Upland peatlands - The current state of vegetation and blanket bog

Peat can be sampled and then analysed in a laboratory for pollen, leaves, seeds, roots, stems, insects, charcoal, tephra and radiocarbon dated by scientists to elucidate an environmental and ecological history. It appears that vegetation communities currently growing on peatlands may be unrepresentative of the vegetation communities that formed peat in the past. Two research papers that sampled and investigated peat vegetation in Wales produced compelling evidence to support the change in vegetation growing in upland peatlands.

Mynydd Llangattock ~ Wales

Palaeoecology of degraded blanket mire in South Wales: Data to inform conservation management

Abstract: Many European blanket mires are degraded and contain few Sphagna. In Wales, more than half exhibit symptoms of degradation. We used palaeoecological techniques to chronicle recent vegetation history at two upland localities in South Wales to provide an understanding of the contribution of various factors in mire degradation and to aid wider conservation management strategies. The data suggest a major vegetation change post-dated the start of the industrial revolution. There was evidence for increased burning activity, but as this phenomenon was not present in all profiles it seems unlikely that fire was the principal or sole agent in vegetation change. Rather, increased atmospheric input, plus a change in grazing pressure, may have been responsible. The implications for conservation management are far-reaching. The present overwhelming dominance of Molinia at Hirwaun Common is unprecedented. So also is a local dominance of Calluna, shown in one area at Mynydd Llangatwg. Hence, the approbation often accorded to Callunetum needs to be tempered with the knowledge that its presence in the Mynydd Llangatwg landscape is not long-standing. Indeed, millennial-scale dominance of Sphagnum imbricatum characterizes the earlier record. Its demise and that of Drosera intermedia took place in historical times. Both localities show floristic impoverishment within the 20th Century, with relatively recent single-taxon supremacy. So, conservation management to reduce the current pre-eminence of Molinia would not run counter to long-established dominance; ways to achieve this are suggested. The methods used in this study have wide applicability in mire conservation. 

Frank M. Chambers, Dmitri Mauquoy, Andy Gent, Freya Pearson, John R.G. Daniell, Peter S. Jones, Biological Conservation, Volume 137, Issue 2, 2007, Pages 197-209, ISSN 0006-3207, http://dx.doi.org/10.1016/j.biocon.2007.02.002.

View south from Drygarn Fawr over the Elenydd peatlands ~ Wales

Recent vegetation history of Drygarn Fawr (Elenydd SSSI), Cambrian Mountains, Wales: implications for conservation management of degraded blanket mires 

Abstract: Many areas of blanket mire in Britain display apparently degraded vegetation, having a limited range of ericaceous and Sphagnum species. Data are presented here from Wales from the upland locality of Drygarn Fawr (Elenydd SSSI), which is dominated overwhelmingly by Molinia caerulea. Palaeoecological techniques were used to chronicle vegetation history and to determine the nature and timing of vegetation changes, as an aid to devising conservation management and restoration strategies. Although for the past 2000 years the pollen and plant macrofossil data indicate some evidence for cyclic vegetation change, they demonstrate that here the major vegetation change post-dated the start of the industrial revolution. The palaeoecological data show a greater proportion of Sphagnum than currently. Local extinction of some species (e.g., Myrica gale) apparently took place in Medieval times, but most of the degradation and floral impoverishment apparently occurred during the 20th Century. The implications for conservation management are far-reaching. The overwhelming dominance of Molinia is clearly unprecedented. While it was locally present for hundreds of years, some factor(s)—possibly a change in grazer and grazing regime—encouraged its recent ascendancy in the 20th Century. Consequently, any management attempts to reduce the pre-eminence of Molinia would not be countering an ingrained, long-established dominance. It is suggested that investigation of degraded blanket mires elsewhere by historical and multi-proxy palaeoecological techniques—through multiple, dated cores to track species extinctions and directional vegetation changes—would help ascertain previous mire floras and so indicate a range of restoration targets for mire vegetation. 

F. M. Chambers, D. Mauquoy, E. W. Cloutman, J. R. G. Daniell, P. S. Jones Biodiversity and Conservation September 2007, Volume 16, Issue 10, pp 2821–2846https://link.springer.com/article/10.1007/s10531-007-9169-3 

Across the UK peat has been sampled and a picture has emerged of mire vegetation change in some regions as a response to a combination of postulated factors i.e drainage, air pollution, grazing intensification, grazing regime change, afforestation, climate change and other factors.

Hill ponies and sheep grazing on Gwaun Cefnygarreg ~ Wales

Across the UK there are a number of projects actively restoring degraded peatlands and the following two videos outline a project funded by the EU LIFE-nature programme restoring two areas in North Wales.





The International Union for the Conservation of Nature (ICUN) Peatlands Programme has produced a booklet "UK Peatland Restoration - Demonstrating Success" and is well worth a read. The next post will look at the vegetation and habitats in the UK upland peatlands.