Human impact on the vegetation of South Wales during late historical times: palynological and palaeoenvironmental results from Crymlyn Bog NNR, West Glamorgan, Wales, UK

Palynological and palaeoenvironmental analyses of Crymlyn Bog, a lowland fe n in South Wales, reveal insights into the effects of documented industrial activity on the landscape during the last c. 500 years. The pollen and pal aeoenvironmental profiles suggest that a predominantly wooded landscape in which some agriculture but little industrial activity took place, occurred between the sixteenth and early eighteenth centuries. Significant increases in heavy metals, spheroidal carbonaceous particles and SIRM are coincident with rapid and substantial industrialization of the Lower Swansea Valley f rom the mid-eighteenth to early nineteenth centuries, although the pollen e vidence suggests that the vegetation of the area was dominated by birch-haz el woodland. The pollen profile suggests that large-scale woodland clearanc e, that was perhaps caused by increased land-use pressure adjacent to the m ire, occurred in the late nineteenth and early twentieth centuries. At the same time, decreases in the profiles of copper, zinc and lead reflect the d ecline of non-ferrous metal smelting in the Lower Swansea Valley. The spher oidal carbonaceous particle and SIRM profiles from Crymlyn Bog do not corre spond with the national trends depicted in such profiles from elsewhere in the British Isles, probably because of the dominance of locally derived ind ustrial pollution. The apparent integrity of the copper, lead and SIRM prof iles suggest that fen peat is an eminently suitable, and thus much under-us ed, medium from which to reconstruct palaeoenvironmental and industrial his tories. Limitations in the use of the zinc, and the SCP and pollen profiles as palaeoenvironmental indicators and dating tools respectively are demons trated by the lack of correspondence between their profiles and documented historical land-use records.