during the period that it spends on the sea bed before accumulating in the intertidal zone.